Hypernatremia

Hypernatremia is a potentially life-threatening electrolyte abnormality. This problem develops most often because of loss of water from the animal, but in rare cases hypernatremia results from gain of sodium chloride. Important conditions predisposing to hypernatremia include diarrhea, vomiting, heat stroke, fever, limited access to water, excessive diuretic use, renal diseases, and pituitary diabetes insipidus. This condition rarely develops if animals have adequate access to water. Clinical signs relate to central nervous system derangements and can progress to seizures and coma. Diagnosis is based on the serum sodium concentration; treatment should be instituted if it is greater than 170 mEq per L. Treatment is based on knowledge of the volume status of the patient and the probable cause for the hypernatremia. In general, 5 per cent dextrose in water or other hypotonic fluids are given slowly intravenously. The rate of administration should be adjusted so the water deficit is replaced over 48 to 72 h. Too rapid correction of hypernatremia can lead to cerebral edema and worsening of the animal. In cases of salt intoxication, diuretics must be given in addition to slow water replacement to avoid the development of pulmonary edema.