Rheumatic Fever: Problems in Diagnosis

This Featured article was originally published in the September 1961 issue of Consultant. Read the Editorial based on this article, written by XXX, here.

Author:
Alvan R. Feinstein, MD
New York University

Citation:
Feinstein AR. Rheumatic fever: problems in diagnosis. Consultant. 1961:1(9):16-19.

Rheumatic fever gets its name from febrile polyarthritis, its most common feature. However, many patients with rheumatic fever may not be febrile, may not have polyarthritis, or may not be rheumatic at all. This variability of symptoms has led to considerable confusion—and erroneous beliefs—about the causes and treatment of rheumatic fever.

Fortunately, recent studies have clarified the disease process involved. They have improved the objectivity and accuracy of auscultation, and have shown that rheumatic fever invariably develops in association with Group A ß hemolytic streptococcal infections. Thus, rheumatic fever may be defined as a post-streptococcal inflammatory state characterized by arthritis, carditis, or chorea appearing singly or in combination.

Clinical Picture

Arthritis, when it occurs, is easy to recognize; however, it should be verified by objective evidence of inflammation in the joints, and differentiated from arthralgia, myalgia, or bone pains. The presence of febrile arthritis should provoke a search for associated carditis. Keep in mind, however, that carditis is loo often "found" where it does not exist. If carditis is absent in a patient with febrile arthritis, rheumatic fever remains a likely diagnosis unless sequential tests of several antibodies fail to show a streptococcal infection, or unless the arthritis does not respond to appropriate therapy; in that case, you need to rule out lupus erythematosus, rheumatoid arthritis, gout, sickle cell disease, or other alternative diagnoses.

Chorea

Chorea, present in about 8% of rheumatic fever attacks, generally takes longer to develop after a streptococcal infection than arthritis or carditis. Hence the chorea often begins late in a rheumatic attack, as the arthritis and/or carditis are subsiding, or afterwards. Or it may occur as an isolated manifestation, without rheumatic features. In this situation, the preceding streptococcal infection often cannot be demonstrated because the antibodies have returned to normal levels by the time the chorea begins. Chorea, although uncommon, is not usually a diagnostic problem; it can be differentiated from cerebral palsy by its history of recent onset, and from habit spasms or nervous hyperkinesia  by its nonrepetitive, purposeless, subjectively uncontrollable movements.

Carditis

Carditis is the most serious manifestation of rheumatic fever and the one most subject to diagnostic error. The greatest difficulty stems from the fact that post-streptococcal carditis can occur without concomitant arthritis and chorea, and it may not produce any discomfort. In such an instance, the carditis will go unrecognized simply because the patient does not seek medical attention.

In patients whose rheumatic fever does produce symptoms, the presence of carditis is recognized by one or more of 4 features: (1) significant cardiomegaly, (2) pericarditis, (3) congestive heart failure, and (4) significant murmurs. Before considering these 4 features, I would like to mention that prolongation of the P-R interval in the electrocardiogram is no longer considered evidence of carditls. Although P-R prolongation occurs in 20% to 40% of patients with rheumatic fever, it is an electrical rather than a histopathologic phenomenon, and it appears to be due to biochemical factors present in post­streptococcal inflammation. P-R prolongation may be present in patients with carditis, but it alone is not indicative of carditis.

Cardiac Enlargement

Children and adolescents have mobile hearts whose size and shape can change with respiration and phases of the cardiac cycle. Before deciding that the heart has changed size in 2 different films, you must make proper allowance for position of the diaphragm and the possibility that one film was taken in systole and the other in diastole. In my experience, the criteria for “normal” and “slight” heart enlargement can vary so greatly among different observers that I reserve the term significant cardiomegaly only for patients who have at least moderate enlargement (i.e., 2+ on a scale of 0 to 4+) of one or more cardiac chambers. Two other frequent errors in X-ray interpretation occur when a normal, prominent pulmonary artery segment is overread as a “mitralized heart,” and when minor indentations (usually due to air) of one wall of the barium esophogram are erroneously attributed to atrial enlargement.

Pericarditis

A pericardial friction rub is usually unmistakable evidence of pericarditis. Most errors in the diagnosis of pericarditis occur because of unfamiliarity with the wide range of normal variations in the electrocardiogram in children and adolescents. Two common errors are to attribute abnormality to: S-T segment elevations or T-wave inversions in leads V1-V4 (which can be normal in younger patients); and non­specific T-wave changes that can result normally from respiration or changes in placements of the precordial leads.

Congestive Heart Failure

In young rheumatics, congestive heart failure may be asymptomatic or may produce left-sided symptoms (such as dyspnea, cough, and chest discomfort) without corresponding left-sided signs. Its main signs may be tender hepatomegaly, venous distention, or ankle edema. Patients are sometimes mistakenly considered to be dyspneic and in failure when their respirations actually are shallow because of the anxiety of hospitalization, or because of pleuritic pain of pericarditis, or rapid because of salicylate toxicity. Congestive heart failure in rheumatic heart disease occurs only in the presence of significant organic murmurs.

Significant Organic Murmurs

The hallmark of rheumatic heart disease and the sign for which the stethoscope remains a crucial diagnostic tool is the organic murmur. In the acute stages of the disease, murmurs can be present in 4 forms:

1. The blowing decrescendo diastolic murmur of aortic regurgitation;
2. The crescendo pre-systolic rumble of mitral stenosis;
3. The rough, short mid-diastolic murmur of mitral valvulitis; and
4. The blowing systolic murmur of mitral regurgitation.

Errors of Omission

Two errors are common. The aortic regurgitant murmur is often not detected when present either because it is mistimed as systolic, because the examiner fails to listen for it in its customary location along the lower left sternal border, or because the examiner is not accustomed to its sometimes-soft and high-pitched quality.

The presystolic rumble of mitral stenosis is often missed when it is present, not because the examiner has failed to find it, but because such patients frequently do not have rheumatic, choreic or congestive symptoms and hence do not reach medical attention during the acute attack. In both instances, the murmurs are discovered later and are then thought to have developed insidiously, when actually they have been continually present but undetected.

Error of Commission

Again there are 2 common ones. A long physiologic third heart sound is mistakenly considered to represent a mid-diastolic murmur. Here, the differentiation can be made by noting that the true mid-diastolic murmur occurs invariably in association with an organic apical systolic murmur (as described below). When a third sound occurs in diastole in a patient without a systolic murmur at the apex, it can be confirmed as mitral stenosis only if, after exercise, it becomes presystolic and rumbles into the first heart sound. Otherwise, it is most likely physiologic.

The most common auscultatory error in rheumatic fever occurs in differentiating apical systolic   murmurs into those that are physiologic and those that are organic. Since 50% to 90% of normal children have physiologic systolic murmurs arising in the pulmonary valve-artery area, it is common rather than exceptional to find systolic murmurs in any ill child. Such physiologic murmurs, which are usually loudest in the pulmonary artery area or along the left sternal border, may frequently be beard at the apex, may occasionally be transmitted to the axilla, and may even, due to the acoustic properties of blood flow, be high-pitched and blowing. Hence, a loud, high-pitched, blowing apical systolic murmur that transmits to the axilla may erroneously be considered organic when it is actually physiologic. Because physiologic and organic murmurs both arise from blood flow, exercise, and certain changes in position will make them both louder and cannot be used to separate them. The 3 main properties that can be used to separate a physiologic from an organic apical systolic murmur are:

1. Duration: The organic murmur is holosystolic and usually merges with the first sound, often extending into the second sound. The physiologic murmur is short and may often begin after the first sound, ending before the second sound.
2. Site of maximal intensity: The organic murmur is loudest at the apex and to the left of the apex. The physiologic murmur is loudest medial to the apex or along the left sternal border. A systolic murmur audible anywhere in the thorax, which is just as loud or louder than the one at the apex, must be suspected of being the source of the murmur at the apex, even if it appears to have a somewhat different pitch and quality. The common notation found on many charts of “systolic murmur at apex radiating to left sternal border” is usually incorrect and should be “systolic murmur at left sternal border, radiating to apex.”
3. Effect of respiration: With inspiration, which affects the position of the pulmonary artery, the intensity of the physiologic systolic murmur at the apex is sharply reduced, or the murmur may vanish. The intensity of the organic apical murmur is substantially unaffected by this maneuver.

Relationship of Murmurs to Prognosis

Accurate auscultation is not only important for diagnosis but also for prognosis, since patients who do not have any of these significant murmurs during the acute rheumatic attack will not develop rheumatic heart disease. Previous studies that showed the “insidious development” of rheumatic heart disease in patients who were initially free of it are now believed to have contained significant errors in auscultatory and follow-up procedures. Of the patients who have only systolic murmurs during the acute attack, only about 25% will have residual heart disease. Of those who have diastolic murmurs, with or without systolic murmurs, about 50% will have residual heart disease. Of those who have significant cardiomegaly and/or congestive heart failure, about 80% will have residual heart disease. Pericarditis per se, if not associated with any of the above factors, subsides without residua.

Alvan R. Feinstein, MD, is Medical Director of Irvington House, a research and treatment center for rheumatic fever and heart disease, and is Assistant Professor of Medicine at New York University School of Medicine. His investigative interest is focused mainly on rheumatic fever and heart disease, and on problems of nutrition; on these subjects, he has published more than 30 articles in various journals. He is a member of The American Federation for Clinical Research, the Harvey Society, and the American Heart Association.