Peripheral neuropathy

From Wikipedia, the free encyclopedia
  (Redirected from Mononeuropathy)
Jump to: navigation, search
Peripheral neuropathy
Classification and external resources
Vasculitic neuropathy - plastics - intermed mag.jpg
Micrograph showing a vasculitic peripheral neuropathy. Plastic embedded. Toluidine blue stain.
ICD-10 G64, G90.0
ICD-9 356.0, 356.8
DiseasesDB 9850
MedlinePlus 000593
MeSH D010523

Peripheral neuropathy (PN) is damage or disease affecting nerves, which may affect sensation, movement, gland or organ function, and other aspects of health, depending on the type of nerve affected. Common causes include systemic diseases (such as diabetes or leprosy), vitamin deficiency, medication (e.g., chemotherapy), traumatic injury, excessive alcohol consumption, immune system disease, or infection, or it may be inherited (present from birth).[1][2][3] In conventional medical usage, the word neuropathy (neuro- + -pathy) without modifier usually means peripheral neuropathy.


Peripheral neuropathy may be chronic (a long term condition where symptoms begin subtly and progress slowly) or acute (sudden onset, rapid progress and slow resolution). Acute neuropathies demand urgent diagnosis. Motor nerves (that control muscles), sensory nerves, or autonomic nerves (that control automatic functions such as heart rate, body temperature and breathing), may be affected. More than one type of nerve may be affected at the same time. Peripheral neuropathies may be classified according to the type of nerve predominantly involved, or by the underlying cause. Where the cause is unknown it is described as idiopathic neuropathy.[1][2][3]



Peripheral neuropathy may be classified according to the number and distribution of nerves affected (mononeuropathy, mononeuritis multiplex or polyneuropathy), the type of nerve cell predominantly affected (motor, sensory, autonomic), or the process affecting the nerves; e.g., inflammation (neuritis), compression (compression neuropathy), chemotherapy (chemotherapy-induced peripheral neuropathy).


Mononeuropathy is a type of neuropathy that only affects a single nerve.[4] It is diagnostically useful to distinguish them from polyneuropathies because the limitation in scope makes it more likely that the cause is a localized trauma or infection.

The most common cause of mononeuropathy is by physical compression of the nerve, known as compression neuropathy. Carpal tunnel syndrome and axillary nerve palsy are examples of this. The "pins-and-needles" sensation of one's "foot falling asleep" (paresthesia) is caused by a compression mononeuropathy,[citation needed] albeit a temporary one which can be resolved merely by moving around and adjusting to a more appropriate position. Direct injury to a nerve, interruption of its blood supply (ischemia), or inflammation can also cause mononeuropathy.

Mononeuritis multiplex[edit]

Mononeuritis multiplex, occasionally termed polyneuritis multiplex, is simultaneous or sequential involvement of individual noncontiguous nerve trunks, either partially or completely, evolving over days to years and typically presenting with acute or subacute loss of sensory and motor function of individual nerves. The pattern of involvement is asymmetric; however, as the disease progresses deficit(s) becomes more confluent and symmetrical, making it difficult to differentiate from polyneuropathy. Therefore, attention to the pattern of early symptoms is important.

Mononeuritis multiplex may also cause pain, which is characterized as deep, aching pain that is worse at night and frequently in the lower back, hip, or leg. In people with diabetes mellitus, mononeuritis multiplex is typically encountered as acute, unilateral, severe thigh pain followed by anterior muscle weakness and loss of knee reflex.

Electrodiagnostic studies will show multifocal sensory motor axonal neuropathy.




The effect of this is to cause symptoms in more than one part of the body, often on left and right sides symmetrically. As for any neuropathy, the chief symptoms include weakness or clumsiness of movement (motor); unusual or unpleasant sensations such as tingling or burning; reduction in the ability to feel texture, temperature, etc.; and impaired balance when standing or walking (sensory). In many polyneuropathies, these symptoms occur first and most severely in the feet. Autonomic symptoms may also occur, such as dizziness on standing up, erectile dysfunction, and difficulty controlling urination.

Polyneuropathies are usually caused by processes that affect the body as a whole. Diabetes and impaired glucose tolerance are the most common causes. Other causes relate to the particular type of polyneuropathy, and there are many different causes of each type, including inflammatory diseases such as lyme disease, vitamin deficiencies, blood disorders, and toxins (including alcohol and certain prescribed drugs). Most types of polyneuropathy progress fairly slowly, over months or years, but rapidly progressive polyneuropathy also occurs. It is important to recognize that glucose levels in the blood can spike to nerve-damaging levels after eating even though fasting blood sugar levels and average blood glucose levels can still remain below normal levels (currently typically considered below 100 mg/dL for fasting blood plasma and 6.0% for HGBA1c, the test commonly used to measure average blood glucose levels over an extended period). Studies have shown that many of the cases of peripheral small fiber neuropathy with typical symptoms of tingling, pain, and loss of sensation in the feet and hands are due to glucose intolerance before a diagnosis of diabetes or pre-diabetes. Such damage is often reversible, particularly in the early stages, with diet, exercise, and weight loss.


Autonomic neuropathy[edit]

Autonomic neuropathy is a form of polyneuropathy which affects the non-voluntary, non-sensory nervous system (i.e., the autonomic nervous system), affecting mostly the internal organs such as the bladder muscles, the cardiovascular system, the digestive tract, and the genital organs. These nerves are not under a person's conscious control and function automatically. Autonomic nerve fibers form large collections in the thorax, abdomen, and pelvis outside the spinal cord. However, they have connections with the spinal cord and ultimately the brain. Most commonly autonomic neuropathy is seen in persons with long-standing diabetes mellitus type 1 and 2. In most but not all cases, autonomic neuropathy occurs alongside other forms of neuropathy, such as sensory neuropathy.

Autonomic neuropathy is one cause of malfunction of the autonomic nervous system but not the only one; some conditions affecting the brain or spinal cord can also cause autonomic dysfunction, such as multiple system atrophy, and therefore cause similar symptoms to autonomic neuropathy.

The signs and symptoms of autonomic neuropathy include the following:


Neuritis is a general term for inflammation of a nerve[6] or the general inflammation of the peripheral nervous system. Symptoms depend on the nerves involved but may include pain, paresthesia (pins & needles), paresis (weakness), hypoesthesia (numbness), anesthesia, paralysis, wasting, and disappearance of the reflexes. Causes include:

One common cause of neuritis and subsequent inflammation of the nerves to the toes is the wearing of high-heeled shoes or ill-fitting shoes that bind the toes painfully. This can cause temporary numbness and pain in the affected toes for several days.

Types of neuritis include:

Signs and symptoms[edit]

Those with diseases or dysfunctions of their nerves can present with problems in any of the normal nerve functions.

In terms of sensory function, there are commonly loss of function (negative) symptoms, which include numbness, tremor, and gait abnormality.

Gain of function (positive) symptoms include tingling, pain, itching, crawling, and pins and needles. Pain can become intense enough to require use of opioid (narcotic) drugs (i.e., morphine, oxycodone).


There is also pain in the muscles (myalgia), cramps, etc., and there may also be autonomic dysfunction.

During physical examination, specifically a neurological examination, those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, though those with a pathology (problem) of the nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies like Guillain–Barré syndrome; or may show focal sensory disturbance or weakness, such as in mononeuropathies. Ankle jerk reflex is classically absent in peripheral neuropathy.


The causes are broadly grouped as follows:


Many treatment strategies for peripheral neuropathy are symptomatic. Some current research in animal models has shown that neurotrophin-3 can oppose the demyelination present in some peripheral neuropathies.[17]

A range of drugs that act on the central nervous system such as drugs originally intended as antidepressants and antiepileptic drugs have been found to be useful in managing neuropathic pain. Commonly used treatments include using a tricyclic antidepressant (such as amitriptyline) and antiepileptic therapies such as gabapentin or sodium valproate. These have the advantage that besides being effective in many cases they are relatively low cost.

A great deal of research has been done between 2005 and 2010 which indicates that synthetic cannabinoids and inhaled cannabis are effective treatments for a range of neuropathic disorders.[18] Research has demonstrated that the synthetic oral cannabinoid Nabilone is an effective adjunct treatment option for neuropathic conditions, especially for people who are resistant, intolerant, or allergic to common medications.[19] Orally, opiate derivatives were found to be more effective than cannabis for most people.[20] Smoked cannabis has been found to provide relief from HIV-associated sensory neuropathy.[21] Smoked cannabis was also found to relieve neuropathy associated with CRPS type I, spinal cord injury, peripheral neuropathy, and nerve injury.[22]

Pregabalin is an anticonvulsant drug used for neuropathic pain. It has also been found effective for generalized anxiety disorder. It was designed as a more potent successor to gabapentin but is significantly more expensive, especially now that the patent on gabapentin has expired and gabapentin is available as a generic drug. Pregabalin is marketed by Pfizer under the trade name Lyrica.

Duloxetine, a serotonin-norepinephrine reuptake inhibitor, is also being used to reduce neuropathic pain.

Transcutaneous electrical nerve stimulation therapy may be effective and safe in the treatment of diabetic peripheral neuropathy. A recent review of three trials involving 78 patients found some improvement in pain scores after 4 and 6 but not 12 weeks of treatment, and an overall improvement in neuropathic symptoms at 12 weeks.[23] A second review of four trials found significant improvement in pain and overall symptoms, with 38% of patients in one trial becoming asymptomatic. The treatment remains effective even after prolonged use, but symptoms return to baseline within a month of treatment cessation.[24]



  4. ^ "Dorlands Medical Dictionary:mononeuropathy". 
  6. ^ "neuritis" at Dorland's Medical Dictionary
  8. ^ Chin, RL; Latov, N (2005 Jan). "Peripheral Neuropathy and Celiac Disease.". Current treatment options in neurology 7 (1): 43–48. PMID 15610706. 
  18. ^ Hazekamp, Arno; Grotenhermen, Franjo (2010). "Review on clinical studies with cannabis and cannabinoids 2005-2009". Cannabinoids (International Association for Cannabinoid Medicines) (5): 1–21. Retrieved 21 May 2013. 

Further reading[edit]

  • Committee on Standards and Practice Parameters, American Society of Anesthesiologists (2011). "Practice advisory for the prevention of perioperative peripheral neuropathies: an updated report by the American Society of Anesthesiologists Task Force on prevention of perioperative peripheral neuropathies". Anesthesiology 114 (4): 1168–82. PMID 10754638.