New Test, Old Disease: A Case Series of Diabetic Ketoalkalosis

Diabetic ketoalkalosis (DKAlk) was first described in 1967 as a rare complication of diabetic ketoacidosis with normal or elevated pH/bicarbonate and elevated anion gap (AG) from high β-hydroxybutyrate (BHB).

We report a case series of patients with DKAlk to show how venous blood gas (VBG) electrolytes alone may misdiagnose these patients.

This was a case series of DKAlk patients with concomitant VBG and basic metabolic panel (BMP) electrolytes who met the following criteria for DKAlk: BMP hyperglycemia (glucose >250 mg/dL), elevated AG (>15 mEq/L), elevated BHB (>1.2 mmol/L), and high Delta (Δ) gap (>6 mEq/L [bicarbonate gap (BG): measured bicarbonate - 24] - [AG - 12]). Data are reported as median with interquartile range (IQR) (25%, 75%) and group comparisons utilized Mann-Whitney U test (two-tailed, α = 0.05).

We found 10 patients with DKAlk in 2 months. Patients ranged in age from 13 to 77 years, 50% were male, and all were African American. Most patients (8 of 10) were vomiting with hyperglycemia (350 to >600 mg/dL). DKAlk BMP AG ranged from 18 to 34 mmol/L and BHB from 1.74 to 9.09 mmol/L. For bicarbonate, we found no significant difference between VBG (24 mmol/L) and BMP (22 mmol/L) (p = 0.796). VBG chloride (98 mmol/L) was significantly higher than BMP chloride (88 mmol/L) (p < 0.005). This falsely elevated VBG chloride resulted in undervaluing of all VBG AGs, missing almost all of the patients with DKAlk.

We found that DKAlk is more common than previously reported. We recommend screening with BMP electrolytes and BHB levels for hyperglycemic ED patients who are vomiting or suspected of hypovolemia.