Missed Insulin Doses and a Sick Day in Type 1 Diabetes
A 19-year-old man with type 1 diabetes on basal-bolus insulin (glargine 22 units at night, aspart 8 units with meals) is brought to the pharmacy by his mother. He has had vomiting and diarrhoea for 24 hours, has not eaten, and has skipped his last two aspart doses because he 'didn't eat anything'. He is drowsy, has deep rapid breathing, and his breath smells of acetone. His glucose meter reads 'HI' (above 33 mmol/L). He has no ketone strips at home. He is reluctant to go to hospital because he has an exam tomorrow. His mother asks whether he can just take some glucose and rest.
1. Identify the clinical problem and explain why his reasoning about skipping insulin is dangerous.
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This is likely diabetic ketoacidosis (DKA): hyperglycaemia above the meter's range, vomiting, drowsiness, Kussmaul breathing and acetone breath are classic. His reasoning is the dangerous misconception that insulin is only needed when eating. Basal insulin is required continuously to suppress hepatic ketogenesis, and during illness, counter-regulatory hormones (cortisol, glucagon, catecholamines) increase insulin resistance and raise glucose even without food. Skipping bolus insulin while ill worsens ketone production. Vomiting and diarrhoea also cause dehydration and electrolyte loss, which accelerate DKA. He needs urgent hospital assessment with IV fluids, insulin infusion and electrolyte monitoring, particularly potassium, since total-body potassium is depleted even if serum potassium looks normal or high on admission. This is a medical emergency and cannot be managed at home.
2. The mother asks whether he can take oral glucose and rest. Formulate your response and your immediate actions.
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Explain clearly and kindly that oral glucose would make things worse, because his glucose is already dangerously high and his body is producing ketones; he needs insulin and fluids, not sugar. Do not send him home. Call emergency services or arrange immediate transfer to an emergency department, and stay with him until transport arrives. If he is drowsy, do not give anything by mouth because of aspiration risk. Check whether he has any hypoglycaemia treatment on him and remove the temptation to use it. Document the presentation, the 'HI' reading, the vomiting and the missed doses, and communicate this to the receiving team. His exam is not a reason to delay care; explain that DKA can be life-threatening and that arrangements can be made for a deferred or special sitting afterwards.
3. Assuming he recovers, what sick-day education would you provide before discharge to prevent recurrence?
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Teach the standard sick-day rules: never stop basal insulin, even when not eating; check glucose at least every 2-4 hours; check blood or urine ketones when glucose is above 14 mmol/L or when unwell, and act on the result; maintain fluids and, if unable to eat, use carbohydrate-containing fluids such as sugary drinks or juice to prevent hypoglycaemia while still taking insulin. Provide a written plan with clear thresholds for calling the diabetes team or attending hospital, for example persistent vomiting, ketones above 1.5 mmol/L on a blood meter, or inability to keep fluids down. Ensure he has a supply of ketone strips and a glucagon kit at home. Involve his mother in the education with his consent, and arrange follow-up with the diabetes specialist team. Reinforce that illness, not food intake, is the trigger for extra insulin and monitoring.