| IHS | Diagnosis | ICD-10 |
|---|---|---|
| 4.6 | Primary thunderclap headache | G44.80 |
| Previously used terms | Benign thunderclap headache | |
| Coded elsewhere | 4.2 Primary cough headache , 4.3 Primary exertional headache and 4.4 Primary headache associated with sexual activity can all present as thunderclap headache but should be coded as those headache types, not as 4.6 Primary thunderclap headache . | |
Description:
High-intensity headache of abrupt onset mimicking that of ruptured cerebral aneurysm.
Diagnostic criteria:
- Severe head pain fulfilling criteria B and C
- Both of the following characteristics:
- sudden onset, reaching maximum intensity in <1 minute
- lasting from 1 hour to 10 days
- Does not recur regularly over subsequent weeks or months1
- Not attributed to another disorder2
Notes:
- Headache may recur within the first week after onset.
- Normal CSF and normal brain imaging are required.
Comment:
Evidence that thunderclap headache exists as a primary condition is poor: the search for an underlying cause should be expedient 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), CNS angiitis, reversible benign CNS angiopathy and pituitary apoplexy. Other organic causes of thunderclap headache are colloid cyst of the third ventricle, CSF hypotension and acute sinusitis (particularly with barotrauma). 4.6 Primary thunderclap headache should be the diagnosis only when all organic causes have been excluded.
