Ischemic chiasma syndrome.

Thirty patients with chiasma syndrome attributed to ischemic processes of various origins are described. The initial diagnosis was made after an investigation based on polytome pneumoencephalography and angiography. This diagnosis was confirmed later with the use of high-resolution computed tomography (CT) and refined angiographic techniques. The ischemic chiasma syndrome may be classified into five pathogenetic categories: (1) mechanical compression of the chiasm secondary to ectatic tortuous arteries; (2) vascular occlusion secondary to atheromatous plaque formation; (3) arachnoiditis with fibrosis; (4) arteritis of various origins; and (5) postpartum necrosis. Sophisticated neurologic procedures including magnification angiography and high-resolution CT are essential in ruling out a mass lesion and correlating the clinical and radiologic findings of this syndrome.