What is the correct initial management for a dehydrated diabetic patient with hyperglycemia, vomiting, and a history of omitted insulin, presenting with severe illness and dehydration?

Management of Suspected Diabetic Ketoacidosis

Low molecular weight heparin should be administered (Option C) is the correct statement for this patient presenting with suspected diabetic ketoacidosis (DKA). 1

Initial Assessment and Diagnosis

This patient presents with classic features of DKA: severe hyperglycemia (glucometer reading "high" suggests >600 mg/dL), vomiting, dehydration, omitted insulin doses, and appearing severely unwell. 1, 2 The clinical picture demands immediate action with specific management priorities.

Critical Laboratory Evaluation Required

Obtain immediately: 1

• Venous blood gas (pH, bicarbonate)
• Complete metabolic panel (glucose, electrolytes, BUN, creatinine)
• Calculate anion gap: [Na⁺] - ([Cl⁻] + [HCO₃⁻])
• Direct measurement of β-hydroxybutyrate (not urine ketones)
• Complete blood count
• Urinalysis
• Bacterial cultures if infection suspected

The anion gap will be elevated (>12 mEq/L), not reduced, making Option E incorrect. 1

Why Each Statement is Correct or Incorrect

Option A: Total Body Potassium - INCORRECT

Total body potassium is actually depleted in DKA, not elevated. 1 While serum potassium may appear normal or even elevated initially due to extracellular shift from acidosis and insulin deficiency, total body stores are severely depleted from osmotic diuresis and vomiting. 1 Once insulin therapy begins, potassium rapidly shifts intracellularly, potentially causing life-threatening hypokalemia if not aggressively replaced. 1

Option B: Concurrent Rehydration and Insulin - INCORRECT

Rehydration and insulin should NOT always commence immediately concurrently. 1, 2 This is a critical management pitfall. The correct sequence is:

1. Check serum potassium first - If K⁺ <3.3 mEq/L, delay insulin and aggressively replace potassium first to prevent fatal cardiac arrhythmias 1, 2
2. Begin aggressive fluid resuscitation immediately with isotonic saline at 15-20 mL/kg/hour 1, 2
3. Start insulin only after confirming adequate potassium (>3.3 mEq/L) and adequate urine output 1

Starting insulin before correcting severe hypokalemia can precipitate cardiac arrest. 1

Option C: Low Molecular Weight Heparin - CORRECT

Prophylactic anticoagulation with low molecular weight heparin should be administered in DKA. 1 Patients with hyperglycemic crises are at significantly increased risk for vascular thrombosis, including deep vein thrombosis, pulmonary embolism, myocardial infarction, and stroke. 3 The hypercoagulable state results from severe dehydration, hyperosmolality, and increased blood viscosity. 3

Option D: Sodium Bicarbonate - INCORRECT

Intravenous sodium bicarbonate should NOT be routinely considered and provides no benefit in DKA management. 1, 2 The American Diabetes Association recommends against bicarbonate therapy except in the rare circumstance where pH <6.9. 1 Bicarbonate does not improve DKA resolution, may worsen hypokalemia, can cause paradoxical CNS acidosis, and delays ketone clearance. 1

Option E: Reduced Anion Gap - INCORRECT

Arterial blood gases would reveal an INCREASED anion gap, not reduced. 1 DKA is characterized by high anion gap metabolic acidosis (anion gap >10-12 mEq/L) due to accumulation of ketoacids (β-hydroxybutyrate and acetoacetate). 1 After initial diagnosis, venous pH adequately monitors acidosis resolution without requiring repeated arterial blood gases. 1

Complete Initial Management Algorithm

Immediate Actions (First 30 Minutes)

1. Obtain IV access and draw labs (as listed above) 1
2. Begin aggressive isotonic saline at 15-20 mL/kg/hour (1-1.5 L in average adult) 1, 2
3. Administer prophylactic low molecular weight heparin 1
4. Check serum potassium before starting insulin 1, 2

Insulin Therapy (After Confirming K⁺ >3.3 mEq/L)

• Start continuous IV regular insulin infusion at 0.1 units/kg/hour (typically 5-7 units/hour) without bolus 1, 2
• Target glucose decline of 50-75 mg/dL per hour 1
• If glucose doesn't fall by 50 mg/dL in first hour, double insulin rate hourly until steady decline achieved 1
• Do NOT stop insulin when glucose normalizes - this is a critical pitfall 1, 2

Potassium Replacement Strategy

• If K⁺ <3.3 mEq/L: Hold insulin, aggressively replace potassium first 1, 2
• If K⁺ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to IV fluids 1
• If K⁺ >5.5 mEq/L: Hold potassium replacement, recheck in 2 hours 1
• Target serum potassium 4-5 mEq/L throughout treatment 1

Dextrose Addition

When glucose falls to 200-250 mg/dL, add 5-10% dextrose to IV fluids while continuing insulin infusion to clear ketones and resolve acidosis. 1, 2 Premature insulin cessation causes recurrent ketoacidosis. 1, 2

Monitoring Frequency

Check every 2-4 hours: 1

• Blood glucose
• Electrolytes (sodium, potassium, chloride, bicarbonate)
• Venous pH
• β-hydroxybutyrate
• Anion gap

Resolution Criteria

DKA is resolved when ALL of the following are met: 1

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

Transition to Subcutaneous Insulin

Administer basal subcutaneous insulin 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia and recurrent ketoacidosis. 1, 2 This timing is essential and frequently missed. 4

Common Pitfalls to Avoid

• Never start insulin before checking potassium - can cause fatal arrhythmias if K⁺ <3.3 mEq/L 1, 2
• Never stop IV insulin when glucose normalizes - ketoacidosis takes longer to resolve than hyperglycemia 1, 2, 4
• Never give bicarbonate routinely - no benefit unless pH <6.9 1, 2
• Never rely on urine ketones for monitoring - they don't measure β-hydroxybutyrate and paradoxically worsen during treatment 1
• Never forget subcutaneous insulin overlap - give basal insulin 2-4 hours before stopping IV insulin 1, 2, 4
• Never overlook thromboprophylaxis - hyperglycemic crises create hypercoagulable state 1, 3