Muscle hypertrophy with neuropathy.

Area of Science:

• Neurology
• Muscle Physiology
• Peripheral Nerve Disorders

Background:

• Describing a rare case of neuromuscular disease with unusual clinical and electrophysiological features.
• Investigating the underlying mechanisms of sustained muscle activity and impaired neural signaling.

Observation:

• Patient presented with insidious weakness, muscle atrophy/hypertrophy, and spasms mimicking myotonia.
• Electromyography confirmed sustained muscle fiber activity and impaired reciprocal inhibition.
• Clinical findings included thickened peripheral nerves and significantly slowed motor nerve conduction (sensory normal).

Findings:

• Histological analysis of sural nerve biopsy revealed Schwann cell vacuolation with unknown material and onion-bulb formations.
• Electromyography demonstrated sustained muscle fiber activity as the cause of spasms.
• Impaired reciprocal inhibition was a key electrophysiological finding.

Implications:

• Suggests a potential metabolic error leading to abnormal material storage within Schwann cells.
• Highlights the diagnostic value of combining clinical, electrophysiological, and histological data in neuromuscular disorders.
• Contributes to understanding the pathophysiology of rare peripheral neuropathies with myotonic-like features.