Endocarditis is an inflammation of the inner layer of the heart. Bacterial (bacterial endocarditis) or severe immune reactions (rheumatic endocarditis) are usually the reason for the inflammation. Endocarditis can cause scarring and growths on the inner layer of the heart, and damage the heart's valves.

Overview of endocarditis

The inner lining of the heart, also known as the endocardium, is the innermost layer of the heart. It consists of a thin layer of tissue that lines the inner chambers of the heart and extends over the heart valves. The endocardium is very smooth, which supports the unimpeded flow of blood through the heart and prevents the formation of blood clots.

Endocarditis is an inflammation of the endocardium. A distinction is made between infective and non-infective endocarditis.

Causes and risk factors

The causes of endocarditis can vary in nature and differ depending on whether it is an infective or non-infective form.

Causes and risk factors of infective endocarditis

Infective endocarditis is mainly caused by infections with microorganisms, especially bacteria, which enter the bloodstream and colonise the endocardium, particularly the heart valves. More rarely, fungi or viruses can also trigger the infection. The following risk factors may lead to the development of infective endocarditis:

Heart valve diseases

Heart valve diseases increase your risk of developing endocarditis. Damage to, or a malfunction of, the heart valves can make them susceptible to colonisation by microorganisms, which leads to inflammation of the endocardium.

Prosthetic heart valves

Artificial heart valves, which are used to treat valve diseases, pose a higher risk of endocarditis as they are foreign bodies that can be more easily colonised by bacteria.

Intravenous drug use

Intravenous drug use is a risk factor for the development of infective – especially bacterial – endocarditis. By injecting drugs directly into the bloodstream, bacteria and other microorganisms can easily enter the body. People who inject drugs can often use unclean needles or contaminated substances, which increases the risk of infection. However, for patients who have been prescribed medication via intravenous injections, it is also important that the injection materials are sterile in order to minimise the risk of infection.

Weakened immune system

People with a weakened immune system, whether due to HIV/AIDS, cancer treatment, diabetes or other diseases, are more susceptible to infections and therefore have an increased risk of developing endocarditis. 

Medical interventions

Surgical interventions, especially on the heart, but also dental treatments and other invasive procedures can introduce bacteria into the bloodstream.

Causes of non-infective endocarditis

Non-infective endocarditis occurs without the influence of microorganisms and can be caused by rheumatic fever, congenital heart disease or an autoimmune disease. It occurs when fibrous blood clots that do not contain microorganisms (sterile vegetations) form on damaged heart valves.

Systemic lupus erythematosus (SLE)

SLE is characterised by an excessive immune response in which the immune system attacks the body’s own tissue and causes inflammatory reactions. This inflammation can also affect the endocardium and lead to sterile vegetations forming on the heart valves, also known as Libman-Sacks endocarditis.

Rheumatoid arthritis

Rheumatic endocarditis is caused by the body’s excessive immune response following an infection with streptococcal bacteria (rheumatoid arthritis). This immune response, known as rheumatic fever, then leads to inflammation of the inner lining of the heart or in the kidneys.

Herz-Patient mit Angina Pectoris

Disease progression

The progression of the disease can vary greatly depending on the type of infection and the individual reaction of the body. Infective endocarditis typically begins with the colonisation of the heart valves by bacteria, fungi or, more rarely, viruses. This or the formation of fibrous blood clots without the presence of microorganisms in non-infective endocarditis leads to an inflammatory response in the endocardium and to the formation of vegetative deposits. In the acute form, symptoms such as fever, chills, fatigue and heart murmurs often occur quickly and can be severe. In the subacute form, the symptoms develop gradually and may be less pronounced. If left untreated, endocarditis can lead to serious complications, which, in the worst case, can be fatal. These include valvular insufficiency or regurgitation, septic emboli causing a strokeor pulmonary embolism, and sepsis.

Endocarditis symptoms

Endocarditis has many different symptoms which vary depending on the type of disease, whether it is infective or non-infective. A distinction is also made between acute and subacute endocarditis, as the symptoms can vary depending on the course of the disease.

Acute endocarditis

Acute endocarditis is characterised by the sudden onset of symptoms and rapid progression of the disease. Those affected often have the following symptoms:

  • High fever (often over 39 degrees Celsius)
  • Chills
  • Fatigue and weakness
  • Abnormal heart sounds
  • Shortness of breath
  • Oedema
  • Weight loss
  • Loss of appetite
  • Palpitations (tachycardia)

Subacute endocarditis

Subacute endocarditis is characterised by a slower, more gradual progression of the disease and the symptoms may be less pronounced. Those affected often have the following symptoms:

  • Mild fever (but usually below 39 degrees Celsius)
  • Slight increase in heart rate
  • Pain in the limbs
  • Night sweats
  • Generally feeling unwell

Subacute endocarditis can be more easily missed as the symptoms are less specific and less dramatic than in the acute form. However, early diagnosis and treatment are crucial in order to avoid serious complications such as valvular insufficiency or emboli.

Diagnosis

The diagnosis of endocarditis is usually made by a cardiologist, often in collaboration with an infectious disease specialist, and usually involves clinical examinations, laboratory tests and imaging techniques:

Clinical examination

The doctor first takes the patient’s medical history and determines which symptoms are present, such as fever, heart murmur or other signs of possible endocarditis. In addition, an auscultation is performed in which the doctor listens to the heart with a stethoscope in order to detect any abnormal heart sounds.

Blood tests

A blood sample is usually taken from the patient to detect bacteria or other microorganisms in the blood. This helps to identify the pathogen and select suitable antibiotics for treatment.

Echocardiography

Echocardiography (cardiac ultrasound) is an essential imaging technique for diagnosing endocarditis. The procedure allows medical staff to identify vegetations on the heart valves, determine their size and position, and evaluate how well the heart valves are working.

Treatment

Treatment of endocarditis depends on whether it is infective or non-infective, which pathogen is causing the disease and how severe the symptoms are. In general, treatment includes the following measures:

Antibiotic therapy

Both bacterial endocarditis and rheumatic endocarditis require long-term antibiotic treatment.  The kind of antibiotic used depends on the pathogen identified and the results of the blood samples. Anti-inflammatory medication may also be used.

Surgery

Surgical and interventional treatment options  can be used to repair or replace infected heart valves in the event of damage to the heart valves and heart valve disease.

Symptomatic therapy

Supportive measures such as antipyretic (fever-reducing) medication can be used to alleviate symptoms such as fever or pain.

Prevention

Prevention of endocarditis aims to reduce the risk of endocardial infection, especially in people at increased risk owing to predisposing factors such as heart valve disease or invasive medical procedures.

Prophylactic antibiotics (endocarditis prophylaxis)

In high-risk patients, preventive antibiotics should be administered prior to certain invasive medical procedures that may increase their risk of bacteraemia. This applies to surgical procedures carried out in the mouth and throat area, but also to dental treatment. The following conditions make you a high-risk patient:

  • Previous case of endocarditis
  • Critical congenital heart disease
  • Heart valve replacement or heart valve reconstruction
  • Heart transplant with valve disease

Further preventive measures

Further preventive measures include good oral hygiene to reduce the risk of bacteraemia caused by gingivitis or dental procedures. For patients who are dependent on intravenous injections, it is important that the injection materials are sterile in order to minimise the risk of infection. Regular medical check-ups are also crucial for patients with known risk factors such as previous cases of endocarditis or congenital heart disease in order to identify and treat potential sources of infection at an early stage.

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