An 11-year-old girl with syndrome of inappropriate antidiuretic hormone secretion

An 11-year-old girl presented with a syndrome of inappropriate antidiuretic hormone secretion, which was transitory and, initially, of obscure origin. Subsequently, the patient's hypothalamic disorder emerged as a component of a steroid-responsive relapsing encephalomyelitis with cerebral pathology restricted to the basal ganglia and brainstem. Where such a disorder fits in the spectrum from acute disseminating encephalomeylitis to multiple sclerosis is discussed.