Thunderclap headache

A non-haemorrhagic "thunderclap" headache (TCH) is a diagnosis of exclusion made in patients whom present with severe headache but have a negative CT and LP.

• differential diagnosis with the sentinel headache observed during the development of an aneurysmal rupture is extremely important (1)
  • all patients with TCH should be investigated with at least a CT scan and MR angiography, since this type of headache is not a frequent benign recurrent headache disorder, and may represent a serious underlying process

TCH is defined by the ICHD-II as a severe intense headache which is of rapid onset mimicking a subarachnoid hemorrhage (SAH) from a ruptured aneurysm with maximum intensity being reached in less than a minute (1)

• the incidence in the developed world is estimated to be around 43 per 100 000 adults per year (2)

Thunder clap headaches can be

• primary
  • diagnosed when no underlying cause is discovered (3)
  • ICHD-II classification states that normal brain imaging and CSF are required before a diagnosis (1)
  • although introduced in the second version of the International Classification of Headache Disorders as a different entity, there are doubts about whether primary thunderclap headaches really exists
• secondary

Patients with a first presentation of thunderclap headache should be referred immediately to hospital for same day specialist assessment (1).

Notes (1):

• the pathophysiology of TCH in the absence of underlying pathology is not well understood
  • primary TCH has a distinctive clinical and angiographic profile and must be distinguished from central nervous system vasculitis and SAH

Reference:

• (1) SIGN (March 2008).Diagnosis and Management of headaches in adult.
• (2) Ducros A, Bousser MG. Thunderclap headache. BMJ. 2013;346:e8557
• (3) Schwedt TJ, Matharu MS, Dodick DW. Thunderclap headache. Lancet Neurol. 2006;5(7):621-31
• (4) Valenca MM et al. Cerebral vasospasm and headache during sexual intercourse and masturbatory orgasms. Headache. 2004 Mar;44(3):244-8.