Objective:

In cases of atypical presentations or “idiopathic” conditions, clinicians should continually re-evaluate the suspected underlying diagnosis to account for new or progressing symptoms.

Background:

Spinocerebellar ataxias (SCA) represent a group of hereditary neurodegenerative disorders which are phenotypically heterogeneous, but most uniformly characterized by progressive incoordination. SCA type 2 (SCA2) is the result of a pathogenic CAG triplet repeat in the N-terminal coding region of the ATXN2 gene and commonly clinically manifests in the third to fourth decade with cerebellar dysfunction, peripheral neuropathy, hyporeflexia, and slow visual saccades.

Design/Methods:

Not applicable.

Results:

We present the case of a gentleman who first developed prominent limb cramping and exercise intolerance at age 59. Following several years of gradual symptomatic progression, he sought evaluation where the constellation of his physical exam, spinal imaging, and an EMG were felt to be most consistent with cervical and lumbosacral polyradiculopathies. Gradual clinical deterioration included sensory impairment, progressive dysphagia initially attributed to GERD, muscle twitching, and imbalance. A repeat EMG demonstrated stable polyradiculopathies which were attributed to spinal stenosis along with a new sensory, axonal, large-fiber polyneuropathy. Subsequent work-up was negative for identifiable causes of neuropathy. Due to a prominent complaint of imbalance, an MRI of the brain was pursued. The presence of moderate cerebellar atrophy prompted evaluation for inherited causes of ataxia. A pathogenic expansion in the ATXN2 gene was discovered, consistent with a diagnosis of SCA2.

Conclusions:

This case highlights the importance of approaching each case with critical listening and an open mind to avoid anchoring bias. Atypical features or symptomatic progression should prompt consideration of alternative etiologies. In our patient with a history of polyradiculopathy and polyneuropathy, had workup ceased following evaluation for peripheral nervous system causes of imbalance, the diagnosis of SCA2 and subsequent management considerations would not have been recognized.