What is the appropriate management for a type 1 diabetic patient presenting with nausea, vomiting, diarrhea and mild‑to‑moderate diabetic ketoacidosis (blood glucose 171 mg/dL, serum ketones 2.44 mmol/L, bicarbonate 21 mmol/L, anion gap 19 mEq/L, pH 7.35)?

Management of Mild Diabetic Ketoacidosis with Gastrointestinal Symptoms

This patient has mild diabetic ketoacidosis (pH 7.35, bicarbonate 21 mEq/L, anion gap 19 mEq/L, ketones 2.44 mmol/L) and should be treated with aggressive fluid resuscitation, continuous intravenous insulin infusion, and early addition of dextrose-containing fluids given the relatively low glucose of 171 mg/dL. 1

Initial Assessment and Classification

Your patient meets criteria for mild DKA based on:

• pH 7.35 (mild DKA: 7.25-7.30; this is borderline) 2
• Bicarbonate 21 mEq/L (mild DKA: 15-18 mEq/L; this is borderline) 2
• Anion gap 19 mEq/L (elevated, consistent with DKA) 2
• Ketones 2.44 mmol/L (significantly elevated; normal <0.5 mmol/L) 2
• Glucose 171 mg/dL (below the typical 250 mg/dL threshold, suggesting euglycemic DKA) 2, 3

The combination of nausea, vomiting, and diarrhea with inadequate carbohydrate intake has precipitated starvation ketosis superimposed on insulin deficiency, creating this euglycemic presentation. 4, 5

Critical Initial Management Steps

1. Fluid Resuscitation (First Priority)

Begin isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour for the first hour to restore circulatory volume and tissue perfusion. 1 For a 70-kg patient, this equals approximately 1,050-1,400 mL in the first hour. 1

• The typical total body water deficit in DKA is 6-9 liters, and replacement should correct this over 24 hours. 1
• After the first hour, continue isotonic saline at 4-14 mL/kg/hour depending on hydration status and corrected sodium. 1

2. Potassium Assessment (Before Insulin)

Check serum potassium immediately and do NOT start insulin if potassium is <3.3 mEq/L. 1 This is a Class A recommendation (highest level of evidence). 1

• If K⁺ <3.3 mEq/L: Hold insulin and aggressively replace potassium first to prevent fatal cardiac arrhythmias. 1
• If K⁺ 3.3-5.5 mEq/L: Start insulin AND add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄). 1
• If K⁺ >5.5 mEq/L: Start insulin immediately but delay potassium supplementation until levels fall. 1

3. Modified Insulin Protocol for Euglycemic DKA

Because the glucose is only 171 mg/dL, you must modify the standard DKA protocol:

Start dextrose-containing fluids (D5W with 0.45-0.75% NaCl) immediately along with insulin infusion. 1, 3 This is the critical difference from typical DKA management.

• Begin continuous IV regular insulin at 0.1 units/kg/hour (no bolus needed for mild DKA). 1
• The dextrose prevents hypoglycemia while insulin clears ketones, which takes longer than glucose normalization. 1, 6
• Target glucose range of 150-200 mg/dL until ketoacidosis resolves. 1

4. Carbohydrate Replacement

The patient requires 150-200 grams of carbohydrate daily to suppress ketogenesis. 4 The nausea and vomiting have created a starvation state that perpetuates ketone production even with insulin. 4

• If the patient can tolerate oral intake, provide liquid carbohydrates (juice, broth, sports drinks) in small frequent amounts. 4
• If unable to tolerate oral intake, the IV dextrose provides the necessary carbohydrate substrate. 1

Monitoring Protocol

Check the following every 2-4 hours until stable: 1

• Blood glucose (bedside)
• Serum electrolytes (especially potassium)
• Venous pH (arterial blood gases are unnecessary after initial diagnosis) 6
• Serum bicarbonate
• Anion gap
• Blood β-hydroxybutyrate (if available; superior to urine ketones) 2

Do NOT rely on urine ketones for monitoring treatment response because they only measure acetoacetate and acetone, not β-hydroxybutyrate (the predominant ketone), and can paradoxically worsen as the patient improves. 2, 6

Resolution Criteria

DKA is resolved when ALL of the following are met: 6

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Anion gap ≤12 mEq/L

Ketone clearance lags behind glucose normalization, so continue insulin infusion until these metabolic parameters normalize. 6

Transition to Subcutaneous Insulin

Once DKA resolves and the patient can eat:

1. Administer long-acting basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping the IV insulin infusion. 1 This overlap is essential to prevent rebound ketoacidosis. 1

2. Calculate the basal dose as approximately 50% of the total 24-hour IV insulin amount, given as a single daily injection. 1

3. Divide the remaining 50% equally among three meals as rapid-acting prandial insulin. 1

4. Continue the IV insulin infusion for 1-2 hours after the basal dose to ensure adequate absorption. 1

Common Pitfalls to Avoid

• Never stop IV insulin when glucose normalizes—ketoacidosis takes longer to resolve than hyperglycemia, and premature cessation is the most common cause of recurrent DKA. 1, 6

• Never withhold dextrose when glucose is low during DKA treatment—both insulin AND glucose are required to clear ketones. 1

• Never start insulin if potassium is <3.3 mEq/L—this can cause fatal arrhythmias. 1

• Never rely solely on urine ketones—they do not measure β-hydroxybutyrate and lag behind clinical improvement. 2

Special Considerations for This Case

The gastrointestinal symptoms (nausea, vomiting, diarrhea) combined with inadequate carbohydrate intake created a starvation ketosis superimposed on insulin deficiency. 4, 5 The patient likely continued taking insulin without eating, leading to euglycemic DKA. 5

Antiemetic therapy should be provided to allow oral carbohydrate intake as soon as possible. 4 Once nausea resolves, the patient should consume 45-50 grams of carbohydrate every 3-4 hours (liquid or soft foods if solids not tolerated). 4

Investigate precipitating factors: infection (obtain cultures if febrile), medication non-compliance, or other acute illness. 1 The diarrhea may represent gastroenteritis as a precipitant. 7