The Pathophysiology of Rheumatic Heart Disease: How This Disease Affects Cardiovascular System Function

Rheumatic heart disease (RHD) is a severe complication occurring after a rheumatic fever (RF) episode. Rheumatic fever is an inflammatory disease that develops after being infected by the group A beta-hemolytic Streptococci bacteria. It is commonly seen in children 5 to 15 year old, although RF can also develop in adults.

Rheumatic fever usually starts as a simple sore throat, but its complications can be life-threatening. A number of acute RF patients may develop various degrees of carditis, an inflammation of the tissues of the heart, with accompanying valve insufficiency, pericarditis, heart failure and sometimes, even death. Patients with chronic RHD may also have valve stenosis or narrowing of the heart valves with various degrees of valve regurgitation, ventricular dysfunction and arrhythmias or irregular heart rhythms.

The cause of acute RF and RHD is still not clear, but it is thought to be an autoimmune disease.

Pathophysiology of Rheumatic Heart Disease

RF generally occurs in children and adolescents after an episode of upper respiratory tract infection (URTI) caused by the group A beta-hemolytic Streptococcus bacteria. The bacteria attach themselves to the epithelial cells of the respiratory tract and produce substances or enzymes that cause destruction to the surrounding tissues. Symptoms of the inflammatory process usually manifest after two to four days of incubation period and these include high fever, sore throat, headache, body weakness, and increase in WBC count. URTI caused by these bacteria are often contagious and spreads easily through oral and respiratory secretions. Most individuals who get treatment and those with strong immune systems usually recover from the infection without complications.

Some patients however, about 3% of them, may develop RF several weeks after the infection has resolved. A serious complication of RF is rheumatic heart disease.

It is believed that certain proteins produced by the group A Streptococci are structurally similar to those found in the heart. The immune system reacts to the presence of bacteria by producing specific substances, called antibodies, to attack them and stop their spread inside the body. But as these antibodies attack the bacteria, some of them also attack or cross-react with the tissues in the heart, and this often results in the manifestation of many RHD symptoms, like carditis, endocarditis, pericarditis and myocarditis. When the heart muscles are affected by inflammation, the result is myocarditis. Pericarditis occurs when there is inflammation of the sac that surrounds the heart, and endocarditis happens when the inner layer of the heart is involved in the inflammatory process.

Rheumatic Heart Disease Treatment

Treatment for rheumatic heart disease intends to get rid of the streptococcal infection, give relief to symptoms and prevent recurrence of the disease. Medications often given to patients include antibiotics, anti-inflammatory drugs and other medications to treat the heart problems.

References

emedicine: Rheumatic Fever

MamasHealth.com: Rheumatic Heart Disease