The three main components of the neuromuscular junction (NMJ) include the presynaptic region, the synaptic cleft, and the postsynaptic region. The NMJ acts as an interface between the motor nerve and muscle by converting the motor nerve electric currents into chemical signals and then back into electric currents in the muscle. This chapter reviews electrodiagnostic testing in NMJ disorders, including repetitive nerve stimulation and single-fiber electromyography. Myasthenia gravis, congenital myasthenic syndromes, Lambert-Eaton myasthenic syndrome, botulism, and organophosphate poisoning and other toxins are discussed, including epidemiology, etiology/genetics, pathogenesis, diagnosis, differential diagnosis, management, complications, and prognosis. Tables include an overview of neuromuscular disorders, drugs with adverse effects on the NMJ, common immunomodulatory agents used for treatment of myasthenia gravis, congenital myasthenic syndromes, and toxins and venoms. Figures illustrate the NMJ structure and function, structure of the presynaptic and postsynaptic regions, electrodiagnostic studies in NMJ disorders, and dysfunction of the NMJ in acetylcholine receptor myasthenia gravis.
This chapter contains 5 highly rendered figures, 5 tables, 65 references, and 5 MCQs.