Nontraumatic subdural haemorrhage typically occurs as a result of a ruptured aneurysm or arteriovenous malformation in the brain. It may also be caused by a congenital vascular malformation, or by a tear in the bridging veins that connect the brain to the dura.
Diagnosis is usually made through CT or MRI scans of the brain, which can detect the presence of a haemorrhage. Cerebral angiography may be used to identify the cause of the haemorrhage.
Differential diagnosis includes traumatic subdural haemorrhage, intracerebral haemorrhage, and hydrocephalus.
Treatment depends on the cause of the haemorrhage, but typically involves surgical intervention to repair or remove the affected area.
The prognosis for non-traumatic subdural haemorrhage depends on the cause and extent of the haemorrhage. In general, the prognosis is good if the haemorrhage is identified and treated quickly.