What are the diagnosis criteria for diabetic ketoacidosis (DKA)?

Diagnostic Criteria for Diabetic Ketoacidosis (DKA)

DKA is diagnosed by the triad of hyperglycemia (blood glucose >250 mg/dL), metabolic acidosis (pH <7.3, serum bicarbonate <18 mEq/L), and elevated ketones in blood or urine. 1

Essential Diagnostic Criteria

• Blood glucose >250 mg/dL (though euglycemic DKA with glucose <250 mg/dL can occur, especially with SGLT2 inhibitor use) 1, 2
• Arterial pH <7.3 3, 1
• Serum bicarbonate <18 mEq/L 3, 1
• Positive serum and urine ketones 3, 1
• Elevated anion gap >10-12 mEq/L 3
• Mental status ranging from alert to coma depending on severity 3

Severity Classification

DKA can be classified into three severity levels based on arterial pH and serum bicarbonate 3:

• Mild DKA:

  • Arterial pH: 7.25-7.30
  • Serum bicarbonate: 15-18 mEq/L
  • Mental status: Alert 3

• Moderate DKA:

  • Arterial pH: 7.00-7.24
  • Serum bicarbonate: 10 to <15 mEq/L
  • Mental status: Alert/drowsy 3

• Severe DKA:

  • Arterial pH: <7.00
  • Serum bicarbonate: <10 mEq/L
  • Mental status: Stupor/coma 3

Laboratory Evaluation

• Essential tests for confirming DKA diagnosis:

  • Plasma glucose 1
  • Arterial blood gases for pH measurement 1
  • Serum bicarbonate 1
  • Serum ketones (preferably β-hydroxybutyrate) 1
  • Electrolytes with calculated anion gap 1
  • Urinalysis and urine ketones 1
  • Complete blood count with differential 1
  • Blood urea nitrogen/creatinine 1

• β-hydroxybutyrate measurement is preferred over nitroprusside-based ketone tests for diagnosis and monitoring of DKA, as nitroprusside methods do not measure β-hydroxybutyrate, which is the predominant ketone in DKA 3, 1

Clinical Presentation

• Common symptoms include polyuria, polydipsia, polyphagia, weight loss, vomiting, abdominal pain, dehydration, weakness, and altered mental status 3, 4
• Physical findings may include poor skin turgor, Kussmaul respirations (deep, rapid breathing), tachycardia, hypotension, and potentially altered mental status 3, 1
• DKA typically evolves rapidly (usually <24 hours) 3, 1
• Up to 25% of DKA patients may present with emesis, which can be coffee-ground in appearance due to hemorrhagic gastritis 3

Special Considerations

• Euglycemic DKA: Blood glucose <250 mg/dL with ketoacidosis can occur with:

  • SGLT2 inhibitor use 1, 5
  • Pregnancy 1, 2
  • Reduced food intake/starvation 1, 5
  • Alcohol use 1, 5
  • Liver disease 1, 2

• Differential diagnosis for high anion gap metabolic acidosis includes:

  • Lactic acidosis 3, 1
  • Salicylate, methanol, ethylene glycol ingestion 3, 1
  • Alcoholic ketoacidosis (distinguished by clinical history and glucose levels rarely >250 mg/dL) 3, 1
  • Chronic renal failure 3

Common Precipitating Factors

• Infection (most common) 3, 1
• New-onset type 1 diabetes 3, 1
• Insulin omission or inadequate insulin dosing 3, 1
• Cerebrovascular accident 3, 1
• Myocardial infarction 3, 1
• Drug use (corticosteroids, thiazides, sympathomimetic agents) 3, 1
• Alcohol abuse 3, 1
• Pancreatitis 3, 1

Monitoring During Treatment

• β-hydroxybutyrate levels should be used to monitor treatment response rather than nitroprusside-based ketone tests 3, 1
• Resolution of acidosis or reduction in blood β-hydroxybutyrate is the marker for successful treatment 3, 1
• Blood ketone determinations that rely on the nitroprusside reaction should not be used to monitor treatment of DKA 3