Hirayama disease presenting as isolated triceps atrophy

Area of Science:

• Neurology
• Clinical Neuroscience
• Musculoskeletal Disorders

Background:

• Hirayama disease (HD) is a rare, juvenile-onset motor neuron disease.
• It typically affects the distal upper extremities, involving the C7, C8, and T1 spinal segments.
• The pathophysiology involves dynamic compression of the cervical spinal cord.

Observation:

• This report presents an atypical case of Hirayama disease.
• The patient exhibited unilateral triceps atrophy, a presentation not commonly associated with HD.
• Triceps innervation originates from the C6 and C7 cervical segments, distinct from typical HD involvement.

Findings:

• The case highlights an unusual manifestation of Hirayama disease with isolated triceps atrophy.
• This presentation expands the spectrum of clinical findings in HD.
• The involvement of C6 and C7 segments in this case contrasts with the usual C7, C8, T1 predilection.

Implications:

• This case broadens the diagnostic considerations for unilateral upper limb atrophy in adolescents.
• Understanding atypical presentations is crucial for timely diagnosis and management of Hirayama disease.
• Further research into the pathomechanisms of HD may explain these varied clinical presentations.