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

Diagnostic Criteria for Diabetic Ketoacidosis (DKA)

The diagnostic criteria for DKA include blood glucose >200 mg/dL, venous pH <7.3 or serum bicarbonate <15 mEq/L, and elevated serum ketones or ketonuria. 1, 2

Classification of DKA Severity

DKA severity can be categorized based on the following parameters:

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

3

Essential Diagnostic Components

1. Hyperglycemia:

   • Blood glucose >200 mg/dL
   • Exception: Euglycemic DKA (glucose <250 mg/dL) can occur in patients with:
     • Pregnancy
     • SGLT2 inhibitor use
     • Starvation
     • Alcohol use
     • Chronic liver disease
     • Infection 4

2. Ketosis:

   • Elevated serum ketones >3 mmol/L
   • Presence of ketonuria
   • Quantifying ketosis helps distinguish between simple hyperglycemia and metabolic decompensation 5

3. Metabolic Acidosis:

   • Venous pH <7.3
   • Serum bicarbonate <18 mEq/L
   • Elevated anion gap 3, 2

Clinical Presentation

Common symptoms include:

• Polyuria with polydipsia (98%)
• Weight loss (81%)
• Fatigue (62%)
• Dyspnea (57%)
• Vomiting (46%)
• Preceding febrile illness (40%)
• Abdominal pain (32%)
• Polyphagia (23%) 2

Advanced symptoms indicating DKA progression:

• Drowsiness
• Flushed face
• Fruity breath odor (acetone)
• Loss of appetite
• Heavy breathing (Kussmaul respiration)
• Rapid pulse 6

Laboratory Evaluation

A comprehensive workup should include:

• Blood glucose
• Venous pH or arterial blood gas
• Serum bicarbonate
• Serum ketones (β-hydroxybutyrate preferred)
• Electrolytes and calculation of anion gap
• Blood urea nitrogen and creatinine
• Complete blood count
• Urinalysis for ketones 2, 7

Resolution Criteria

DKA is considered resolved when:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH ≥7.3 3

Clinical Pitfalls to Avoid

1. Missing euglycemic DKA: Don't rule out DKA based solely on glucose levels <250 mg/dL, especially in patients using SGLT2 inhibitors or during pregnancy 4

2. Delayed diagnosis: Near-patient testing for blood glucose and ketones can facilitate rapid diagnosis within minutes of presentation 5

3. Overlooking precipitating factors: Always identify and treat underlying causes such as:

   • Insulin omission or inadequate insulin
   • Infection
   • Trauma
   • Myocardial infarction
   • Stroke
   • Medications (glucocorticoids, thiazides)
   • New-onset diabetes 6, 2

4. Underestimating severity: About one-third of DKA cases occur in persons without a known history of diabetes mellitus 2

Remember that DKA is a medical emergency requiring prompt diagnosis and treatment to prevent complications and reduce mortality, which currently stands at 1-5% 2.