IS THUNDERCLAP HEADACHE A SEPARATE ENTITY

Acute severe headache indicative of subarachnoid haemorrhage (SAH), bu t without the requisite proof, is defined as thunderclap. A special pa thophysiological mechanism for the development of this headache is not known as yet. This retrospective study comprised 84 patients. All had the typical clinical signs of a SAH, but cranial computer tomography and lumbar puncture excluded this diagnosis. In 82% of these patients the headache was classified according to aetiologically defined sympto matic groups. One patient with headache of vascular aetiology had an a ngiographically proven, but not ruptured aneurysm. No definite cause f or the headache was found in 18% of cases. None of the patients follow ed up over a period of between 12 months and 6 years developed SAH or any other severe neurological disorder. 9% reported repeat of the head ache event. Thunderclap headache seems to be only a descriptive term f or patients with symptoms typical of a SAH without signs of bleeding. Thunderclap headache has no diagnostic or prognostic specificity and t herefore we recommend use of this term only as a description of the he adache characteristic. Thunderclap headache is not a predictor of a fu ture SAH. Cerebral angiography should be restricted to cases with neur ological deficits.