Cerebral venous thrombosis in the rhesus monkey.

Cerebral venous thrombosis was identified in four rhesus monkeys. Two initially showed neurologic signs and three had diarrhea or dysentery. All four had severe intestinal disease, including three cases of ulcerative colitis complicated by extracerebral thromboembolic disease. Central nervous system lesions, confined to the centrum semiovale, were multiple thrombi of internal cerebral veins, perivenular demyelination, and gemistocytic astrocytosis. The lesions resembled those found in people with cerebral venous thrombosis, and support the hypothesis that perivenular demyelination may occur as a sequela to venous occlusion. The lesions were identical to those found in "leukoencephalosis and perivascular myelosis," an entity of unknown cause previously described in monkeys.