Muscle biopsies, though less common today, are crucial for diagnosing neuromuscular disorders. They are particularly valuable for patients with muscle weakness, elevated serum creatine kinase levels, myopathic electrodiagnostic findings, or abnormal muscle imaging. While many myopathies can be diagnosed with less invasive tests, muscle biopsies are essential for conditions like inflammatory myopathies or when genetic testing is inconclusive. They help confirm diagnoses such as inclusion body myositis and identify specific myositis subtypes, guiding further surveillance and treatment.

In suspected genetic myopathies, muscle biopsies reveal histopathologic features aiding diagnosis, especially when genetic tests are unremarkable. For toxic myopathies, biopsies show distinct features linked to specific medications. They also complement nerve biopsies in diagnosing vasculitis, increasing diagnostic yield. Biopsy site selection involves choosing muscles with moderate weakness, using EMG and MRI for accuracy. Open biopsies offer larger samples, while needle biopsies are simpler and often sufficient. Despite advances in non-invasive testing, muscle biopsies remain vital for diagnosing acquired or genetic myopathies and conditions like vasculitis.

Reference: McIntosh P. Neuromuscular Notes: When to Order a Muscle Biopsy. Practical Neurology. Accessed May 21, 2024. https://practicalneurology.com/articles/2023-nov/neuromuscular-notes-when-to-order-a-muscle-biopsy?c4src=topic:feed