• Clinical science

Rheumatic fever

Summary

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 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 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.

Definition

Epidemiology

  • Peak incidence: 5–15 years of age [2]
  • Prevalence: more common in resource-limited countries [3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Pathophysiology

Clinical features

Rheumatic heart disease tends to involve the high-pressure valves (i.e., the mitral and aortic valves).

The symptoms of acute rheumatic fever can be remembered by reading the JONES criteria (see “Diagnostics” below) as an acronym that replaces the “o” with a heart: J = Joints, ♥ = Pancarditis, N = Nodules, E = Erythema marginatum, S = Sydenham chorea

Diagnostics

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.

Jones criteria [8]

Two major criteria or one major plus two minor criteria or three minor criteria are required for diagnosis.

Low risk population

High risk population
Major criteria
Minor criteria

Additional findings [1]

Pathology

Treatment

Prognosis

  • Cardiac involvement is the most important prognostic factor.
    • Early death from rheumatic fever is usually due to myocarditis rather than valvular defects.
    • Patients with a history of carditis (and possible post-inflammatory scarring and calcification) during an initial rheumatic fever episode are at high risk of developing valvular heart defects with recurrent episodes → rheumatic heart disease

Prevention