Clinical Reasoning: A 55-Year-Old Woman With Painless Hand Weakness and Atrophy.

Area of Science:

• Neurology
• Clinical Neuroscience
• Musculoskeletal Disorders

Background:

• Hand weakness and atrophy are common neurological complaints.
• Thenar muscle atrophy, particularly in the dominant hand, warrants thorough investigation.
• Previous carpal tunnel surgery can complicate the diagnosis of hand weakness.

Purpose of the Study:

• To present a case of isolated thenar muscle atrophy.
• To discuss the differential diagnosis of hand weakness and atrophy.
• To emphasize the importance of myotomal innervation in diagnosing intrinsic hand muscle weakness.

Main Methods:

• Case report of a 55-year-old woman with chronic right hand weakness.
• Review of differential diagnoses for isolated thenar muscle atrophy.
• Analysis of myotomal innervation patterns in intrinsic hand muscles.

Main Results:

• The patient presented with selective thenar muscle atrophy without sensory deficits.
• A systematic diagnostic approach was crucial for identifying the underlying cause.
• The case underscores the need to consider uncommon etiologies for common symptoms.

Conclusions:

• Isolated thenar atrophy can present without sensory symptoms, mimicking other conditions.
• Understanding myotomal innervation is key to differentiating causes of hand weakness.
• A structured diagnostic strategy aids in identifying rare causes of prevalent neurological issues.