How should uncontrolled diabetes mellitus be managed in an adult patient?

Management of Uncontrolled Diabetes Mellitus

Uncontrolled diabetes requires immediate insulin therapy for Type 1 diabetes and insulin initiation when oral agents fail to control glycemic levels in Type 2 diabetes, with treatment intensity guided by diabetes type, clinical context, and presence of acute complications. 1

Initial Assessment and Diagnosis Confirmation

Confirm the diagnosis and determine diabetes type:

• Measure fasting blood glucose ≥126 mg/dL (7.0 mmol/L) on two occasions or HbA1c ≥6.5% to confirm diabetes 1, 2
• Check HbA1c to distinguish pre-existing diabetes (HbA1c ≥6.5%) from stress hyperglycemia (HbA1c <6.5%) in acutely ill patients 3
• Assess for diabetic ketoacidosis in Type 1 diabetes by checking for ketones, as insulin deficiency results in DKA within hours 1, 4
• Rule out hyperosmolar hyperglycemic state in Type 2 diabetes when glucose >180 mg/dL (10 mmol/L) with polyuria/glycosuria 1

Type 1 Diabetes Management

Type 1 diabetes always requires insulin therapy using a basal-bolus regimen:

• Administer basal insulin with one or two injections of slow- or intermediate-acting insulin daily 1
• Never stop basal insulin, even with normoglycemia, due to major risk of ketoacidosis 1
• Add prandial insulin using ultra-rapid analogues (5-minute onset) before meals, with larger amounts after carbohydrate-rich meals 1
• Avoid rapid (regular) insulin due to delayed action (20 minutes vs. 5 minutes) and prolonged duration (6 hours vs. 3 hours needed post-prandially) 1
• Alternative: continuous subcutaneous insulin delivery via pump 1
• Reduce basal insulin dose if hypoglycemia occurs, but maintain continuous coverage 1

Type 2 Diabetes Management

For Type 2 diabetes, escalate therapy systematically based on glycemic control:

Initial Therapy

• Start with non-insulin therapies including oral glucose-lowering drugs 1
• Metformin is first-line if renal function is normal (eGFR >30 mL/min/1.73 m²) 2
• Consider GLP-1 receptor agonists, noting they reduce gastric emptying and may cause gastroparesis 1

When to Add Insulin

• Initiate insulin when non-insulin therapies no longer control glycemic levels 1
• For blood glucose ≥250 mg/dL with symptoms, start insulin immediately at 0.2-0.3 U/kg/day as basal insulin plus correction doses 2
• Insulin and oral agents can be combined 1

Acute Hyperglycemic Crisis Management

For critically ill patients or those with hyperglycemic emergencies:

• Initiate continuous IV insulin infusion when blood glucose >180 mg/dL, targeting glucose ≤180 mg/dL 1, 3
• In ICU settings, maintain glucose 140-180 mg/dL (7.8-10 mmol/L) for most patients 1
• More stringent targets of 110-140 mg/dL may be appropriate for cardiac surgery patients, if achievable without hypoglycemia 1
• Administer IV insulin, rehydrate with NaCl solutions, and provide IV potassium (usually after initial hours of insulin/NaCl treatment) 5
• Administer NaHCO3 only if blood pH <7.1 5

Glycemic Targets and Monitoring

Set appropriate glucose targets based on clinical context:

• General inpatient target: 140-180 mg/dL (7.8-10 mmol/L) 1
• Outpatient target: systolic BP <130 mmHg, with HbA1c goals individualized 1
• In advanced CKD (eGFR <30), target HbA1c 7-8% to balance control with hypoglycemia risk 2
• Monitor blood glucose at every routine visit 1

Hypoglycemia Prevention and Management

Preventing and treating hypoglycemia is critical, especially in elderly and critically ill patients:

• Administer 15-20 g glucose orally for conscious patients with hypoglycemia 1
• Retest after 15 minutes; repeat treatment if hypoglycemia persists 1
• Prescribe glucagon for all patients at significant risk of severe hypoglycemia 1
• Raise glycemic targets for several weeks in patients with hypoglycemia unawareness to reverse the condition 1
• Elderly patients have increased hypoglycemia risk due to renal failure, malnutrition, and impaired counterregulatory responses 1

Lifestyle and Adjunctive Measures

Implement comprehensive lifestyle modifications:

• Prescribe at least 150 minutes/week of moderate-intensity aerobic exercise (50-70% maximum heart rate), spread over at least 3 days with no more than 2 consecutive days without exercise 1
• Add resistance training at least twice weekly 1
• Consider bariatric surgery for BMI >35 kg/m² with difficult-to-control diabetes 1
• Provide annual influenza vaccine and pneumococcal vaccine for patients ≥2 years 1

Common Pitfalls to Avoid

• Never discontinue basal insulin in Type 1 diabetes, even with normal glucose, as this leads to rapid ketoacidosis 1
• Avoid overly aggressive glucose lowering in elderly or critically ill patients, as hypoglycemia increases mortality 1
• Do not rely solely on continuous glucose monitor readings for diagnosis; confirm with venous plasma glucose 6
• Recognize that stress hyperglycemia is an independent prognostic factor for morbidity and mortality, requiring treatment even in non-diabetics 1, 3
• In patients with renal insufficiency, decreased gluconeogenesis and impaired insulin clearance increase hypoglycemia risk 1, 2