Insulin Management During Illness in Diabetes
During illness, insulin should never be discontinued in people with diabetes, even if the patient is unable to eat or is vomiting. Instead, insulin dosages should be adjusted based on more frequent blood glucose monitoring.1, 2
General Principles for Insulin During Illness
- Insulin therapy must be continued during illness for all patients with diabetes, as insulin requirements often increase during illness despite decreased food intake 1, 2
- Self-monitoring of blood glucose (SMBG) should be performed more frequently during illness to guide insulin adjustments 1
- During acute illnesses, testing blood glucose and blood or urine for ketones, drinking adequate amounts of fluids, and ingesting carbohydrate are important preventive measures 1
Type 1 Diabetes-Specific Recommendations
- For patients with type 1 diabetes, continuing insulin is absolutely essential to prevent diabetic ketoacidosis, which can develop rapidly during illness 2
- Insulin dosage adjustments should be based on blood glucose measurements, not on food intake alone 1
- Even if the patient is unable to eat or is vomiting, insulin administration must continue to prevent ketoacidosis 1
Type 2 Diabetes-Specific Recommendations
- Patients with type 2 diabetes who use insulin should also continue their therapy during illness, with adjustments based on glucose monitoring 1
- Basal insulin should be maintained, while prandial insulin may need adjustment based on food intake 1
- If oral intake is poor, supplemental rapid-acting insulin may be required to correct hyperglycemia 1
Specific Insulin Adjustment Strategies
Carbohydrate Intake During Illness
- Oral ingestion of 150-200g of carbohydrate per day is recommended during illness to prevent starvation ketosis 1
- If regular food is not tolerated, liquid or soft carbohydrate-containing foods (sugar-sweetened drinks, juices, soups, ice cream) should be consumed 1
- Patients should increase fluid intake to prevent dehydration, preferably with fluids containing sodium (broth, tomato juice, sports drinks) 1
Insulin Dosing Adjustments
- For patients with hyperglycemia during illness, supplemental insulin may be required in addition to their usual regimen 1
- For patients experiencing hypoglycemia, treatment with 15-20g of glucose is effective, but blood glucose should be evaluated again in 60 minutes as additional treatment may be necessary 1
- Basal insulin should generally be maintained at the usual dose, while mealtime insulin may need adjustment based on carbohydrate intake and glucose levels 1
Monitoring Recommendations During Illness
- More frequent blood glucose monitoring is essential during illness, typically every 2-4 hours 1
- Testing for ketones in blood or urine is recommended for type 1 diabetes patients during illness, especially when glucose levels are elevated 1
- Patients should contact healthcare providers if blood glucose remains >250 mg/dL, if moderate to large ketones are present, or if unable to maintain adequate hydration 1
Special Considerations
- For patients on insulin pumps, basal rates may need to be temporarily increased during illness 1
- For patients on multiple daily injections, maintaining the long-acting basal insulin is critical while adjusting rapid-acting insulin as needed 1
- Patients should have a sick-day management plan established in advance with their healthcare provider 2
Warning Signs to Seek Immediate Medical Attention
- Persistent vomiting or inability to retain fluids 1
- Blood glucose levels consistently above 300 mg/dL despite supplemental insulin 1
- Presence of moderate to large ketones 1
- Signs of dehydration (dry mouth, decreased urination, dizziness) 1
- Changes in mental status or level of consciousness 1
Remember that discontinuing insulin during illness can lead to serious complications including diabetic ketoacidosis in type 1 diabetes and severe hyperglycemia in type 2 diabetes, both of which can be life-threatening conditions 2.