CEREBRAL INFARCTION IN 2 CYNOMOLGUS MACAQUES (MACACA-FASCICULARIS) WITH HYPERNATREMIA

Hypernatremia resulting in neurologic symptoms ranging from lethargy t o coma, and with underlying lesions of cerebral hemorrhage and thrombo sis, has been reported in human beings. Herein we report two cases of cerebral infarction with venous thrombosis in cynomolgus monkeys. Both animals were severely hypernatremic because of water deprivation, wit h serum sodium levels of 185 and 193 meq/liter, respectively. At necro psy, there were bilateral multiple hemorrhagic and malacic areas visib le on the surface of the cerebrum and extending into the parenchyma, p rimarily involving the occipital lobes. These lesions were interpreted microscopically as infarcts because, in addition to hemorrhage and ne crosis, multiple thrombi were present in small and medium-sized veins of gray matter and meninges. The pathogenesis of hypernatremia-induced cerebral. lesions is believed to involve cellular dehydration that ca used shrinkage of the brain. Because the vasculature of the brain is t ightly adherent to the skull, this shrinkage results in tearing of blo od vessels, with consequent hemorrhage and thrombosis.