From the Guidelines
Diabetic ketoacidosis (DKA) is typically associated with an elevated anion gap, and the most recent evidence suggests that this gap is often greater than 12 mEq/L, though values can exceed 20-30 mEq/L in severe cases 1.
Key Points to Consider
- The anion gap represents the difference between measured cations (primarily sodium) and measured anions (chloride and bicarbonate) in the blood.
- In DKA, the accumulation of ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) creates unmeasured anions that increase this gap.
- This occurs when insulin deficiency leads to increased fat breakdown, producing these acidic ketone bodies.
- While an elevated anion gap is characteristic of DKA, diagnosis requires additional criteria including:
- Hyperglycemia (typically >250 mg/dL)
- Metabolic acidosis (pH <7.3)
- The presence of ketones in blood or urine
Clinical Context and Other Considerations
- Other conditions can also cause an elevated anion gap acidosis, including lactic acidosis, certain poisonings, and renal failure, so clinical context is essential for proper diagnosis.
- Management goals for DKA include restoration of circulatory volume and tissue perfusion, resolution of hyperglycemia, and correction of electrolyte imbalance and acidosis, as outlined in recent guidelines 1.
- The use of bicarbonate in patients with DKA has been shown to make no difference in the resolution of acidosis or time to discharge, and its use is generally not recommended 1.
From the Research
Diabetic Ketoacidosis (DKA) and Anion Gap
- DKA is typically characterized by an anion gap greater than 10 mEq/L, as stated in the study 2.
- A study published in 2015 found that patients with severe DKA had a mean anion gap of 30.3 ± 2.9 3.
- Another study published in 2024 found that an anion gap ≤12 mEq/L is recommended before transitioning from intravenous to subcutaneous insulin, but the study showed no difference in success of insulin transition between patients with an anion gap ≤12 mEq/L and those with an anion gap >12 mEq/L 4.
- The diagnosis of DKA is confirmed when all three criteria are present: elevated blood glucose levels, the presence of high urinary or blood ketoacids, and a high anion gap metabolic acidosis, as stated in the study 5.
- A study published in 2024 found that hyperchloremia can develop during treatment for pediatric DKA, leading to hyperchloremic metabolic acidosis, and monitoring anion gap, blood ketones, and Cl-/Na+ ratio may help differentiate DKA from hyperchloremic metabolic acidosis 6.
Anion Gap Threshold for DKA
- The anion gap threshold for DKA is generally considered to be greater than 10 mEq/L 2.
- However, a study published in 2024 found that an anion gap ≤12 mEq/L is recommended before transitioning from intravenous to subcutaneous insulin 4.
- The optimal anion gap threshold for DKA diagnosis and treatment may vary depending on the individual patient and the specific clinical context, as suggested by the studies 3, 2, 4, 5, 6.