Clinical Reasoning: A 16-year-old girl with ataxia, oscillopsia, and behavioral changes

Abstract

A 16-year-old girl with no relevant medical history presented with 1 week of vertigo, tremulousness, and gait instability. She described the room as "moving and unsteady." She reported anxiety and had a panic attack in the emergency department. In the months prior to presentation, she displayed atypical irritability and aggressiveness toward her siblings. One week before the onset of vertigo, she completed a 5-day course of azithromycin for presumed sinusitis. She had not traveled in the prior year. The patient denied drug or alcohol use, sexual activity, sick contacts, or any recent tick or mosquito bites. On examination, the patient had slow, soft, and deliberate speech but was alert and oriented to person, place, time, and situation. She had intact naming, comprehension, and repetition. She was able to register and recall 3/3 words. Her ocular ductions were full. However, there were constant, rapid eye movements in both horizontal and vertical directions, mostly observed in primary gaze and with fixation. The movements were conjugate and of moderate amplitude and high frequency (video 1, part 1). There was no slow phase. Dix-Hallpike and head impulse testing were negative. There was no intention tremor, dysdiadochokinesia, or dysmetria on initial examination, although the patient later developed bilateral dysmetria on day 3 of her hospitalization. She had prominent truncal ataxia, which limited gait assessment. The remainder of her examination was unremarkable. Questions for consideration: 1. How would you localize this patient's presentation? 2. How would you characterize her eye movements? GO TO SECTION 2