polioencephalomalacia (redirected from ruminant polioencephalomalacia)

polioencephalomalacia

softening of the cerebrocortical gray matter distributed in a laminar pattern. Called also laminar cortical necrosis, cortical necrosis.

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periventricular polioencephalomalacia

degenerative changes in periventricular nuclei in carnivores in thiamin deficiency. See thiamin nutritional deficiency.

ruminant polioencephalomalacia

a sporadic disease of unknown etiology occurring in cattle and sheep. The lesion is associated with thiamin deficiency or a disturbance in thiamin metabolism. It is characterized by a sudden onset of blindness, nystagmus, opisthotonos and tonic convulsions. Mild cases may remain standing, walk aimlessly and head press. At autopsy there is cerebral edema and laminar necrosis of the gray matter of the brain. Called also cerebrocortical necrosis.