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INFECTIVE ENDOCARDITIS

What is Infective Endocarditis ?

Infective endocarditis is an infection of the lining (the endocardium) that covers the whole inside of the heart. It particularly affects the lining of the valves and abnormal structures like holes in the heart. The symptoms are similar to those of other infections: fever, sweating and weight loss with a sense of ill health. They may go on for quite a long time before the patient seeks medical help. There may be rashes and joint pains but the symptoms are often vague.

How does Infective Endocarditis occur ?

Infection usually affects heart valves that are already abnormal, for example those abnormal from birth or damaged by rheumatic fever in childhood. It can affect valves that have only a minor abnormality. Artificial heart valves, used to replace a patient's diseased ones, are also more prone to become infected. Occasionally, it may happen to a normal valve with a particularly aggressive germ. It may also occur in congenital heart disease. To affect a valve, the germs must enter the bloodstream. This may be through the gums during dental treatment or the skin with a skin infection. Additional routes of entry include the chest, the urinary bladder, or the bowel. Germs only enter if there is something abnormal or when instruments are passed into the body for investigation. Sometimes, we do not know how they enter.

Why does Infective Endocarditis occur ?

Prevention, here, is much better than cure. For most people known to be at risk, only a single dose of antibiotic is required. This is given just before dental treatment, surgery or an investigation which carries the risk. Penicillins are most frequently used, or erythromycin in people who are allergic to penicillin. Patients with an artificial valve or who have endocarditis previously need more powerful antibiotics given through a vein. Some people are unaware of a minor valve abnormality and therefore cannot avoid the risk. It should be discovered, however, on a routine medical examination when the doctor listens to your heart with a stethoscope. A card should be carried which gives important information such as details of the heart or valve abnormality and the recommended antibiotic. Show it to any doctor or dentist consulted.

Treatment Involved for Infective Endocarditis

DIAGNOSIS A blood culture allows a definite diagnosis to be made. For this test, several blood samples are taken over a 48-hour period. The blood is injected into special culture bottles and incubated in a low-temperature laboratory oven. Any bacteria that grow are tested for the most suitable antibiotic. The diagnosis must be suspected or the test may not be done. Any antibiotic taken beforehand makes it difficult to grow any bacteria. Echocardiograms are also valuable. This uses ultrasound (high frequency sound) to produce a television image of the heart. The germs may actually be seen growing in what are called vegetations on a valve. TREATMENT Antibiotics are essential. They must be given in high dose for a long period if all germs are to be killed. Since high doses by mouth will often cause diarrhoea, antibiotics are given through a vein by drip. A large vein near the base of the neck is often used as the antibiotics may inflame small veins. The treatment, therefore, has to be administered in hospital for 2 to 6 weeks. Shorter courses may be followed for a few weeks with a lower dose by mouth after discharge from hospital. Unless these guidelines are followed there will probably be a relapse. PREVENTION It is essential that you take antibiotics whenever you are at risk. This includes dental treatment if there is any chance that it may draw blood. Antibiotics are needed for most types of surgery, most other infections, and childbirth. They are also needed for investigations where instruments are passed into the body especially into the rectum or urinary bladder. Diagnosis and treatment of the condition are difficult; prevention is much easier, if you are known to be at risk.

During Treatment for Infective Endocarditis

The treatment will be given in hospital. The doctors will watch for complications of infection and side-effects of the antibiotics. Because the germs grow in the bloodstream there is a small risk that they might break free and float to other parts of your body. If this is a serious risk, the doctor may advise an operation to replace the valve and remove the infection (heart valve replacement). Surgery might also be needed if infection is not completely controlled by antibiotics. Damage to the valve may strain the heart and cause heart failure; this may be another reason for valve surgery.

After Treatment for Infective Endocarditis

Usually, the antibiotics will get rid of the infection. There is always a small possibility, however, that it will return. You should keep a watch for a recurrence by taking your temperature and noting any return of symptoms. Medical advice should be sought quickly if there is any suspicion. Sometimes infective endocarditis causes a valve leak Therefore, symptoms of heart failure should be watched for over the following weeks or months. The symptoms of heart failure are breathlessness and swelling of the feet and ankles. If there is little damage to the heart, life may not be affected. Later on, it will be necessary to have regular check-ups with the doctor, perhaps once per year. Most importantly, you must take antibiotics every time a risk of further infection occurs.

If Infective Endocarditis is Left Untreated

Treatment with antibiotics is the only treatment and is essential. The condition is invariably fatal if it is not treated.

Effects on Family of Infective Endocarditis

Valve damage may decrease your ability to undertake physical activity. Most people find that they are able to do what they wish at a slightly slower pace. Your family should recognise this slight restriction on your activities. There may have been very little damage to the valve, in which case exercise can be taken normally.