Postpartum dissecting aneurysm of the posterior cerebral artery.

Intracranial dissecting aneurysm may cause subarachnoid hemorrhage (SAH) or infarction, and postpartum dissecting aneurysm is rare. A 30-year-old 6 days postpartum woman presented with posterior cerebral artery (PCA) dissection evolving dramatically over a short period. She had been well until 6 days after delivery when she suffered sudden onset of headache, vomiting, and unconsciousness. CT scan demonstrated SAH and digital subtraction angiography (DSA) revealed a fusiform dilatation of the left PCA (P3/P4 segment). The initial diagnosis was ruptured dissecting aneurysm, and conservative management was recommended in the acute period. DSA showed smoothening of the vascular wall 6 days after onset, and obliteration of the left P3/P4 segment was observed 13 days after onset. She was discharged without neurological deficits 26 days after onset. Postpartum SAH due to dissecting aneurysm of the PCA is rare, but should be considered in the differential diagnosis of postpartum headache.