infective endocarditis infective endocarditis infective endocarditis is an infection of the inner surface of the heart, usually the valves. signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. complications may include backward blood flow in the heart, heart failure – the heart struggling to pump a sufficient amount of blood to meet the body's needs, abnormal electrical conduction in the heart, stroke, and kidney failure. infective endocarditisother namesbacterial endocarditisa mitral valve vegetation caused by bacterial endocarditis.specialtycardiology, infectious diseasesymptomsfever, small areas of bleeding into the skin, heart murmur, feeling tired, low red blood cellscomplicationsvalvular insufficiency, heart failure, stroke, kidney failure blood clot in a lung artery (pulmonary embolism) enlarged and painful spleen, kidney damage, ulmonary embolism, damage to the distal extremities such as fingers and toes.causesbacterial infection, fungal infectionrisk factorsvalvular heart disease including rheumatic disease, congenital heart disease, artificial valves, hemodialysis, intravenous drug use, electronic pacemakersdiagnostic methodbased on symptoms, blood cultures, ultrasoundtreatmentantibiotics, heart surgeryprognosis25% risk of deathfrequency5 per 100,000 per year the cause is typically a bacterial infection and less commonly a fungal infection. risk factors include valvular heart disease, including rheumatic disease, congenital heart disease, artificial valves, hemodialysis, intravenous drug use, and electronic pacemakers. the bacteria most commonly involved are streptococci or staphylococci. diagnosis is suspected based on symptoms and supported by blood cultures or ultrasound of the heart. there is also a noninfective form of endocarditis. the usefulness of antibiotics following dental procedures for prevention is unclear. some recommend them for people at high risk. treatment is generally with intravenous antibiotics. the choice of antibiotics is based on the results of blood cultures. occasionally heart surgery is required. the number of people affected is about 5 per 100,000 per year. rates, however, vary between regions of the world. infective endocarditis occurs in males more often than in females. the risk of death among those infected is about 25%. without treatment, it is almost universally fatal. classification infective endocarditis is divided into the three categories of acute, subacute, and chronic based on the duration of symptoms. acute infective endocarditis refers to the presence of signs and symptoms of infective endocarditis that are present for days up to six weeks. if these signs and symptoms persist for more than six weeks but less than three months, this is subacute infective endocarditis. chronic infective endocarditis refers to the presence of such signs and symptoms when they persist for more than three months. subacute bacterial endocarditis (sbe) is often due to streptococci of low virulence (mainly viridans streptococci) and mild to moderate illness which progresses slowly over weeks and months (>2 weeks) and has low propensity to hematogenously seed extracardiac sites. acute bacterial endocarditis (abe) is a fulminant illness over days to weeks (<2 weeks), and is more likely due to staphylococcus aureus, which has much greater virulence or disease-producing capacity and frequently causes metastatic infection. this classification is now discouraged, because the ascribed associations (in terms of organism and prognosis) were not strong enough to be relied upon clinically. the terms short incubation (meaning less than about six weeks) and long incubation (greater than about six weeks) are preferred. culture results infective endocarditis may also be classified as culture-positive or culture-negative. by far the most common cause of "culture-negative" endocarditis is prior administration of antibiotics. sometimes microorganisms can take a longer period of time to grow in the culture media, for example cutibacterium spp. and the hacek bacteria group. some organisms are said to be fastidious because they have demanding growth requirements. some examples include pathogens like aspergillus species, brucella species, coxiella burnetii, chlamydia species. due to delay in growth and identification in these cases, patients may be erroneously classified as "culture-negative" endocarditis. heart side endocarditis can also be classified by the side of the heart affected: people who intravenously inject opioids such as heroin or methamphetamine may introduce infection which can travel to the right side of the heart, classically affecting the tricuspid valve, and most often caused by s. aureus. regardless of cause, left-sided endocarditis is more common in people who inject iv drugs and people who do not use substances than right-sided endocarditis. infection setting another form of endocarditis is healthcare-associated endocarditis when the infecting organism is believed to be transmitted in a health care setting like hospital, dialysis unit or a residential nursing home. nosocomial endocarditis is a form of healthcare associated endocarditis in which the infective organism is acquired during a stay in a hospital and it is usually secondary to presence of intravenous catheters, total parenteral nutrition lines, pacemakers, etc. valve type finally, the distinction between native-valve endocarditis and prosthetic-valve endocarditis is clinically important. prosthetic valve endocarditis can be early (< 60 days of valvular surgery), intermediate (60 days to 1 year) or late (> 1 year following valvular surgery). early prosthetic valve endocarditis is usually due to intraoperative contamination or postoperative bacterial contamination which is usually nosocomial in nature. late prosthetic valve endocarditis is usually due to community-acquired microorganisms. prosthetic valve endocarditis is commonly caused by staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces. cutibacterium acnes almost exclusively causes endocarditis on prosthetic heart valves. signs and symptoms fever occurs in 97% of people; malaise and endurance fatigue in 90% of people. a new or changing heart murmur, weight loss, and coughing occurs in 35% of people. vascular phenomena: septic embolism (a piece of infected debris or tissue breaking off and traveling through the bloodstream to a distant site) (causing thromboembolic problems such as a stroke or gangrene of the fingers), janeway lesions (painless hemorrhagic cutaneous lesions on the palms and soles), bleeding in the brain, conjunctival hemorrhage, splinter hemorrhages, kidney infarcts, and splenic infarcts. infective endocarditis can also lead to the formation of mycotic aneurysms. immunologic phenomena: glomerulonephritis which allows for blood and albumin to enter the urine, osler's nodes ("ephemeral spots of a painful nodular erythema, chiefly in the skin of the hands and feet"), roth's spots on the retina, positive serum rheumatoid factor other signs may include night sweats, rigors, anemia, spleen enlargement cause many microorganisms can cause infective endocarditis. these are generally isolated by blood culture, where the patient's blood is drawn and any growth is noted and identified. the term bacterial endocarditis (be) commonly is used, reflecting the fact that most cases of ie are due to bacteria; however, infective endocarditis (ie) has become the preferred term. bacterial staphylococcus aureus is the leading cause of infective endocarditis in most parts of the world and is responsible for about 31% of cases. staphylococcus aureus is the most common cause of endocarditis in people who use intravenous drugs. viridans streptococci and enterococci are the second and third most common organisms responsible for infective endocarditis. viridans streptococci are a common cause of infective endocarditis in south america. other streptococci are also a frequent cause. infective endocarditis due to streptococcus bovis occurs more commonly in europe than in north america. hacek group of bacteria are also rare causes of infective endocarditis in north america. the viridans group includes s. oralis, s. mitis, s. sanguis, s. gordonii and s. parasanguis. the primary habitats for these organisms are the oral cavity and upper respiratory tract. these bacteria are present in the normal oral flora and enter the bloodstream due to disruption of tissues in the mouth when dental surgical procedures are performed (tooth extractions) or genitourinary manipulation. similarly, hacek organisms are a group of bacteria that live on the dental gums and can be seen with people who inject drugs who contaminate their needles with saliva. patients may also have a history of poor dental hygiene or pre-existing valvular disease. viridans alpha-hemolytic streptococci, that are present in the mouth, are the most frequently isolated microorganisms when the infection is acquired in a community setting. in contrast, staphylococcus bloodstream infections are frequently acquired in a health care setting where they can enter the bloodstream through procedures that cause breaks in the integrity of skin, such as surgery, catheterization, or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs. enterococcus can enter the bloodstream as a consequence of abnormalities in the gastrointestinal or genitourinary tracts. some organisms, when isolated, give valuable clues to the cause, as they tend to be specific. pseudomonas species, which are very resilient organisms that thrive in water, may contaminate street drugs that have been contaminated with drinking water. p. aeruginosa can infect a child through foot punctures, and can cause both endocarditis and septic arthritis. s. bovis and clostridium septicum, which are part of the natural flora of the bowel, are associated with colon cancers. when they present as the causative agent in endocarditis, it usually prompts a colonoscopy to be done immediately due to concerns regarding spread of bacteria from the colon through the bloodstream due to the cancer breaking down the barrier between the inside of the colon (lumen) and the blood vessels which drain the bowel. less commonly reported bacteria responsible for so called "culture negative endocarditis" include bartonella, chlamydia psittaci, and coxiella. such bacteria can be identified by serology, culture of the excised valve tissue, sputum, pleural fluid, and emboli, and by polymerase chain reaction or sequencing of bacterial 16s ribosomal rna. multiple case reports of infective endocarditis caused by unusual organisms have been published. cutibacterium spp., which are normal skin flora, have been responsible for infective endocarditis, preferably in patients with prosthetic heart valves, in rare cases leading to death.tropheryma whipplei has caused endocarditis without gastrointestinal involvement. citrobacter koseri was found in an immunocompetent adult. neisseria bacilliformis was found in a person with a bicuspid aortic valve. fungal fungal endocarditis (fe) is often fatal and one of the most serious forms of infective endocarditis. the types of fungi most seen associated with this disease are: candida albicans is found as a spherical or oval budding yeast. it is associated with endocarditis in people who inject drugs, patients with prosthetic valves, and immunocompromised patients. it forms biofilms around thick-walled resting structures like prosthetic heart valves and additionally colonizes and penetrates endothelial walls. c. albicans is responsible for 24-46% of all the cases of fe, and its mortality rate is 46.6–50%. other fungi demonstrated to cause endocarditis are histoplasma capsulatum and aspergillus. aspergillus contributes to roughly 25% of fe cases. endocarditis with tricosporon asahii has also been reported in a case report. risk factors risk factors for infective endocarditis are based on the premise that in a healthy individual, bacteremia (bacteria entering the bloodstream) is cleared quickly with no adverse consequences. however, if a heart valve is damaged, the bacteria can attach themselves to the valve, resulting in infective endocarditis. additionally, in individuals with weakened immune systems, the concentration of bacteria in the blood can reach levels high enough to increase the probability that some will attach to the valve. some significant risk factors are listed here: artificial heart valves intracardiac devices, such as implantable cardioverter-defibrillators unrepaired cyanotic congenital heart defects history of infective endocarditis neoplastic disease chronic rheumatic heart disease, which is an autoimmune response to repeated streptococcus pyogenes infection (mostly in the developing world) age-related degenerative valvular lesions congenital heart valve abnormalities hemodialysis, a medical procedure that filters the blood of individuals with kidney failure poor oral hygiene coexisting conditions, especially ones that suppress immunity. diabetes mellitus, alcohol use disorder, chronic liver disease, hiv/aids, and intravenous drug use all fall in this category more detailed descriptions of these and other risk factors are provided below. other conditions that result in large numbers of bacteria entering into the bloodstream include colorectal cancer (mostly streptococcus bovis), serious urinary tract infections (mostly enterococci), and drug injection (staphylococcus aureus). with a large number of bacteria, even a normal heart valve may become infected. a more virulent organism (such as staphylococcus aureus) can cause infective endocarditis by infecting even a normal heart valve. people who inject drugs tend to get their right-sided heart valves infected because the veins that are injected drain into the right side of the heart. in rheumatic heart disease, infection occurs on the aortic and the mitral valves on the left side of the heart. other factors that increase the risk of developing infective endocarditis are low levels of white blood cells,