• 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'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.

Definition

References:[1]

Epidemiology

  • Peak incidence: 5–15 years
  • Prevalence
    • Developing countries: the most common cause of cardiovascular disease in children and adolescents
    • Developed countries: rare

References:[2][3][4]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Rheumatic fever is not associated with streptococcal skin infections (e.g., erysipelas, impetigo, cellulitis).

References:[3][5][6][7][8]

Clinical features

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

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

References:[9][10][1][4][11][12][13][14]

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

Additional findings

References:[1][4][15]

Pathology

References:[10][16]

Treatment

References:[4][17][18]

Prognosis

  • Cardiac involvement is the most important prognostic factor.

References:[19]

Prevention

  • Primary prevention: prompt antibiotic treatment (e.g., penicillin V) of GAS tonsillopharyngitis diagnosed by throat culture or rapid strep test
  • Secondary prevention
    • 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)

References:[20]