Abstract

Objective: Thunderclap headache is a sign of a medical emergency such as a life-threatening subarachnoid hemorrhage (SAH). However, it also may occur in primary headache conditions such as cough, physical exertion, sexual activity and even without any provoking factors. International Headache Society classified thunderclap headache disorders into four different subtypes: (1) primary thunderclap headache(PTH); (2) primary cough headache(PCH); (3) primary exertional headache (PEH); and (4) primary headache associated with sexual activity(PSH). Subtypes of thunderclap headaches are reported to share many common characteristics, although studies on the clinical features and triggering factors of thunderclap headaches are limited. Methods: Seventy and two patients with thunderclap headache were prospectively enrolled from March 2008 to June 2010. The patients presented sudden severe headaches, reaching maximal intensity within 1 minute, without focal neu- rologic deficit. SAH and other organic disorders were excluded in this study. We described clinical features, triggering factors and vasospasm, and compared between the four subtypes of thunderclap headache. Results: Of the 72 recruited patients, PTH(n=25, 34.7%) was the most frequent thunderclap headache subtype, followed by PCH(n=23, 31.9%), PSH(n=15, 20.1%) and PEH(n=9, 12.5%). 49(68.1%) patients suffered recurrent thunderclap head- ache attacks at presentation. 49(68.1%) patients had more than one provoking factor. Defecation(n=13, 16.0%) was the most frequent provoking factor followed by sexual intercourse(n=11, 13.7%). Mean age was 45.1±12.6 years(range: 15-70). PEH group (36.6 years old) was younger than other groups. Overall male to female ratio in this study was 1:1.7. Mean duration of headache was 40.7±56.3 minutes(range: 0.17-720). The headache duration was shorter in PEH(25.2±14.2 minutes) than other groups. Vasospasm was documented in 10 patients(13.9%). Conclusions: More than two-thirds of patients with thunderclap headache have more than one provoking factor at presentation. Contrary to the previous studies, vasospasm was associated in small proportion of patients.