Streptococcal Group A Disease

Streptococcal Group A Disease

 

Streptococcus group A causes a broad spectrum of diseases, most commonly causing pharyngitis and tonsillitis.

Epidemiology

  • Incidence – Streptococcal pharyngitis represents 1% of primary care visits and is one of the top 20 reported diseases
  • Age – most predominate in patients under 20 years of age
  • Transmission – hand contact with nasal discharge
  • Organism
    • Gram-positive cocci are the primary bacterial cause of exudative tonsillitis and pharyngitis
    • Organism may evoke cross-reacting immune response with human tissue leading to rheumatic fever, rheumatic heart disease and acute glomerulonephritis
      • Acute glomerulonephritis also associated with streptococcal skin disease

Clinical Presentation

  • Primary symptoms – sore throat, fever, dysphagia
  • Constitutional symptoms – headache, nausea, vomiting, abdominal pain
  • Clinical findings – pharyngeal erythema, tonsillar exudates, anterior cervical adenopathy, palatine petechiae
  • Poststreptococcal disease
    • Glomerulonephritis
    • Rheumatic fever
    • Rheumatic heart disease

Risk Factors

  • Pharyngitis and tonsillitis
    • Age – occurs more frequently in young children
    • Presence of tonsils

Diagnosis

  • Laboratory testing
    • Rapid antigen detection with reflex to culture for initial negative antigen testing
    • Antibody tests can provide serologic evidence of prior and current infection
      • When both ASO and anti-DNase-B are used, 95% of patients have elevated titers
      • Elevated serum ASO titers are found in about 85% of individuals with rheumatic fever
      • Skin infections with group A streptococci are often associated with a poor ASO response but DNase-B titers are increased after skin infection

Differential Diagnosis

  • Infectious mononucleosis
  • Viral pharyngitis – rhinovirus, adenovirus, RSV, influenza, coxsackie
  • Bacterial pharyngitis – chlamydia, gonorrhea
  • Lymphadenitis
  • Treatment
  • Antibiotics necessary to eradicate toxin-producing organisms and prevent rheumatic fever

See Also