Increased osmolal gap in alcoholic ketoacidosis and lactic acidosis.
OBJECTIVE
To determine whether an elevated osmolal gap is specific for toxic alcohol ingestion.


METHODS
Cross-sectional.


METHODS
Emergency room and medical and surgical inpatient wards at a university-affiliated hospital.


METHODS
Twenty-three patients with lactic acidosis, 19 with alcoholic ketoacidosis, and 10 randomly selected controls.


RESULTS
Calculated and measured serum osmolality was determined in all study participants. The osmolal gap was increased in patients with lactic acidosis (17.4 +/- 5.4 mmol/kg) and alcoholic ketoacidosis (26.9 +/- 7.6 mmol/kg) when compared with controls (-1.7 +/- 1.7 mmol/kg, P less than 0.05 for both comparisons). When ethanol was included in the calculation, the osmolal gap remained elevated in the lactic acidosis (10.3 +/- 2.0 mmol/kg) and alcoholic ketoacidosis (11.1 +/- 3.2 mmol/kg) groups (P less than 0.05 for both comparisons).


CONCLUSIONS
The osmolal gap is often used as a screen for toxic alcohol ingestion. When calculating the osmolal gap, the contribution of ethanol should be considered. An elevated osmolal gap is not specific for toxic alcohol ingestion, as the osmolal gap was elevated in patients with lactic acidosis and alcoholic ketoacidosis. These two conditions should be considered when using the osmolal gap to design therapy (for example, hemodialysis) in the setting of anion gap metabolic acidosis and suspected toxic alcohol ingestion.
Denver General Hospital, Colorado.
J R
JR
Schelling
R L
RL
Howard
S D
SD
Winter
S L
SL
Linas
D000138:Acidosis / Q000097:blood*; D000140:Acidosis, Lactic / Q000097:blood* / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000435:Alcoholic Intoxication / Q000097:blood* / Q000175:diagnosis; D000704:Analysis of Variance; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007662:Ketosis / Q000097:blood* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration