What is the most appropriate medication for an 18-year-old man presenting with hyperglycemia (elevated blood glucose), nausea, frequent urination, unintentional weight loss, hypotension (low blood pressure), tachycardia (rapid heart rate), and dry oral mucosa?

Management of Hyperglycemia in an 18-Year-Old with Diabetic Ketoacidosis

Insulin is the most appropriate medication for this patient presenting with severe hyperglycemia, weight loss, and signs of dehydration.

Clinical Assessment

This 18-year-old male presents with classic symptoms of undiagnosed diabetes:

• Random blood glucose of 565 mg/dL (severely elevated)
• 9.1 kg unintentional weight loss over 10 weeks
• Polyuria (frequent urination)
• Nausea
• Signs of dehydration (dry oral mucosa)
• Tachycardia (HR 110/min) and hypotension (BP 95/70 mmHg)
• Labored respirations

These findings strongly suggest diabetic ketoacidosis (DKA), a medical emergency requiring immediate insulin therapy.

Treatment Rationale

The American Diabetes Association (ADA) guidelines clearly state that insulin should be used with any combination regimen in newly diagnosed patients when severe hyperglycemia causes unintentional weight loss 1. This patient's presentation meets these criteria.

For patients with marked hyperglycemia (blood glucose ≥250 mg/dL), significant symptoms, and weight loss, basal insulin is the recommended initial therapy 1. In cases with ketosis/ketoacidosis, treatment with subcutaneous or intravenous insulin should be initiated to rapidly correct the hyperglycemia and metabolic derangement 1.

Why Other Options Are Inappropriate

• Exenatide (GLP-1 receptor agonist): Not appropriate for patients with suspected type 1 diabetes or DKA. These agents are contraindicated in acute severe hyperglycemia requiring rapid correction 1.

• Glimepiride (sulfonylurea): Inappropriate for patients with severe hyperglycemia and suspected DKA. Sulfonylureas stimulate endogenous insulin production, which is ineffective if the patient has significant beta-cell dysfunction or type 1 diabetes 2.

• Pioglitazone (thiazolidinedione): Has slow onset of action and is not suitable for acute hyperglycemia management. It's contraindicated in patients with heart failure, which can develop in severe DKA 1.

• Sitagliptin (DPP-4 inhibitor): Has modest glucose-lowering effects and is insufficient for severe hyperglycemia management. Not appropriate for suspected type 1 diabetes or DKA 1.

Treatment Protocol

1. Initial management:

   • Intravenous (IV) insulin infusion if DKA is confirmed 1
   • Fluid resuscitation to correct dehydration
   • Electrolyte replacement as needed

2. Transition to subcutaneous insulin:

   • Once metabolically stable, transition to basal-bolus insulin regimen
   • Basal insulin (glargine, detemir, or degludec) plus mealtime insulin 1
   • Initial dosing: 0.3-0.5 units/kg/day total, divided between basal and bolus insulin 3

Monitoring and Follow-up

• Frequent blood glucose monitoring initially (hourly during IV insulin)
• Electrolyte monitoring, particularly potassium
• Assessment for resolution of acidosis if DKA present
• HbA1c measurement to assess chronic glycemic control 1
• Diabetes education prior to discharge

Important Considerations

• This patient's presentation is highly suspicious for type 1 diabetes given his age, acute presentation, and significant weight loss
• Autoantibody testing should be performed to confirm diagnosis
• Insulin therapy should not be delayed while awaiting test results 1
• The patient will likely require lifelong insulin therapy if type 1 diabetes is confirmed

Common Pitfalls to Avoid

• Misdiagnosing as type 2 diabetes based solely on prevalence
• Attempting oral agents before insulin in a patient with this severe presentation
• Inadequate fluid resuscitation alongside insulin therapy
• Failure to monitor for and prevent hypoglycemia during treatment
• Discharging without comprehensive diabetes education and follow-up plan