Rheumatic heart disease

Rheumatic heart disease

Rheumatic heart disease is a group diseases which occur secondary to heart valve damage from a disease known as rheumatic fever. Rheumatic fever is a disease in which antibodies produced by the body against a bacteria known as streptococci cross react with cells in the body. Streptococci are bacteria which cause sore throat, often in children. Most of the long term damage in the body is caused by damage to heart valves following rheumatic fever. Initial manifestation of rheumatic fever is with pain and swelling of multiple large joints like knee, ankle and elbow. But it does not usually cause long lasting damage to the joints, though in the initial stage the joints are quite painful. Heart valve damage may be initially silent and manifest later with severe rheumatic heart disease.

Other likely manifestations of rheumatic fever are involuntary movements known chorea, small nodules under the skin and reddish rash at various parts of the body. Fortunately, joint pain and abnormal movements do not occur at the same time. Otherwise, it would have cause severe pain in the diseased joints. Usually the abnormal movements are a delayed manifestation of rheumatic fever while joint pain is an early manifestation. Nodules under the skin and reddish rash do not cause much problem to the child and usually disappear soon. Joint pains also subside sooner or later, even without treatment. But heart valve damage progresses most often, either slowly or rapidly.

In the initial stage of rheumatic fever, the heart valves are inflamed and may become leaky. Most commonly affected valves are the mitral valve and the aortic valve. Mitral valve is between the left upper and lower chambers of the heart. Aortic valve is between the lower left chamber of the heart and the aorta. Aorta is the largest blood vessel in the body, taking oxygenated blood to the whole body from the left ventricle. Left ventricle is the lower left chamber of the heart. It receives blood from the left atrium through the mitral valve and pumps to the aorta through the aortic valve.

Inflammation of the heart valves in rheumatic fever is known as rheumatic carditis. Occasionally inflammation of the heart muscle and its covering can also occur in rheumatic fever. These are called rheumatic myocarditis and rheumatic pericarditis respectively. Pericarditis can cause chest pain in children with rheumatic fever. When there is severe damage to the heart valves in the initial stage, producing severe leaks, some of them may develop heart failure with breathlessness. Breathlessness occurs when the heart is not able to pump out blood well. This leads to back pressure in the lungs and collection of fluid in the lungs known as pulmonary edema.

Long term damage to heart valves can occur in any of the four heart valves, though it is most common in mitral and aortic valves. The leaks in mitral and aortic valves may recover partly after the initial attack of rheumatic fever. Sometimes the leaks progress and produce heart failure. Very often it is a recurrent attack of rheumatic fever, which is not uncommon in developing countries, that causes more damage to the heart valves. That is why prevention of recurrence of rheumatic fever with regular long term antibiotic treatment is so important. If there is no recurrence of rheumatic fever valve damage in the initial phase may recover and become normal later.

Long term rheumatic heart disease occurs when the valve damage does not recover and progresses. The valves which are severely damaged and leaky initially, may become narrowed later. This causes obstruction to the flow of blood within the heart. When the mitral valve is obstructed, the medical term is mitral stenosis. Aortic stenosis is the medical term for narrowing of the aortic valve. Both are very important heart valve diseases which can occur secondary to rheumatic fever. Narrowing of both valves can cause breathlessness, more often with mitral stenosis. When aortic valve is obstructed, it can cause giddiness as the body does not get enough blood when one is exerting.

Tricuspid valve can be involved in rheumatic heart disease in two ways. Direct damage to the valve can cause leak or narrowing. Narrowing is called tricuspid stenosis. Tricuspid valve is the valve between the right upper and lower chambers of the heart. Another way of involvement of tricuspid valve is by increase in the pressure in blood vessels of the lungs. When the mitral valve is narrowed, back pressure is transmitted to the lungs. Pressure in the blood vessels of lungs increase and cause increased pressure in the right ventricle. Right ventricle is the lower right chamber of the heart which pumps blood to the lungs. When the pressure in the right ventricle rises too much, tricuspid valve is unable to hold on and becomes leaky. It leaks blood back into the right atrium, the right upper chamber, when the right ventricle contracts.

Disease of the tricuspid valve increases pressure in the right atrium and in the veins draining blood to the right atrium. Veins are blood vessels returning blood to the heart for transmission to lungs for oxygen enrichment. When pressure in the veins rise, it manifests as enlarged veins in the neck. Increase in back pressure causes enlargement of the liver, which can sometimes produce pain in the right upper part of the tummy. Fluid may collect under the skin of the legs due to the back pressure. In severe cases, fluid may also collect in the tummy, known as ascites.

Pulmonary valve is the least commonly involved valve in the rheumatic process. But it can become leaky like the tricuspid valve, even without damage due to rheumatic fever. As in case of tricuspid valve, when the pressure in the blood vessels of lungs rise pulmonary valve is unable to hold on and becomes leaky. Increase in pressure of blood vessels of lungs is known as pulmonary hypertension. Leak in pulmonary valve is known as pulmonary regurgitation. Leak of any valve is named like that by adding the term regurgitation, after the name of the valve. Pulmonary valve is the valve which normally prevents back flow of blood from pulmonary artery to the right ventricle. Pulmonary artery is the blood vessel which takes blood from right ventricle to the lungs for oxygenation. Very rarely, pulmonary valve can also be narrowed in rheumatic heart disease.

Severely narrowed heart valves will have to be opened either by balloon dilatation or by surgery. Sometimes they may have to be repaired or replaced with an artificial valve by open surgery. Balloon dilatation is the procedure of enlarging narrowed valves using sturdy balloons attached to thin tubes known as balloon catheters. These are introduced through blood vessels in the groin and guided to the heart under continuous X-ray imaging. Once across the narrowed valve, balloon is inflated to relieve the obstruction in the valve. The device is then removed from the body. Long term medications to prevent recurrence of rheumatic fever have to be continued even after this treatment. Balloon dilatation is routinely done for rheumatic mitral stenosis with good results and occasionally for tricuspid stenosis. The procedure may be better avoided if there is significant leak in the valve in addition to narrowing.

Heart valves which have severe leak are usually repaired by open surgery or more often replaced. This is because heart valves damaged by rheumatic fever are seldom suitable for repair. If a mechanical heart valve is placed, regular medications to prevent formation of blood clots in them will have to be taken long term. Regular monitoring of blood clotting function is needed in that case to prevent bleeding and check effectiveness. Though new procedures for repairing heart valves using devices introduced through blood vessels without surgery have come up recently, they are not ready for use in rheumatic heart disease. This is for the same reason mentioned in case of surgical repair, the damage and distortion in valve structure often make these procedures unsuitable for rheumatic heart disease. Moreover, being new technologies, they are very costly, beyond the reach of patients with rheumatic heart disease located mostly in underprivileged regions of the world.