Primary Thunderclap Headache
Previously used term:
Benign thunderclap headache.
4.1 Primary cough headache, 4.2 Primary exercise headache and 4.3 Primary headache associated with sexual activity can all present as thunderclap headache. When such headache is attributed uniquely to one of these triggers, it should be coded accordingly as one of these headache types.
High-intensity headache of abrupt onset, mimicking that of ruptured cerebral aneurysm, in the absence of any intracranial pathology.
A. Severe head pain fulfilling criteria B and C
B. Abrupt onset, reaching maximum intensity in <1 min
C. Lasting for ≥5 min
D. Not better accounted for by another ICHD-3 diagnosis.
Evidence that thunderclap headache exists as a primary disorder is poor: the search for an underlying cause should be expedited and exhaustive. Thunderclap headache is frequently associated with serious vascular intracranial disorders, particularly subarachnoid haemorrhage: it is mandatory to exclude this and a range of other such conditions including intracerebral haemorrhage, cerebral venous thrombosis, unruptured vascular malformation (mostly aneurysm), arterial dissection (intra- and extracranial), reversible cerebral vasoconstriction syndrome (RCVS) and pituitary apoplexy. Other organic causes of thunderclap headache are meningitis, colloid cyst of the third ventricle, CSF hypotension and acute sinusitis (particularly with barotrauma). 4.4 Primary thunderclap headache should be a diagnosis of last resort, reached only when all organic causes have been demonstrably excluded. This implies normal brain imaging, including the brain vessels, and/or normal CSF. Of note, vasoconstrictions may not be observed in the early stage of RCVS. For this reason, probable primary thunderclap headache is not a diagnosis that should be made even temporarily.
ICDH lists Primary thunderclap headache[i] which is defined as “a high-intensity headache of abrupt onset mimicking that of ruptured cerebral aneurysm.” The headache pain should have sudden onset and reach maximum intensity in less than one minute. This type of headache does not recur regularly. It is related to primary cough headache, primary exertional headache, and primary headache associated with sexual activity. It may occur in the setting of sexual relations but also at other times. It should be vigorously worked up with testing as described for primary headache related to sexual activity.
Linn and Wijdicks[ii] in an article in 2002 in Neurologist entitled, “Causes and Management of Thunderclap Headache: A Comprehensive Review” found a serious cause in one third of patients in a primary care setting and in two thirds of patients in a hospital setting. They felt that:
Clues in history and physical examination can point to a possible serious underlying cause of thunderclap headache, such as subarachnoid hemorrhage, intracranial hematoma, or cerebral venous thrombosis. The remaining patients with thunderclap headache, however, have a primary headache disorder, such as migraine or (less frequently) tension headache with an unusual sudden onset, exertional headache, coital headache, cough headache, or cluster headache.
[i] The International Classification of Headache, 2nd Edition. Thunderclap headache. Cephalalgia 2004. 24;(Supplement 1):51-52.
[ii] Linn FHH, Wijdicks EFM. Causes and Management of Thunderclap Headache: A Comprehensive Review. Neurologist. 2002;8(5):279-289.