- Clinical science
Rheumatic fever is an inflammatory sequela involving the heart, joints, skin, and central nervous system (CNS) that occurs two to four weeks after an untreated infection with group A streptococcus (GAS). The pathogenic mechanisms that cause rheumatic fever are not completely understood, but molecular mimicry between streptococcal M protein and human cardiac myosin proteins is thought to play a role. Because of the structural similarities between the two proteins, antibodies and T cells activated to respond to streptococcal proteins also react with the human proteins, causing tissue injury and inflammation. In addition to nonspecific symptoms (e.g., fever, malaise, and fatigue), patients present with symptoms involving the heart (pancarditis), joints (migratory polyarthritis), skin (subcutaneous nodules, erythema marginatum), and/or CNS (Sydenham's chorea). The diagnosis of acute rheumatic fever is primarily a clinical one, and is based on the Jones criteria. Diagnostic evaluation in acute rheumatic fever typically shows elevated inflammatory markers, positive antistreptococcal antibodies, and valvular damage on echocardiogram. The first-line treatment is penicillin, and is combined with symptomatic anti-inflammatory treatment, typically with salicylates or glucocorticoids (if salicylates are not effective). Acute rheumatic fever may be complicated by progressive, permanent damage to the heart valves (especially the mitral valve), resulting in chronic rheumatic heart disease. Preventing the cardiac complications of rheumatic fever is the goal of both primary prophylaxis (i.e., antibiotic therapy for GAS pharyngitis) and secondary prophylaxis (antibiotic administration following an episode of acute rheumatic fever.
- Delayed inflammatory complication of group A β-hemolytic streptococcal (GAS) pharyngitis that usually occurs within 2–4 weeks of acute infection
- Rheumatic heart disease refers to two clinical entities:
- Most commonly accepted mechanism : Group A β-hemolytic streptococcus (Streptococcus pyogenes) (GAS): or pharyngitis (“strep throat”) without antibiotic treatment → antibodies develop against streptococcal M protein → cross-reaction of antibodies with nerve and myocardial proteins due to molecular mimicry → type II hypersensitivity reaction; → acute inflammatory sequela
The symptoms of acute rheumatic fever can be remembered with the JONES criteria, written with a heart-shaped O (see also “Diagnostics” above): J = Joints, ♥ = Pancarditis, N = Nodules, E = Erythema marginatum, S = Sydenham chorea
- Constitutional symptoms: fever, malaise, fatigue
- Joints: (∼ 75% of cases): migratory polyarthritis
Heart (30–60% of cases)
- Pancarditis (endocarditis, myocarditis, and pericarditis)
Mitral valve (∼ 65% of cases)
- Early mitral regurgitation or prolapse
- Late mitral stenosis: Rheumatic fever is the most frequent cause of mitral stenosis.
- Mixed mitral stenosis/regurgitation also possible
- Aortic valve (∼ 25% of cases)
- Tricuspid valve (∼ 10% of cases)
- Mitral valve (∼ 65% of cases)
- Dilated cardiomyopathy due to severe valvular disease, myocarditis
CNS (up to 25% of cases)
- Occurs 1–8 months after the inciting infection
- Involuntary, irregular, nonrepetitive movements of the limbs, neck, head, and/or face, sometimes asymmetrical or confined to one side (hemichorea)
- Additional motor symptoms (e.g., ballismus, muscle weakness) and speech disorders (slurred or “jerky” speech)
- Neuropsychiatric symptoms (e.g., inappropriate laughing/crying, agitation, anxiety, apathy, obsessive-compulsive behavior)
- Pathophysiology: Streptococcal antigens lead to antibody production → antibodies cross-react with structures of the basal ganglia; (particularly the striatum) and cortical structures → reversible dysfunction of cortical and striatal circuits
- Sydenham chorea
Skin (∼ 10% of cases)
- Subcutaneous nodules
- Centrifugally expanding pink or light red rash; with a well-defined outer border (erythema marginatum → marginated rash) and central clearing.
- Location: The trunk and limbs are affected; the face is spared. May rapidly appear and disappear at different locations.
- Painless and nonpruritic
Rheumatic heart disease tends to involve the high-pressure valves, i.e., the mitral and aortic valves!
Diagnosis of acute rheumatic fever is based on the Jones criteria; , which primarily describe the clinical findings of the condition. Evidence of a preceding GAS infection is also preferred (unless carditis or chorea are present). Laboratory tests and imaging may be necessary to assess any outstanding Jones criteria.
- Interpretation: two major OR one major plus two minor criteria are required for diagnosis.
- Major criteria
- Minor criteria
- Normochromic, normocytic anemia of chronic inflammation
- Confirmation of GAS infection
- Echocardiogram (may show mitral or aortic regurgitation)
- Aschoff bodies:
- Anitschkow cells:
- General measures: bedrest (especially important in patients with carditis)
- Antibiotics: to eradicate GAS
- Therapy for arthritis and fever
- Therapy for heart failure: diuretics and conventional therapy (see )
- Therapy for myocarditis: monitoring and treatment for arrhythmias (see )
- Damage to the cardiac valves: Surgery or interventional reconstructive measures may be considered at least one year after the acute inflammatory phase.
- Cardiac involvement is the most important prognostic factor.
- Primary prevention: prompt antibiotic treatment (e.g., penicillin V) of GAS tonsillopharyngitis diagnosed by throat culture or rapid strep test
- Antibiotic prophylaxis to prevent recurrence
- Drug of choice: IM penicillin G benzathine
- Immediately follows antibiotic treatment of acute rheumatic fever (see “Treatment” above)
- Duration depends on risk and severity of original episode
- Rheumatic fever without carditis: 5 years or until the patient is age 21 (whichever is longer)
- Rheumatic fever with carditis: 10 years or until the patient is age 21 (whichever is longer)
- Rheumatic fever with carditis and permanent valvular heart defects: 10 years or until age 40 (whichever is longer)