Abstract

NEUROMUSCULAR TRANSMISSION DEFECTS IN MYASTHENIA GRAVIS: PATHOPHYSIOLOGY, DIAGNOSIS, AND TREATMENT AND MANAGEMENT

Anagha K. P.*, Gnanapriya K., Gokulnath S., Harshini S., Vigneshwaran M.

ABSTRACT

Myasthenia gravis (MG) is an autoimmune disease that causes neuromuscular junction (NMJ) dysfunction, which disrupts normal nerve-to-muscle transmission and causes muscle weakness and fatigue. The NMJ is a specific location where motor neurons release acetylcholine (ACh), which attaches to nicotinic acetylcholine receptors (AChRs) on the postsynaptic membrane to cause muscle contraction. This mechanism is restricted in MG because pathogenic autoantibodies are present. These antibodies often target AChRs (AChR-MG), but they can also target muscle-specific kinase (MuSK), resulting in different disease subtypes. Antibodies, mostly of the IgG1 and IgG3 subclasses, activate complement in AChR-MG, resulting in membrane degradation, receptor loss, and structural alterations at the postsynaptic membrane. MuSK-MG, on the other hand, contains IgG4 antibodies that disrupt receptor function without causing substantial complement-mediated degradation, suggesting a distinct pathogenic mechanism. Thetypical fatigable muscle weakness is caused by a reduction in the quantity and function of AChRs, which lowers the effectiveness of neuromuscular transmission. To identify transmission problems, diagnostic techniques like single-Fiber electromyography and repeated nerve stimulation are crucial. Targeted treatments such as complement inhibitors (e.g., eculizumab) have shown therapeutic advantages in resistant instances, and complement-mediated damage is a major contributor in the development of the disease. To investigate the pathophysiological mechanisms that underlie neuromuscular junction dysfunction in myasthenia gravis, with an emphasis on the function of autoantibodies that target muscle-specific kinase and acetylcholine receptors. To assess how these immune-mediated changes affect neuromuscular transmission, contribute to muscle weakness and fatigability, and affect diagnostic and treatment strategies.

Keywords: Myasthenia gravis, Neuromuscular junction, Acetylcholine receptors, Autoantibodies, Immunopathogenesis.