Tissue made of endothelial cells line the inner surface of everybody organ, including the heart. The exquisitely sensitive and complex endothelium in the heart, called the endocardium, smoothes our over large surfaces and pinches up to form and line the heart valves. Normally, the endocardium is resistant to infection. However, if a valve has been injured or damaged, the body sends our platelets and fibrin to heal the scar over the area. Plotelets are blood cells that form clots, a normal part of healing; fibrin is a body protein that helps in the clotting process. In people with valve damage, this attempt at self healing may lead to infective endocarditis, because the thrombocyte-fibrin conglumerate is a magnet for any microorganisms circulating in the blood stream.
Infective endocarditis is an infection of the endocardial living of heart valves (native or prosthetic) chambers or vascular endothelium. Infective endocarditis is a different disease than it was in the past. Previously, it was called subacute or acute bacterial endocarditis because the most common and almost exclusive cause of an infected endocardium was bacterial, usually group a strep. Today, the endocardium can become infected by many types of bacteria as well as by other types of microorganisms, including viruses and fugi. So the name subacute or acute bacterial endocarditis no more exists and has been replaced by infective endocarditis.
Endocarditis often cause no symptoms. At every moment, the body is host to bacteria and other microorganisms and the immune system nearly always prevents them from multiplying sufficiently to cause infection. But as microorganisms gather on the scarred area of a valve, they can increase in number and cause an infection that damages the valve.
Symptoms which are occasional :
- Persistent or intermittent fever
- Unusual tiredness
- Malaise, anorexia, weight loss and backage may be present.
Some delayed features may be
a) Cerebral embolic manifestations (15 percent) haemiplagia, paraplagia
b) Systemic embolic manifestations (7 percent)
1) Anaemia, 2) Changing murmur may be present, 3) Shifting apex beat due to heart enlargement, 4) Signs of heart failure (40-50 percent), 5) Conduction disorder (10-20 percent), 6) Haematoria (60-70 percent), 7) Petachiol haemorrage (40-50 percent), 8) Spkinter (nail bed) haemorrhage (10 percent), 9) May also present clubbing (10 percent), Osler node (5 percent), roth spot (5 percent).
It is important that all infections in the body be treated early and completely, even in people who appear healthy. Often, a person who develops infective endocarditis does not recall having had a tooth abscess or skin infection. However, he or she could have had a minor injury (and unnoticed) to the mucous membranes lining the mouth, the gastro-intestinal system, or the genitourinary system, which allowed bacteria to enter the body and attack the endocrdium. The infection the heart progresses silently and may not be recognised until symptoms arise.
Groups at risk for infective endocarditis :
At particular risk for developing endocurditis are people who have heart valve structural abnormalities or prosthetic valves or are intravenous drug users.
A person with infective endocarditis may show a variety of symptoms depending on what parts of the heart are infected. The most common symptoms are fever, weight loss, red marks on the skin and fingernails, heart murmurs and liver enlargement. Chills and night sweats are common.
Investigations to be done are
1. Blood for
HB percentage (usually decreased)
ESR (Usually increased)
Clture - atleast 3 samples to be taken at 2-3 hours interval (to idenify bacteria)
C-reactive protein - increased.
2. ECG - to see conduction defect
3. X-ray chest to find any under lying cause of heart disease.
4. Doppler echocardiograpy - It is the most important diagnostic test to confirm infective endocarditis. If doppler echocadiography does not clearly show the damage, other tests may be ordered, including cardiac nuclear scanning and MRI.
A. Antimicrobial treatment is the best way to start. Treatment should be according to sensitivity. But empirical regimens for endocarditis which culture results are awaited should include agents active against common pathogenic organisms. Such as regimen is : Nafcillin or Oxacillin 1.5gm every 4 hours plus injection penicillin G 2-3 million units every 4 hours, plus gentamycin 1 gm/kg every 8 hours. (Vancomycin may be used in penicillion sensitive patients)
When the culture results are available treatment should be given according to sensitivity.
Indication for surgery
- Valve rupture
- Intractable cardiac failure
- Resistant infection
- High relapse rate.
1. Ensure and maintain good dental health.
People at risk for infective endocarditis are advised to maintain good care of their teeth and gums including regular dental checkups. Some research shows, however, that people with valve abnormalities avoid regular dental checkups and cleaning for fear that it will place them at risk of infection. In so doing, they are increasing the chance they will develop dangerously high levels of bacteria in their mouths.
Careful, gentle and meticulous daily oral hygiene and frequent visits to the dentist are necessary to prevent endocarditis in people who are of risk of this infection, but brushing too vigorously or using a toothpick on high pressure water cleaning device can drive these bacteria into the bloodstream and lead to endocarditis.
Antibiotics are often prescribed before and after dental procedures to prevent the spread of bacteria to the damaged valve.
2. Operation on GI tract or Urinary Tracts Antibiotic cover before and after procedure recommended.
Further Reading :
- American heart association: Infective Endocarditis : http://www.americanheart.org/presenter.jhtml?identifier=4436
- Diagnosis and Management of Infective Endocarditis and Its Complications : http://circ.ahajournals.org/cgi/content/full/98/25/2936
- Infective Endocarditis in Adults — New England Journal of Medicine (NEJM) : http://www.nejm.org/doi/full/10.1056/NEJMra010082
This Article is Submitted By: DR. MASWOODUR RAHMAN PRINCE
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