Rheumatic heart disease is caused by an inflammatory response to a group A streptococcal throat infection, which can damage the heart valves and cause them to leak or become obstructed. It most commonly affects children between ages 5-15 and is associated with poor living conditions and seasonal upper respiratory infections. Symptoms include fever, joint pain, and heart murmurs. Diagnosis involves throat cultures, blood tests, echocardiograms and x-rays. Treatment focuses on eradicating the infection, managing symptoms, and may include surgery to repair or replace damaged valves if medication is not effective.