Headache caused by non-traumatic acute subdural haemorrhage, typically severe and sudden, peaking in seconds (thunderclap headache) or minutes. It is usually accompanied or rapidly followed by focal signs and decrease in consciousness.
A. Any new headache fulfilling criterion C
B. Acute subdural haemorrhage (ASDH) in the absence of head trauma has been diagnosed
C. Evidence of causation demonstrated by at least two of the following:
1. headache has developed in very close temporal relation to other symptoms and/or clinical signs of ASDH, or has led to the diagnosis of ASDH
2. either or both of the following:
a) headache has significantly worsened in parallel with worsening of ASDH
b) headache has significantly improved in parallel with improvement of other symptoms or clinical or radiological signs of ASDH
3. headache has either or both of the following two characteristics:
a) sudden or thunderclap onset
b) localized in accordance with the site of the haemorrhage
D. Not better accounted for by another ICHD-3 diagnosis.
Most cases of acute subdural haemorrhage (ASDH) occur after head trauma and should be coded accordingly. Non-traumatic ASDH without other intracranial haemorrhage (“pure ASDH”) is rare and represents a life-threatening condition. It is a neurosurgical emergency.
The bleeding may be from arterial or venous origin. Reported causes include ”spontaneous” cortical artery rupture, aneurysm rupture, arteriovenous malformations and dural arteriovenous fistulae, tumours or metastasis, coagulopathies, moya-moya disease, cerebral venous thrombosis and intracranial hypotension. Isolated cases or small series have mostly been reported by neurosurgeons. Headache is described in 25-100% of cases depending on the series and the underlying cause. Isolated headache can be the presenting sign; but usually it is associated or followed by a rapid neurological deterioration.