Chiasmal apoplexy due to intrachiasmatic vascular malformation rupture.

Hemorrhage from an intrinsic vascular malformation of the optic chiasm (chiasmal apoplexy) is an uncommon cause of sudden visual loss with chiasmal visual field defects. This paper describes one case of sudden visual loss with an anterior chiasmal visual field defect due to rupture of an intrachiasmatic venous angioma and contrasts it with the clinical presentation of a case of hemorrhage from an intrachiasmatic arteriovenous malformation causing severe headache and a less apoplectic onset of visual symptoms. The variable clinical presentation and the accuracy of high resolution post-contrast cranial CT scan in the diagnosis of intrachiasmal hemorrhage is highlighted.