Carlson College of Veterinary Medicine

Decreased serum and CSF chloride concentrations were documented in a 5-year-old Manx cat referred for evaluation of anorexia. Inadequate chloride intake coupled with chloride loss through a fistulated meningomyelocele probably caused chloride deficiency. The inciting cause of anorexia was not determined. The cat was treated with 0.9% NaCl solution. Normal serum and CSF chloride concentrations were restored. Lumbar myelography was performed to delineate the meningocutaneous tract, which then was dissected surgically and was ligated. The cat's body attempted to maintain normal CSF chloride concentration even though the serum chloride concentration was decreased markedly. Calculations made on the basis of rate of CSF production, CSF chloride concentration, and duration of anorexia provided supportive evidence for an active transport system for chloride from plasma to CSF.