Sydenham’s chorea may be relevant to common childhood idiopathic conditions

Doctors studying neurological disorders arising in children after streptococcal infections have suggested that understanding how these are expressed could greatly improve our knowledge of common but unexplained childhood movement and psychiatric conditions.

The disorders in question are dyskinesias which routinely occur with disabling psychiatric conditions—the legacy of infection with β haemolytic streptococci. Doctors at a tertiary referral centre found a wide range of psychiatric conditions among 40 children seen between 1999 and 2002 with neurological complications after such infection. Sex differences and a genetic component were also evident.

Chorea—including Sydenham’s chorea, the classic dyskinesia after streptococcal infection (20 patients)—and motor tics (16, 40%) were the most common neurological complications. Chorea occurred mostly in girls (65%) and tics in boys (69%).Only children with chorea had systemic complications of infection—carditis and arthritis—which always preceded neurological complications. Acute emotional or behavioural changes became evident in 33 (83%) children after their streptococcal infection, with emotional lability, anxiety, obsessive compulsive disorder, and depression occurring most commonly.

All 40 children were positive for β haemolytic streptococcal antibody, but 34 (85%) had clinical evidence of such infection before the neurological disorder appeared, after a mean interval of 18.9 (range 1–67) days. Almost three quarters have continuing symptoms of movement disorders after an average of two and a half years, some for as long as 13 years. Forty per cent had a family history of psychiatric or movement disorders in first degree relatives and a similar proportion autoimmune complications in first or second degree relatives.

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