II. Epidemiology
- Peak ages affected
- Ages 8 to 14 years old
- Ages 21 to 37 years old
III. Pathophysiology
- Autoimmune response to Group A Streptococcus
- Onset 7-10 days after Group A Streptococcal Pharyngitis
- May occur with or without Rheumatic Fever
- Part of Jones Criteria for Rheumatic Fever diagnosis
IV. Symptoms
- Persistent or recurrent non-Migratory Arthritis
- Distribution
- Most commonly affects hip, knee, ankle and wrist
V. Labs
- Complete Blood Count (CBC)
- Acute phase reactants (lower levels than with Rheumatic Fever)
-
Streptococcus Testing
- GAS Rapid Antigen test with reflex to Throat Culture if negative
- ASO Titer
VI. Differential Diagnosis
-
Septic Arthritis
- Always exclude in Monoarthritis
-
Rheumatic Fever
- Arthritis with other Rheumatic Fever criteria (see Jones Criteria)
- Viral Arthritis
- Reactive Arthritis
VII. Management
- Antiinflammatory medications
- NSAIDs and Aspirin are less effective than in the Arthritis of Rheumatic Fever
- Monitor for carditis (and Rheumatic Fever)
- Monitoring for one year
- Benzathine Penicillin G IM monthly for one year