What is the next step in managing a patient with severe hyperglycemia (glucose level over 500 mg/dL)?

Management of Severe Hyperglycemia (Glucose >500 mg/dL)

Immediately assess for diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS) and initiate urgent fluid resuscitation with 0.9% sodium chloride at 15-20 mL/kg/hour during the first hour, followed by intravenous insulin therapy. 1, 2

Immediate Assessment (First 30 Minutes)

Check for life-threatening hyperglycemic emergencies by evaluating mental status, hydration status, and signs of metabolic decompensation 1, 2:

• Altered mental status, drowsiness, or confusion suggest severe metabolic derangement requiring ICU-level care 1, 3
• Dehydration signs including dry mucous membranes, poor skin turgor, tachycardia, and hypotension 1
• Ketosis indicators such as fruity breath odor, nausea, vomiting, or abdominal pain 3
• Respiratory pattern noting Kussmaul breathing (deep, rapid respirations) which indicates severe acidosis 3

Obtain urgent laboratory tests 1, 2:

• Blood glucose, serum electrolytes (sodium, potassium, chloride, bicarbonate)
• Blood urea nitrogen (BUN) and creatinine
• Serum or urine ketones
• Arterial or venous blood gas for pH
• Serum osmolality
• Complete blood count to assess for infection

Initial Treatment Protocol

Fluid Resuscitation (Start Immediately)

Begin 0.9% sodium chloride at 15-20 mL/kg/hour (approximately 1-1.5 liters) during the first hour to restore circulatory volume and tissue perfusion 1. This aggressive initial fluid replacement is critical as patients with glucose >500 mg/dL typically have severe volume depletion of 5-10 liters.

After the first hour, adjust fluid rate based on hydration status, electrolytes, and urine output 1:

• Continue 0.9% saline at 250-500 mL/hour if corrected sodium is low or normal
• Switch to 0.45% saline at 250-500 mL/hour if corrected sodium is elevated

Insulin Therapy (Start After Initial Fluid Bolus)

Administer intravenous insulin bolus of 0.1 units/kg body weight, followed by continuous infusion at 0.1 units/kg/hour 1. The continuous IV insulin infusion is the preferred method for achieving glycemic targets in this critical situation 4.

Monitor blood glucose every 1-2 hours initially and adjust insulin infusion to achieve a glucose decline of 50-75 mg/dL per hour 1, 3:

• If glucose does not fall by at least 50 mg/dL in the first hour, double the insulin infusion rate
• When glucose reaches 250 mg/dL, reduce insulin infusion rate and add dextrose-containing fluids to prevent hypoglycemia while continuing to clear ketones

Electrolyte Management

Potassium replacement is critical even if initial levels are normal or elevated, as insulin therapy and correction of acidosis will drive potassium intracellularly 1:

• Hold insulin if potassium <3.3 mEq/L and replace aggressively
• Add 20-30 mEq potassium to each liter of IV fluid once potassium is 3.3-5.0 mEq/L
• Monitor potassium every 2-4 hours during acute management

Draw blood every 2-4 hours for electrolytes, glucose, BUN, creatinine, osmolality, and venous pH to guide ongoing therapy 1.

Transition to Subcutaneous Insulin

Transition from IV to subcutaneous insulin 2-4 hours before stopping the IV infusion to prevent rebound hyperglycemia 1, 2. This overlap period is essential as subcutaneous insulin takes time to reach therapeutic levels.

Use a basal-bolus insulin regimen rather than sliding scale insulin alone, which is strongly discouraged and ineffective 4, 2:

• Calculate total daily insulin dose at 0.5-0.8 units/kg/day based on patient's weight 2
• Divide into 50% basal insulin (long-acting analog such as glargine or detemir) given once daily 4, 2
• Divide remaining 50% as prandial insulin (rapid-acting analog such as aspart, lispro, or glulisine) before meals 4, 2

Target Glucose Range

Target glucose range of 140-180 mg/dL for most hospitalized patients once the acute crisis is resolved 4, 1, 2. This range balances glycemic control with hypoglycemia risk. More stringent targets of 110-140 mg/dL may be appropriate for select patients if achievable without significant hypoglycemia, but avoid overly strict control during acute illness as this increases hypoglycemia risk 4, 2.

Critical Pitfalls to Avoid

Never use sliding scale insulin as monotherapy as this approach is ineffective and leads to wide glucose fluctuations 4, 2, 5. The sliding scale only treats hyperglycemia after it occurs rather than preventing it.

Never discontinue insulin completely in type 1 diabetes patients even when infection or acute illness resolves, as this can precipitate DKA 4, 2, 3.

Avoid oral hypoglycemic agents during acute severe hyperglycemia especially with impaired oral intake or signs of DKA/HHS 2. Insulin is the only appropriate therapy in this setting 4, 5, 6.

Do not delay fluid resuscitation while waiting for laboratory results, as severe dehydration contributes significantly to morbidity and mortality 1.

Ongoing Monitoring and Discharge Planning

Monitor blood glucose every 4-6 hours once stabilized on subcutaneous insulin and adjust doses daily based on results 2, 6.

Develop a structured discharge plan that addresses the precipitating cause (infection, medication non-adherence, new-onset diabetes), ensures diabetes self-management education focusing on medication adherence, glucose monitoring, and sick-day management 1, 2. Never discontinue insulin during intercurrent illness as this can precipitate recurrent DKA 1, 2.