is a delayed, immune-mediated complication of group A streptococcal pharyngitis that appears two to four weeks after the sore throat has resolved. It inflames joints, skin, brain and heart, and the heart valves are where lasting damage occurs. During the acute episode the treatment is aimed at the bacterium that started it, at the inflammation it has produced, and at — involuntary, purposeless movements — which is a neurological phenomenon rather than an inflammatory joint process. The choice of anti-inflammatory drug is stratified by how much the heart is involved, because carditis is the manifestation that decides the long-term prognosis.
Eradicating the streptococcus
Antibiotics are given to eliminate any residual group A Streptococcus, regardless of the throat swab result at the time of diagnosis, because the bacterium may still be present even though the immune consequences are already established. Penicillin or amoxicillin for 10 days is the usual choice. The regimens are the same ones used to treat streptococcal pharyngitis.
Anti-inflammatory treatment
Treatment is stratified by the severity of cardiac involvement. Arthritis without carditis is treated with non-steroidal anti-inflammatory drugs (NSAIDs); as carditis becomes more severe, treatment moves to salicylates (aspirin and related drugs) or NSAIDs for longer, and then to a corticosteroid.
| Clinical picture | Treatment |
|---|---|
| Arthritis without carditis | NSAIDs — for example ibuprofen 30 mg/kg/day in 3 divided doses, or naproxen 10-20 mg/kg/day in 2 doses — continued for 2-3 weeks, then tapered over 1-2 weeks |
| Arthritis with mild carditis | Salicylates or NSAIDs for about 6-8 weeks |
| Arthritis with moderate or severe carditis | Prednisone 1-2 mg/kg/day in 2 divided doses for 2-4 weeks, then tapered. Aspirin is added during the final week of the taper in some protocols, to cover the withdrawal of steroid |
Aspirin was the historical first-line anti-inflammatory drug for rheumatic fever and remains in use for carditis, but it is avoided in children wherever an equally effective alternative exists because of the association with Reye syndrome, an acute illness of the brain and liver. Ibuprofen and naproxen are equally effective for the arthritis and are safer; the choice for carditis should follow local protocol and cardiology advice.
Chorea
Chorea is a neurological immune phenomenon rather than an inflammatory joint process, and anti-inflammatory drugs are not used for it.
- Mild chorea — rest, and reduction of physical and emotional stress; the movements usually resolve over months.
- Severe or disabling chorea — carbamazepine or valproate are usually tried first, with haloperidol or phenobarbital used when these are ineffective or not tolerated; response to any of them is variable, and no drug is uniformly effective.
Chorea resolves over months and leaves no structural damage of its own. The damage that lasts in rheumatic fever is valvular, and anti-inflammatory treatment relieves symptoms and fever without it being established that it changes the eventual valve damage. What does change it is preventing the next attack, because each recurrence risks further scarring of valves that have already been injured.