What causes high ketones in a patient with type 2 diabetes receiving insulin?

Causes of High Ketones in Type 2 Diabetes Patients Receiving Insulin

Insulin deficiency or omission is the primary cause of elevated ketones in patients with type 2 diabetes who are receiving insulin therapy. 1 When insulin levels are inadequate, the body shifts to fat metabolism, producing ketone bodies that can lead to diabetic ketoacidosis (DKA).

Primary Causes of Elevated Ketones

1. Insulin-Related Factors:

   • Missed or inadequate insulin doses - The most common cause 1, 2
   • Insulin pump malfunction (if applicable) - Disconnection, occlusion, or leakage 2
   • Insulin degradation due to improper storage 3

2. Physiological Stressors:

   • Acute illness or infection - Increases counterregulatory hormones 1, 2
   • Surgery or trauma - Triggers stress response 1
   • Myocardial infarction - Creates metabolic demand 1

3. Medication-Related Factors:

   • SGLT2 inhibitor use - Can cause euglycemic DKA (ketoacidosis with normal or only mildly elevated blood glucose) 1, 2
   • Glucocorticoid therapy - Increases insulin resistance 1
   • Second-generation antipsychotics - Affect glucose metabolism 1

4. Dietary and Lifestyle Factors:

   • Very low-carbohydrate diets - Promote ketogenesis 2
   • Prolonged fasting - Depletes glycogen stores 2, 4
   • Alcohol consumption - Impairs gluconeogenesis 2
   • Dehydration - Concentrates ketones and impairs clearance 1

5. Specific Clinical Scenarios:

   • Ketosis-prone type 2 diabetes - A subtype with tendency for ketosis 1
   • Severe hyperglycemia (HbA1c >10%) - Indicates profound insulin deficiency 1

Clinical Presentation and Monitoring

Patients with elevated ketones may present with:

• Nausea, vomiting, abdominal pain
• Dehydration
• Fruity breath odor
• Rapid breathing (Kussmaul respiration)
• Altered mental status in severe cases

Ketone levels can be classified as 2:

• <0.5 mmol/L: Normal range
• 0.5-1.5 mmol/L: Mild elevation
• 1.5-3.0 mmol/L: Moderate elevation

• 3.0 mmol/L: Dangerous level

Management Approach

1. For mild to moderate ketosis:

   • Increase insulin dosage according to a correction scale
   • Ensure adequate hydration
   • Consume 150-200g carbohydrates daily 2
   • Monitor blood glucose and ketones frequently

2. For severe ketosis or DKA:

   • Immediate hospital admission
   • IV fluids, electrolyte replacement
   • IV insulin infusion at 0.1 unit/kg/hr 2
   • Close monitoring of acid-base status

Prevention Strategies

1. Patient education on sick day management:

   • Never discontinue basal insulin, even when not eating 2
   • Increase monitoring during illness
   • Have a clear plan for insulin dose adjustments
   • Know when to seek medical attention

2. Technology utilization:

   • Consider continuous glucose monitoring for early detection of problems
   • For pump users, regular inspection of infusion sites and equipment

3. Medication considerations:

   • For patients on SGLT2 inhibitors, consider temporary discontinuation during acute illness 1
   • Ensure proper insulin storage and handling 3

Special Considerations

• Euglycemic DKA: Can occur with SGLT2 inhibitors even when blood glucose is <200 mg/dL 2
• Measuring ketones: Blood β-hydroxybutyrate measurement is preferred over urine ketones 2, 4
• Resolution criteria: DKA is considered resolved when glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap <12 mEq/L 2

Understanding these causes and implementing appropriate monitoring and management strategies can help prevent the progression to diabetic ketoacidosis, a potentially life-threatening complication in patients with type 2 diabetes receiving insulin therapy.