What is diabetic ketoacidosis (DKA), how is it diagnosed, and how is it managed?

Diabetic Ketoacidosis: Diagnosis and Management

Diabetic ketoacidosis (DKA) is a life-threatening complication of diabetes characterized by insulin deficiency leading to hyperglycemia, ketosis, and metabolic acidosis, requiring immediate treatment with fluid resuscitation, insulin therapy, and electrolyte replacement to prevent mortality. 1

Definition and Pathophysiology

DKA results from absolute or relative insulin deficiency with concurrent elevation of counterregulatory hormones, causing:

• Hyperglycemia (though not always present in euglycemic DKA)
• Ketone body production
• Metabolic acidosis
• Dehydration and electrolyte imbalances

Diagnostic Criteria

According to the American Diabetes Association, DKA diagnosis requires all of the following criteria 2, 1:

• Blood glucose >250 mg/dL (though ~10% present with euglycemic DKA with glucose <200 mg/dL)
• Arterial pH <7.3
• Serum bicarbonate <15 mEq/L
• Moderate ketonemia or ketonuria

Severity Classification

Parameter	Mild	Moderate	Severe
Arterial pH	7.25-7.30	7.00-7.24	<7.00
Bicarbonate (mEq/L)	15-18	10-14	<10
Mental Status	Alert	Alert/drowsy	Stupor/coma

Clinical Presentation

Common symptoms include:

• Polyuria and polydipsia (most common)
• Nausea, vomiting, abdominal pain
• Weight loss
• Severe fatigue
• Dyspnea
• Altered mental status in severe cases 3

Diagnostic Evaluation

Essential Laboratory Tests:

• Blood glucose
• Arterial blood gas or venous pH
• Serum bicarbonate
• Anion gap calculation
• Serum ketones (preferred) or urine ketones
• Electrolytes (sodium, potassium, chloride)
• BUN and creatinine
• Complete blood count with differential
• HbA1c

Additional Tests to Consider:

• Phosphate levels
• ECG (to assess for cardiac abnormalities)
• Urinalysis
• Blood and urine cultures (if infection suspected)
• Chest radiography
• Amylase, lipase (if pancreatitis suspected)
• Hepatic transaminases
• Troponin, creatine kinase (if cardiac involvement suspected) 3

Management

1. Fluid Resuscitation

• Initial fluid resuscitation with isotonic saline (0.9% NaCl)
• Adults: 15-20 mL/kg/hr during first hour (typically 1-1.5 L)
• After initial resuscitation, continue IV fluids at 4-14 mL/kg/hr
• Switch to 0.45% saline when serum sodium is normal or elevated 1

2. Insulin Therapy

• Start with IV insulin infusion at 0.1 units/kg/hr
• Continue until resolution of ketoacidosis (pH >7.3, bicarbonate ≥18 mEq/L)
• If glucose falls below 200 mg/dL before ketoacidosis resolves, add dextrose to IV fluids while continuing insulin 1

3. Electrolyte Replacement

• Potassium: Start replacement when serum potassium <5.2 mEq/L and patient is producing urine
  • Typical replacement: 20-30 mEq potassium in each liter of IV fluid
  • Hold insulin if potassium <3.3 mEq/L until corrected
• Phosphate: Consider replacement if serum phosphate <1.0 mg/dL or if cardiac dysfunction, anemia, or respiratory depression occurs
• Bicarbonate: Generally not recommended except in severe acidosis (pH <6.9) with hemodynamic instability 1

4. Transition to Subcutaneous Insulin

• Begin subcutaneous insulin 2-4 hours before discontinuing IV insulin
• Calculate total daily insulin requirement based on IV insulin rate (approximately 36 units/24 hours if IV rate was 1.5 units/hour)
• Continue IV insulin for 2-4 hours after first subcutaneous dose to prevent rebound hyperglycemia 1

Monitoring During Treatment

• Hourly monitoring of:
  • Vital signs
  • Neurological status
  • Blood glucose
  • Fluid input/output
• Every 2-4 hours:
  • Electrolytes
  • BUN, creatinine
  • Venous pH 1

Resolution Criteria

DKA is considered resolved when:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3 1

Complications to Monitor

Cerebral Edema

• More common in children
• Prevention: avoid too rapid correction of serum osmolality (not exceeding 3 mOsm/kg/h)
• In pediatric patients, limit initial vascular expansion to 50 ml/kg in first 4 hours 1

Hypoglycemia

• Monitor glucose frequently
• Add dextrose to IV fluids when glucose <200 mg/dL 1

Hypokalemia

• Monitor potassium levels closely
• Replace as needed 1

Prevention of Recurrence

• Identify and treat underlying causes (infection, missed insulin, etc.)
• Patient education on:
  • Diabetes self-management
  • Blood glucose monitoring
  • Sick-day management
  • When to seek medical attention
  • Proper insulin administration
• Schedule follow-up appointment prior to discharge 1

Special Considerations

Euglycemic DKA

• Can occur with SGLT2 inhibitor use, pregnancy, reduced food intake, alcohol use, or liver failure
• Diagnosis requires ketoacidosis with blood glucose <200 mg/dL
• Management principles remain the same 2

Recurrent DKA

• Often associated with insulin omission
• Higher incidence of psychiatric illness, especially depression
• May require psychological counseling and social support 2

Pregnancy

• Up to 2% of pregnancies with pregestational diabetes may be complicated by DKA
• Pregnant patients may present with euglycemic DKA
• Requires immediate attention due to risk of feto-maternal harm 2

By following this structured approach to diagnosis and management, the mortality rate from DKA can be significantly reduced from the historical 2-5% to lower levels reported by tertiary care centers 2, 4.