Disclosures: Elizabeth R. Selvaggio, BA: Nothing to disclose

Case Description: The patient presented with progressive right hand weakness and atrophy over the course of 3 months without any inciting event. He first noticed involuntary twitching of his right index finger and then developed progressive weakness in his right hand with gradual difficulty holding his keys and turning door knobs. He then noticed progressive atrophy of his right hand muscles. He denied any pain, numbness/tingling in the hand or bowel/bladder changes. He also endorses occasional neck pain and radiation down his contralateral arm. He denied any family history of rheumatologic or neurologic diseases. Physical exam was remarkable for of 3+/5 strength with right thumb abductors and finger adductors. The rest of the neurologic exam and cervical spine exam was normal.

Setting: Outpatient musculoskeletal/sports clinic

Patient: 28-year-old man right handed male without any significant past medical history.

Assessment/Results: The patient’s labs were within normal limits except for a slightly elevated CPK of 200. He had an EMG performed on bilateral upper extremities that showed acute and chronic denervation of C8 and T1 muscles in the right hand that was reported most consistent with a right C8>T1 radiculopathy. Later on, an MRI demonstrated focal cord volume loss spanning the C6 vertebral body suspicious for Hirayama disease. Further developments will be discussed.

Discussion: Hirayama’s disease also known as monomelic amyotrophy is a very rare variant of amyotrophic lateral sclerosis that involves a single upper extremity and is not commonly seen in musculoskeletal clinic. Without a full work-up performed, this can often be misdiagnosed.

Conclusion: Hirayama is a rare disease that providers should be aware of and consider ordering full work-up for when young males with no significant past history present with progressive painless weakness of a single limb.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/hand-weakness-and-atrophy-in-a-young-man-a-case-report/