Definition of Euglycemic Diabetic Ketoacidosis
Euglycemic diabetic ketoacidosis (euglycemic DKA) is defined as the presence of diabetic ketoacidosis—characterized by metabolic acidosis, elevated anion gap, and ketonemia or ketonuria—occurring with blood glucose levels less than 200-250 mg/dL, rather than the typical hyperglycemia seen in classic DKA. 1, 2, 3
Diagnostic Criteria
The specific diagnostic features that distinguish euglycemic DKA include:
- Blood glucose <200 mg/dL (some sources use <250 mg/dL as the threshold) 2, 3, 4
- Metabolic acidosis with arterial pH <7.3 3
- Serum bicarbonate <18 mEq/L 3
- Elevated anion gap (>10-12 mEq/L) 5
- Positive serum or urine ketones 5, 2
This contrasts sharply with classic DKA, which requires plasma glucose >250 mg/dL according to American Diabetes Association criteria 5.
Clinical Context and Prevalence
Euglycemic DKA occurs in approximately 10% of all DKA cases 1. This represents a diagnostic challenge because the absence of marked hyperglycemia can mask the underlying ketoacidosis, leading to delayed recognition and treatment 2, 4.
Common Precipitating Factors
The American Diabetes Association identifies several key triggers for euglycemic DKA 1, 6:
- SGLT2 inhibitor use (increasingly recognized as a major cause) 1, 7, 8
- Pregnancy 1, 3
- Reduced food intake or starvation 1, 2, 3
- Alcohol use 1, 3
- Liver failure or chronic liver disease 1, 3
- Recent insulin administration (which lowers glucose but may not fully suppress ketogenesis) 2, 3
- Insulin pump failure 2, 4
- Intercurrent illness with decreased oral intake 2
Pathophysiologic Mechanism
The underlying mechanism differs from classic DKA in that there is:
- Relative or absolute carbohydrate deficit preventing marked hyperglycemia 4
- Milder degree of insulin deficiency (enough to prevent severe hyperglycemia but insufficient to suppress lipolysis and ketogenesis) 4
- Increased glucagon-to-insulin ratio driving ketone production despite relatively normal glucose 4
- Continued ketone body production from unrestrained fatty acid oxidation 6
Critical Diagnostic Pitfall
The most dangerous aspect of euglycemic DKA is that normal or near-normal blood glucose levels can mislead clinicians into overlooking the diagnosis entirely. 2, 4 This is particularly problematic because:
- Physicians may not check blood pH or ketones in diabetic patients presenting with normal glucose 2
- The condition remains a medical emergency requiring immediate treatment despite euglycemia 3
- Delayed diagnosis leads to worse outcomes 4
Essential Diagnostic Approach
When evaluating any ill diabetic patient, blood pH and blood or urine ketones should be checked regardless of blood glucose levels 2. The diagnosis is one of exclusion, requiring consideration in any sick diabetic patient with metabolic acidosis, even with lower blood glucose or absent urine ketones 4.