Editor,—Gelastic seizures are recurrent attacks of inappropriate laughter not precipitated by external stimulation. Usually, they are poorly responsive to antiepileptic drugs.1 I report a case of tuberous sclerosis with gelastic seizures that disappeared after treatment with adrenocorticotrophic hormone (ACTH).

A 6 month old girl had repetitive tonic spasms of her head and arms and was referred to hospital. There was no significant family history. Pregnancy and delivery were uncomplicated and developmental milestones were normal. Physical examination revealed retinal hamartomas and hypomelanotic macules on her chest and back. The EEG showed hypsarrhythmia. Computed tomography and magnetic resonance imaging (MRI) of her brain showed multiple subependymal calcified nodules and cortical tubers. She was diagnosed with tuberous sclerosis and treated with ACTH (synthetic ACTH, 0.015 mg/kg/day).2 Her seizures and hypsarrhythmia on the EEG disappeared soon after ACTH treatment, which was administered every day for two weeks and tapered gradually.

Six months later, she started to have episodes of sudden inappropriate laughter followed by salivation and unconsciousness for a few minutes. These episodes occurred a few times a week. The EEG showed sporadic spikes or polyspikes in the left posterior temporal region. MRI showed no hypothalamic masses. These gelastic seizures were difficult to control and lasted for three months, despite the administration of valproate, zonisamide, and nitrazepam. Repetitive tonic spasms of her head and arms recurred. She was treated with ACTH in the same way as before and gelastic seizures disappeared. Her tonic spasms also diminished but still occurred a few times a week after eight weeks of ACTH treatment.

The sudden laughter observed in this case is consistent with the criteria of gelastic seizures.3 ACTH might be useful to treat gelastic seizures in selected cases.