Acute rheumatic fever (ARF) is an inflammation of the heart, skin, joints and/or brain which develops after infection with Group A streptococci, such as "strep" throat, or scarlet fever. The incubation period is about 20 days. Less than 3% of those with untreated strep infection may develop rheumatic fever. Most of the affected patients are between six and fifteen years of age.
In ARF, antibodies against the M antigen found in the streptococcal cell wall cross- react with cardiac myosin.
Signs and symptoms of rheumatic fever include fever, migratory arthritis, abdominal pain, erythema marginatum (a ring-shaped rash located on trunk and upper parts of arms and legs), Sydenham's chorea, subcutaneous nodules, epistaxis, shortness of breath and chest pain.
Making the diagnosis
Using the Jones Criteria to make the diagnosis of ARF, there must first be evidence of previous streptococcal infection.
In addition, the patient must have two major criteria
- Polyarthritis. This is the most common manifestation of ARF, usually involves large joints, and is migratory in nature. It responds dramatically to high-dose salicylates.
Carditis. Occuring in ~50% of patients with ARF, carditis presents with tachycardia out of proportion to the fever. A heart murmur of MR or AI indicates valvulitis. Pericarditis may present with chest pain, friction rub, pericardial effusion and EKG changes. Signs of CHF may be present.
Chorea. Syndenham's chorea occurs in about 15% of patients with ARF and is more common in prepubertal girls. It is characterized by emotional labilty, personality changes, poor motor coordination and the classic purposeless spontaneous movements. It is also characterized by hyperextension of the fingers (spooning) and irregular contractions of the muscles of the hands (milkmaid's grip). It usually resolves within 2-4 weeks. This may be oleic manifestation of rheumatic fever and may occur in isolation; however, it is considered pathognomonic for rheumatic fever and the diagnosis can be made on the basis of this finding alone.
- Erythema marginaturn. An uncommon sign of ARF, this rash is truncal and is usually nonpruritic and serpigenous with well defined borders.
- Subcutaneous nodule. The least common signs of ARF, these are found on the extensor surfaces of the extremities or along the spine. The nodules are small, non-tender, and freely moveable.
or one major(above) and two minor clinical or laboratory findings .
- Clinical Findings: arthralgia or fever
- Laboratory Findings: elevated acute-phase reactants (erythrocyte sedimentation rate, C-reactive protein), or prolonged PR interval
Streptococcal infection should be treated with Benzathine penicillin. The arthritis responds well to high dose salycilates. Corticosteroids may be used in severe carditis. Heart failure, if present, requires diuretics and digoxin. Syndenham's chorea may be treated with Phenobarbital or haloperidol.
Patients with a documented history of ARF should receive antibiotic prophylaxis until age 21, or for a minimum of five years if there is no cardiac involvement. Patients with valvular abnormalities should receive lifetime prophylaxis. Prophylaxis consists of monthly injections of benzathine pencillin; alternatively, twice daily oral pencillin V may be used. Oral sulfadiazine may be used for patients with penicillin allergy, but it is not as effective as penicillin.
more info: Rheumatic Fever (A). from Emedicine
more info: Rheumatic Fever (B). from Emedicine