Is a dose of 900 units (u) of insulin considered lethal due to severe hypoglycemia?

Management of 900 Units Insulin Overdose

A 900-unit insulin overdose is potentially lethal and requires immediate emergency intervention to prevent severe hypoglycemia, neurological damage, and death. 1

Immediate Management Protocol

1. Initial Assessment and Stabilization

   • Establish IV access immediately
   • Monitor vital signs continuously
   • Obtain baseline blood glucose, electrolytes, liver function tests, and ECG

2. Hypoglycemia Treatment

   • Immediately administer 10-20g of hypertonic (50%) dextrose intravenously 2, 3
   • Stop any ongoing insulin infusion 3
   • Initiate continuous IV glucose infusion (10-20% dextrose) 4, 1
   • Titrate glucose infusion rate based on blood glucose levels 2

3. Monitoring Requirements

   • Check blood glucose every 15 minutes until stable, then hourly 3
   • Monitor serum potassium levels closely (insulin overdose causes hypokalemia) 4, 5
   • Monitor for hepatic disturbances and cardiac toxicity 1

Expected Clinical Course

With a 900-unit insulin overdose, expect:

• Prolonged hypoglycemic effect requiring 24-96 hours of continuous glucose infusion 1, 6
• Total glucose requirement can be estimated using the formula: Glucose (g) = 52 + (0.699 × insulin dose in units) 7
• For 900 units: approximately 681g of glucose may be needed
• Duration of IV glucose treatment (hours) = 10.5 + (0.028 × insulin dose in units) 7
• For 900 units: approximately 36 hours of IV glucose treatment

Complications to Monitor and Manage

• Neurological complications: 73% of insulin overdose cases experience intermittent cerebral impairment 1
• Electrolyte disturbances:
  • Hypokalemia (49% of cases) - requires careful potassium replacement 1, 5
  • Delayed hyperkalemia may occur 3-5 days after overdose as insulin effects wane 5
• Hepatic disturbances (7% of cases) 1
• Cardiac toxicity including arrhythmias (9% of cases) 1

Additional Treatment Options

If standard glucose infusion is insufficient:

• Glucagon (IV or IM) 1
• Octreotide (IV or IM) to reduce endogenous insulin secretion 1
• Surgical excision of the injection site if identified early 1, 6
• Hydrocortisone IV to promote gluconeogenesis 1

Prognosis

With appropriate and aggressive treatment:

• Most patients survive without long-term complications 1
• Hospitalization duration averages 94 hours (range 12-721 hours) 1
• One-third of cases require ICU admission 1
• Mortality is rare but possible with delayed treatment 1

Important Caveats

• Non-diabetic patients are more likely to develop recurrent hypoglycemia than diabetic patients 7
• Conventional duration of action of insulin preparations does not predict the duration of hypoglycemia in overdose cases 7
• Monitoring serum insulin concentration can help predict when the effects of overdose will cease 6, 8
• The risk of death appears to linearly correlate with the degree of hyperglycemia, with no clear cut-off 2

Prompt recognition and aggressive treatment of insulin overdose is essential to prevent mortality and long-term neurological sequelae.