231.An undomiciled 49-year-old man presents to the ED with altered
mental status. His BP is 149/75 mm Hg, HR is 93 beats per minute, tem-
perature is 97.5°F, RR is 18 breaths per minute, and O 2 saturation is 99%
on room air. Physical examination reveals an unkempt man with the odor
of “alcohol” on his breath. His head is atraumatic and pupils are 4 mm,
equal, and reactive. The neck is supple. Cardiovascular, pulmonary, and
abdominal examinations are unremarkable. There is no extremity edema
and his pulses are 2+ and symmetric. Neurologically, he withdraws all four
extremities to deep stimuli. ECG is sinus rhythm. Laboratory results reveal:
Sodium 141 mEq/L Arterial blood pH 7.26
Potassium 3.5 mEq/L Lactate 1.7 mEq/L
Chloride 101 mEq/L Ethanol level undetectable
Bicarbonate 14 mEq/L Measured serum osmolarity 352 mOsm/L
BUN 15 mg/dL Calculated serum osmolarity 292 mOsm/kg
Creatinine 0.7 mg/dL
Glucose 89 mg/dL Urinalysis: no blood, ketones, or proteinWhich of the following statements below best describes the laboratory
findings?
a. Anion gap metabolic acidosis and osmol gap
b. Anion gap metabolic acidosis without osmol gap
c. Nonanion gap metabolic acidosis and osmol gap
d. Nonanion gap metabolic acidosis without osmol gap
e. Metabolic alkalosis with secondary acidosis
242 Emergency Medicine