What is the recommended rate of dextrose (intravenous glucose) administration in cases of starvation ketosis?

Management of Starvation Ketosis with Dextrose Infusion

For starvation ketosis, dextrose should be administered at 5-10% concentration when plasma glucose reaches 250-300 mg/dL, with insulin infusion adjusted to maintain these glucose values until acidosis resolves. 1

Initial Assessment and Diagnosis

• Starvation ketosis is distinguished from diabetic ketoacidosis (DKA) by clinical history and plasma glucose concentrations that range from mildly elevated (rarely >250 mg/dL) to hypoglycemic 1
• Serum bicarbonate in starvation ketosis is usually not lower than 18 mEq/L, helping differentiate it from other forms of ketoacidosis 1
• Laboratory evaluation should include plasma glucose, blood urea nitrogen, creatinine, serum ketones, electrolytes with calculated anion gap, osmolality, and arterial blood gases 2

Dextrose Infusion Protocol

• Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour to restore circulatory volume and tissue perfusion 2
• When plasma glucose reaches appropriate levels (250-300 mg/dL), add dextrose (5-10%) to intravenous fluids 1
• The rate of dextrose administration should be adjusted to maintain glucose values until acidosis resolves 1
• For patients with mild starvation ketosis, oral carbohydrate intake of 150-200g per day (45-50g every 3-4 hours) will reduce or prevent ketosis 2

Insulin Considerations

• If insulin is being used (in cases with more severe acidosis), the insulin infusion rate may be decreased to 0.05-0.1 U/kg/h (3-6 U/h) when dextrose is added 1
• The ratio of insulin to glucose should be approximately 1 unit of insulin for every 4g of glucose when treating ketosis with concurrent hyperkalemia 1

Electrolyte Management

• Once renal function is assured and serum potassium is known, add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) to the infusion 1, 2
• Monitor phosphorus levels closely, as rapid correction of ketosis can lead to hypophosphatemia 3
• Phosphorus is a critical cofactor necessary for NADH oxidation and correction of acidosis 3

Monitoring and Ongoing Management

• During therapy, blood should be drawn every 2-4 hours for determination of serum electrolytes, glucose, blood urea nitrogen, creatinine, and osmolality 1, 2
• Monitor venous pH and anion gap to follow resolution of acidosis 1
• Be aware that ketonemia typically takes longer to clear than hyperglycemia 1

Expected Response to Treatment

• Consuming 15g of carbohydrates will raise blood glucose by approximately 40 mg/dL over 30 minutes 4
• Pure glucose produces a greater rise in plasma glucose than equivalent amounts of carbohydrate from other sources 4
• The initial response to treatment should be seen within 10-20 minutes, but blood glucose should be evaluated again in 60 minutes as additional treatment may be necessary 4

Common Pitfalls and Caveats

• Do not confuse starvation ketosis with diabetic ketoacidosis or alcoholic ketoacidosis, as treatment approaches differ 2, 5
• Assessments of urinary or serum ketone levels by the nitroprusside method should not be used as an indicator of response to therapy, as it only measures acetoacetic acid and acetone, not β-hydroxybutyrate (the strongest and most prevalent acid in ketosis) 1
• Starvation ketosis can occur in various scenarios including strict ketogenic diets, pregnancy, and childhood illness, requiring prompt recognition and treatment 5, 6, 7
• Avoid rapid correction of osmolality to prevent cerebral edema 2