Clinical Reasoning: An 83-year-old woman with progressive hemiataxia, tremor, and infratentorial lesions

Abstract

An 83-year-old woman was hospitalized with 6 weeks of progressive left hand incoordination, dysarthria, and gait ataxia, followed by oscillopsia, dysphagia, and left upper limb tremor. She denied cognitive decline, headaches, diplopia, and sensory or systemic symptoms. Ten years previously, she had been diagnosed with locally invasive intraductal breast cancer and treated with lumpectomy, radiation, tamoxifen, and letrozole without recurrence. She denied tobacco or alcohol use. There was no family history of neurologic disease. Results of the general medical examination were unremarkable. Her mental status was normal, although she had severe cerebellar dysarthria. On cranial nerve examination, visual acuity degraded during attempted reading. She had saccadic pursuits and gaze-evoked, rebound, and downbeat nystagmus, without ophthalmoparesis. Saccades had a normal latency and velocity but were inaccurate. She had a left upper limb tremor and slight head tremor (videos 1–3 on the Neurology ® Web site at www.neurology.org). Strength, sensation, and tendon reflexes were normal, with flexor plantar responses. She had significant dysmetria, dysdiadochokinesis, and rebound of the left limbs. Her gait was wide-based and ataxic. ### Questions for consideration: 1. What are the findings displayed in the videos? 2. What is their localization? Video 1 demonstrates bilateral saccadic hypermetria, with macrosaccadic oscillations, which may be due to a fastigial nucleus lesion. Videos 2 and 3 illustrate a low-frequency kinetic > postural > rest tremor (i.e., Holmes tremor), which localizes near the red nucleus. Normal or negative blood test results included complete blood count (absolute lymphocytes 1,535 cells/mm3), chemistry panel, thyroid function, Lyme titer, HIV, vitamin E, anti-GAD65 antibody, antinuclear antibody, paraneoplastic panel (anti-Hu, Ma1, Ma2, Yo, Ri, CV2, and Zic4), and antibodies to anti-Ro, anti-La, gliadin, endomysium, and tissue transglutaminase. Brain MRI performed on initial presentation was reported as normal, but in retrospect showed subtle abnormalities (figure, A). CSF revealed …