How to manage severe hyperglycemia?

Management of Blood Glucose 420 mg/dL

Immediately initiate insulin therapy for this severe hyperglycemia, with the specific approach depending on whether the patient has signs of diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS). 1, 2

Immediate Assessment

First, evaluate for hyperglycemic crisis by checking for:

• Mental status changes, confusion, or altered consciousness 1, 2
• Dehydration signs (dry mucous membranes, poor skin turgor, tachycardia, hypotension) 1, 2
• Fruity breath odor (acetone breath suggesting ketosis) 1, 2
• Abdominal pain, nausea, or vomiting 1, 2
• Rapid, deep breathing (Kussmaul respirations in DKA) 3

Obtain stat labs:

• Complete metabolic panel (assess anion gap, bicarbonate, potassium) 1, 2
• Serum or urine ketones 1, 2
• Arterial blood gas if DKA suspected (pH <7.3 indicates DKA) 1, 2

Treatment Algorithm Based on Clinical Presentation

If DKA or HHS Present (Ketosis, Acidosis, or Severe Dehydration)

Start continuous intravenous insulin infusion immediately - this is the standard of care for hyperglycemic crises. 3, 1, 2

• Begin aggressive IV fluid resuscitation to restore circulatory volume before or concurrent with insulin 1, 2
• Monitor potassium closely and replace aggressively - hypokalaemia occurs in ~50% of cases during treatment and severe hypokalaemia (<2.5 mEq/L) increases mortality 3
• Target glucose range of 140-180 mg/dL during IV insulin therapy 1, 2
• Check blood glucose every 30 minutes to 2 hours during IV insulin infusion 2
• Do not use bicarbonate - studies show no benefit in resolution of acidosis 1

If No DKA/HHS (Asymptomatic or Mild Symptoms, No Ketosis)

For blood glucose ≥250 mg/dL with symptoms (polyuria, polydipsia, weight loss), start basal insulin while initiating metformin. 3, 1, 2

• Calculate initial basal insulin dose at 0.2-0.25 units/kg once daily (using glargine or detemir) 2
• Add prandial rapid-acting insulin (lispro, aspart, or glulisine) at 0.1-0.15 units/kg divided into three pre-meal doses 2
• Provide correction doses with rapid-acting insulin for persistent hyperglycemia 2
• Start metformin simultaneously if renal function is normal 3, 1, 2

Critical Care Patients

Use continuous IV insulin infusion targeting 140-180 mg/dL - this is the preferred regimen for ICU patients with hyperglycemia. 3, 1, 2

Transition from IV to Subcutaneous Insulin

When transitioning from IV insulin (once patient is stable, glucose consistently <200 mg/dL, anion gap normalized):

• Administer basal subcutaneous insulin 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia 1, 2
• Calculate total daily subcutaneous insulin dose from the average hourly IV insulin rate over the preceding 12 hours (e.g., 1.5 units/hour × 24 = 36 units/day total) 3
• Distribute as 50% basal and 50% prandial insulin 2

Common Pitfalls to Avoid

Never use sliding scale insulin alone without basal insulin - this approach is widely condemned in guidelines and associated with poor glycemic control. 3, 2

Do not transition to subcutaneous insulin too early - ensure the patient has stable glucose for 4-6 hours consecutively, normal anion gap, resolution of acidosis, hemodynamic stability, and stable nutrition plan. 3

Watch for hypokalaemia during treatment - this is the most common and dangerous electrolyte abnormality, occurring in approximately 50% of hyperglycemic crisis cases. 3

Monitoring and Tapering

• Monitor blood glucose before meals and at bedtime once on subcutaneous insulin 2
• Adjust insulin doses daily based on blood glucose patterns 2
• For patients meeting glucose targets on insulin plus metformin, taper insulin over 2-6 weeks by decreasing the dose 10-30% every few days 3, 1

Follow-up and Prevention

• Schedule follow-up within 1-2 weeks to reassess glycemic control 1, 2
• Provide diabetes self-management education to prevent recurrence 1, 2
• Consider combination therapy for patients with A1C >8.5% at diagnosis to achieve more rapid control 1