Type 1 diabetes: insulin therapy, technology and ambulatory care — formative SAQs

SAQ 1 — The sick child whose insulin was stopped (10 marks)

A 9-year-old with established type 1 diabetes on a basal-bolus regimen develops a febrile viral illness with poor appetite. The parents, concerned that she is eating little, omit her insulin for 24 hours. She now presents with vomiting, deep sighing respirations and drowsiness; glucose is 24 mmol/L, blood ketones 4.2 mmol/L, and venous pH 7.12. This is presentation diabetic ketoacidosis precipitated by the most common sick-day error. [2]

Answer the following

1. Identify the critical error in the sick-day management that precipitated the deterioration, and state the governing principle of sick-day insulin management. [2]
2. Outline the correct sick-day routine the family should have followed at home. [2]
3. List the escalation criteria that should have prompted urgent review before ketoacidosis developed. [2]
4. State two specific education points you would reinforce with this family before discharge to prevent recurrence. [1]

Model marking guide

1. The critical error was stopping insulin during illness. The governing principle is that insulin is never stopped during intercurrent illness — fever and the stress response raise insulin needs, so the dose is usually increased, and withholding insulin is the commonest precipitant of sick-day ketoacidosis. [2]
2. Check glucose every 2–4 hours; check blood ketones (beta-hydroxybutyrate) at every glucose check; maintain hydration with small frequent carbohydrate-containing fluids; give extra rapid-acting insulin for hyperglycaemia with ketones per the sick-day plan; never omit basal insulin. [2]
3. Escalate for: vomiting preventing fluid retention; ketones rising despite extra insulin (above 1.5 mmol/L and climbing); deep or rapid breathing; drowsiness; persistent hyperglycaemia above 15–20 mmol/L. [2]
4. Reinforce that insulin is never stopped during illness and the dose usually rises; ensure a written sick-day plan with a named team contact and clear thresholds for calling; confirm ketone strips and sick-day supplies at home; teach the family to call early in the ketotic-but-not-acidotic window. [1]

SAQ 2 — The pump-treated child with ketones (10 marks)

A 7-year-old on an insulin pump for two years presents with 6 hours of abdominal pain and vomiting. Glucose is 19 mmol/L, blood ketones 2.8 mmol/L. The cannula site appears normal and the pump reservoir is half full. The rapid ketosis in a well-appearing site is the hallmark of pump-site failure. [4]

Answer the following

1. Explain why a child on an insulin pump can develop ketones and ketoacidosis within hours, even when the cannula site looks normal and the reservoir is full. [4]
2. State the immediate management at this point. [2]
3. State the ISPAD 2024 HbA1c and time-in-range targets you would aim for once she is stabilised, and give one reason time-in-range adds information beyond HbA1c. [3]
4. Describe one structured intervention that reduces the risk of being lost to follow-up and deteriorating at the eventual transition to adult care. [1]

Model marking guide

1. A pump delivers only a rapid-acting analogue as a micro-pulsed basal with no long-acting depot. A blocked, kinked or dislodged cannula removes all insulin within a few hours, so ketones and ketoacidosis develop far faster than in a child on injections. A site that looks normal does not exclude a subcutaneous occlusion. [4]
2. Give a rapid-acting insulin correction by pen (not through the suspect site), insert a new cannula site, check ketones hourly, hydrate, and escalate to the DKA pathway if ketones rise or acidosis develops. [2]
3. The targets are an HbA1c below 7 percent (53 mmol/mol) and a time-in-range above 70 percent with time-below-range below 4 percent. Time-in-range reveals the hypoglycaemia burden and glycaemic variability that HbA1c — a mean measure — masks. [3]
4. A structured transition beginning in the early to mid-teens, using joint paediatric-adult clinics, skills checklists, and a formal handover that carries the medical summary and psychosocial context, is the intervention most associated with preventing loss to follow-up and deterioration. [1]