Introduction A severe headache of abrupt onset without identifiable cause is termed Primary Thunderclap Headache. Cranial CT and CSF examination will exclude aneurysmal subarachnoid haemorrhage, but may not identify other causes. In the MRI era, there is a need to create a comprehensive list of potential causes to guide investigation. To date there are no systematic reviews of aetiology of acute severe headache.
Background A systematic review of MEDLINE (1950–September 2009) and EMBASE (1980–September 2009) databases identified 1227 papers. Copies of full articles were reviewed using a structured proforma.
Results 331 papers described 759 cases with 59 different causes of Acute Severe Headache. Idiopathic and Vascular causes predominate: Primary Headache Associated with Sexual Activity, Reversible Cerebral Vasoconstriction Syndrome (RCVS), Non-aneurysmal Subarachnoid Haemorrhage, Pituitary Apoplexy, Arterial Dissection, and Cerebral Venous Sinus Thrombosis. Non-vascular neurological causes included pneumocephalus, spontaneous intracranial hypotension and colloid cyst of third ventricle. Non-neurological causes included Phaeochromocytoma, Acute Q fever, Transitional Personality Disorder, Dengue Haemorrhagic Fever, and Acute Myocardial Infarction.
Conclusion Our systematic review identified many causes of acute severe headache which would remain unidentified using solely Cranial CT and CSF examination. An up to date study of aetiology and investigation of acute severe headache is required, and guidelines on acute headache will need to be aware of these causes.
Statistics from Altmetric.com