How do I manage a dog or cat presenting in diabetic ketoacidosis, including fluid and insulin protocols?

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Immediate stabilization with IV crystalloid fluid therapy is the cornerstone of DKA management in dogs and cats, initiated before insulin is started to correct hypovolemia, hypotension, and electrolyte derangements. 13 Fluid resuscitation should use isotonic crystalloids, with 0.9% sodium chloride (NaCl) reported as safe and effective for resuscitation in feline DKA. 7 Electrolyte abnormalities — hyponatremia, hypokalemia, hypophosphatemia, and hypomagnesemia — are over three times more common than above-normal values in DKA patients despite aggressive supplementation, so frequent monitoring and proactive correction are required throughout hospitalization. 7 Insulin therapy is the definitive treatment to halt ketogenesis, and three IV continuous rate infusion (CRI) protocols have been described in dogs and cats. Regular insulin CRI and fixed-rate insulin infusion (FRI) at 0.01 IU/kg/h are both established options. 6 Lispro insulin CRI at a starting dose of 0.09 U/kg/h is safe and effective in cats, achieving blood glucose below 250 mg/dL in a median of 7 hours, compared to a median of 12.5 hours with regular insulin CRI. 7 Two cats treated with lispro developed non-clinical hypoglycemia (blood glucose 40 mg/dL), so close glucose monitoring is required regardless of protocol. 7 For IV regular insulin CRI, maintaining the insulin infusion rate constant until target beta-hydroxybutyrate (BHB) is reached — rather than reducing the rate when glucose falls — is associated with faster resolution of ketonemia. In cats managed with this approach, median time to resolution of ketonemia was 42 hours. 10 When blood glucose falls below 180 mg/dL (10 mmol/L), 5% dextrose solutions should be co-administered to allow continued insulin delivery without inducing hypoglycemia. 10 If hypoglycemia develops and a dextrose bolus is needed, 0.5–1 mL/kg (0.25–0.5 g/kg) of 50% dextrose diluted 1:2–1:4 and administered over 2–5 minutes is appropriate, followed by a CRI of 1.25–5% dextrose. 8