Iatrogenic water intoxication in two cats

Objective To describe 2 cats that developed acute iatrogenic water intoxication, one associated with a continuous infusion of water provided via an esophagostomy tube and one following SC administration of 5% dextrose in water (D5W). Case or Series Summary A 10‐year‐old cat with squamous cell carcinoma was hospitalized for treatment of dehydration. Rehydration was provided with water via an esophagostomy tube at 5.7 mL/kg/h. After 30 hours of therapy, the cat was found dull and weak. Serum sodium was markedly decreased at 116 mmol/L (116 mEq/L). Supplemental water was stopped, and IV furosemide and mannitol were provided to eliminate free water. Hypertonic saline (1.5%) was admininstered IV to rapidly restore the sodium concentration. The serum sodium concentration corrected over 17 hours, and the cat was discharged without neurological complications. The second cat had previously received 300 mL D5W subcutaneously and represented 8 hours later with lethargy and paresis with a serum sodium level of 126 mmol/L (126 mEq/L). Intravenous fluid therapy was provided using 0.9% NaCl. Over the following day, the cat's mentation and paresis resolved and sodium concentrations normalized. New or Unique Information Provided These 2 cases describe a presumed uncommon iatrogenic complication of severe hyponatremia due to water provided either via an esophagostomy tube or subcutaneously. While oral rehydration is often considered ideal, it may result in signs of water intoxication if not carefully monitored; additionally, D5W is never considered an acceptable fluid choice as a SC bolus. If promptly recognized, acute hyponatremia may be corrected rapidly with no lasting consequences.