disseminated encephalomyelitis

SUMMARY A 7 year old girl developed acute disseminated encephalomyelitis following a Myco-plasma pneumoniae respiratory infection. The illness followed a relapsing course during the first two months. Computed tomography (CT) showed cerebral lesions of a severity and extent out of proportion to the clinical manifestations. The CT abnormalities altered with changes in her clinical state. Acute disseminated encephalomyelitis (ADEM) is thought to be an autoimmune mediated disorder which is usually post-infectious or follows immun-isation.'3 The pathology affects white matter prin-cipally, with perivenous lymphocytic infiltration and foci of demyelination which may become confluent. Relapsing cases have been described.'48 The relation-ships between ADEM, relapsing ADEM and multiple sclerosis are a matter of speculation.'9 Clinically, ADEM may present in a manner identical to acute viral encephalitis, but in some cases of ADEM focal neurological deficits are the predominating clinical manifestations. '° We report a girl with relapsing ADEM in whom the cerebral computed tomography (CT) appearances were alarmingly severe even at times when clinical manifestations were relatively slight. Case report A 7 year old right-handed girl, born in the UK to parents of Italian origin, was admitted on 19 December 1986. Two weeks prior to admission she had developed a moderately severe productive cough lasting several days, and for one week had suffered progressive weakness of the right leg without any other symptoms. There was no past medical or family history. Examination revealed right upper quadrant visual inatten