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Friday, January 29, 2016

Rheumatic Heart Disease (RHD) ::


Rheumatic heart disease (RHD) is the most common acquired heart disease in children in many countries of the world, especially in developing countries. It is a chronic heart condition caused by rheumatic fever that can be prevented and controlled. Rheumatic fever is caused by a preceding group A streptococcal (strep) infection. Treating strep throat with antibiotics can prevent rheumatic fever. Moreover, regular antibiotics (usually monthly injections) can prevent patients with rheumatic fever from contracting further strep infections and causing progression of valve damage.
Facts
1. The global burden of disease caused by rheumatic fever and RHD currently falls disproportionately on children and young adults living in low-income countries and is responsible for about 233,000 deaths annually.
2. At least 15.6 million people are estimated to be currently affected by RHD with a significant number of them requiring repeated hospitalization and, often unaffordable, heart surgery in the next five to 20 years.
3. The worst affected areas are sub-Saharan Africa, south-central Asia, the Pacific and indigenous populations of Australia and New Zealand.
4. Up to 1 per cent of all schoolchildren in Africa, Asia, the Eastern Mediterranean region, and Latin America show signs of the disease.
Acute rheumatic heart disease
In the acute stages, all layers of the heart wall are inflamed (pancarditis, ‘pan-’ meaning ‘all of’). The heart valves, especially the mitral valve, are frequently affected. Fibrotic nodules develop on their cusps, which shrink as they age, distorting the cusp and causing stenosis and incompetence of the valve. The inflamed myocardium can fail, leading to signs of heart failure, including tachycardia, breathlessness and cardiac enlargement. Inflammation of the pericardium can lead to friction within the pericardial cavity as the heart beats, pain behind the sternum and interference with the pumping action of the heart. Permanent fibrotic damage may fuse the visceral and parietal layers of the serous pericardium together, restricting the heart’s action.
Chronic rheumatic heart disease
Inflamed tissue becomes fibrous as it heals, and this fibrous tissue interferes with the action of the myocardium and the heart valves. At least half of acute cases develop chronic valvular incompetence following recovery. The great majority of these patients have mitral valve damage, but the aortic valve is frequently affected too. Chronic fibrotic changes in the pericardium and myocardium cause heart failure. Sometimes rheumatic valvular disease presents with no history of acute rheumatic fever or streptococcal infection.