Myopathies with finger flexor weakness: Not only inclusion-body myositis

Area of Science:

• Neurology
• Myology

Background:

• Muscle disorders present with varied patterns of muscle group involvement.
• Finger flexor weakness is an uncommon presentation, often associated with sporadic inclusion-body myositis.
• This symptom's significance is heightened when typical inclusion-body myositis histopathology is absent.

Purpose of the Study:

• To explore the differential diagnosis of prominent finger flexor weakness.
• To highlight the range of myopathies presenting with finger flexor weakness.

Main Methods:

• Literature review of case reports and series.
• Analysis of clinical, histopathological, genetic, and electrodiagnostic findings.
• Consideration of muscle imaging in diagnosis.

Main Results:

• Sporadic inclusion-body myositis is a frequent cause of finger flexor weakness, even without full histopathological confirmation.
• Other myopathies, including myotonic dystrophy types 1 and 2, sarcoid myopathy, amyloid myopathy, and inherited myopathies (e.g., ACTA1, DMD, VCP mutations), also present with this symptom.

Conclusions:

• Finger flexor weakness necessitates a broad differential diagnosis beyond inclusion-body myositis.
• Integrated diagnostic approaches combining clinical, pathological, genetic, and imaging data are crucial for accurate diagnosis.