Non-aneurysmal perimesencephalic subarachnoid haemorrhage with associated pontine haemorrhagic infarction. A case report and subject review.

SUMMARY: Non-aneurysmal perimesencephalic subarachnoid saemorrhage is characterized by an accumulation of blood in the perimesencephalic and prepontine cisterns identified on sectional imaging together with persistently negative cerebral angiography. Magnetic resonance imaging usually contributes no further information on the possible cause of the bleed but may occasionally show further features including associated parenchymal infarcts such as the pontine haemorrhagic infarct seen in the case described here.