Abdominal Distension {#cesec1}
====================

Organomegaly {#cesec2}
------------

Hepatomegaly (infiltrative, inflammatory, lipidosis, neoplasia)Splenomegaly (infiltrative, inflammatory, neoplasia, hematoma)Renomegaly (neoplasia, infiltrative)Miscellaneous neoplasia (GI tract, ovaries, uterus, pancreas, prostate, adrenal glands)Generalized neoplasia (carcinomatosis, lymphosarcoma)Granuloma (pythiosis, aspergillosis)Pregnancy

Fluid {#cesec3}
-----

### Contained in Organs {#cesec4}

Congestion resulting from splenic torsion or volvulus, or hepatic congestion from right-sided heart failureCysts (paraprostatic, perinephric, hepatic)HydronephrosisDistended urinary bladderObstruction of intestines or stomachIleusPyometra

### Free Fluid in Abdomen {#cesec5}

Transudate (portal hypertension, right-sided heart failure, hypoproteinemia secondary to protein-losing enteropathy, protein-losing nephropathy, or hepatic failure)Modified transudate (neoplasia, postsinusoidal portal hypertension, right-sided heart failure, heartworm caval syndrome, liver disease)Exudate (pancreatitis, feline infectious peritonitis, urine, bile, neoplasia, bowel perforation, foreign body)Chyle (trauma, neoplasia, infection, right-sided heart failure)Blood (coagulopathy, trauma, neoplasia)

Gas {#cesec6}
---

### Contained in Organs {#cesec7}

Gastric dilatation/volvulusIntestines secondary to obstructionParenchymal organs infected with gas-producing bacteria

### Free in Abdomen {#cesec8}

Iatrogenic (after laparoscopy, laparotomy)Rupture of gastrointestinal tract or uterus

Fat {#cesec9}
---

Obesity/lipoma

Weakened Abdominal Musculature {#cesec10}
------------------------------

Hyperadrenocorticism

Feces {#cesec11}
-----

Obstipation/megacolon

Abdominal Effusions and Ascites {#cesec12}
===============================

Transudate (\<1000 Cells, \<2.5 Total Solids, \<1.017 Specific Gravity) {#cesec13}
-----------------------------------------------------------------------

### Portal Hypertension {#cesec14}

Presinusoidal or sinusoidal liver diseaseRight-sided heart failure

### Hypoalbuminemia (see Albumin p. 286) {#cesec15}

Liver failureProtein-losing enteropathy

### Glomerulopathy {#cesec16}

 

Modified Transudate (\>1000 but \<10000 Cells, 2.5--5.0 Total Solids, \<1.025 Specific Gravity) {#cesec17}
-----------------------------------------------------------------------------------------------

### Postsinusoidal Portal Hypertension {#cesec18}

 

### Right-Sided Heart Failure {#cesec19}

Heartworm caval syndromeLiver disease

### Neoplasia {#cesec20}

 

### Increased Hydrostatic Pressure {#cesec21}

 

### Vasculitis {#cesec22}

 

Exudate (\>5000 Cells, \>3.0 Total Solids, \>1.025 Specific Gravity) {#cesec23}
--------------------------------------------------------------------

### Nonseptic {#cesec24}

PancreatitisFeline infectious peritonitis (FIP)UrineBileNeoplasia

### Septic {#cesec25}

Bowel perforationForeign body

Chyle {#cesec26}
-----

TraumaNeoplasiaInfectionRight-sided heart failure

Blood {#cesec27}
-----

CoagulopathyTraumaNeoplasia (hemangiosarcoma)Iatrogenic (postsurgical)

Abdominal Pain, Acute {#cesec28}
=====================

Gastrointestinal System {#cesec29}
-----------------------

Gastrointestinal ulcerationForeign bodyGastric dilation-volvulusGastroenteritisObstipationColitisNeoplasiaAdhesionsIntestinal ischemiaIntestinal spasm

Urogenital System {#cesec30}
-----------------

Lower urinary tract infectionLower urinary tract obstructionNonseptic cystitis (idiopathic cystitis---cats)Prostatitis/prostatic neoplasiaUroliths/renoliths/ureterolithPyelonephritisNeoplasmMetritisPyometra/uterine ruptureUterine torsion (rare)Testicular torsionMastitisDystociaOvarian cyst

Pancreatitis {#cesec31}
------------

 

Spleen {#cesec32}
------

RuptureNeoplasmInfectionTorsion

Peritoneum {#cesec33}
----------

Peritonitis•Septic•Nonseptic (e.g., uroabdomen)AdhesionsMesenteric neoplasia, volvulus, inflammation

Hepatobiliary {#cesec34}
-------------

HepatitisHepatic abscessHepatic trauma, ruptureHepatobiliary neoplasiaCholelithiasis or cholecystitisCholangiohepatitis

Musculoskeletal {#cesec35}
---------------

FracturesIntervertebral disk diseaseDiskospondylitisAbscessStrangulated hernia

Miscellaneous {#cesec36}
-------------

Adrenalitis (associated with hypoadrenocorticism)Heavy metal intoxicationVasculopathy•Rocky Mountain spotted fever•InfarctAutonomic (abdominal) epilepsyIatrogenic•Misoprostol•Bethanechol•Postoperative pain

Aggressive Behavior {#cesec37}
===================

Cats {#cesec38}
----

### Pathophysiologic Causes of Feline Aggression {#cesec39}

RabiesHyperthyroidismSeizures (epilepsy, central nervous system inflammation)Paradoxical effects of therapeutic drugs (e.g., benzodiazepines)Toxins (side effects)Cognitive dysfunctionBrain neoplasia

### Species-Typical Patterns of Feline Aggression {#cesec40}

PlayFearPetting inducedInterspecies aggressionRedirectedStatus/assertivenessPain induced/irritableMaternalTerritorialPredatoryIdiopathic

Dogs {#cesec41}
----

### Pathophysiologic Causes of Canine Aggression {#cesec42}

RabiesSeizure activityIntracranial neoplasiaCerebral hypoxiaNeuroendocrine disturbances

### Species-Typical Patterns of Canine Aggression {#cesec43}

Fear relatedConflict relatedResource guardingTerritorial/protectiveIntraspecific (intradog)RedirectedPredatoryPain/medical/irritablePlayMaternal/hormonalIdiopathic

Alopecia {#cesec44}
========

Inflammatory Alopecia {#cesec45}
---------------------

### Traumatic {#cesec46}

Allergy (flea, atopy, food)Parasitic dermatitis (flea, scabies, *Cheyletiella* spp., lice, chiggers, etc.)

### Infectious {#cesec47}

PyodermaDemodicosisDermatophytosisViralLeishmaniasis*Malassezia* spp.

### Immune Mediated {#cesec48}

Sebaceous adenitisSuperficial pemphigusAlopecia areataErythema multiformeSystemic lupus erythematosus (SLE), discoid lupus erythematosus (DLE)Epitheliotrophic lymphomaVasculitis

### Atrophic {#cesec49}

DermatomyositisCutaneous vasculitisPostvaccinal alopeciaLymphocytic mural folliculitisParaneoplastic exfoliative dermatitisPseudopelade

Noninflammatory Alopecia {#cesec50}
------------------------

### Hormonal {#cesec51}

HyperadrenocorticismIatrogenic Cushing\'s syndromeHypothyroidismSex hormone imbalanceAlopecia XHyperthyroidism (cat)

### Canine and Feline Pinnal Alopecia {#cesec52}

 

### Canine Pattern Baldness {#cesec53}

 

### Canine Follicular Dysplasia {#cesec54}

Tricorrhexis nodosaPili tortiColor mutant alopeciaBlack hair follicular dysplasia

### Feline Congenital/Hereditary {#cesec55}

Alopecia universalis (Sphinx)Congenital hypotrichosisHair shaft dysplasia (Abyssinian)Follicular dysplasia (Cornish rex)Pili torti

### Other {#cesec56}

Anagen effluviumTelogen defluxionParaneoplastic alopeciaCyclic follicular dysplasia (seasonal flank alopecia)Postclipping alopeciaCicatricial alopeciaFeline preauricular alopeciaFeline acquired symmetric alopeciaPsychogenic alopecia

Anaphylaxis {#cesec57}
===========

Venoms {#cesec58}
------

Insects of Hymenoptera order (bees, hornets, ants)Spiders (brown recluse, black widow)Snakes (rattlesnakes, copperheads, water moccasins)Lizards (Gila monster, Mexican beaded lizard)

Drugs {#cesec59}
-----

Antibiotics (penicillins, sulfonamides, lincomycin, cephalosporins, aminoglycosides, tetracyclines, chloramphenicol, polymyxin B, doxorubicin)VaccinesAllergen extractsBlood productsParasiticides (dichlorophen, levamisole, piperazine, dichlorvos, diethylcarbamazine, thiacetarsamide)Anesthetics/sedatives (acepromazine, ketamine, barbiturates, lidocaine, bupivacaine, narcotics, diazepam)Nonsteroidal antiinflammatory drugs (NSAIDs)Hormones (insulin, corticotropin, vasopressin, parathyroid hormone, glucocorticoids)AminophyllineAsparaginaseIodinated contrast mediaNeostigmineAmphotericin BEnzymes (trypsin, chymotrypsin)Vitamins (vitamin K, thiamine, folic acid)Dextrans and gelatinsCalcium disodium edetate

Foods {#cesec60}
-----

Milk, egg white, shellfish, legumes, citrus fruits, chocolate, grains

Physical Factors {#cesec61}
----------------

Cold, heat, exercise

Anuria and Oliguria {#cesec62}
===================

Prerenal Azotemia {#cesec63}
-----------------

Dehydration/hypovolemia

Acute Renal Failure {#cesec64}
-------------------

One third of cases are anuric, one third are oliguric, and one third are nonoliguric; more likely to be oliguric/anuric with severe renal toxicosisToxic: exogenous (drugs, biologic or environmental toxins), endogenous (calcium, pigments)Infectious: pyelonephritis, leptospirosis, infectious canine hepatitis, borreliosis, sepsisIschemia: progression of prerenal azotemia, NSAIDs, vascular disease (avulsion, thrombosis, stenosis), shock, decreased cardiac output, deep anesthesia, extensive surgery, hypothermia, hyperthermia, hyperviscosity (polycythemia vera, multiple myeloma, extensive cutaneous burns, transfusion reaction, disseminated intravascular coagulation (DIC)Immune mediated: acute glomerulonephritis, systemic lupus erythematosus (SLE), transplant rejection, vasculitisNeoplasia: lymphomaSystemic disease with renal manifestations•Infections (feline infectious peritonitis, borreliosis, babesiosis, leishmaniasis, bacterial endocarditis)•Pancreatitis•Sepsis•Multiple organ failure•Heart failure•SLE•Hepatorenal disease•Malignant hypertension

Postrenal Azotemia {#cesec65}
------------------

Obstruction (may appear similar to anuria/oliguria)

Anxiety and Phobias {#cesec66}
===================

Fears and Phobias {#cesec67}
-----------------

Fear: apprehension associated with the presence of an object, individual, or object; may be normal or abnormal, depending on contextPhobia: quickly developed, immediate, profound abnormal response to a stimulus leading to catatonia or panic

### People {#cesec68}

Babies, children, elderlyPeople in uniformPeople who appear different than family members•Color, height, facial hairDisabled peopleMen or women, depending on circumstance

### Animals {#cesec69}

Same speciesOther species

### Noise {#cesec70}

Especially gunshots, fireworks, thunder

### Places {#cesec71}

 

Anxiety {#cesec72}
-------

### Separation Anxiety {#cesec73}

#### Initiators {#cesec74}

Change in owner\'s routineOwner returning to school or workMove to new homeVisit to new environmentAfter stay in kennelNew baby, new petMedical, cognitive

#### Common Features of Separation Anxiety {#cesec75}

Hyperattached to ownerSigns of anxiety as owner leavesProblems manifest when owner absent or when pet unable to gain access to ownerProblem behavior begins shortly after owner leavesMay even occur during short absencesPet shows exuberant greeting behavior

### Generalized Anxiety {#cesec76}

Poorly socialized, nervous pet

Ascites {#cesec77}
=======

*See* [Abdominal Effusions and Ascites](#cesec12){ref-type="sec"}.

Ataxia and Incoordination {#cesec78}
=========================

Forebrain Disease {#cesec79}
-----------------

Typically, mild ataxia and other neurologic signs predominate.Generalized disease: generalized ataxiaUnilateral disease: contralateral conscious proprioceptive deficits, mild gait disturbancePostictal paraparesis: transient in natureParaparesis may be a side effect of anticonvulsant therapy (especially potassium bromide).

Brain Stem {#cesec80}
----------

Hemiparesis or tetraparesis; lesions severe enough to cause paralysis usually result in respiratory arrest.

Vestibular nuclei may be affected, causing vestibular ataxia, head tilt, and nystagmus; distinguish central vestibular disease from peripheral vestibular disease by presence of ipsilateral conscious proprioceptive deficits.

Peripheral Vestibular Disease {#cesec81}
-----------------------------

Generalized ataxia accompanied by head tilt, rotary or horizontal nystagmus, positional strabismus, and oculovestibular eye movements

Conscious proprioceptive deficits absent

Cerebellum {#cesec82}
----------

Lesions cause dysmetria, usually hypermetria.

Unilateral lesions cause ipsilateral signs.

Cervical Spinal Cord {#cesec83}
--------------------

May cause forelimb monoparesis (lesions affecting spinal segments C6-T2), hemiparesis, tetraparesis; may progress to paralysis

Thoracic (T3-L3) Spinal Cord {#cesec84}
----------------------------

Mild to marked rear limb ataxia, paraparesis, paraplegia, monoparesis, or monoplegiaRear limb reflexes exaggeratedReduced to absent panniculus reflex caudal to lesion

Lumbosacral (L4-S2) Spinal Cord {#cesec85}
-------------------------------

Mild to marked rear limb ataxia, paraparesis, paraplegia, monoplegiaReduced to absent rear limb reflexesMay see bladder and anal sphincter hypotonia

Peripheral Nerve {#cesec86}
----------------

Mild to marked ataxia, paresis, paralysis of one or more limbsDegenerative, inflammatory, toxic, traumatic neuropathiesHyporeflexia usually seenParesis or paralysis of muscle or muscles innervated by affected nerve

Blindness {#cesec87}
=========

Corneal Lesions {#cesec88}
---------------

Edema (trauma, glaucoma, immune-mediated keratitis such as keratouveitis caused by canine adenovirus-1, endothelial dystrophy, neurotropic keratitis)Keratoconjunctivitis siccaExposure keratitisSuperficial keratitis (pannus)Corneal melanosis (entropion, ectropion, lagophthalmos, facial nerve paralysis)Cellular infiltrate (bacterial, viral, fungal)Dystrophies (lipid, genetic)Fibrosis (scar)

Aqueous Humor Lesions {#cesec89}
---------------------

Fibrin (anterior uveitis: many causes)Hypopyon (immune-mediated, neoplastic \[lymphosarcoma\], infectious \[blastomycosis, cryptococcus, histoplasmosis, coccidioidomycosis, toxoplasmosis, FIP, protothecosis, brucellosis, septicemia\])Hyphema (trauma, blood-clotting deficiencies, ehrlichiosis, rickettsia, systemic hypertension, retinal detachment neoplasia)Lipid (hyperlipidemia with concurrent anterior uveitis to disrupt the blood-aqueous barrier)

Lens Lesions {#cesec90}
------------

Cataracts (genetic, metabolic/diabetic, nutritional, traumatic, toxic, retinal degeneration, hypocalcemia, electric shock, chronic uveitis, lens luxation)

Vitreous Humor Lesions {#cesec91}
----------------------

Hemorrhage (trauma, systemic hypertension, clotting deficiency, neoplasia, retinal detachment)Hyalitis (numerous infectious diseases such as feline infectious peritonitis, penetrating injury causing cellular infiltrate)

Retinal Lesions {#cesec92}
---------------

GlaucomaSudden acquired retinal degeneration (SARD)Progressive retinal atrophyCentral progressive retinal atrophyToxicity (fluoroquinolone administration in cats)Systemic hypertensionRetinal detachment•Exudative/transudative (systemic hypertension, mycoses, rickettsial, toxoplasmosis, viral, bacterial, fungal)•Neoplasia•Retinal dysplasia•Hereditary/congenital (e.g., Collie eye anomaly)

Failure to Transmit Visual Message {#cesec93}
----------------------------------

Viral infections (canine distemper, feline infectious peritonitis \[FIP\])Systemic and ocular mycoses (blastomycosis, cryptococcosis, histoplasmosis, coccidioidomycosis)NeoplasiaTraumatic avulsion of optic nerve (traumatic proptosis)Granulomatous meningoencephalitisHydrocephalusOptic nerve hypoplasiaColobomaImmune-mediated optic neuritis

Failure to Interpret Visual Message {#cesec94}
-----------------------------------

Canine distemper virusFeline infectious peritonitis (FIP)Granulomatous meningoencephalitisSystemic mycosesTraumaHeat strokeHypoxiaHydrocephalusHepatoencephalopathyNeoplasiaStorage diseasesPostictalMeningitis

Bradycardia, Sinus {#cesec95}
==================

Normal variation (fit animal)HypothyroidismHypothermiaDrugs (tranquilizers, anesthetics, β-blockers, calcium entry blockers, digitalis)Increased intracranial pressureBrain stem lesionSevere metabolic disease (e.g., uremia)Ocular pressureCarotid sinus pressureHigh vagal toneCardiac arrest (before and after)Sinus node disease

Cachexia and Muscle Wasting {#cesec96}
===========================

Cachexia {#cesec97}
--------

Certain chronic disease processes stimulate the release of cytokines that suppress appetite and stimulate hypercatabolism.Cardiac diseaseEnd-stage renal diseaseChronic infectionChronic feverChronic inflammationNeoplasia

Muscle Wasting {#cesec98}
--------------

### Endocrine Disease {#cesec99}

HyperadrenocorticismHyperthyroidismHyperparathyroidism

### Starvation {#cesec100}

UnderfeedingPoor-quality feedCompetition for foodDental disease

### Impaired Ability to Use or Retain Nutrients {#cesec101}

MaldigestionMalabsorptionParasitismHistoplasmosisExocrine pancreatic insufficiencyDiabetes mellitusProtein-losing nephropathy or gastroenteropathy

### Inflammatory Myopathies {#cesec102}

Masticatory myositisDermatomyositisCanine idiopathic polymyositisFeline idiopathic polymyositis

### Protozoal Myositis {#cesec103}

Toxoplasma gondiiNeospora caninum

### Inherited Myopathies {#cesec104}

Muscular dystrophyHereditary Labrador retriever myopathy

### Neurologic Disorders {#cesec105}

Spinal and peripheral neuropathiesDisuse atrophy

Compulsive Behavior Disorders {#cesec106}
=============================

Compulsive Disorders in Dogs {#cesec107}
----------------------------

### Locomotor {#cesec108}

Spinning or tail chasingStereotypic pacing/circling/jumpingFixation; staring/barking/freezing/scratchingChasing lights, reflections, shadowsBarking; intense/rhythmic/difficult to interruptHead bob/tremor/head shakingAttacking food bowl, attacking inanimate objects

### Apparent Hallucinatory {#cesec109}

Air biting or fly snappingStaring, freezing, startledStar/sky gazing

### Self-Injurious or Self-Directed {#cesec110}

Tail attacking, mutilation, growl/attack legs or rearFace rubbing/scratchingAcral lick dermatitis, licking/chewing/barberingNail bitingFlank suckingChecking rear

### Oral {#cesec111}

Sucking/lickingPica, rock chewingPolydipsia/polyphagiaLicking of objects/owners

Compulsive Disorders in Cats {#cesec112}
----------------------------

### Locomotor {#cesec113}

Skin ripple/agitation/running, feline hyperesthesiaCirclingFreezingExcessive/intense chasing of imaginary objectsExcessive vocalization/howling

### Apparent Hallucinatory {#cesec114}

Staring at shadows/wallsStartleAvoiding imaginary objects

### Self-Injurious or Self-Directed {#cesec115}

Tail attacking, mutilation, growl/attack legs or rearFace scratching/rubbingChewing/licking/barbering/overgroomingNail bitingHyperesthesia

### Oral {#cesec116}

Wool suckingPicaPolydipsia/polyphagiaLicking of objects/owners

Constipation {#cesec117}
============

Dietary Causes {#cesec118}
--------------

Excessive fiber in dehydrated patientIngestion of hair, bones, indigestible materials

Colonic Obstruction {#cesec119}
-------------------

Deviation of rectal canal: perineal herniaIntraluminal or intramural disorders•Tumor•Granuloma•Cicatrix•Rectal foreign body•Congenital stricturePseudocoprostasisPerineal herniaExtraluminal disorders•Tumor•Granuloma•Abscess•Healed pelvic fracture•Prostatomegaly•Prostatic or paraprostatic cyst•Sublumbar lymphadenopathy

Behavioral or Environmental Causes {#cesec120}
----------------------------------

Change in routineSoiled or absent litter boxRefusal to defecate in houseInactivity

Drugs {#cesec121}
-----

OpiatesAnticholinergicsSucralfateBarium

Refusal to Defecate {#cesec122}
-------------------

Pain in rectal or perineal area (perianal fistulas)Inability to posture to defecateOrthopedic or neurologic problem

Colonic Weakness {#cesec123}
----------------

### Systemic Disease {#cesec124}

HypercalcemiaHypokalemiaHypothyroidismChagas disease

### Localized Neuromuscular Disease {#cesec125}

Spinal cord diseasePelvic nerve damageDysautonomiaChronic dilatation of colon/irreversible stretching of colonic musculature

Miscellaneous Causes {#cesec126}
--------------------

Severe dehydrationIdiopathic megacolon (cats)

Coughing {#cesec127}
========

Disorders of Upper Airway {#cesec128}
-------------------------

### Inflammatory {#cesec129}

PharyngitisTonsillitisTracheobronchitisChronic bronchitisAllergic bronchitisBronchiectasisCollapsed trachea*Oslerus osleri* infection

### Neoplastic {#cesec130}

MediastinalLaryngealTracheal

### Allergic {#cesec131}

Bronchial asthma

### Other {#cesec132}

Bronchial compression: left atrial enlargement, hilar lymphadenopathyForeign bodyInhalationTracheal stenosis

Disorders of Lower Respiratory Tract {#cesec133}
------------------------------------

### Inflammatory {#cesec134}

#### Pneumonia {#cesec135}

BacterialViral: canine distemper virusFungal: blastomycosis, histoplasmosis, coccidioidomycosisProtozoal: toxoplasmosis, pneumocystis pneumonia

#### Granuloma, Abscess {#cesec136}

 

#### Chronic Pulmonary Fibrosis {#cesec137}

 

### Parasitic Disease {#cesec138}

Heartworm disease *(Dirofilaria immitis)*Lungworm disease (*Aelurostrongylus abstrusus*---cat; *Paragonimus kellicotti*---dog, cat; *Capillaria aerophilia*---dog, cat; *Filaroides hirthi*---dog; *Crenosoma vulpis*---dog; *Angiostrongylus vasorum*---dog)

### Neoplasia {#cesec139}

Primary or metastaticLymphoma

### Cardiovascular {#cesec140}

Left-sided heart failure: pulmonary edemaPulmonary thromboembolism

### Noncardiogenic Pulmonary Edema {#cesec141}

 

### Allergic {#cesec142}

Eosinophilic pneumonitisEosinophilic pulmonary granulomatosisPulmonary infiltrate with eosinophils (PIE)

### Other {#cesec143}

Lung lobe torsionSystemic bleeding disorderPleural effusionNeoplasia of chest wall

Cyanosis {#cesec144}
========

Central Cyanosis {#cesec145}
----------------

### Cardiac {#cesec146}

#### Intracardiac {#cesec147}

Tetralogy of FallotAtrial or ventricular septal defect with pulmonic stenosis, tricuspid valve dysplasia, or pulmonary hypertensionTransposition complexes (double outlet right ventricle, other)

#### Extracardiac {#cesec148}

Pulmonary arteriovenous fistulasPatent ductus arteriosus (reversed)

### Pulmonary {#cesec149}

#### Hypoventilation {#cesec150}

Pleural effusionPneumothoraxRespiratory muscle failure (fatigue, neuromuscular disease)Anesthetic overdosePrimary neurologic disease

#### Obstruction {#cesec151}

Laryngeal paralysisForeign body in airwayMass lesion of large airway (neoplasia, parasitic, inflammatory)Low oxygen concentration of inspired air (high altitude, anesthetic complications)

#### Ventilation-Perfusion Mismatch {#cesec152}

Pulmonary thromboembolismPulmonary infiltrate (edema, inflammation/infection, neoplasia, acute respiratory distress syndrome, chronic obstructive pulmonary disease, fibrosis, pulmonary contusions/hemorrhage)

#### Methemoglobinemia {#cesec153}

 

Peripheral Cyanosis {#cesec154}
-------------------

Central cyanosis (heart failure)Decreased arterial supplyPeripheral vasoconstriction (hypothermia, shock)Arterial thromboembolismLow cardiac outputObstruction of venous drainage•Tourniquet or foreign object (e.g., rubber band)•Venous thrombosis•Right-sided heart failure

Deafness {#cesec155}
========

Congenital Sensorineural Deafness {#cesec156}
---------------------------------

### Inherited {#cesec157}

Many breeds of dogs•Dalmatians•Merle or dapple coat patterns in Collies, Shetland Sheepdogs, Great Danes, Dachshunds•Piebald pattern in Dalmatians, Bull Terriers, Great Pyrenees, Sealyham Terriers, Greyhounds, Bulldogs, and Beagles)•Many other dog breeds affectedWhite cats with blue irides and white coloration in some breeds of dogs

Congenital Acquired Sensorineural Deafness {#cesec158}
------------------------------------------

In utero exposure to bacteria, ototoxic drugs, low oxygen tensions, or trauma

Acquired Late-Onset Conductive Deafness {#cesec159}
---------------------------------------

Lack of transmission of sound through tympanic membrane and auditory ossiclesOtitis externa/mediaOtic neoplasiaPolypsTrauma-induced fluid accumulation in middle earAtresia of tympanum or ossiclesFused ossiclesStenosis of ear canal leading to accumulation of fluid in middle ear

Acquired Late-Onset Sensorineural Deafness {#cesec160}
------------------------------------------

Presbycusis (age-related hearing loss)OtotoxicityChronic exposure to loud noiseHypothyroidismTraumaBony neoplasia

Diarrhea, Acute {#cesec161}
===============

Diet {#cesec162}
----

Intolerance/allergyRapid dietary changeBacterial food poisoningDietary indiscretionPoor quality food

Parasites {#cesec163}
---------

HelminthsProtozoa (*Giardia, Tritrichomonas,* Coccidia spp.)

Infections {#cesec164}
----------

Viral (parvovirus, coronavirus, feline leukemia virus \[FeLV\], feline immunodeficiency virus \[FIV\], canine distemper virus, rotavirus)Bacterial *(Salmonella* spp., *Clostridium perfringens, Escherichia coli, Campylobacter jejuni, Yersinia enterocolitica*, other bacteria)Rickettsial•Salmon poisoning

Other Causes {#cesec165}
------------

Hemorrhagic gastroenteritisIntussusceptionIrritable bowel syndromeToxins (chemicals, heavy metals, toxic plants)Drugs (antibiotics, cancer chemotherapeutic agents, anthelmintics, NSAIDs, digitalis, lactulose)PancreatitisHypoadrenocorticismPyometraPeritonitis

Diarrhea, Chronic {#cesec166}
=================

Small Bowel Diarrhea {#cesec167}
--------------------

Food intolerance or allergyInflammatory bowel diseaseGastrointestinal lymphomaPancreatic exocrine insufficiencyChronic parasitism (hookworm, *Giardia*)HistoplasmosisIntestinal lymphangiectasiaPartial obstructionPancreatic carcinomaGastrinomaLiver disease (hepatocellular failure, cholestasis)Endocrine disease (hypoadrenocorticism, hypothyroidism, hyperthyroidism)Renal disease (uremia, nephrotic syndrome)Chronic intussusceptionSmall intestinal bacterial overgrowthPythiosis

Large Bowel Diarrhea {#cesec168}
--------------------

Food intolerance or allergyParasitism (whipworm, *Giardia, Tritrichomonas*)Clostridial colitisIrritable bowel syndromeHistoplasmosisPythiosisInflammatory bowel disease•Lymphocytic-plasmacytic colitis•Eosinophilic colitis•Chronic ulcerative colitis•Histiocytic ulcerative colitis (boxers)Neoplasia (lymphoma, adenocarcinoma)FeLV/FIV (infections secondary to these viruses)

Dyschezia {#cesec169}
=========

*See* [Tenesmus and Dyschezia](#cesec505){ref-type="sec"}.

Dysphagia {#cesec170}
=========

Oral Lesions {#cesec171}
------------

Fractured bones or teethPeriodontitisTrauma (laceration, hematoma)Feline resorptive lesions (caries)OsteomyelitisRetrobulbar abscess/inflammationTemporal-masseter myositisStomatitis, glossitis, pharyngitis, gingivitis, tonsillitis, sialoadenitis•Immune-mediated disease•Feline herpesvirus, calicivirus, leukemia virus, immunodeficiency virus•Lingual foreign bodies or granulomas•Tooth root abscess•Uremia•Caustic chemicalsCleft palateLingual frenulum disorderCricopharyngeal achalasia/asynchrony

Obstructive Lesion {#cesec172}
------------------

Esophageal stricture/foreign objectEsophagitisElectric cord burnsNeoplasia (malignant or benign)Inflammatory (abscess, polyp, granuloma)LymphadenopathyEosinophilic granulomaForeign object (oral, pharyngeal, laryngeal)SialoceleNasopharyngeal polyp

Neuromuscular Disease {#cesec173}
---------------------

Myasthenia gravisAcute polyradiculitisMasticatory myositisTick paralysisBotulismPolymyositisTemporomandibular joint diseaseRabiesTrigeminal nerve paralysis or neuritisNeuropathies of cranial nerves V, VII, IX, X, or XIIBrain stem diseaseTetanusHypothyroidism

Dyspnea {#cesec174}
=======

Inspiratory Dyspnea {#cesec175}
-------------------

### Nasal Obstruction {#cesec176}

Rhinitis•Viral: feline herpesvirus, feline calicivirus, canine distemper virus•Bacterial•Fungal: aspergillosis, cryptococcosis, penicilliosis, rhinosporidiosisNeoplasia: adenocarcinoma, squamous cell carcinoma, fibrosarcoma, osteosarcoma, chondrosarcoma, lymphoma, transmissible venereal tumorStenotic naresNasal foreign bodyThick nasal discharge of any etiology

### Pharyngeal or Laryngeal Disease {#cesec177}

Elongated soft palate, everted laryngeal sacculesNeoplasia/mass, abscess, granuloma, extraluminal massNasopharyngeal polypForeign bodyLaryngeal paralysis, acute/obstructive laryngitis, laryngeal collapse, laryngeal trauma

### Extrathoracic Trachea {#cesec178}

Collapsing tracheaTracheal hypoplasiaTracheal trauma/stricture, foreign body, neoplasia

Expiratory or Mixed Dyspnea {#cesec179}
---------------------------

### Intrathoracic Trachea and Bronchi {#cesec180}

Collapsing trachea or main-stem bronchusTrauma, stricture, foreign body, neoplasia

### Small Airway Disease {#cesec181}

Feline asthmaBronchitisSmoke inhalationBronchopneumonia

### Pulmonary Parenchymal Disease {#cesec182}

Pneumonia (viral, bacterial, fungal, protozoal, aspiration)Pulmonary edemaPulmonary thromboembolismBronchial asthmaChronic obstructive lung disease

### Parasites/Severe Infestations/Heartworm, Lungworms {#cesec183}

Pulmonary fibrosisNeoplasia

### Pleural Space Disease {#cesec184}

Pleural effusionPneumothoraxPleural space massesDiaphragmatic hernia

### Noncardiopulmonary Disease {#cesec185}

Severe anemiaHypovolemiaAcidosisHyperthermiaNeurologic disease

Dysuria {#cesec186}
=======

*See* [Stranguria, Dysuria, and Pollakiuria](#cesec479){ref-type="sec"}.

Ecchymoses {#cesec187}
==========

*See* [Petechiae and Ecchymoses](#cesec404){ref-type="sec"}.

Edema {#cesec188}
=====

Increased Hydrostatic Pressure {#cesec189}
------------------------------

### Impaired Venous Return {#cesec190}

Congestive heart failureConstrictive pericarditisAscites (cirrhosis)Budd-Chiari syndromeVenous obstruction or compression (thrombosis, external pressure, extremity inactivity)Iatrogenic overhydrationHeartworm disease

### Small-Caliber Arteriolar Dilatation {#cesec191}

HeatNeurohumoral dysregulation

Reduced Plasma Osmotic Pressure {#cesec192}
-------------------------------

### Hypoproteinemia {#cesec193}

Cirrhosis (ascites)MalnutritionProtein-losing enteropathyProtein-losing glomerulonephropathy (nephrotic syndrome)Lymphangiectasia

Lymphatic Obstruction {#cesec194}
---------------------

Various inflammatory causesNeoplasiaPostsurgicalAfter radiation therapy

Sodium Retention {#cesec195}
----------------

Excessive dietary intake with renal diseaseRenal hypoperfusionIncreased renin-angiotension-aldosterone secretion

Inflammation {#cesec196}
------------

Acute and chronicAngiogenesis

Increased Microvascular Permeability {#cesec197}
------------------------------------

SepsisAcute respiratory distress syndromePancreatitisInfection (fungal, bacterial, viral)

Mixed Mechanisms {#cesec198}
----------------

Noncardiogenic pulmonary edema (head trauma, seizures, electrocution, upper airway obstruction)AnaphylaxisOrgan torsion

Epistaxis {#cesec199}
=========

Systemic Causes {#cesec200}
---------------

Thrombocytopenia•Decreased production of thrombocytes (infectious, myelophthisis secondary to neoplasia, drugs, immune mediated phenomena)•Increased destruction (immune mediated, microangiopathy)•Increased consumption (disseminated intravascular coagulation, vasculitis, hemorrhage)Thrombocytopathia•Primary (von Willebrand disease)•Secondary (uremia, ehrlichiosis, multiple myeloma, drugs such as NSAIDs)Coagulation factor defects (e.g., hemophilia A and B)Acquired coagulopathies (anticoagulant rodenticides, hepatic failure)Increased capillary fragility (hypertension, hyperviscosity syndromes, hyperlipidemia, thromboembolic disease)PolycythemiaSystemic hypertension

Local Causes {#cesec201}
------------

Neoplasia (nasal adenocarcinoma, lymphoma, benign polyps)Bacterial infection (usually secondary; rarely, *Bordetella, Pasteurella,* or *Mycoplasma* can be primary cause of epistaxis)Fungal rhinitis (*Aspergillus, Cryptococcus* spp.)Dental disease with oronasal fistulationNasal parasites: *Pneumonyssus caninum* (nasal mite), *Eucoleus boehmi* (formerly *Capillaria* spp.), *Cuterebra* spp.Eosinophilic and lymphoplasmacytic rhinitis (uncommon)Arteriovenous malformations

Erosions and Ulcers of Skin and Mucous Membranes {#cesec202}
================================================

Canine Diseases {#cesec203}
---------------

### Infectious {#cesec204}

•Bacterial pyoderma•Surface: Acute moist dermatitis (pyotraumatic dermatitis), intertrigo•Deep: folliculitis/furunculosis (including pyotraumatic folliculitis), oral bacterial infections

### Fungal {#cesec205}

•Yeast infections (Malassezia pachydermatis, Candida spp.), systemic/subcutaneous

### Parasitic {#cesec206}

•Demodecosis

### Metabolic {#cesec207}

•Calcinosis cutis (hyperadrenocorticism)•Uremia/renal failure•Necrolytic migratory erythema/metabolic epidermal necrosis

### Neoplastic {#cesec208}

•Epitheliotropic lymphoma•Squamous cell carcinoma

### Physical, Chemical {#cesec209}

•Drug reactions•Solar injury•Thermal injury (freeze, burn)•Urine scald

### Immune-Mediated/Autoimmune {#cesec210}

•Discoid lupus erythematosus•Pemphigus group•Uveodermatologic syndrome•Miscellaneous autoimmune subepidermal vesiculobullous diseases: bullous pemphigoid, epidermolysis bullosa acquisita, linear IgA bullous disease, mucocutaneous pemphigoid, bullous systemic lupus-type 1

### Miscellaneous {#cesec211}

•Arthropod bites•Dermatomyositis•Dystrophic epidermolysis bullosa•Idiopathic ulceration of Collies•Junctional epidermolysis bullosa•Toxic epidermal necrolysis/erythema multiforme

Feline Diseases {#cesec212}
---------------

### Infectious {#cesec213}

•Viral: calicivirus and herpesvirus•Bacterial: atypical mycobacteriosis•Fungal: Subcutaneous and systemic mycoses, cryptococcosis, sporotrichosis

### Metabolic {#cesec214}

•Uremia/renal disease

### Neoplastic {#cesec215}

•Fibrosarcoma•Lymphoma•Squamous cell carcinoma

### Physical/Chemical {#cesec216}

•Drug reactions•Thermal

### Immune-Mediated/Autoimmune {#cesec217}

•Bullous pemphigoid•Pemphigus foliaceous•Toxic epidermal necrolysis/erytherma multiformed

### Miscellaneous/Idiopathic {#cesec218}

•Arthropod bites•Dystrophic epidermolysis bullosa•Eosinophilic plaque•Idiopathic ulceration of dorsal neck•Indolent ulcer•Junctional epidermolysis bullosa

Failure to Grow/Failure to Thrive {#cesec219}
=================================

Small Stature and Poor Body Condition {#cesec220}
-------------------------------------

Dietary insufficiencyUnderfeedingPoor-quality dietGastrointestinal disease•Parasitism•Inflammatory bowel disease•Obstruction (foreign body, intussusception)•HistoplasmosisHepatic dysfunction•Portovascular anomaly•Hepatitis•Glycogen storage diseaseCardiac disorder•Congenital anomaly•EndocarditisPulmonary diseaseEsophageal disease•Megaesophagus•Vascular ring anomaly (persistent right aortic arch)Exocrine pancreatic insufficiencyRenal diseaseRenal failure (congenital or acquired)•Glomerular disease•PyelonephritisInflammatory diseaseHormonal disease•Diabetes mellitus•Hypoadrenocorticism•Diabetes insipidus•Juvenile hyperparathyroidism

Small Stature and Good Body Condition {#cesec221}
-------------------------------------

ChondrodystrophyHormonal disease•Congenital hypothyroidism•Congenital hyposomatotropism (pituitary dwarfism)•Hyperadrenocorticism

Fever of Unknown Origin {#cesec222}
=======================

Infection {#cesec223}
---------

### Bacterial {#cesec224}

Abscessation (inapparent subcutaneous, stump pyometra, liver, pancreas)PyelonephritisDiskospondylitisProstatitisPeritonitisPyothoraxClosed pyometraSplenic abscessSeptic arthritisBartonellosis*Mycoplasma haemofilis* (formerly *Hemobartonella felis*)BorreliosisBacterial endocarditisPlagueTuberculosis

### Fungal {#cesec225}

BlastomycosisHistoplasmosisCoccidioidomycosis

### Viral {#cesec226}

Feline immunodeficiency virus (FIV)Feline leukemia virus (FeLV)Feline infectious peritonitis (FIP; *Coronavirus*)

### Rickettsial {#cesec227}

Rocky Mountain spotted feverEhrlichiosisSalmon poisoning

### Protozoal {#cesec228}

ToxoplasmosisBabesiosisHepatozoonosisCytauxzoonosisTrypanosomiasis (Chagas disease)Leishmaniasis

Neoplasia {#cesec229}
---------

LymphomaMultiple myelomaLeukemiaMalignant histiocytosisNecrotic solid tumors

Immune Mediated {#cesec230}
---------------

PolyarthritisVasculitisMeningitisSLEImmune-mediated anemiaSteroid-responsive feverSteroid-responsive neutropenia

Other {#cesec231}
-----

HyperthyroidismTissue damagePharmacologic agents•Tetracycline•Penicillins•SulfasMetabolic bone diseaseIdiopathic

Flatulence {#cesec232}
==========

Dietary intolerance (high-fiber, high-protein, or high-fat foods; high-sulfur diets; spoiled food; food change)Maldigestion•Exocrine pancreatic insufficiency•Lactose intoleranceMalabsorptionMotility disorders (disrupt passage of gas)AerophagiaBehavior (aerophagia associated with competitive eating habits)Various gastrointestinal disorders

Gagging {#cesec233}
=======

Nutritional {#cesec234}
-----------

Food textureFood size

Infectious {#cesec235}
----------

Viral encephalitis (rabies, pseudorabies)Fungal (focal, systemic)Bacterial encephalitis

Toxic {#cesec236}
-----

Chemical (caustic chemicals, smoke)Botulism

Developmental {#cesec237}
-------------

Cleft palateHydrocephalusAchalasia

Degenerative {#cesec238}
------------

Laryngeal paralysisMuscular dystrophyMyasthenia gravisNeuropathy of cranial nerves V, VII, IX, or XII

Mechanical {#cesec239}
----------

Foreign bodyStyloid disarticulation

Metabolic {#cesec240}
---------

UremiaHypocalcemia

Neoplasia {#cesec241}
---------

Tonsils, pharynx, epiglottis, glottis, inner ear, nasal, central nervous system

Trauma {#cesec242}
------

Tracheal rupturePharyngeal hematomaMedulla or pons ischemia or edema

Allergic or Immune Mediated {#cesec243}
---------------------------

RhinitisPharyngitisLaryngitisAsthmaGranuloma complexIdiopathic glossopharyngitis

Genital Dermatoses {#cesec244}
==================

Lesions of the Prepuce/Sheath {#cesec245}
-----------------------------

Bacterial folliculitis/furunculosisAllergic dermatitis affecting the abdomen with hyperpigmentation/lichenification/hypertrophy of the sheathLocalized demodicosisVasculitisAutoimmune skin diseasesLinear dermatosis of the prepuce (estrogen-secreting tumor)Linear epidermal nevusVascular nevusVarious neoplasms (Stricker sarcoma, hemangiosarcoma, mast cell tumor)

Lesions of the Scrotum {#cesec246}
----------------------

Contact dermatitis (most common scrotal skin disease)FrostbiteIntertrigoMalassezia dermatitisProtothecosisBabesiosisCuterebrosisBrucellosisInfection with *Erysipelothrix rhusiopathiae*Rocky Mountain spotted feverAutoimmune diseases (bullous diseases, lupus)Erythema multiformeFixed pigmented erythemaCutaneous histiocytosisVascular hamartomaNeoplasms (squamous cell carcinoma, apocrine adenocarcinoma, myxoma and fibrosarcoma, hemangioma, recurrent cystic hemangioma and hemangiosarcoma, plasmocytoma, lymphoma, histiocytoma, benign fibrous histiocytoma, mast cell tumor, melanoma)

Female {#cesec247}
------

IntertrigoAllergic dermatitis affecting the abdomen with hyperpigmentation/lichenification/hypertrophy of the vulvaMalassezia dermatitisDemodicosisBacterial furunculosisContact dermatitisAutoimmune diseases (lupus, bullous diseases)Endocrine disorders (especially hyperestrogenism)Neoplasms

Halitosis {#cesec248}
=========

Oral Disease {#cesec249}
------------

Periodontal disease (gingivitis, periodontitis, abscessation)CalculusFood traps (periodontal pockets, exposed tooth roots, oral ulcers)Neoplasia (melanoma, fibrosarcoma, squamous cell carcinoma)Foreign bodyTrauma/fractureElectric cord injuryPharyngitisStomatitis/glossitis

Metabolic Disease {#cesec250}
-----------------

Renal failure (uremia)Diabetic ketoacidosis

Gastrointestinal Disease {#cesec251}
------------------------

MegaesophagusInflammatory bowel diseaseExocrine pancreatic insufficiency

Respiratory Disease {#cesec252}
-------------------

Rhinitis/sinusitisNeoplasiaPneumonia or pulmonary abscess

Dermatologic Disease {#cesec253}
--------------------

Lip fold pyodermaEosinophilic granulomaPemphigus complexBullous pemphigoidLupus erythematosusDrug eruptionCutaneous lymphomaExposure to dimethyl sulfoxide (DMSO)

Dietary {#cesec254}
-------

Aromatic foods (onions, garlic)Fetid food (carrion)Coprophagy

Grooming Behavior {#cesec255}
-----------------

Anal sacculitisVaginitis/balanoposthitisLower urinary tract infectionsHair retained in periodontal pockets

Head Tilt {#cesec256}
=========

Peripheral Vestibular Disease {#cesec257}
-----------------------------

Otitis media/internaFeline idiopathic vestibular diseaseGeriatric canine vestibular diseaseFeline nasopharygeal polypsMiddle ear tumor•Ceruminous gland adenocarcinoma•Squamous cell carcinomaTraumaAminoglycoside ototoxicityHypothyroidism (possibly)Congenital (German Shepherd, Doberman Pinscher, English Cocker Spaniel, Siamese and Burmese cats)

Central Vestibular Disease {#cesec258}
--------------------------

Trauma/hemorrhageInfectious inflammatory disease•Rocky Mountain spotted fever•Feline infectious peritonitis (FIP)•Bacterial•Protozoal•Mycotic•Rickettsial•OthersGranulomatous meningoencephalitisNeoplasia (meningioma, choroid plexus tumors)Vascular infarctThiamine deficiencyMetronidazole toxicityViral (canine distemper virus, FIP)Toxic (lead, hexachlorophene)Degenerative diseases (storage diseases, neuronopathies, demyelinating diseases)Hydrocephalus

Hematemesis {#cesec259}
===========

Alimentary Tract Lesion {#cesec260}
-----------------------

### Gastritis {#cesec261}

Acute gastritis (common cause)Hemorrhagic gastroenteritisChronic gastritis*Helicobacter*-associated disease

### Foreign Body {#cesec262}

 

### Gastrointestinal Tract Ulceration/Erosion {#cesec263}

#### Iatrogenic {#cesec264}

Nonsteroidal antiinflammatory drugs (NSAIDs)CorticosteroidsNSAIDs used in combination with corticosteroids

### Infiltrative Disease {#cesec265}

NeoplasiaInflammatory bowel diseasePythiosis (young dogs, southeastern United States)Stress ulceration•Hypovolemic shock•Septic shock•After gastric dilatation/volvulus•Neurogenic shockHyperacidity•Mast cell tumor•Gastrinoma (rare)Other causes•Hepatic disease•Renal disease•Hypoadrenocorticism•Inflammatory disease

### Esophageal Disease (Uncommon) {#cesec266}

TumorSevere esophagitisTrauma

### Bleeding Oral Lesion {#cesec267}

 

### Gallbladder Disease (Rare) {#cesec268}

 

Coagulopathy {#cesec269}
------------

Thrombocytopenia/platelet dysfunctionClotting factor deficiencyDIC

Extraalimentary Tract Lesion {#cesec270}
----------------------------

Respiratory tract lesionLung lobe torsionPulmonary tumorPosterior nares lesion

Hematochezia {#cesec271}
============

Anal Disease {#cesec272}
------------

Perianal fistulasAnal sacculitis or abscessStrictureNeoplasia (anal sac adenocarcinoma)Anal traumaPerineal herniaForeign body

Rectal and Colonic Disease {#cesec273}
--------------------------

Hemorrhagic gastroenteritisProctitisColitis•Idiopathic•Dietary allergy•Inflammatory bowel disease•Stress•Infectious (*Campylobacter* spp., *Clostridium perfringens*)•Histoplasmosis•PythiosisParvovirusParasites•Whipworms•Hookworms•CoccidiaNeoplasia•Rectal polyp•Adenocarcinoma•Lymphoma•Leiomyoma or leiomyosarcomaProlapsed rectumMucosal trauma•Foreign body or foreign material•Pelvic fractures•Iatrogenic (thermometers, enemas, fecal loops, rectal palpation)Iliocecal intussusception

Hematuria {#cesec274}
=========

Renal or Lower Urinary Tract Disease {#cesec275}
------------------------------------

Inflammation/infectionUrolithiasisObstructionTraumaNeoplasiaBleeding disorderHeat strokeRenal infarctGranulomatous urethritisFeline lower urinary tract disease (FLUTD)ParasitismDrug induced (cyclophosphamide)Renal pelvic hematomaVascular malformationIdiopathic renal hematuriaRenal telangiectasia of Welsh CorgisRenal hematuria of WeimaranersPseudohematuria (myoglobin, hemoglobin, drugs, dyes)

Extraurinary Disease {#cesec276}
--------------------

Prostatic disease (infection, tumor, cyst, abscess)Uterine disease (pyometra, proestrus, tumor, subinvolution of placental sites)Vaginal (trauma, neoplasia)Preputial/penile (trauma, neoplasia)

Hemoptysis {#cesec277}
==========

Cardiovascular {#cesec278}
--------------

Heartworm diseaseCardiogenic pulmonary edemaArteriovenous fistulaBacterial endocarditis

Pulmonary {#cesec279}
---------

Thromboembolism (secondary to neoplasia, endocrine, cardiac, metabolic disease)Bacterial pneumoniaPulmonary abscessNocardiosis*Bordetella bronchiseptica* infectionChronic bronchitis/bronchiectasisFungal pneumonia (blastomycosis, coccidiomycosis, histoplasmosis)Neoplasia (primary adenocarcinoma, undifferentiated carcinoma, squamous cell carcinoma, chondrosarcoma, metastatic or primary tracheal tumors)Lung lobe torsionParasites *(Paragonimus kellicotti, Capillaria aerophila, Aelurostrongylus abstrusus)*Pulmonary infiltrate with eosinophilsSystemic bleeding disorderPrimary (quantitative or qualitative platelet defects)Secondary (factor deficiencies, anticoagulant rodenticide toxicity, disseminated intravascular coagulopathy)Trauma (pulmonary contusion, tracheal rupture, foreign body)Iatrogenic (endotracheal intubation, complication of lung biopsy/aspirate, transtracheal wash, bronchoscopy)

Hemorrhage, Prolonged {#cesec280}
=====================

*See* **Part Two, Section V: Differential Diagnosis for Thrombocytopenia, Platelet Dysfunction, and Coagulopathies, Inherited and Acquired**.

Horner Syndrome {#cesec281}
===============

2.5% phenylephrine eye drops applied

No Pupillary Dilation (Assume Preganglionic Lesion) {#cesec282}
---------------------------------------------------

### First Order (Central) {#cesec283}

Intracranial disease (neoplasia, trauma, infarct)First cervical to third thoracic (C1-T3) spinal myelopathy (intervertebral disc disease, neoplasia, fibrocartaginous embolism, trauma)

### Second Order (Preganglionic) {#cesec284}

Spinal cord lesion T1-T3 (trauma, neoplasia, fibrocartilaginous embolism)Thoracic disease (cranial mediastinal mass, thoracic spinal nerve root tumor)Brachial plexus avulsionCervical soft-tissue neoplasia, traumaSkull base tumorJugular furrow disease

Pupillary Dilation (Assume Postganglionic Lesion) {#cesec285}
-------------------------------------------------

### Third Order (Postganglionic) {#cesec286}

Feline leukemia virus, feline immunodeficiency virusOtitis media/internaOtic massRetrobulbar injury, neoplasiaIdiopathic

Hyperpigmentation {#cesec287}
=================

Increased melanin in the epidermis

Hereditary Hyperpigmentation {#cesec288}
----------------------------

Lentigenes---darkly pigmented macules that develop on the ventral abdomen of healthy adult dogs and on the lips, nose, gingiva, and eyelids of orange cats. No adverse health effects.Canine acanthosis nigricans---bilateral hyperpigmentation and lichenification of axillary skin. Primary, hereditary form seenin Dachshunds beginning before age 1. When seen in older Dachshunds or other breeds, it is likely a postinflammatory form seen with friction, intertrigo, allergies, or endocrine disease.Acromelanism---dark areas on the points of Siamese, Himalayan-Persian, Balinese, and Burmese cats. Result of a temperature-dependent enzyme controlling melanin production in hair bulbs.

Acquired Hyperpigmentation {#cesec289}
--------------------------

Postinflammatory---Mediators of inflammation (e.g., leukotrienes, thromboxanes) stimulate melanocytes to increase melanin production, which down regulates inflammation by scavenging free radicles. Examples of inflammatory conditions that lead to increased melanin production include allergies, Malassezia dermatitis, bacterial pyoderma, dermatophytosis, demodecosis, scabies, and actinic and intertrigo dermatitis. Inflammation affecting hair follicles may lead to melanotrichia (e.g., sebaceous adenitis, panniculitis, vaccine reactions).Endocrine---hyperadrenocorticism, hypoadrenocorticism, hypothyroidism, hyperestrogenism, and other sex hormone imbalances may result in diffuse hyperpigmentation.Papillomavirus associated---Pugs may be at risk for development of papillomavirus-associated, slightly raised, scaly, hyperpigmented macules and plaques in their groin region, abdomen, ventral thorax, and neck. Similar lesions are described in miniature Schnauzers, American Staffordshire terriers, and Pomeranians. May transform to squamous cell carcinoma.Pigmented tumors---apocrine cysts are bluish, cutaneous hemangiomas and hemangiosarcomas appear red, dark purple, or bluish-black. Melanomas, melanocytomas, and basal cell tumors are frequently black. Squamous cell carcinomas, trichoblastomas, and fibromas also may be dark brown to black.

Hyperthermia {#cesec290}
============

Fever {#cesec291}
-----

Exogenous pyrogens (infectious agents and their products, inflammation or necrosis of tissue, immune complexes, pharmacologic agents, bile acids)Endogenous pyrogens (fever-producing cytokines)

Heat Stroke {#cesec292}
-----------

High ambient temperaturesExercisePoor ventilationBrachycephalic conformationObesity

Exercise Hyperthermia {#cesec293}
---------------------

Sustained exerciseSeizure disorders (especially prolonged or cluster seizures)Hypocalcemic tetany (eclampsia)

Pathologic Etiologies {#cesec294}
---------------------

Lesions in or around anterior hypothalamusHypermetabolic disordersHyperthyroidismPheochromocytomaMalignant hyperthermiaHalothaneSuccinylcholine

Hypopigmentation {#cesec295}
================

Due to melanocyte destruction, dysfunction, or abnormal distribution of melanosomes.

Hereditary Hypopigmentation {#cesec296}
---------------------------

Albinism---hereditary absence of pigmentPiebaldism---presence of white spots where melanocytes are absentWaardenburg-Klein syndrome---affected animals have absence of melanocytes in areas of skin and hair, blue or heterochromatic eyes, and are also deaf. Reported in cats, bull terriers, Sealyham terriers, collies, DalmatiansCanine cyclic hematopoiesis---lethal autosomal recessive disease of collies. Gray coat, light-colored nose, cyclic episodes of neutropenia every 12--14 days resulting in sepsis and amyloidosisChédiak-Higashi syndrome---rare autosomal recessive disease of blue smoke Persian cats. Partial oculocutaneous albinism with abnormal function of granulocytes and platelets resulting in hemorrhage, recurrent infections, and death at a young age.Graying---age-associated, reduction of melanocyte replication.Vitiligo---macular leukoderma and leukotrichia of nose, ears, buccal mucosa, and facial skin. Antimelanocyte antibodies found in serum of some affected dogs. Seen most commonly in Siamese cat, Belgian Tervuren, German Shepherd, collie, Rottweiler, Doberman Pinscher, Giant Schnauzer.Nasal hypopigmentation---season-associated lightening of nasal planum during winter months most common in Siberian Husky, Golden Retriever, Labrador Retriever, and Bernese Mountain Dog. Seen also in many other breeds.

Acquired Hypopigmentation {#cesec297}
-------------------------

Postinflammatory---Discoid lupus erythematosus is the most common cause of postinflammatory nasal depigmentation. Also pemphigus complex, SLE, uveodermatologic syndrome, bullous pemphigoid, mucocutaneous pyoderma, drug eruption, and contact dermatitis. Infectious causes include leishmaniasis, blastomycosis, sporotrichosis, and bacterial folliculitis.Drug related---ketoconazole, procainamide, and vitamin E may cause diffuse coat lightening.Nutritional/metabolic---deficiencies of zinc, pyridoxine, pantothenic acid, and lysine are associated with graying of hair. Dark hairs may become reddish in color with copper deficiency, hypothyroidism, hyperadrenocorticism, hyperestrogenism, hyperprogesteronism, chlorine exposure, and chronic exposure to ultraviolet light.Neoplasia associated---nasal depigmentation, leukoderma, and leukotrichia sometimes seen with epitheliotropic T cell lymphoma, basal cell tumors, mammary adenocarcinoma, and gastric carcinomas.Idiopathic---leukotrichia and patchy hypopigmentation reported as idiopathic in Labrador Retrievers, and black Newfoundlands. Siamese cats may be affected with periocular leukotrichia, which may be associated with upper respiratory tract infections, pregnancy, dietary deficiencies, or systemic illness.

Hypothermia {#cesec298}
===========

Predisposing Factors {#cesec299}
--------------------

AnesthesiaLow ambient temperatureNeonateSmall sizeElderlySickDebilitatedNear drowningEnema

Icterus (Jaundice) {#cesec300}
==================

Hemolysis {#cesec301}
---------

Autoimmune hemolytic anemiaHemolytic anemia secondary to drugs, neoplasiaInfectious (*Ehrlichia canis, Babesia canis, Babesia felis, Mycoplasma hemocanis, Mycoplasma hemofelis, Cytauxzoon felis,* heartworm disease, feline leukemia virus \[FELV\])Toxic (onions, lead, copper, methylene blue, benzocaine, proplylene glycol, acetaminophen \[cats\], phenazopyridine)Fragmentation (disseminated intravascular coagulation, hemangiosarcoma, vena cava syndrome)Erythrocyte membrane or enzyme defects (pyruvate kinase deficiency \[Beagle, Basenji\], phosphofructokinase deficiency \[English Springer Spaniel\], stomatocytosis of chondrodysplastic Malamutes)Congenital porphyriaSnake, brown recluse spider, and bee venoms

Hepatobiliary Disease {#cesec302}
---------------------

CholangiohepatitisChronic inflammatory hepatic diseaseCirrhosisDiffuse neoplasiaCopper toxicityToxic hepatopathy (anticonvulsants, mebendazole, oxibendazole, diethylcarbamazine, inhalation anesthetics, thiacetarsamide, acetaminophen, trimethoprim-sulfa)Hepatic lipidosisFeline infectious peritonitis (FIP)ParasiticIdiosyncratic drug reaction

Posthepatic Biliary Obstruction {#cesec303}
-------------------------------

PancreatitisEnteritis/cholecystitisTraumaNeoplasiaCalculusStrictureMucoceleRuptured bile duct or gallbladder

Inappropriate Elimination {#cesec304}
=========================

Dogs {#cesec305}
----

### Medical Causes {#cesec306}

#### Fecal House Soiling {#cesec307}

Increased volume of feces (maldigestion, malabsorption, high-fiber diets)Increased frequency of voiding (colitis, diarrhea)Compromised neurologic function (peripheral nerve impairment, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)Joint painSensory declineCognitive dysfunction

#### Urinary House Soiling {#cesec308}

Diseases causing polyuria (e.g., renal disease, hyperadrenocorticism, diabetes, pyometra)Increased urinary frequency (urinary tract infection/inflammation, urolithiasis, bladder tumors, prostatitis, abdominal masses)Impaired bladder control (peripheral nerve disease, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)Urethral incompetenceAnatomic problemsUrethral sphincter mechanism incompetence (estrogen-responsive incontinence)Cognitive dysfunction

### Behavioral Causes {#cesec309}

Inadequate trainingSubmissive urinationExcitement urinationMarkingSeparation anxietyManagement-related problemsLocation or surface preference

Cats {#cesec310}
----

### Medical Causes {#cesec311}

#### Fecal House Soiling {#cesec312}

Increased volume of feces (maldigestion, malabsorption, high-fiber diets)Increased frequency of voiding (colitis, diarrhea, inflammatory bowel disease)Compromised neurologic function (peripheral nerve impairment, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)Joint painAnal sacculitisObstipation/constipationHyperthyroidismNeoplasiaCognitive dysfunction

#### Urinary House Soiling {#cesec313}

Diseases causing polyuria (e.g., renal disease, hyperadrenocorticism, diabetes, pyometra)Increased urinary frequency (feline lower urinary tract disease \[FLUTD\], urolithiasis, idiopathic cystitis)Impaired bladder control (peripheral nerve disease, spinal cord disease, brain tumor, encephalitis, infection, degenerative brain disorders)Joint pain, disk diseaseHyperthyroidismNeoplasiaAnatomic problemsCognitive dysfunction

### Behavioral Causes {#cesec314}

#### Litterbox Aversion {#cesec315}

Aversive disorder (deodorant, ammonia)Inadequate cleaningDiscomfort during elimination (FLUTD, constipation, diarrhea, arthritis)Unacceptable litter (texture, depth, odor, plastic liner)Unacceptable box (too small, sides too high, covered)Disciplined, medicated, or frightened in box

#### Location Aversion {#cesec316}

Too much trafficTraumatic/fearful experience in area

#### Other {#cesec317}

Location preferenceSurface preferenceAnxiety (owner absence, high cat density, moving, new furniture, inappropriate punishment, teasing, household changes, remodeling in home)Need for privacy (other pets, anything that makes box less accessible to cat)

#### Urine Marking {#cesec318}

HormonesTemperamentFeline population densityIndirect signaling from other cats (scent on visitor\'s clothing)Changes in environment (new roommate, remodeling home, new furniture, and other novel items in home)Owner absence from homeLack of owner attentionInappropriate punishment

Incontinence, Fecal {#cesec319}
===================

Nonneurologic Disease {#cesec320}
---------------------

### Colorectal Disease {#cesec321}

Inflammatory bowel diseaseNeoplasiaConstipation

### Anorectal Disease {#cesec322}

Perianal fistulaNeoplasiaSurgery (anal sacculectomy, perianal herniorrhaphy, rectal resection and anastomosis)

### Miscellaneous {#cesec323}

Decreased mentationOld ageSevere diarrheaIrritable bowel disease

Neurologic Disease {#cesec324}
------------------

### Sacral Spinal Cord Disease {#cesec325}

DiskospondylitisNeoplasiaDegenerative myelopathyCongenital vertebral malformationSacrococcygeal hypoplasia of Manx catsSacral fractureSacrococcygeal subluxationLumbosacral instabilityMeningomyeloceleViral meningomyelitis

### Peripheral Neuropathy {#cesec326}

TraumaPenetrating woundsRepair of perineal herniaPerineal urethrostomyHypothyroidismDiabetes mellitusDysautonomia

Incontinence, Urinary {#cesec327}
=====================

Bladder Distended {#cesec328}
-----------------

### Neurogenic {#cesec329}

Lower motor neuron disease (sacral \[S1-S3\] segments or peripheral nerves)Bladder easily expressed, dribbles urineDetrusor areflexia with sphincter areflexiaUpper motor neuron diseaseBladder difficult to express; may be associated with paresis, paralysisDetrusor areflexia with sphincter hypertoniaDysautonomia

### Obstructive {#cesec330}

Reflex dyssynergia (functional obstruction)Mechanical obstruction (uroliths, tumors, strictures, granulomatous urethritis, urethral inflammation, prostatic disease, mucoid or crystalline plug \[feline\])

Bladder Not Distended {#cesec331}
---------------------

### Dysuria/Pollakiuria Absent {#cesec332}

Urethral sphincter mechanism incompetence (middle-aged to older spayed or neutered dogs)Congenital (ectopic ureters, patent urachus)

### Dysuria/Pollakiuria Present {#cesec333}

Detrusor hyperreflexia/instability (uroliths, urinary tract infection, urethral mass)

Infertility, Female {#cesec334}
===================

Normal Cycles {#cesec335}
-------------

Improper breeding managementInfertile maleElevated diestrual progesterone•Early embryonic death•Lesions in tubular system (vagina, uterus, uterine tubes)•Placental lesions (brucellosis, herpes infection)Normal diestrual progesterone•Cystic follicles (ovulation failure)

Abnormal Cycles {#cesec336}
---------------

### Abnormal Estrus {#cesec337}

#### Will Not Copulate {#cesec338}

Not in estrusInexperiencePartner preferenceVaginal anomalyHypothyroidism?

#### Prolonged Estrus {#cesec339}

Cystic folliclesOvarian neoplasiaExogenous estrogensProlonged proestrus

#### Short Estrus {#cesec340}

Observation errorGeriatricSplit estrus

### Abnormal Interestrual Interval {#cesec341}

#### Prolonged Interval {#cesec342}

Photoperiod (queen)Pseudopregnant/pregnant (queen)Normal breed variationGlucocorticoids (bitch)GeriatricLuteal cysts

#### Short Interval {#cesec343}

Normal (especially queen)Ovulation failure (especially queen)Corpus luteum failure"Split heat" (bitch)Exogenous drugs

Not Cycling {#cesec344}
-----------

PrepubertalOvariohysterectomyEstrus suppressantsSilent heatUnobserved heatPhotoperiod (queen)Intersex (bitch)Ovarian dysgenesisHypothyroidism (possibly)Glucocorticoid excessHypothalamic-pituitary disorderGeriatricOvarian neoplasiaPremature ovarian failure

Infertility, Male {#cesec345}
=================

Inflammatory Ejaculate {#cesec346}
----------------------

ProstatitisOrchitisEpididymitis

Azoospermia {#cesec347}
-----------

Sperm-rich fraction not collectedSperm not ejaculated•Incomplete ejaculation•Obstruction•Prostate swellingSperm not produced•Endocrine•Testicular•Metabolic

Abnormal Motility/Morphology {#cesec348}
----------------------------

IatrogenicPrepubertalPoor ejaculationLong abstinence

Abnormal Libido {#cesec349}
---------------

Female not in estrusBehavioralPainGeriatric

Normal Libido {#cesec350}
-------------

Improper stud managementInfertile female

Normal Libido/Abnormal Mating Ability {#cesec351}
-------------------------------------

OrthopedicNeurologicProstatic diseasePenile problemPrepuce problem

Joint Swelling {#cesec352}
==============

TraumaDegenerative joint diseaseNeoplasiaInflammatory joint disease---infectious•Septic (bacterial)•Fungal arthritis•Blastomycosis•Coccidioidomycosis•Cryptococcosis•Lyme borreliosis•Rickettsial arthritis•Mycoplasma•Bacterial [l]{.smallcaps}-form--associated arthritis (cats)•Viral arthritis (calicivirus infection---kittens)Inflammatory joint disease---noninfectious•Nonerosive•Immune-mediated polyarthritis (idiopathic)•SLE•Breed-specific polyarthritis syndromes•Akita, Boxer, Weimaraners, Bernese Mountain Dog, German Shorthaired Pointer, Beagle, Shar-Pei•Lymphocytic/plasmacytic synovitis•Drug reaction (e.g., trimethoprim-sulfadiazine in Doberman Pinschers)•Chronic infection causing secondary immune-mediated polyarthritis (bacterial, ehrlichiosis,•Anaplasmosis, Rocky Mountain spotted fever, Lyme borreliosis, heartworm disease)•Erosive•Rheumatoid arthritis•Erosive polyarthritis of greyhounds•Felinex chronic progressive polyarthritis

Lameness {#cesec353}
========

Orthopedic {#cesec354}
----------

### Trauma {#cesec355}

FractureLuxation, subluxationToenail traumaBone contusion

### Infectious {#cesec356}

Osteomyelitis (bacterial, fungal)

### Developmental {#cesec357}

Patellar luxationOsteochondrosisPanosteitisHypertrophic osteodystrophyAvascular necrosis of femoral headNonunited anconeal processBone cysts

### Nutritional {#cesec358}

Vitamin D deficiency (rickets)

### Neoplasia {#cesec359}

OsteosarcomaMultiple myelomaMetastatic to bone

Joint Disease {#cesec360}
-------------

*See* [Joint Swelling](#cesec352){ref-type="sec"}.

Muscles {#cesec361}
-------

### Trauma {#cesec362}

ContusionStrainLacerationRupture

### Inflammatory {#cesec363}

Canine idiopathic polymyositisFeline idiopathic polymyositisDermatomyositis

### Infectious {#cesec364}

Protozoal myositis

Tendons {#cesec365}
-------

### Trauma {#cesec366}

LacerationSeveranceAvulsion

Ligaments {#cesec367}
---------

### Trauma {#cesec368}

RuptureTearHyperextension

Lymphadenopathy (Lymph Node Enlargement) {#cesec369}
========================================

Infiltrative Lymphadenopathies {#cesec370}
------------------------------

### Neoplastic {#cesec371}

Primary hemolymphatic (lymphoma, multiple myeloma, systemic mast cell disease, leukemias, malignant histiocytosis, lymphomatoid granulomatosis)Metastatic neoplasia (carcinomas, sarcomas, malignant melanoma, mast cell tumors)

### Nonneoplastic {#cesec372}

Eosinophilic granuloma complexNonneoplastic mast cell infiltration

Proliferative and Inflammatory Lymphadenopathies {#cesec373}
------------------------------------------------

### Infectious {#cesec374}

Bacterial•Localized bacterial infection•Septicemia•Systemic infection (e.g., *Borrelia burgdorferi, Brucella canis, Yersinia pestis, Corynebacterium, Mycobacterium, Nocardia, Streptococcus, Actinomyces, Bartonella* spp.)•Contagious streptococcal lymphadenopathyParasitic (toxoplasmosis, demodicosis, babesiosis, cytauxzoonosis, hepatozoonosis, leishmaniasis, trypanosomiasis, *Neospora caninum*)Rickettsial (ehrlichiosis, Rocky Mountain spotted fever, anaplasmosis, salmon poisoning)Viral (feline immunodeficiency virus, feline leukemia virus, feline infectious peritonitis, canine viral enteritis, infectious canine hepatitis)Fungal (blastomyosis, cryptococcosis, histoplasmosis, aspergillosis, coccidioidomycosis, phaeohyphomycosis, phycomycosis, sporotrichosis, others)Algal (protothecosis) *Pneumocystis carinii*

### Noninfectious {#cesec375}

Immune-mediated disorders•SLE•Rheumatoid arthritis•Immune-mediated polyarthritis•Juvenile cellulitisDrug reactionsLocalized inflammationPostvaccinalDermatopathic lymphadenopathyIdiopathic•Distinctive peripheral lymph node hyperplasia•Plexiform vascularization of lymph nodes

Melena {#cesec376}
======

Ingested Blood {#cesec377}
--------------

Oral lesionsNasopharyngeal lesionsPulmonary lesionsDiet

Parasitism {#cesec378}
----------

Hookworms

Neoplasia {#cesec379}
---------

AdenocarcinomaLymphomaLeiomyoma or leiomyosarcomaMast cell tumorGastrinoma

Upper Gastrointestinal Inflammation {#cesec380}
-----------------------------------

Acute gastritisGastroduodenal ulceration/erosionHemorrhagic gastroenteritisInflammatory bowel diseaseForeign bodyEsophagitis

Infection {#cesec381}
---------

*CampylobacterClostridium perfringensSalmonellaParvovirusNeorickettsia helminthoeca* (salmon poisoning)*HistoplasmaPythium*

Drugs {#cesec382}
-----

Nonsteroidal antiinflammatory drugs (NSAIDs)Glucocorticoids

Miscellaneous {#cesec383}
-------------

PancreatitisLiver failureRenal failureHypoadrenocorticismGastrointestinal ischemia (shock, volvulus, intussusception)Arteriovenous fistulaPolypsCoagulopathies (thrombocytopenia, factor deficiencies, rodenticide toxicity, DIC)

Muscle Wasting {#cesec384}
==============

*See* [Cachexia and Muscle Wasting](#cesec96){ref-type="sec"}.

Nasal Discharge {#cesec385}
===============

*See* [Sneezing and Nasal Discharge](#cesec456){ref-type="sec"}.

Nystagmus {#cesec386}
=========

Peripheral Vestibular Disease {#cesec387}
-----------------------------

Horizontal nystagmus; fast phase toward normal side; no change with varying head position

Otitis media/internaFeline idiopathic vestibular diseaseCanine geriatric vestibular diseaseNeoplasiaGranulomaTrauma (iatrogenic secondary to ear cleaning)Ototoxic drugsNeuropathy (hypothyroid, cranial nerve VIII disease)Congenital (German Shepherd, English Cocker Spaniel, Doberman Pinscher, smooth-haired Fox Terrier, Siamese, Burmese, Tonkinese)

Central Vestibular Disease {#cesec388}
--------------------------

Horizontal, vertical, or rotary nystagmus; direction may change with varying head position

Trauma/hemorrhageInfectious inflammatory diseaseViral (canine distemper virus, feline infectious peritonitis)Rickettsial (RMSF, ehrlichiosis)Fungal (cryptococcosis)ToxoplasmosisNeosporosisGranulomatous meningoencephalitisNeoplasiaVascular infarctThiamine deficiencyMetronidazole toxicityToxic (lead, hexachlorophene)Degenerative diseases (storage diseases, neuronopathies, demyelinating diseases)HydrocephalusAnomaly (caudal occipital malformation syndrome in Cavalier King Charles Spaniels)Head trauma

Obesity {#cesec389}
=======

Causes {#cesec390}
------

Excessive feedingMalnutritionHigh-carbohydrate diet (especially cats)Lack of exerciseInactivity (indoor life style, middle age)Neutering?Genetic predispositionHypothyroidismHyperadrenocorticismHyperinsulinismAcromegalyHypopituitarismHypothalamic dysfunctionDrugs (glucocorticoids, progestagens, phenobarbital, primidone)

Health Risks {#cesec391}
------------

Degenerative joint diseaseCruciate ligament diseaseHip dysplasiaTraumatic joint diseaseIntervertebral disk diseaseDyspnea: (Pickwickian syndrome)Heat intoleranceExercise intoleranceDiabetes mellitus (insulin resistance)Hepatic lipidosis (cats)PancreatitisDystociaUrinary tract diseaseSkin fold dermatosesIncreased anesthetic risk

Oliguria {#cesec392}
========

*See* [Anuria and Oliguria](#cesec62){ref-type="sec"}.

Pallor {#cesec393}
======

Anemia {#cesec394}
------

### Regenerative Anemia {#cesec395}

Immune-mediated hemolytic anemia (extravascular, intravascular)Erythrocytic parasites (*Bartonella, Babesia, Cytauxzoon* spp.)Fragmentation (disseminated intravascular coagulation, heartworm disease, hemangiosarcoma, vasculitis, hemolytic uremic syndrome, diabetes mellitus)Pyruvate kinase deficiencyPhosphofructokinase deficiencyFeline porphyriaCopper toxicityNeonatal isoerythrolysisOxidative injury (onions, acetaminophen, zinc, benzocaine, mothballs, phenazopyridine)Blood loss (external blood loss, blood loss to a body cavity, coagulopathies, endoparasites, gastrointestinal blood loss)

### Nonregenerative Anemia {#cesec396}

Anemia of chronic diseaseAnemia from renal failureFeline leukemia virus (FeLV)Endocrine (mild anemia associated with hypoadrenocorticism, hypothyroidism)Myeloaplasia/aplastic anemia (FeLV infection, ehrlichiosis, trimethoprim-sulfa, estrogen toxicity, phenylbutazone, chemotherapy, chloramphenicol)MyelodysplasiaMyeloproliferative and lymphoproliferative disordersMyelofibrosis

Shock {#cesec397}
-----

### Cardiogenic {#cesec398}

Decreased ventricular function•Dilated cardiomyopathy•Myocarditis•Myocardial infarctionCompromised ventricular filling•Hypertrophic cardiomyopathy•Cardiac tamponadeSevere endocardiosisOutflow obstruction•Intracardiac tumors•Aortic stenosis•Hypertrophic obstructive cardiomyopathy•Heartworm disease•Thrombosis•Severe arrhythmia

### Noncardiogenic {#cesec399}

TraumaHypovolemia•Severe blood loss•Dehydration•HypoadrenocorticismDisruptions in blood flow•Sepsis and endotoxemia•Hypotension

Papules and Pustules {#cesec400}
====================

•Bacterial pyoderma (papules and pustules)•Demodicosis (papules and pustules)•Dermatophytosis (rare papules, uncommon pustules)•Sarcoptes mange (papules, no pustules)•Cheyletiellosis (rare papules, no pustules)•Otacariosis (rare papules, no pustules)•Trombiculosis (papules, rare pustules)•Hypersensitivity (papules, rare pustules)•Pemphigus (papules and pustules)•Early-stage neoplasia (papules, no pustules)

Paresis and Paralysis {#cesec401}
=====================

Upper Motor Neuron {#cesec402}
------------------

Tetraparesis or hemiparesis•Severe forebrain lesion•Brain stem lesion•First to fifth cervical (C1-C5) spinal lesionParaparesis or rear limb monoparesis•Third thoracic to third lumbar (T3-L3) spinal lesion

Lower Motor Neuron {#cesec403}
------------------

TetraparesisGeneralized lower motor neuron disease•Flaccid paresis/paralysis•Acute polyradiculoneuritis/"coonhound paralysis"•Tick paralysis•Botulism•Myasthenia gravis•Toxicants•Coral snake•Black widow spider•Herbicides (2,4 D)•Macadamia nutsParaparesis•Fourth lumbar to second sacral (L4-S2) spinal lesionHemiparesis with lower motor neuron forelimb•Sixth cervical to second thoracic (C6-T2) spinal lesionAortic thromboembolismDegenerative myelopathyMonoparesisPeripheral nerve lesion

Petechiae and Ecchymoses {#cesec404}
========================

Thrombocytopenia {#cesec405}
----------------

### Increased Platelet Destruction {#cesec406}

Immune-mediated thrombocytopeniaSystemic lupus erythematosus (SLE)Heartworm disease

### Decreased Platelet Production {#cesec407}

#### Bone Marrow Suppression {#cesec408}

Infectious disease (ehrlichiosis, babesiosis, Rocky Mountain spotted fever, leishmaniasis, feline leukemia virus, feline immunodeficiency virus)NeoplasiaDrug reactionsMyeloproliferative diseaseVirus-associated myelodysplasiaEstrogen toxicity

### Consumption of Platelets {#cesec409}

Disseminated intravascular coagulation (DIC)Vasculitis

### Sequestration of Platelets (Unlikely to Cause Clinical Signs) {#cesec410}

SplenomegalyHepatomegalyEndotoxemia

Thrombopathia {#cesec411}
-------------

### Inherited {#cesec412}

Cocker Spaniel, Otterhound, Great Pyrenees, Bassett Hound, American Cocker Spaniel, cats

### Acquired {#cesec413}

Drugs (aspirin, cephalothin, carprofen, hydroxyethyl starch)UremiaLiver diseaseDysproteinemias

### Von Willebrand Disease {#cesec414}

Lack of von Willebrand factor leads to impaired platelet adhesion.

Vascular Purpura {#cesec415}
----------------

Vasculitis secondary to infectious, inflammatory, immune-mediated, neoplasia, drug reaction, hyperadrenocorticism

Pollakiuria {#cesec416}
===========

*See* [Stranguria, Dysuria, and Pollakiuria](#cesec479){ref-type="sec"}.

Polyuria and Polydipsia {#cesec417}
=======================

Renal insufficiency or failureDiabetes mellitusHyperadrenocorticism (Cushing syndrome)Lower urinary tract disease•Infection•Urolithiasis•Neoplasia•Anatomic problem•Neurologic problemPyometraHypercalcemiaHypoadrenocorticism (Addison disease)PyelonephritisHypokalemiaIatrogenic (corticosteroids, diuretics, anticonvulsants)HyperthyroidismHepatic insufficiencyPostobstructiveDiabetes insipidus•Central•RenalPsychogenic drinkingRenal glycosuria

Pruritus {#cesec418}
========

Allergy {#cesec419}
-------

Flea allergyAtopic dermatitisFood allergy/intoleranceContact dermatitisMosquito-bite hypersensitivityEosinophilic plaque (cats)

Parasites {#cesec420}
---------

Flea infestationScabiesPediculosis (lice)CheyletiellosisChiggersCutaneous larval migransDemodicosis (often not pruritic)Otodectic acariasis

Infectious Agents {#cesec421}
-----------------

PyodermaMalassezia dermatitisDermatophytosis

Behavioral {#cesec422}
----------

Acral lick dermatosisPsychogenic alopecia

Immune-Mediated {#cesec423}
---------------

Pemphigus foliaceus

Drug Eruption {#cesec424}
-------------

 

Miscellaneous {#cesec425}
-------------

Cornification defectsSuperficial necrolytic dermatitisTail dock neuromaRhabditic dermatitis

Ptyalism (Excessive Salivation) {#cesec426}
===============================

Oral Cavity Disease {#cesec427}
-------------------

Oral trauma (tooth fractures, mandibular fractures, maxillary fractures, TMJ luxation)Severe periodontal diseaseOral masses (neoplasia, granuloma, eosinophilic granuloma)Stomatitis (toxins, infections, immune-mediated disease, immunologic or nutritional deficiency)Glossitis (chemical or environmental irritants, viral infections, uremia, immune-mediated disease, tumors)Faucitis (cats)Mucocutaneous junction lesionsForeign bodyDevelopmental (severe brachygnathism, lip fold pyoderma)

Oral Cavity Normal {#cesec428}
------------------

Drugs and toxins (bitter taste; insecticides such as organophosphates, pyrethrins, and [d]{.smallcaps}-limonene; caustic chemicals; poison toads and salamanders)NauseaHepatic encephalopathy/portosystemic shuntSeizuresSpace-occupying lesions in pharynxCranial nerve (CN) deficits (CN V: inability to close mouth; CN VII: inability to move lip; CNs X, XI, and XII: loss of gag lesion and inability to swallow)Rabies virusDysphagiaBehavior (associated with food \[Pavlovian\], contentment/mood in cats when purring, pain)Salivary gland hypersecretion

Regurgitation {#cesec429}
=============

Esophageal Disease {#cesec430}
------------------

Megaesophagus (primary or secondary)EsophagitisMechanical obstruction (foreign body, vascular ring anomaly, stricture)

Alimentary Disorders {#cesec431}
--------------------

Pyloric outflow obstructionGastric dilatation/volvulusHiatal hernia

Neuropathies {#cesec432}
------------

Peripheral neuropathy (polyradiculitis, polyneuritis, lead poisoning, giant cell axonal neuropathy)Central nervous system (brain stem lesion, neoplastic, traumatic, distemper)Dysautonomia

Neuromuscular Junction Abnormalities {#cesec433}
------------------------------------

Myasthenia gravis (focal or generalized)TetanusBotulismAcetylcholinesterase toxicity

Immune-Mediated Disorders {#cesec434}
-------------------------

Systemic lupus erythematosus (SLE)PolymyositisDermatomyositis

Endocrine Disease {#cesec435}
-----------------

HypothyroidismHypoadrenocorticism

Infectious {#cesec436}
----------

SpirocercosisPythium insidiosum

Reverse Sneezing {#cesec437}
================

•Loud inspiratory noise, occurs in paroxysms; initiated by nasopharyngeal irritation•Purpose is to move secretions and foreign material into the oropharynx to be swallowed•Causes include excitement, foreign bodies, nasal mites *(Pneumonyussus caninum),* viral infections, and epiglottic entrapment of the soft palate•Often idiopathic, nonprogressive, and common in small dogs and cats

Scaling and Crusting {#cesec438}
====================

Bacterial {#cesec439}
---------

Superficial folliculitisDeep pyodermaMucocutaneous pyodermaPyotraumatic dermatitis

Fungal {#cesec440}
------

Dermatophytosis*Malassezia* dermatitisDeep fungal infection (e.g., blastomycosis, cryptococcosis)

Parasitic {#cesec441}
---------

FleasScabiesDemodecosisCheyletiellosisNotoedric mangePediculosis

Protozoal {#cesec442}
---------

Leishmaniasis

Viral {#cesec443}
-----

Feline leukemia virus

Allergic {#cesec444}
--------

Atopic dermatitisFood hypersensitivityFlea bite hypersensitivityMilitary dermatitis

Endocrine and Metabolic {#cesec445}
-----------------------

HyperadrenocorticismHypothyroidismNecrolytic migratory erythema

Immune-Mediated {#cesec446}
---------------

Pemphigus foliaceusDiscoid lupus erythematosusErythema multiforme

Congenital and Hereditary {#cesec447}
-------------------------

Primary seborrheaIchthyosisSchnauzer comedo syndromeFamilial canine dermatomyositis

Keratinization Defects {#cesec448}
----------------------

Secondary seborrheaVitamin-A responsive dermatosisEar margin dermatosis

Environmental {#cesec449}
-------------

Solar dermatitis

Nutritional {#cesec450}
-----------

Zinc-responsive dermatosisFatty acid deficiency

Other {#cesec451}
-----

Cutaneous lymphomaSebaceous adenitisOtitis externa

Seizure {#cesec452}
=======

Extracranial Causes {#cesec453}
-------------------

Toxins (e.g., strychnine, chlorinated hydrocarbons, organophosphates, carbamates, lead, ethylene glycol, metaldehyde)Metabolic disease (e.g., hepatic encephalopathy, hypoglycemia, hypocalcemia)Hepatic diseaseElectrolyte disturbances (e.g., hypernatremia)Severe uremiaHyperlipoproteinemiaHyperviscosity (multiple myeloma, polycythemia)Hyperosmolality (diabetes mellitus)Heat stroke

Intracranial Causes {#cesec454}
-------------------

*See* **Part Two, Section XI: Differential Diagnosis for Inflammatory Disease of the Nervous System**.

Infectious diseaseNeoplasia (primary brain tumor, lymphoma, metastatic tumors)Granulomatous meningoencephalitisHemorrhage/infarct (renal failure, hypothyroidism, hyperthyroidism, hypertension, septic emboli, neoplasia, coagulopathies, heartworm disease, vasculitis)Congenital malformations (lissencephaly, hydrocephalus)Necrotizing encephalitisDegenerative diseases (metabolic storage diseases, leukodystrophies, hypomyelination disorders, spongy disorders)

Idiopathic Epilepsy {#cesec455}
-------------------

 

Sneezing and Nasal Discharge {#cesec456}
============================

Nasal and Upper Respiratory Disease {#cesec457}
-----------------------------------

### Infectious {#cesec458}

Viral: herpesvirus, calicivirus, canine distemper virusBacterial: *Mycoplasma* spp., *Bordatella bronchiseptica*Fungal: *Aspergillus, Cryptococcus, Rhinosporidium, Penicillium* spp.Parasitic: *Pneumonyssus caninum* (nasal mite), *Eucoleus boehmi* (formerly *Capillaria* spp.), *Cuterebra* spp.

### Inflammatory {#cesec459}

Allergic rhinitisLymphocytic-plasmacytic rhinitisAcquired nasopharyngeal stenosisNasopharyngeal polypsPolypoid rhinitis

### Neoplasia {#cesec460}

Adenocarcinoma, squamous cell carcinomaFibrosarcoma, osteosarcoma, chondrosarcomaLymphoma, transmissible venereal tumor, neuroendocrine carcinoma

### Foreign Body {#cesec461}

 

### Congenital {#cesec462}

Cleft palateCiliary dyskinesiaNasopharyngeal stenosisChoanal atresia

### Dental Disease {#cesec463}

Tooth root abscessOronasal fistula

### Trauma {#cesec464}

 

### Vascular Malformation {#cesec465}

 

Systemic Disease {#cesec466}
----------------

### Infectious {#cesec467}

Canine distemper virusCanine infectious tracheobronchitisPneumonia

### Hypertension {#cesec468}

HyperthyroidismHyperadrenocorticismRenal diseasePheochromocytomaHypothyroidismAcromegalyPolycythemiaDiabetes mellitusOverhydration

### Coagulopathies {#cesec469}

ThrombocytopeniaRocky Mountain spotted feverThrombocytopathiavon Willebrand diseaseFactor deficienciesCongenital (hemophilia A, B, others)Acquired (vitamin K rodenticide toxicity, DIC, hepatic failure)

### Vasculitis {#cesec470}

ToxicInflammatoryImmune mediated (SLE)NeoplasticInfectious (ehrlichiosis, FIP, Rocky Mountain spotted fever, leishmaniasis)

### Hyperviscosity {#cesec471}

Multiple myelomaLymphomaIgM (Waldenstrom) macroglobulinemiaChronic lymphocytic leukemiaEhrlichiosisAmyloidosisPlasma cell leukemiaFIP (rare)

Stertor and Stridor {#cesec472}
===================

Stertor {#cesec473}
-------

Snoring or snorting associated with partial nasal or nasopharyngeal obstruction.

### Intranasal Disorders {#cesec474}

Congenital deformitiesMassesExudatesClotted blood

### Pharyngeal Disease {#cesec475}

Brachycephalic airway syndromeElongated soft palateNasopharyngeal polypForeign bodyNeoplasiaAbscessGranulomaExtraluminal mass

Stridor {#cesec476}
-------

High-pitched wheeze caused by air turbulence in upper airway associated with laryngeal disease or narrowing of extrathoracic trachea.

### Laryngeal Disease {#cesec477}

NeoplasiaPolypsLaryngeal paralysisLaryngeal traumaForeign bodyAcute laryngitis/obstructive laryngitis

### Extrathoracic Tracheal Disease {#cesec478}

NeoplasiaForeign bodyExtrathoracic collapsing tracheaExtraluminal mass

Stranguria, Dysuria, and Pollakiuria {#cesec479}
====================================

Stranguria/Pollakiuria {#cesec480}
----------------------

### Small Bladder {#cesec481}

Cystitis•Infectious agents•Idiopathic cystitis (cats)Detrusor hyperspasticityUrethritisUrethral mass

### Large Bladder {#cesec482}

Lower urinary tract obstruction•Functional•Mechanical

Urinary Retention {#cesec483}
-----------------

### Easy Catheterization {#cesec484}

#### Normal Neurologic Examination {#cesec485}

Cystic calculi or massDetrusor areflexia from overdistensionReflex dyssynergia

#### Abnormal Neurologic Examination {#cesec486}

Detrusor areflexia with sphincter areflexia (lower motor neuron)Detrusor areflexia with sphincter hypertonia (upper motor neuron)Dysautonomia

### Difficult Catheterization {#cesec487}

Urethral spasmUrethral calculiUrethral neoplasiaTransitional cell carcinomaGranulomatous urethritisUrethral inflammationProstatic diseaseMucoid or crystalline plug (cats)

Stomatitis {#cesec488}
==========

Infectious disease•Feline immunodeficiency virus (FIV)•Feline leukemia virus (FeLV)•Feline syncytium-forming virus•Feline calicivirus•Feline herpesvirus•Feline infectious peritonitis (FIP)•Bartonellosis•Canine distemper virus•Feline panleukopenia virus•CandidiasisImmunosuppressive diseaseFeline eosinophilic granuloma complexIdiopathic feline chronic gingivitis/stomatitisImmune-mediated disease•Systemic lupus erythematosus (SLE)•Bullous (pemphigus) disease•Idiopathic vasculitis•Toxic epidermal necrolysis•Ulcerative gingivitis/stomatitis of Maltese TerriersUremic stomatitisRadiation-induced

Stupor and Coma {#cesec489}
===============

Increased Intracranial Pressure {#cesec490}
-------------------------------

EncephalitisMeningitisNeoplasiaGranulomasAbscessVascular eventsTraumaUnderlying metabolic injury (e.g., hypertension)

Cerebral Edema {#cesec491}
--------------

Vasogenic (brain masses that lead to breakdown of blood-brain barrier)Cytotoxic (hypoxia, neuroglycopenia)Interstitial (hydrocephalus)

Herniation of Brain Tissue {#cesec492}
--------------------------

Caudal transtentorial herniationForamen magnum herniation

Extracranial Causes {#cesec493}
-------------------

HypoglycemiaSevere hypothyroidismToxinsHepatic diseaseHyperadrenocorticism

Syncope {#cesec494}
=======

Normal Cerebral Perfusion {#cesec495}
-------------------------

Severe hypoxemiaHypoglycemia

Cerebral Hypoperfusion {#cesec496}
----------------------

### Normotension {#cesec497}

Cerebrovascular diseaseCerebral vasoconstriction

### Systemic Hypotension {#cesec498}

#### Decreased Cardiac Output {#cesec499}

##### Loss of Preload {#cesec500}

Cardiac tamponade, atrial ball thrombi, atrial myxoma, atrioventricular (AV) valve stenosis, hypovolemia, diuretics

##### Obstruction to Flow {#cesec501}

Aortic and subaortic stenosis, pulmonic stenosis, pulmonary hypertension, pulmonary thromboembolism, outflow tract tumors, myocardial infarction, hypertropic and restrictive cardiomyopathy, systolic anterior motion of mitral valve, infundibular stenosis, heartworm disease

##### Arrhythmias {#cesec502}

Bradyarrhythmias: sick sinus syndrome, third-degree AV block, persistent atrial standstill, β-blockers, calcium channel blockersTachyarrhythmias: atrial fibrillation, atrial tachycardia, AV reentrant tachycardia, ventricular tachycardia, drug-induced proarrhythmia, torsades de pointes

##### Loss of Vascular Resistance {#cesec503}

Drug therapy: angiotensin-converting enzyme (ACE) inhibitors, β-blockers, calcium channel blockers, hydralazine, nitrates, β-blockers, phenothiazinesReflex syncope (neurally mediated): orthostatic, postexertion, micturition, defecation, cough, emotional distress, pain, carotid sinus hypersensitivityAutonomic nervous system disease: primary or secondary (diabetes mellitus, paraneoplastic, chronic renal failure, autoimmune disease, amyloidosis)Cyanotic heart disease (tetralogy of Fallot, reversed shunt)

Tachycardia, Sinus {#cesec504}
==================

Anxiety/fearExcitementExercisePainHyperthyroidismHeart failureHyperthermia/feverAnemiaHypoxiaShockHypotensionSepsisDrugs (anticholinergics, sympathomimetics)Toxicity (e.g., chocolate, amphetamines, theophylline)Electric shockAny cause of high sympathetic tone

Tenesmus and Dyschezia {#cesec505}
======================

Colonic or Rectal Obstruction {#cesec506}
-----------------------------

Constipation Pelvic fractureRectal neoplasiaExtraluminal neoplasiaProstatomegalyPerineal herniaPelvic canal massRectal granulomaRectal foreign bodyRectal stricture

Perineal Inflammation or Pain {#cesec507}
-----------------------------

Anal sacculitisPerianal fistulaPerianal abscess/abscessed anal sac

Rectal Inflammation or Pain {#cesec508}
---------------------------

Rectal tumor/polypProctitisHistoplasmosisPythiosis

Colonic Inflammation {#cesec509}
--------------------

Idiopathic colitisBacteriaFungalParasitesDietary indiscretionInflammatory bowel diseaseNeoplasia

Tremor {#cesec510}
======

Physiologic Tremor {#cesec511}
------------------

HypothermiaHeavy exercise/exhaustion

Pathologic Tremor {#cesec512}
-----------------

Metabolic disorders (renal disease, hypoglycemia, hypocalcemia, hypoadrenocorticism)Intracranial infectious disease (*Neospora caninum,* cerebellar hypoplasia secondary to intrauterine panleukopenia infection)Intracranial disease (fibrinoid leukodystrophy, neuraxonal dystrophy, Labrador Retriever axonopathy, spongiform encephalopathy, neuronal abiotrophies, subacute necrotizing encephalopathy, lysosomal storage diseases)Hind end tremor (intervertebral disk herniation, tumors, diskospondylitis, nerve root compression, peripheral neuropathies)Corticoid-responsive tremor syndrome (formerly "white shaker disease")Myasthenia gravisCerebellar malformationHypomyelinationSpongy degenerationTremorgenic toxins (mycotoxins penitrem A and roquefortine produced by *Penicillium* spp. growing on spoiled foods; metaldehyde, hexachlorophene, bromethalin, organophosphates, carbamates, pyrethroids, xanthines, macadamia nuts, strychnine)Idiopathic head tremor in Doberman Pinschers and BulldogsIdiopathic tremor of hind legs of geriatric dogs

Urine, Discolored {#cesec513}
=================

Red, Pink, Red-Brown, Red-Orange, or Orange {#cesec514}
-------------------------------------------

HematuriaHemoglobinuriaMyoglobinuriaPorphyrinuriaPyuria

Orange-Yellow {#cesec515}
-------------

Highly concentrated urineUrobilinBilirubin

Yellow-Brown or Green-Brown {#cesec516}
---------------------------

Bile pigments

Brown to Black {#cesec517}
--------------

MelaninMethemoglobinMyoglobinBile pigments

Brown {#cesec518}
-----

MethemoglobinMelanin

Colorless {#cesec519}
---------

Dilute urine

Milky White {#cesec520}
-----------

LipidPyuriaCrystals

Pale Yellow {#cesec521}
-----------

NormalDilute urine

Urticaria/Angioedema {#cesec522}
====================

Immediate Hypersensitivity Reaction {#cesec523}
-----------------------------------

Insect bites/stingsFoodDrugs/vaccinesAirborne allergens (atopy)

Nonimmunologic Stimulus by Irritant {#cesec524}
-----------------------------------

WeedsInsectsPhysical stimuli (cold, heat, sunlight)Psychogenic stimuli

Vision Loss, Sudden {#cesec525}
===================

*See* [Blindness](#cesec87){ref-type="sec"}.

Vomiting {#cesec526}
========

Gastric Disease {#cesec527}
---------------

GastritisParasitesForeign bodyObstructionUlcerationNeoplasiaDilatation/volvulus*Helicobacter* infectionGastric ulcerHiatal herniaMotility disordersPyloric stenosisGastric antral mucosal hypertrophy

Small Intestinal Disease {#cesec528}
------------------------

ParasitesInflammatory bowel diseaseForeign bodyBacterial overgrowth/enteritisHemorrhagic gastroenteritisNeoplasiaViral enteritis (parvovirus, canine distemper virus)IntussusceptionNonneoplastic infiltrative disease (e.g., pythiosis)

Large Intestinal Disease {#cesec529}
------------------------

ColitisObstipationParasites

Dietary {#cesec530}
-------

IndiscretionIntoleranceAllergy

Drugs {#cesec531}
-----

Cancer chemotherapeutic agentsAntibiotics (especially erythromycin, tetracycline)Nonsteroidal antiinflammatory drugs (NSAIDs)Cardiac glycosidesApomorphineXylazinePenicillamine

Extraalimentary Tract Disease {#cesec532}
-----------------------------

PeritonitisPancreatitisHepatobiliary diseaseNeoplasiaUremiaDiabetes mellitus/ketoacidosisHyperthyroidismHypoadrenocorticismHepatic diseaseHepatic encephalopathySepticemia/endotoxemiaPyometraAcid-base disordersElectrolyte disordersHypertriglyceridemiaGastrinoma (Zollinger-Ellison syndrome)Mastocytosis

Intoxicants {#cesec533}
-----------

Numerous inorganic, organic, and plant toxins can cause gastrointestinal irritation and vomiting.

Neurologic Disease {#cesec534}
------------------

Epilepsy, tumor, meningitis, increased intracranial pressure, dysautonomia

Weakness {#cesec535}
========

Very nonspecific clinical sign of diseaseMetabolic diseaseInflammation•Infectious disease (bacterial, viral, fungal, rickettsial, protozoal, parasitic)•Immune-mediated diseaseFeverElectrolyte disorders•Hypokalemia, hyperkalemia, hyponatremia, hypernatremia, hypocalcemia, hypomagnesemiaAcid-base disordersAnemiaPoor oxygen deliveryEndocrine disease•Diabetes mellitus, hypothyroidism, hypoadrenocorticism, hyperadrenocorticism, hypoglycemia, hyperparathyroidism, hypoparathyroidism, pheochromocytomaCardiovascular diseaseHypotension, hypertensionRespiratory diseaseNeuromuscular disease•Brain disease (encephalitis, cerebrovascular accidents, space-occupying lesions, vestibular disease, idiopathic epilepsy)•Spinal cord diseases•Neuropathies (e.g., polyradiculoneuritis, myasthenia gravis, developmental disorders, toxoplasmosis, neosporosis)NeoplasiaCachexiaPhysical and psychologic stressMalnutritionDrugs•Anticonvulsants, antihistamines, glucocorticoids, tranquilizers, narcotics, cardiac drugsToxinsPain

Weight Gain {#cesec536}
===========

*See* [Obesity](#cesec389){ref-type="sec"}.

Weight Loss {#cesec537}
===========

*See* [Cachexia and Muscle Wasting](#cesec96){ref-type="sec"}.
