Hypodipsic hypernatremia and associated myopathy in a hydrocephalic cat with transient hypopituitarism.

Hypodipsic hypernatremia developed in association with hypopituitarism and hydrocephalus in a 7-month-old cat. Initial clinical signs (generalized weakness, cervical ventroflexion) were related to a hypernatremia-induced polymyopathy. Forced water intake and dietary sodium restriction corrected the hypernatremia and signs of muscle dysfunction. After restoration of eunatremia, secretion of pituitary hormones normalized. It was speculated that hypothalamic dysfunction, possibly related to hydrocephalus, induced both hypodipsia and transient hypopituitarism.