neuromuscular transmission defect
Impaired signal transmission between motor nerves and muscles at the neuromuscular junction.
Full Definition
A neuromuscular transmission defect refers to any disorder affecting the normal transfer of electrical signals from motor nerve terminals to muscle fibers at the neuromuscular junction. These defects can be presynaptic (affecting acetylcholine synthesis, storage, or release), synaptic (involving the synaptic cleft), or postsynaptic (affecting acetylcholine receptors or muscle membrane). Common causes include myasthenia gravis, Lambert-Eaton myasthenic syndrome, congenital myasthenic syndromes, and botulism. Clinical presentation typically involves fatigable weakness that worsens with repetitive activity. Diagnosis relies on specialized electrodiagnostic testing, particularly repetitive nerve stimulation and single-fiber electromyography.
Usage
Usage note: Hyphenate 'neuromuscular' and use 'defect' rather than 'deficit' in formal documentation.
In Context
- "Repetitive nerve stimulation revealed a neuromuscular transmission defect with decremental response." — Electromyography report
- "The patient's fatigable weakness suggested an underlying neuromuscular transmission defect." — Clinical assessment