[Recurrent gelastic syncopes].

Introduction: Laughter-induced syncope or gelastic syncope is a rare and unrecognized phenomenon. We report an additional case.

Case Report: We report a 65-year-old man with no personal past medical history, particularly diabetes or heart disease, was admitted to investigate recent four episodes of loss of consciousness exclusively induced by laugh. The first episode had occurred 8 months earlier after reading a funny story. There were no other symptoms and physical examination, particularly neurological and cardiac was normal. All paraclinical investigations were also unremarkable: laboratory tests (glucose, thyroid function test and blood cobalamin level), cardiac and neurological investigations (electrocardiographic monitoring, echocardiography, electroencephalography and brain MRI). Treatment with propanolol prevented subsequent attacks.

Conclusion: Sustained laugh is accompanied by repetitive bursts of forced expiration, equivalent to short repetition of Valsalva maneuvers. Laughter-induced syncope is thought to be a subtype of the vagal mediated syncopal attacks. Differential diagnosis should rule out especially gelastic atonic seizures and cataplexy. Propanolol is an effective therapy to prevent recurrence.