A 22-year-old woman is brought to the emergency department by her roommate due to progressive lethargy, confusion, and recurrent vomiting over the last 48 hours. The patient has a history of bipolar I disorder and generalized tonic-clonic seizures. Her home medications include valproic acid, which was initiated six weeks ago, and a daily multivitamin. She does not use alcohol, tobacco, or illicit drugs.
On presentation, her temperature is 36.8°C (98.2°F), blood pressure is 118/74 mm Hg, pulse is 88/min, and respiratory rate is 14/min. Physical examination shows a somnolent woman who is oriented only to her name. A bilateral flapping tremor of the hands is elicited upon wrist extension. No jaundice, scleral icterus, or abdominal distension is noted.
Laboratory studies are obtained:
| Test | Result | Reference Range |
|---|---|---|
| Sodium | 139 mEq/L | 136-145 mEq/L |
| Potassium | 4.1 mEq/L | 3.5-5.0 mEq/L |
| Blood urea nitrogen | 12 mg/dL | 8-20 mg/dL |
| Creatinine | 0.8 mg/dL | 0.6-1.2 mg/dL |
| Aspartate aminotransferase (AST) | 28 U/L | 10-40 U/L |
| Alanine aminotransferase (ALT) | 30 U/L | 7-56 U/L |
| Total bilirubin | 0.7 mg/dL | 0.1-1.2 mg/dL |
| Alkaline phosphatase | 75 U/L | 44-147 U/L |
| Valproic acid level | 82 µg/mL | 50-125 µg/mL |
| Venous ammonia | 180 µmol/L | 15-45 µmol/L |
Which of the following is the most appropriate next step in the management of this patient's current condition?
- Discontinue valproic acid and administer intravenous levocarnitineAnswer
- BDiscontinue valproic acid and administer oral lactulose
- CDecrease the valproic acid dose to target a trough level of 50 µg/mL
- DMaintain the current valproic acid dose and order an electroencephalogram
- EDiscontinue valproic acid and consult nephrology for emergent hemodialysis