What is the appropriate management for a 55-year-old male with type 2 Diabetes Mellitus (DM) and Hypertension (HTN) presenting with acute Diabetic Ketoacidosis (DKA)?

Management of Acute Diabetic Ketoacidosis in a 55-Year-Old Male with Type 2 DM

Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 900-1200 mL in the first hour for this 60 kg patient), followed by continuous intravenous regular insulin infusion at 0.1 units/kg/hour (6 units/hour) once potassium is ≥3.3 mEq/L. 1, 2, 3

Initial Assessment and Laboratory Evaluation

Obtain the following immediately 4, 1, 3:

• Plasma glucose, blood urea nitrogen/creatinine, serum ketones
• Electrolytes with calculated anion gap, osmolality
• Arterial blood gases (or venous pH)
• Complete blood count with differential
• Electrocardiogram
• Urinalysis with urine ketones
• Bacterial cultures (blood, urine, throat) if infection suspected
• Chest X-ray if respiratory symptoms present

Confirm DKA diagnosis: glucose >250 mg/dL, arterial pH <7.30, serum bicarbonate <18 mEq/L, and positive serum/urine ketones 1, 3

Fluid Resuscitation Protocol

First Hour

Administer isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour 4, 1, 2, 3

• For this 60 kg patient: 900-1200 mL in the first hour
• Goal: restore intravascular volume and renal perfusion

Subsequent Fluid Management

After the initial hour, adjust based on corrected serum sodium 4, 3:

• If corrected sodium is normal or elevated: use 0.45% NaCl at 4-14 mL/kg/hour (240-840 mL/hour for 60 kg)
• If corrected sodium is low: continue 0.9% NaCl at similar rate
• When glucose reaches 250 mg/dL: switch to 5% dextrose with 0.45% NaCl to prevent hypoglycemia while continuing insulin 3

Recent evidence suggests balanced crystalloids (lactated Ringer's or Plasma-Lyte) may achieve faster DKA resolution than normal saline 5, 6, though isotonic saline remains the guideline-recommended standard 4, 1, 2, 3. Balanced crystalloids showed median time to resolution of 13.0 hours versus 16.9 hours with saline 5.

Insulin Therapy

Critical Pre-Insulin Check

DO NOT start insulin if serum potassium <3.3 mEq/L 3

• Aggressively replace potassium first to prevent life-threatening arrhythmias and respiratory muscle weakness
• Wait until K+ ≥3.3 mEq/L before initiating insulin

Insulin Infusion Protocol

Start continuous IV regular insulin at 0.1 units/kg/hour (6 units/hour for 60 kg patient) 1, 2, 3

• No initial bolus required 1
• Target glucose decline: 50-75 mg/dL per hour 1
• If glucose does not fall by 50 mg/dL in first hour: verify adequate hydration, then double insulin infusion rate hourly until steady decline achieved 1, 3

Critical Pitfall to Avoid

Continue insulin infusion until COMPLETE resolution of ketoacidosis, regardless of glucose levels 2, 3

• Do not stop insulin when glucose reaches 250 mg/dL—this is when you add dextrose to IV fluids
• Premature insulin cessation causes recurrent ketoacidosis

Potassium Management

This is the most critical electrolyte to monitor—hypokalemia is a leading cause of DKA mortality 3

Potassium Replacement Protocol 4, 1, 3

• If K+ <3.3 mEq/L: Hold insulin, give aggressive potassium replacement until ≥3.3 mEq/L
• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄) once urine output confirmed
• If K+ >5.5 mEq/L: Withhold potassium initially but monitor closely—levels will drop rapidly with insulin therapy
• Target range throughout treatment: 4-5 mEq/L 3

Rationale: Despite possible initial hyperkalemia, total body potassium is universally depleted in DKA. Insulin therapy drives potassium intracellularly, causing rapid serum decline 2, 3.

Monitoring During Treatment

Check blood glucose every 1-2 hours 1

Draw blood every 2-4 hours for: 1, 2, 3

• Serum electrolytes (especially potassium)
• Glucose
• Blood urea nitrogen/creatinine
• Osmolality
• Venous pH (typically 0.03 units lower than arterial pH) 3
• Anion gap

Follow venous pH and anion gap to monitor acidosis resolution 1, 3

Bicarbonate Therapy

DO NOT administer bicarbonate if pH >6.9-7.0 3, 7

• No benefit shown in resolution time or outcomes 3
• Increases risk of hypokalemia, worsening ketosis, and cerebral edema 3, 7
• Exception: Consider if pH <6.9 or in peri-intubation period to prevent hemodynamic collapse 7

Resolution Criteria

DKA is resolved when ALL of the following are met: 1, 2, 3

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

Transition to Subcutaneous Insulin

This is the second most common error leading to DKA recurrence 2

Critical Timing

Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin infusion 1, 2, 3

• Prevents recurrence of ketoacidosis and rebound hyperglycemia
• Never stop IV insulin without prior basal insulin administration

Dosing for Transition

Start with 0.3-0.4 units/kg/day total daily dose 4

• For this 60 kg patient: 18-24 units/day
• Give 50% as once-daily long-acting insulin (glargine/detemir)
• Give 50% as divided prandial doses (rapid-acting analog)

Identification of Precipitating Factors

Search for and treat underlying causes 4, 3, 8:

• Infection (most common—obtain cultures, start antibiotics if indicated)
• Myocardial infarction (check troponin, ECG)
• Cerebrovascular accident
• Insulin omission or inadequate dosing
• Medications: corticosteroids, thiazides, sympathomimetics, SGLT2 inhibitors 4, 3
• Pancreatitis, trauma, alcohol abuse

Note: Patients may be normothermic or hypothermic despite infection due to peripheral vasodilation; hypothermia is a poor prognostic sign 4

Special Considerations for Type 2 DM

This patient with type 2 DM presenting with DKA requires the same aggressive management as type 1 DM 8

• DKA in type 2 DM is increasingly recognized, particularly in obese patients 9
• Up to one-third of patients have mixed DKA/HHS features 8
• May have residual beta-cell function and potentially transition off insulin after acute episode, unlike type 1 DM 8

Common Pitfalls to Avoid

1. Starting insulin before correcting severe hypokalemia (K+ <3.3 mEq/L) 3
2. Stopping IV insulin when glucose reaches 250 mg/dL instead of continuing until full ketoacidosis resolution 2, 3
3. Failing to add dextrose when glucose falls below 250 mg/dL 3
4. Discontinuing IV insulin without prior basal insulin administration 2
5. Inadequate potassium monitoring and replacement 3
6. Using bicarbonate in patients with pH >7.0 3, 7
7. Overly rapid correction of osmolality (increases cerebral edema risk, though rare in adults) 3, 7