Rheumatic fever (RF) in turn is a complication to infection with the bacteria by name group-A beta hemolytic streptococci; and usually develops one to few weeks after streptococcal throat infection (rarely scarlet fever, a skin disease).
It is considered to be an autoimmune disease meaning the body’s immune system; instead of helping the body paradoxically attacks it.
During the streptococcal infection certain antibodies are formed and they cross react with various tissues in the body including heart, brain, joints, skin etc and can damage these structures.
Frequency & distribution
Rheumatic fever mostly affects children especially around age 5 and 15. It predominantly occurs in developing countries particularly when there is a prolonged overcrowding of people e.g. low socioeconomic families.
Classification of RHD
Although this classification is not universally used, for the convenience of discussion RHD may be generally divided into two types as below;
- * Acute &
- * Chronic types.
Acute RHD presents as a manifestation of rheumatic fever, it is called as rheumatic carditis, and it is one of the major Jones criteria for the diagnosis of rheumatic fever.
The chronic type is not a new disease as such and it is the long term complication related with any residual cardiac damage especially the valvular damage and generally it begins manifesting few to several years after the acute attack.
Recurrent streptococcal infection may occur in some patients especially those who do not take long term penicillin antibiotic and results in accruing of additional damage to the valves.
More about RHD
It is a pan-carditis meaning it usually involves all three layers of heart. The inflammation of the three layers of the heart, the pericardium, myocardium & endocardium are respectively called as pericarditis, myocarditis & endocarditis.
The acute rheumatic pericarditis and myocarditis are most often self limiting illnesses and resolve without any sequelae. However patients are not that lucky with the endocarditis as many of these patients develop valvular abnormalities; and even after the acute attack is over the residual or progressive valvular dysfunction can compromise the functioning of the heart and may even result in death if not intervened appropriately.
The acute attack passes away with general & supportive care although some patients may develop heart failure, serious cardiac arrhythmias and even death.
As pointed out above chronic RHD is a result of prior episode of the rheumatic carditis especially the endocarditis and its valvular complications. There are total four heart valves; they are named as below and in the bracket their relative involvement in RHD is shown;
- * Mitral (commonest)
- * Aortic (next common)
- * Tricuspid
- * Pulmonary (least common)
The initial damage to the valves may occur at their cusps, or the chordae tendinae structures or both. This initial endocarditis causes an inflammatory reaction resulting in anatomical changes in these valves and they do not function properly as a result of this.
The valves either become stenotic (narrow) or leaky and this alters the normal blood flow pattern from one chamber of the heart to another or from the heart to aorta or pulmonary artery. This will overburden the heart muscle and results in a chronic malfunctioning.
Also recurrent streptococcal infections might add on more valve damage, and if that happens, it will only hasten the deterioration of the functioning of the heart.
As the heart function and the blood flow patterns change certain serious consequences might develop including; left atrial dilatation, clot or thrombus development in that chamber, cardiac arrhythmias, abnormal thickening and or dilatation of different heart chambers and the complications like heart failure.
The clot formed can break up and the fragments can get pumped out of the heart and block the arterial circulations resulting in stroke etc.
The cardiac arrhythmias can also contribute for the formation of the clot and heart failure. Infective endocarditis is another serious and life threatening complication of chronic RHD.
The diagnosis of RHD is both clinical and investigational and it can be discussed at three levels including;
- Acute RF/RHD
- Chronic RHD
- Complications related with chronic RHD
Acute RF/RHD stage:
Antibody titers (e.g. ASO titers)
Blood tests (discussed under Jones criteria)
When the patient already has presented with acute RHD/rheumatic fever stage the streptococcal infection has been resolved most often. So throat swab to look for streptococcal bacteria is not always going to help.
However the bacteria may continue to harbor the throat even after the throat symptoms have subsided so it is worth trying.
Certain antibody tests like ASO titer may be of some assistance too. These antibodies generally appear in the blood within several day of a streptococcal infection and the titer rises gradually for about a month or so.
Then the titer remains stable for few months and finally returns to normal gradually within a year or so.
If the titer is performed early in the disease, and repeated a couple of weeks later, and if a rise in the titer can be demonstrated it is highly suggestive of recent streptococcal infection.
ECG studies the electrical activities of the heart. Although no diagnostic ECG changes are seen however the presences certain ECG changes as below indicate the involvement of the heart;
- Tachycardia (fast heart rate)
- Bradycardia (slow heart rate)
- Prolonged PR interval
- ST segment elevation if pericarditis is present
Echocardiogram is an ultrasound investigation and used to check the real time images of the heart muscle, heart chambers, valve structures and motion blood flow etc. It is an extremely invaluable investigation for the evaluation of RHD/RF.
For the proper diagnosis of acute RF, revised Jones criteria needed to be employed and there are major & minor criteria as below.
- * Arthritis
- * Carditis
- * Sydenham’s chorea
- * Subcutaneous nodules
- * Erythema marginatum
- * Fever
- * Raised ESR
- * Raised C reactive protein
- * Arthralgia (minor joint pain without swelling)
- * Prolonged P-R interval (on ECG)
The arthritis characteristically involves the large joints of the limbs and usually migrates from one joint to the other. Rheumatic carditis discussed along with acute rheumatic heart disease.
Chorea is the term used for certain characteristic rapid, purposeless involuntary movements of the limbs and face and affects girls more than the boys.
The rheumatic nodules develop under the skin due to collections of connective tissue like collagen and are typically painless and occur on the back of the elbow, wrists and front aspect the knee joints.
The skin rash involves the arms or the trunk which spreads outwards with a pink serpiginous margin and a fading center.
For the diagnosis of acute rheumatic fever you need;
- * Two major criteria OR
- * One major criterion plus two minor criteria AND
- * Evidence for a recent streptococcal infection in the form of one or all of following;
Throat swab positive for streptococci
Raising ASO tires
History of scarlet fever
The presence of rheumatic chorea or indolent carditis can be themselves considered as suggestive of rheumatic fever and do not require other points mentioned with Jones criteria.
Chronic rheumatic heart disease stage:
- * Echocardiogram
- * ECG
- * Cardiac catheterization etc
The role of ECG & echocardiogram is as discussed above. During cardiac catheterization a catheter is passed in to the heart chambers and the anatomy and functioning of the heart valves and other structures studied.
Stage of chronic RHD complications: It is not a distinct stage by itself rather overlaps with the stage of chromic RHD and the complications include;
- * Left atrial dilatation
- * Clot in the heart
- * Cardiac arrhythmias
- * Endocarditis etc.
These conditions are diagnosed by using ECG, echocardiogram, blood cultures etc as necessary.
Management of RHD can be dealt at acute RF & chronic RHD levels.
Acute RF/RHD management;
- * Bed rest
- * Aspirin for pain, fever & inflammation of joints
- * Penicillin antibiotic
- * If chorea is present treat with appropriate medications
- * If heart failure or arrhythmia develops treated accordingly
Penicillin is the antibiotic of choice for streptococcal throat infections. At the time acute RF diagnosis majority of the times the sore throat is better however a course of penicillin is still generally recommended as the bacteria may be still present in the throat and it can spread to close contacts.
Penicillin prophylaxis is recommended for patients who had rheumatic fever; and how long or how often etc depend upon how much heart damage is present.
Rheumatic fever has a tendency to recur and such recurrences increase the chances of additional heart valve damage so it is of paramount significance to take penicillin, or a suitable alternative if penicillin allergy is present, for the recommended duration.
Management of chronic RHD & its complications includes (on a case-by-case basis)
- * Valvular surgery (e.g. replacement with a prosthetic valve)
- * Chronic blood thinner treatment
- * Treatment of heart failure
- * Treatment of cardiac arrhythmias
- * Prevention & treatment of infective endocarditis etc.