Endocarditis is an
inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
of the inner layer of the
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
, the
endocardium
The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the v ...
. It usually involves the
heart valve
A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...
s. Other structures that may be involved include the
interventricular septum
The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricles, the lower chambers of the heart, from one another.
The ventricular septum is directed obliquely backwar ...
, the
chordae tendineae
The chordae tendineae (tendinous cords), colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.
Structure
The chorda ...
, the mural endocardium, or the surfaces of intracardiac devices. Endocarditis is characterized by lesions, known as ''
vegetations'', which is a mass of
platelet
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...
s,
fibrin,
microcolonies of microorganisms, and scant inflammatory cells.
In the
subacute form of infective endocarditis, the vegetation may also include a center of
granulomatous tissue, which may fibrose or calcify.
There are several ways to classify endocarditis. The simplest classification is based on cause: either ''infective'' or ''non-infective'', depending on whether a
microorganism
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
is the source of the inflammation or not. Regardless, the diagnosis of endocarditis is based on clinical features, investigations such as an
echocardiogram
An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart.
It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound.
Echocardiography has become routinely used in th ...
, and
blood culture
A blood culture is a medical laboratory test used to detect bacteria or fungi in a person's blood. Under normal conditions, the blood does not contain microorganisms: their presence can indicate a bloodstream infection such as bacteremia or ...
s demonstrating the presence of endocarditis-causing microorganisms.
Signs and symptoms include fever, chills, sweating, malaise, weakness, anorexia, weight loss,
splenomegaly
Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of ''hypersplenism'' which include: some reduction in number of circulatin ...
, flu-like feeling, cardiac murmur, heart failure,
petechia
A petechia () is a small red or purple spot (≤4 mm in diameter) that can appear on the skin, conjunctiva, retina, and Mucous membrane, mucous membranes which is caused by haemorrhage of capillaries. The word is derived from Italian , 'freckle,' ...
(red spots on the skin),
Osler's node
Osler's nodes are painful, red, raised lesions found on the hands and feet. They are associated with a number of conditions, including infective endocarditis, and are caused by immune complex deposition. Their presence is one definition of Osler' ...
s (subcutaneous nodules found on hands and feet),
Janeway lesion
Janeway lesions are rare, non- tender, small erythematous or haemorrhagic macular, papular or nodular lesions on the palms or soles only a few millimeters in diameter that are associated with infective endocarditis and often indistinguishable fro ...
s (nodular lesions on palms and soles), and
Roth's spot
Roth's spots, also known as Litten spots or the Litten sign, are non-specific red spots with white or pale centres, seen on the retina and although traditionally associated with infective endocarditis, can occur in a number of other conditions inc ...
s (retinal hemorrhages).
Infective endocarditis
Infective endocarditis is an
infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
of the
inner surface of the heart, usually the
valves
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...
.
[ Symptoms may include ]fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
, small areas of bleeding into the skin, heart murmur
Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound di ...
, feeling tired, and low red blood cells. Complications may include valvular insufficiency
Regurgitation is blood flow in the opposite direction from normal, as the backward flowing of blood into the heart or between heart chambers. It is the circulatory equivalent of backflow in engineered systems. It is sometimes called reflux.
Regur ...
, heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
, stroke, and kidney failure
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
.[
The cause is typically a ]bacterial infection
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number ...
and less commonly a fungal infection.[ Risk factors include ]valvular heart disease
Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart (the aortic and mitral valves on the left side of heart and the pulmonic and tricuspid valves on the right side of heart). These ...
including rheumatic disease
Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including art ...
, congenital heart disease
A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...
, artificial valves
An artificial heart valve is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly (valvular heart disease). Artificial heart valves can be separated into three broad classes: mechanical hear ...
, hemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
, intravenous drug use
Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle, which is pierced through the skin into the body (usually intravenously, but also at an intramuscular or subcutaneous location). Intravenous t ...
, and electronic pacemaker
An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart eith ...
s.[ The bacterial most commonly involved are streptococci or ]staphylococci
''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical ( cocci), and form in grape-like clusters. ''Staphylococcus'' species are facultati ...
.[
The diagnosis of infective endocarditis relies on the Duke criteria, which were originally described in 1994 and modified in 2000. Clinical features and microbiological examinations are the first steps to diagnose an infective endocarditis. The imaging is also crucial. Echocardiography is the cornerstone of imaging modality in the diagnosis of infective endocarditis. Alternative imaging modalities as computer tomography, magnetic resonance imaging, and positron emission tomography/computer tomography (PET/CT) with 2- luorodeoxyglucose (FDG)">8Fluorodeoxyglucose (FDG) are playing an increasing role in the diagnosis and management of infective endocarditis.
The usefulness of ]antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...
following dental procedure
Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions of ...
s for prevention is unclear. Some recommend them in those at high risk.[ Treatment is generally with ]intravenous antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
.[ The choice of antibiotics is based on the blood cultures.][ Occasionally ]heart surgery
Cardiac surgery, or cardiovascular surgery, is surgery on the heart or great vessels performed by cardiac surgeons. It is often used to treat complications of ischemic heart disease (for example, with coronary artery bypass grafting); to corr ...
is required.[
The number of people affected is about 5 per 100,000 per year.][ Rates, however, vary between regions of the world.][ Males are affected more often than females.][ The risk of death among those infected is about 25%.] Without treatment it is almost universally fatal.[
]
Non-infective endocarditis
Nonbacterial thrombotic endocarditis
Nonbacterial thrombotic endocarditis (NBTE) is a form of endocarditis in which small sterile vegetations are deposited on the valve leaflets. Formerly known as marantic endocarditis, which comes from the Greek , meaning "wasting away". The term ...
(NBTE) is most commonly found on previously undamaged valves.[ As opposed to infective endocarditis, the vegetations in NBTE are small, sterile, and tend to aggregate along the edges of the valve or the cusps.][ Also unlike infective endocarditis, NBTE does not cause an inflammation response from the body.][ NBTE usually occurs during a hypercoagulable state such as system-wide bacterial infection, or pregnancy, though it is also sometimes seen in patients with venous catheters.][ NBTE may also occur in patients with cancers, particularly mucinous adenocarcinoma][ where Trousseau syndrome can be encountered. Typically NBTE does not cause many problems on its own, but parts of the vegetations may break off and embolize to the heart or brain, or they may serve as a focus where bacteria can lodge, thus causing infective endocarditis.][
Another form of sterile endocarditis is termed Libman–Sacks endocarditis; this form occurs more often in patients with ]lupus erythematosus
Lupus erythematosus is a collection of autoimmune diseases in which the human immune system becomes hyperactive and attacks healthy tissues. Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blo ...
and is thought to be due to the deposition of immune complexes.[ Like NBTE, Libman-Sacks endocarditis involves small vegetations, while infective endocarditis is composed of large vegetations.][ These immune complexes precipitate an inflammation reaction, which helps to differentiate it from NBTE. Also unlike NBTE, Libman-Sacks endocarditis does not seem to have a preferred location of deposition and may form on the undersurfaces of the valves or even on the endocardium.][
]
References
Further reading
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External links
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{{Authority control
Inflammations
Rodent-carried diseases
Valvular heart disease