Unique Manifestation of Hirayama Disease: Bilateral Radial and Ulnar Nerve Palsy with Hypothenar Atrophy, and Atypical Snake Eye Appearance

A rare cervical myelopathy called Hirayama disease usually manifests as muscle atrophy and distal upper limb weakness that develops gradually in young males. A 42-year-old male presented with progressive weakness and atrophy in both upper limbs for over 12 years, accompanied by fine tremors. Neurological examination revealed weakness in wrist extension and finger movements, profound atrophy of the hypothenar and interosseous muscles, and sensory deficits consistent with radial and ulnar nerve involvement. Cervical spine Magnetic Resonance Imaging (MRI) in a flexed position revealed anterior displacement of the posterior dural sac (from C3 to C7 level), with compression of the lower cervical cord, confirming the diagnosis of Hirayama disease. This case highlights a rare and severe manifestation of Hirayama disease, emphasising the bilateral involvement of multiple peripheral nerves, a finding uncommon in classical presentations. Early diagnosis, aided by dynamic MRI imaging, is crucial to prevent further neurological deterioration. Treatment options, including cervical collar immobilisation, aim to halt disease progression. This report underscores the importance of considering Hirayama disease in the differential diagnosis of atypical peripheral neuropathy presentations, particularly in young patients and, in this case, in an older age group (40-45 years). It also provides insight into the varied clinical spectrum of this condition.