Hypoglycaemic crisis from insulinoma: how to give dextrose
9-year-old Boxer with a recent insulinoma diagnosis presenting with seizures. Blood glucose is 28 mg/dL (1.6 mmol/L).
What is the most appropriate treatment?
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A. Repeated undiluted 50% dextrose boluses until blood glucose is high
Undiluted 50% dextrose is hyperosmolar and causes phlebitis. Large boluses also stimulate insulin secretion by the tumour and cause rebound hypoglycaemia.
B. Intravenous diazepam and phenobarbital to control the seizures
The seizures are caused by neuroglycopenia: treatment is correcting glucose. Anticonvulsants do not treat the cause and may mask the clinical course.
C. A small bolus of diluted dextrose until signs resolve, then a constant rate infusion of 2.5–5% dextrose, with small, frequent meals
Correct. The goal is to control clinical signs, not high-normal glucose. A constant rate infusion avoids peaks that stimulate the tumour. If insufficient, dexamethasone or a glucagon infusion is added.
D. Complete fasting until blood glucose stabilises
Fasting worsens hypoglycaemia. As soon as it is safe, small, frequent meals rich in protein and fibre are given.
lightbulb Key takeaway
In hypoglycaemia due to excess insulin (insulinoma), less is more: a small, diluted bolus followed by a constant rate infusion. At home during a crisis, the owner can rub honey or glucose syrup on the gums and come to the clinic. Other causes of hypoglycaemia in emergencies include sepsis, insulin overdose, xylitol, hypoadrenocorticism and juvenile hypoglycaemia in toy breeds.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.