Clinical Reasoning: A 62-year-old woman with bizarre behavior and recurrent episodes of behavioral arrest

SECTION 1

A 62-year-old woman was brought to the emergency department by family members after experiencing 3 episodes of behavioral and speech arrest over the past day, with the third episode reportedly ending in convulsive shaking. Her medical history was significant for chronic abdominal and low back pain, for which she had been taking diazepam for the past 9 years, at a stable dose of 10 mg 4 times daily, in addition to tramadol 50–100 mg every 6 hours as needed. She also had a history of migraine headaches and was taking Topamax 100 mg twice daily. There was no history of seizure.

She had 2 events while in the emergency department, one of which was witnessed by the neurology team and consisted of sudden behavioral arrest and decreased responsiveness. She attended to the examiner when her name was called; however, she did not verbally respond or follow commands. The event lasted 5 minutes and ended when she suddenly interrupted a side conversation regarding MRI, to state that she was allergic to contrast dye. She was then immediately oriented and able to answer questions. In between these spells, the patient exhibited pressured, tangential speech with some verbal perseveration and ideas of grandeur. Her behavior was described in nursing notes as “disinhibited and silly,” but she was otherwise alert and oriented. Her neurologic examination was otherwise unremarkable, with the exception of brisk but symmetric reflexes. CT head was without acute abnormality and blood count and chemistry including electrolytes, liver function tests, thyroid-stimulating hormone, urinalysis, and urine drug screen were unremarkable.

The patient continued to have similar spells overnight as described above.

SECTION 2

The differential diagnosis at this time was broad. The differential diagnoses of discrete stereotyped events in this case included epileptic seizures, nonepileptic spells, benzodiazepine withdrawal seizures, and migraines. However, as the patient's baseline mental status was unclear to the team at presentation, further diagnoses of altered mental status were considered as well, including nonconvulsive status epilepticus (NCSE), psychiatric disturbance, and toxic/metabolic encephalopathy. On further questioning, the patient admitted to abrupt cessation of her valium 3–4 days prior to admission as she ran out of her prescription. Given this information, there was high suspicion for benzodiazepine discrete withdrawal seizures or benzodiazepine-associated NCSE. Therefore, the patient was put on continuous video EEG monitoring, which captured several spells. These were similar to those described previously. During one such episode, the patient picked up her cell phone, pressing the touchscreen several times, then held the phone up to her head. She said, “Hello, huh? I'm fine. No, I'm fine, um—I'm great,” followed by apparent behavioral arrest lasting several minutes. Following this, she began waving her arms around, smiling, then laughing. She said to the staff at bedside, “I can function,” while gesturing with her hands. She said, “I am still seeing… it is pleasant. Everything is going on.” She answered all orientation questions correctly.

Excerpts of the EEG are depicted in the figure.

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Figure EEG shows the frequency of stereotyped episodes and corresponding ictal activity over approximately 20 hours

The amplitude integrated EEG measured on channel C3-C4 is shown with amplitude (y-axis) shown over time (x-axis), showing the frequency of stereotyped episodes and corresponding ictal activity over approximately 20 hours. Samples of EEG are also shown during (A) period of low-amplitude mixed frequencies and (B) period of continuous, generalized, rhythmic to quasi-rhythmic irregular spike-and-slow wave discharges.

SECTION 3

Continuous EEG revealed background activities of relatively low amplitude, mixed frequency activities interrupted by long runs of continuous, generalized, rhythmic to quasi-rhythmic, irregular 2–3 Hz spike-and-slow wave activities occurring every 20–40 minutes, with these periods of spike-and-slow wave activity correlating with stereotyped episodes. Based on EEG findings, the patient was treated acutely with 1 mg IV ativan, loaded with 20 mg/kg IV Depakote, and her home valium was resumed. Her episodes resolved and her EEG improved, demonstrating resolution of the spike-and-slow wave activity and return of normal waking background activity. Her labile affect and concentration improved. Clinical and electrographic improvement following administration of benzodiazepine and antiepileptic drug (AED) treatment suggests the diagnosis of NCSE. Her MRI brain revealed only small 4 mm left periophthalmic aneurysm, unchanged from prior studies and of doubtful significance. She was discharged on maintenance valproate 750 mg BID, and her tramadol was discontinued. She was seen in follow-up 8 weeks later, and was noted to have normal mental status and language function at that time. A follow-up routine EEG revealed enhanced beta activity but no evidence of epileptiform discharges.