In a 70-year-old woman 2 days after an ischemic stroke with a random blood glucose of 12–13 mmol/L, should we observe, start an insulin infusion, or administer tPA?

Management of Hyperglycemia in a 70-Year-Old Woman 2 Days Post-Ischemic Stroke

The correct answer is A—OBSERVE. At 2 days post-stroke with a random blood glucose of 12–13 mmol/L (216–234 mg/dL), this patient does not require immediate insulin intervention; instead, confirm persistent hyperglycemia with repeat measurements every 6 hours before initiating subcutaneous insulin if levels consistently exceed 180 mg/dL (10 mmol/L). 1

Why Not Insulin Infusion Now?

• Intravenous insulin infusion is reserved for critically ill patients or those with persistent severe hyperglycemia (>200 mg/dL) in the hyperacute phase (first hours after stroke onset), not for stable patients 48 hours post-event. 1
• A single random glucose reading of 12–13 mmol/L does not warrant immediate insulin therapy; you must document sustained elevation through serial measurements every 6 hours over the first 24–48 hours. 1
• The patient is now stable in the stroke unit 2 days after onset, well beyond the critical hyperacute window where aggressive glucose control might theoretically matter. 1

Why Not tPA?

• tPA is absolutely contraindicated at 2 days post-stroke—the therapeutic window closed at 4.5 hours after symptom onset. 1 This option is irrelevant to glucose management and represents a dangerous misunderstanding of thrombolytic timing.

The Correct Approach: Observation with Serial Monitoring

Step 1: Confirm Persistent Hyperglycemia

• Measure blood glucose every 6 hours for the next 24–48 hours to determine whether the elevation is sustained or represents a transient stress response. 1
• Hyperglycemia occurs in >40% of acute stroke patients and is frequently stress-related, often resolving without pharmacologic intervention. 1
• Do not start insulin based on a single glucose reading—this is a common pitfall that leads to unnecessary treatment and hypoglycemia risk. 1

Step 2: Initiate Subcutaneous Insulin Only If Needed

• If repeat measurements persistently exceed 180 mg/dL (10 mmol/L), start subcutaneous insulin with a target range of 140–180 mg/dL—not intravenous infusion for a stable, non-critically ill patient. 1, 2
• Subcutaneous insulin protocols can safely lower and maintain blood glucose below 180 mg/dL in acute stroke patients without excessive healthcare resources. 1
• Use a basal-bolus regimen: long-acting basal insulin plus rapid-acting correction insulin for out-of-range values; add prandial insulin if the patient is eating. 3

Step 3: Avoid Aggressive Glucose Lowering

• Target 140–180 mg/dL, not normoglycemia (<140 mg/dL)—the GIST-UK trial and meta-analyses showed no functional benefit from tight control and increased rates of severe hypoglycemia and mortality. 1, 2
• Hypoglycemia (<60 mg/dL) can cause permanent brain damage and worsen ischemic injury, making it more immediately dangerous than moderate hyperglycemia in this setting. 1, 2

Evidence Supporting Conservative Management

• The American Heart Association/American Stroke Association guidelines recommend treating hyperglycemia only when blood glucose persistently exceeds 180 mg/dL, with a target of 140–180 mg/dL for critically ill patients. 1, 2
• The only large randomized trial (GIST-UK) testing insulin therapy in acute stroke showed no difference in clinical outcomes between insulin-treated and control groups, supporting a conservative approach. 1
• Hyperglycemia is more likely a marker of stroke severity and stress response rather than a direct cause of poor outcomes, based on observational data. 1

Additional Monitoring Considerations

• Check serum potassium before initiating any insulin therapy to prevent hypokalemia, a common and potentially dangerous electrolyte disturbance with insulin use. 4
• Continue cardiac telemetry to detect atrial fibrillation, which may emerge after stroke and require anticoagulation. 1
• Remain vigilant for signs of cerebral edema, which commonly peaks between days 3 and 5 after large infarctions. 1

Common Pitfalls to Avoid

• Do not reflexively start insulin for a single elevated glucose reading—confirm sustained hyperglycemia first. 1
• Do not use intravenous insulin infusion in stable, non-critically ill patients 48 hours post-stroke—subcutaneous protocols are appropriate and safer. 1
• Do not target glucose <140 mg/dL—this increases hypoglycemia risk without proven benefit. 1, 2
• Do not use sliding-scale insulin alone (reactive approach)—it is not recommended for managing hyperglycemia. 4

2, 1, 4, 3