There is no single specific clinical manifestation or specific laboratory test that unequivocally establishes the diagnosis of rheumatic fever. Rather, there are a number of selective clinical findings, called Jones criteria, that make the diagnosis of acute rheumatic fever highly probable and necessitate discussing the clinical manifestations and the diagnosis together. Although the Jones criteria have been changed several times since their original publication, they have remained basically stable and are the accepted method by which the diagnosis of this disease is confirmed.

Major Criteria. Because the five major criteria are considered to be the most specific findings, more weight is given to major criteria.
 

CARDITIS

 This important finding in acute rheumatic fever is a pancarditis that involves the pericardium, epicardium, myocardium, and endocardium. Carditis is the only residual of acute rheumatic fever that results in chronic changes. Common manifestations include evidence of valvular insufficiency, most frequently affecting the mitral valve, but the mitral and the aortic valve may be affected. Isolated involvement of the aortic valve is rare. Tricuspid valve or pulmonary valve involvement is unusual. Valvular insufficiency is present in the acute state of the disease. Later, in the chronic stage, scarring of the valve with either typical "fishmouth" abnormality or even calcified valve tissue may lead to stenosis. Often there is a combination of insufficiency and stenosis. Carditis occurs in 40{endash}–80% of patients with rheumatic fever. In the recent outbreaks in the United States, more than 80% of patients in one of the large series had evidence of carditis.

 

Other manifestations of carditis include pericarditis, pericardial effusion, and arrhythmias (usually 1st-degree heart block, but 3rd-degree or complete heart block may occur). The carditis of rheumatic fever may be mild or very severe, leading to intractable heart failure; rarely, surgical intervention, even in the acute stage of the disease, may be necessary if medical management cannot control the heart failure. These patients usually have myocardial involvement and significant valvular insufficiency.

 

POLYARTHRITIS

This is the most confusing of the major criteria and probably leads to more diagnostic errors than any of the other manifestations. The arthritis of acute rheumatic fever is exquisitely tender. It is not uncommon for children with this form of arthritis to refuse to allow even bed sheets or clothing to cover an affected joint. The joints are red, warm, and swollen. The arthritis is migratory and affects several different joints: the elbows, knees, ankles, and wrists. It rarely occurs in the fingers, toes, or spine. It need not be symmetric. Effusions may be present. If the joint is aspirated, a leukocytosis is usually found; polymorphonuclear leukocytes are the cells found most frequently. However, there are no specific laboratory findings in the synovial fluid.

 

The arthritis does not result in chronic joint disease. After initiating anti-inflammatory therapy, the arthritis may disappear in 12{endash}–24 hr. Untreated, it may persist for a week or more. In many patients with early arthritis of rheumatic fever, because of treatment with anti-inflammatory drugs, the classic migratory polyarthritis does not develop, confusing the diagnosis.

 

CHOREA

Sydenham chorea, a unique part of the rheumatic fever syndrome, occurs much later than other manifestations. These choreoathetoid movements may begin very subtly. The latent period following streptococcal pharyngitis may be as long as several months, and the movements are often very difficult to detect at the onset. However, careful questioning of parents and teachers usually reveals evidence of increased clumsiness. One of the best signs of this in school-aged children is a marked deterioration in their handwriting. Emotional lability is a frequent finding. Sydenham chorea may affect all four extremities or may be unilateral. Although at one time it could be seen in as many as one half of patients with acute rheumatic fever, more recent evidence suggests that it is seen, at least in the United States, in 10% or fewer cases. Sydenham chorea frequently is the only symptom of rheumatic fever. It is for this reason that this symptom alone is adequate to satisfy the Jones criteria. Sydenham chorea usually disappears within weeks to months. It may return, but this has become a rare occurrence.

ERYTHEMA MARGINATUM

The unique rash seen in patients with rheumatic fever is another of the major manifestations that can be very difficult to diagnose. It occurs very infrequently, and therefore few clinicians have had extensive experience in recognizing it. Although early in the disease it may manifest as nonspecific pink macules that are usually seen over the trunk, later in its fully developed form, there is blanching in the middle of the lesions, sometimes with fusing of the borders, resulting in a serpiginous-looking lesion. This rash can be made worse with application of heat, but characteristically it is evanescent. The rash does not itch. It often occurs in patients with chronic carditis. The rash of erythema marginatum can be mistaken for the rash seen with Lyme disease.

 

SUBCUTANEOUS NODULES

These lesions occur infrequently and are most commonly observed in patients with severe carditis. These pea-sized nodules are firm and nontender, and there is no inflammation. They are characteristically seen on the extensor surfaces of the joints, such as the knees and elbows, and also over the spine.

Minor Criteria. The minor manifestations are much less specific but are necessary to confirm a diagnosis of rheumatic fever. They include the clinical findings of fever and arthralgia. Arthralgia is present if the patient feels discomfort in the joint in the absence of objective findings (e.g., pain, redness, warmth) on physical examination. (Arthralgia cannot be counted in satisfying the Jones criteria if arthritis is present.) Fever, usually no higher than 101º{degree} or 102º{degree} F, may be present. High fever of 103º{degree} or 104º{degree} F requires careful re-evaluation and consideration of other diagnoses.

Included in the minor criteria are several laboratory tests. Acute-phase reactants, such as the ESR or C-reactive protein, may be elevated. These tests may remain elevated for prolonged periods of time (months) and are used by some clinicians as a guideline for modifying doses of anti-inflammatory drugs (see later). A prolonged PR interval on the electrocardiogram is also included among the minor criteria. This also is a nonspecific finding and should be used only after careful consideration.

Evidence of Group A Streptococcal Infection. This is one of the most important aspects of the Jones criteria. There must be evidence of a preceding group A streptococcal infection documented by a positive throat culture, a history of scarlet fever, or elevated streptococcal antibodies such as antistreptolysin O (ASO), antideoxyribonuclease B (anti-DNase B), or antihyaluronidase (AH). The diagnosis of rheumatic fever should not be seriously considered in patients without evidence of a recent group A streptococcal infection (see later exceptions for chorea and indolent carditis). Approximately 80% of individuals with rheumatic fever have an elevated ASO titer, but if the titers of two additional streptococcal antibodies are also elevated or rising, an elevation of at least one antibody is found in more than 95% of patients with rheumatic fever.

There are three categories of patients who may be diagnosed as having acute rheumatic fever even in the absence of two major criteria or one major and two minor criteria, as required by the revised Jones criteria. These include strongly considering rheumatic fever if chorea or indolent carditis is present with no other likely cause. In addition, a recurrence of rheumatic fever should be considered in patients with prior rheumatic fever or rheumatic heart disease who have evidence of a recent streptococcal infection with one major or two minor criteria.