what is endocarditis?

The heart consists of the heart wall and four cavities (the two atria and the two heart chambers) in which the incoming blood is collected and pumped on. So that the blood flow is directed in the intended direction, the heart also has four heart valves, which serve as valves.

If an inflammation of the endocardium to designate this as doctors endocarditis. The infection destroys tissue areas in the inner lining of the heart. It usually arises on the heart valves, but can also occur in the heart cavities.

The inflammation of the lining of the heart is mainly caused by an infection with bacteria. Doctors call this bacterial endocarditis . In rare cases, viruses or fungi can also be the trigger, in which case it is a viral endocarditis or mycotic endocarditis .

The pathogens usually attack one or more heart valves and cause inflammation there. The most common areas affected are the heart valve between the left atrium and the left ventricle, the so-called mitral valve, and the heart valve that directs the blood into the main artery, the so-called aortic valve . This is known as mitral valve endocarditis or aortic valve endocarditis.

If the heart valves are damaged, they no longer close properly and the heart can no longer properly pump blood into the circulation. This can lead to heart failure ( heart failure ). Endocarditis can have dangerous consequences in other parts of the body as well. Blood clots can form on the valves, which are carried along with the bloodstream and cause a life-threatening embolism in other organs.

Forms of endocarditis: acute and subacute endocarditis

Depending on how aggressive the pathogens are (doctors call this virulence) and how well the person's immune system works, infectious endocarditis progresses faster or slower. Doctors distinguish between two forms of progression:

• The acute course (so-called endocarditis acuta), in which the patient's condition rapidly deteriorates.
• The subacute course (so-called endocariditis lenta), in which the symptoms develop gradually (over several weeks).

In addition to infectious endocarditis, there are other, albeit less common, forms of cardiac inflammation. These include:

• rheumatic endocarditis
• Libman-Sacks endocarditis, which occurs with systemic lupus erythematosus
• the Löffler endocarditis (endomyocarditis eosinophilica)
• Tumor diseases

It can also happen that non-infectious endocarditis develops first and then bacteria colonize the damaged tissue site. In this case, doctors speak of a superinfection. 

frequency

Around 1,700 people die from endocarditis every year. It mainly affects older people aged 50 and over; men are twice as likely to develop it as women.

Endocarditis: causes

Heart inflammation is mostly caused by bacteria, rarely viruses or fungi are the trigger. If the pathogens get into an intact endocardium, they usually cannot attach themselves to the smooth inner skin of the heart and do not cause any damage. Only occasionally does it happen that an infection develops in healthy heart valves.

The situation is different if the heart is already damaged and there are small injuries to the inner lining of the heart. Then germs can settle there more easily and cause inflammation.

This is the case when a person:

• has a congenital or acquired heart defect
• has a damaged heart valve
• has already had heart surgery
• a foreign body has been insert into the heart (e.g. an artificial heart valve, a pacemaker, a defibrillator). Doctors refer to this as prosthetic endocarditis.

Those who have received long-term antibiotic therapy also have an increased risk of endocarditis. This also applies to patients who have a weakened immune system (e.g. due to diseases such as HIV or immunosuppressants, e.g. in the case of an autoimmune disease or after an organ transplant).

Endocarditis: common pathogen

Acute endocarditis is usually caused by staphylococci , whereas a subacute variant is mainly caused by streptococci . Sometimes other bacteria such as enterococci, viruses or fungi such as Candida and Aspergillus can also be the trigger.

The risk of endocarditis is generally greatest when bacteria get into the bloodstream . This can happen:

• if there is injury to the skin, mucous membrane or gums
• if there is a focus of inflammation in the body (e.g. periodontitis )
• if there is an operation in which germs penetrate the organism
• if pathogens get directly into the blood through infected intravenous catheters or contaminated needles when injecting drugs.

Endocarditis: non-infectious causes
In addition to the infection, there are other factors that can trigger endocarditis:

• the rheumatic endocarditis is the most common non-infectious triggers of endocarditis. It develops as a result of a rheumatic fever, which in turn is caused by an infection with streptococci (such as an inflammation of the tonsils or throat). The immune system then not only attacks the pathogens, but also mistakenly the body's own cells, for example in the joints and the inner lining of the heart, and triggers inflammation there. The heart valves are often affected.
• the Libman-Sacks endocarditis , which erythematosus occurs in systemic lupus. This is an autoimmune disease in which fibrin (a protein that is made when blood clots) builds up on the heart valves and causes inflammation.
• the Loeffler endocarditis (Endomyocarditis eosinophilica), it comes in to a strongly increased production of certain white blood cells (eosinophils). These can be deposited on the inner lining of the heart and form thrombi there. As a result, the endocardium thickens and is less elastic. As a results, the heart can no longer expand enough and its ability to pump is weakened.   
• some tumors can also damage the heart and lead to endocarditis.

 

Endocarditis: symptoms

Symptoms differ depending on their cause and the course of the endocarditis. The following symptoms occur with infectious endocarditis :

• Fever (in the acute form mostly over 39 degrees, in the subacute form usually not over 38 degrees), chills
• Night sweats (especially in the acute form)
• abnormal, changed or increased heart sounds as well as racing heart ( tachycardia )
• Anemia (noticeably pale)
• Feeling weak, tired
• Loss of appetite and weight loss
• shortness of breath
• impaired kidney function or enlargement of the spleen
• Pinhead-sized skin hemorrhages (petechiae) as well as lenticular, painful, reddened, inflamed skin nodules (Osler nodules), which occur mainly on the fingers and toes, or small, painless reddish spots or lumps in the palms of the hands or soles (Janeway lesions)
• Rounded hemorrhages in the eye (Roth spots), retinal vascular occlusions

For non-infectious causes, the symptoms may be slightly different. In the case of rheumatic fever, for example, in which the immune system of an affected person mistakenly fights the cells of the inner lining of the heart, the symptoms usually only appear two to three weeks after the actual infection (for example after tonsillitis ). The following symptoms can occur:

• painfully stiff and swollen joints and joint pain (which typically travel from joint to joint)
• Cardiac arrhythmias
• Racing heart
• Shortness of breath
• a reddish, blotchy rash

Endocarditis: diagnosis

First of all, the doctor asks about the patient's medical history (anamnesis) and asks, among other things, whether he has an increased risk of endocarditis. The risk patients include people:

• who have had an impaired heart valve surgically restored (a so-called heart valve reconstruction) or who have an artificial heart valve
• who have a congenital or acquired heart defect (and have had surgery or catheterisation in the past six months)
• who have a pacemaker
• who have had infectious endocarditis before.

In addition, the doctor asks whether the patient has had other surgical interventions recently, for example at the dentist. Whether he has had previous infections, whether he suffers from an autoimmune disease and whether he uses drugs.

This is followed by a physical examinations, during which the doctor listens to the heart and checks whether there are any abnormal heart murmurs. He can also check the skin for suspicious symptoms such as small bleeding and scan the liver and spleen for any enlargement.

If he suspects endocarditis, he will do an ultrasound scan of the heart called an echocardiography. It is a very important element of the diagnosis, with its help the doctor can recognize the size and structure of the heart chambers and heart valves and any changes there.

There are two variants of the examination : the doctor can look at the heart through the chest (so-called transthoracic echocardiography, TTE for short) or guide a thin tube with an ultrasound head through the esophagus to the vicinity of the heart and push it up to heart level (so-called transesophageal Echocardiography, TEE for short or also called "swallowing echo").

If abnormalities arise, further examinations usually follow, such as computed tomographic angiography (CTA for short). With this imaging method, the condition of the (artificial) heart valves can be precisely assessed and existing abscesses can be discovered.

Other imaging methods that can be used are magnetic resonance tomography ( MRT ) and positron emission tomography ( PET- CT). With the help of a blood test, the doctor can also determine whether certain inflammatory values ​​(e.g. sedimentation rate and C-reactive protein (CRP)) are increased.

The second important element of the examination is the blood culture analysis. It provides information about whether certain pathogens are present in the body. A laboratory should carry out a longer incubation in order to be able to detect slowly growing bacteria. 

If no cause for the inflammation of the lining of the heart is found, other examination methods are used, such as a tissue sample from the lining of the heart (endocardial biopsy).

Endocarditis: therapy

If left untreated, bacterial endocarditis is usually fatal, so treatment must be started early. A team of cardiologists, heart surgeons and microbiologists decide which treatment is best for each patient. 

In order to select the right drug, the responsible pathogen must first be determined. If, for example, the bacterium is found, the doctor adjusts the antibiotic treatment precisely to this germ. This takes at least two to eight weeks and is usually given directly into the vein (intravenously).

Endocarditis: surgery

Antibiotic treatment is not sufficiently effective in about thirty percent of all patients with infectious endocarditis. Then an operation is usually unavoidable.

An operation is also necessary if the infection has developed through prosthetic material (such as an implanted artificial heart valve) or the natural heart valve is seriously damaged by the inflammation and heart failure develops. In the latter case, doctors remove the infected tissue and either reconstruct the natural heart valve or insert an artificial heart valve. Surgery is also performed if there is an abscess or if there are repeated embolisms. 

For non-infectious endocarditis, therapy is primarily to treat the underlying disease. In the case of rheumatic fever, for example, antibiotics are administered to eliminate the streptococci, and the reactions of the immune system can in turn be reduced with anti-inflammatory drugs.