Blood Glucose Levels in Diabetic Ketoacidosis (DKA)
No, blood glucose does not have to be elevated in diabetic ketoacidosis (DKA), as euglycemic DKA can occur with normal or only mildly elevated glucose levels while still meeting other diagnostic criteria for ketoacidosis.
Classic DKA Diagnostic Criteria
The American Diabetes Association defines classic DKA using three main criteria:
- Blood glucose >250 mg/dL 1
- Venous pH <7.3 and serum bicarbonate <15 mEq/L 1
- Presence of moderate ketonuria or ketonemia 1
These criteria are typically presented in a severity classification:
- Mild DKA: Venous pH 7.25-7.30, bicarbonate 15-18 mEq/L 1
- Moderate DKA: Venous pH 7.00-7.24, bicarbonate 10-15 mEq/L 1
- Severe DKA: Venous pH <7.00, bicarbonate <10 mEq/L 1
Euglycemic DKA
Euglycemic DKA is characterized by:
- Normal or mildly elevated blood glucose levels (<250 mg/dL) 2
- Metabolic acidosis (arterial pH <7.3, serum bicarbonate <18 mEq/L) 2
- Presence of ketosis 2
Causes of Euglycemic DKA
Several factors can lead to euglycemic DKA:
- Recent insulin use 2
- Decreased caloric/carbohydrate intake 3
- Pregnancy 2
- Heavy alcohol consumption 2
- Chronic liver disease 2
- Glycogen storage disorders 2
- Use of SGLT-2 inhibitors (sodium-glucose cotransporter-2 inhibitors) 4
SGLT-2 inhibitors are particularly notable as they:
- Cause a low level of ambient ketones 4
- Promote glycosuria which limits hyperglycemia 4
- Can lead to prolonged euglycemic DKA due to their half-life 4
Pathophysiology
The underlying mechanism for both classic and euglycemic DKA is:
- Reduction in effective insulin action 5
- Elevation of counterregulatory hormones (glucagon, catecholamines, cortisol, growth hormone) 5
- Release of free fatty acids leading to ketone production 5
In euglycemic DKA, ketogenesis occurs despite normal glucose levels because:
- Patients may maintain some insulin intake (preventing severe hyperglycemia) 3
- Adequate hydration may help clear glucose 3
- Reduced carbohydrate intake limits glucose availability 3
Clinical Implications
This distinction is clinically important because:
- Relying solely on blood glucose levels for DKA diagnosis may lead to missed cases 3
- Euglycemic DKA requires the same urgent treatment as classic DKA 4
- In euglycemic DKA, immediate use of glucose-containing IV fluids is recommended to induce endogenous insulin secretion and stop ketogenesis 4
Management Considerations
For euglycemic DKA:
- Continue insulin therapy despite normal glucose levels 6
- Add dextrose to hydrating solution while continuing insulin infusion 6
- Monitor for resolution based on pH >7.3, bicarbonate ≥18 mEq/L, and anion gap ≤12 mEq/L, not just glucose levels 6
Common Pitfalls to Avoid
- Failing to check ketones in diabetic patients with acidosis but normal glucose levels 3
- Interrupting insulin therapy when glucose normalizes before ketoacidosis resolves 6
- Relying solely on urine ketones rather than direct measurement of β-hydroxybutyrate in blood 6
- Missing the diagnosis in patients taking SGLT-2 inhibitors who present with normal glucose levels 4
Remember that DKA remains a medical emergency regardless of glucose levels and requires prompt treatment with fluids, insulin, and electrolyte management 7.