A 38-year-old mechanic is evaluated in the hospital after being found confused and lethargic in his workshop. He has a history of alcohol use disorder. Vital signs show a temperature of 37.1°C (98.8°F), blood pressure of 135/85 mmHg, pulse of 92/min, and respiratory rate of 22/min. Physical examination reveals a disoriented patient with dry mucous membranes.
Initial laboratory evaluation reveals the following:
| Parameter | Value |
|---|---|
| Sodium | 140 mEq/L |
| Potassium | 4.1 mEq/L |
| Chloride | 98 mEq/L |
| Bicarbonate | 14 mEq/L |
| Blood urea nitrogen | 20 mg/dL |
| Serum creatinine | 1.5 mg/dL |
| Glucose | 105 mg/dL |
Based on the provided laboratory results, what is this patient's serum anion gap?
Answer: 28 mEq/L
Answer
28
The serum anion gap is calculated by subtracting the primary measured serum anions (chloride and bicarbonate) from the primary measured serum cation (sodium). Using the formula Anion Gap = , the calculation for this patient is mEq/L. A normal anion gap is typically between 8 and 12 mEq/L. This patient has a significantly elevated high anion gap metabolic acidosis (HAGMA), which is consistent with toxic alcohol ingestion (such as methanol or ethylene glycol), given his presentation and history.
Step-by-Step Solution
Key Concept
Calculation of the serum anion gap to evaluate metabolic acidosis.