Syndrome of inappropriate antidiuretic hormone secretion in a cat.

A 3-year-old, spayed female, domestic shorthaired cat was presented for evaluation of liver disease. Following anesthesia, laparoscopy, and medical therapy, the cat developed severe hyponatremia that was unresponsive to fluid therapy. Further evaluation of serum and urine osmolality determined that the cat fulfilled the criteria for syndrome of inappropriate antidiuretic hormone secretion. Treatment with fluid restriction resulted in resolution of the hyponatremia and clinical signs associated with the electrolyte imbalance.