In the intensive care unit, her temperature was 37.1°C (98.8°F), her pulse rate was 80 to 120 beats per minute, her blood pressure was 113/59 mm Hg, and her oxygen saturation was 100% on a fraction of inspired oxygen of 65%. On further examination, she was found to be intermittently agitated without eye opening or purposeful movements, but she did withdraw all 4 extremities to pain. Her face was symmetric, and she had normal gag and cough. Hypersalivation was noted. She did blink both eyes to visual threat, and her pupils were reactive from 4 to 3 mm. She had moderate upper extremity and severe lower extremity spasticity with inducible clonus of her ankles bilaterally. Muscle stretch reflexes were 3+ with spread in her upper extremities and 4+ with spread in her lower extremities. The results of arterial blood gas analysis were normal, and the results of serum and urine toxicology studies were negative. All additional serologic test results, including those for complete blood count, chemistry, creatine kinase, liver and thyroid function, vitamin B12, folate, and lactate levels, were also normal. Urinalysis was unremarkable. The results of electrocardiography, computed tomography of the head, and magnetic resonance imaging/magnetic resonance angiography of the head and neck were normal. Continuous video electroencephalograms recorded for 24 hours showed diffuse slowing but no epileptiform activity. Citalopram and antiemetics were discontinued, and the patient was treated supportively with intravenous fluid and intermittent benzodiazapines for agitation. Her mental status improved minimally, and she was extubated after 48 hours. At 72 hours, she was minimally responsive and rarely following commands; however, her spasticity and clonus remained.