Myasthenia gravis is best described as

• A. Muscular weakness with atrophy
• B. Muscular weakness without atrophy due to defect in acetylcholine at the neuromuscular junctions
• C. Seizure activity
• D. Cardiomyopathy

Answer: (B)

Myasthenia gravis is an autoimmune disruption of neuromuscular transmission. Antibodies attack acetylcholine receptors on the postsynaptic muscle membrane, reducing the number of functional receptors and impairing the signal from nerve to muscle. Because transmission is faulty, muscles become weak with use and improve with rest, and the muscle bulk stays normal or near normal—there isn’t significant muscle fiber atrophy. This distinguishes it from conditions that cause true muscle wasting or from unrelated issues like seizure activity or heart muscle disease. So the best description is weakness without atrophy due to a defect at the neuromuscular junction from acetylcholine receptor abnormalities.