[Acute, stroke or thunderclap headache?].

Sudden, acute headache occurring for the first time in life may represent subarachnoid or perimesencephalic haemorrhage but it can also occur in the absence of pathologic conditions. This headache is widely named as "thunderclap" (TCH) or "stroke headache". Pathogenesis, diagnostic evaluation and headache characteristics is presented basing on retrospective evaluation of such patients admitted to Neurological Department between 1990-2002 with symptoms of TCH. The diagnosis of idiopathic TCH was established in 74 (21%) of 368 patients. No clinically significant difference between clinical manifestation of idiopathic and symptomatic TCH was observed. The most common concomitant diseases in idiopathic TCH patients were acute or chronic infections and hypertension. 40% of those patients had elevated inflammatory markers which normalised during hospitalisation in 20% of cases. We observed seasonal incidence with the highest incidence in summer and winter. 20% of patients presented to Neurological Dept with TCH consist of idiopathic, benign condition of unknown aetiology. Observed seasonal incidence with coexisting signs of infection may suggest the role of inflammatory process in benign TCH pathogenesis.