AEMCA Practice Exam

What is myasthenia gravis?

1. A genetic disorder affecting multiple organ systems

2. An autoimmune neuromuscular disorder causing muscle weakness

3. A rare cancer affecting nerve tissues

4. An infectious disease that impairs lung function

The correct answer is: An autoimmune neuromuscular disorder causing muscle weakness

Myasthenia gravis is best described as an autoimmune neuromuscular disorder that leads to muscle weakness. In this condition, the immune system mistakenly attacks the communication between nerves and muscles, specifically targeting the acetylcholine receptors at the neuromuscular junction. This disruption prevents the normal transmission of nerve signals to muscles, resulting in varying degrees of weakness. Individuals with myasthenia gravis often experience muscle fatigue and weakness that typically worsens with activity and improves with rest. Commonly affected muscle groups include those controlling eye and eyelid movement, facial expressions, and swallowing, but any skeletal muscle can be involved. The other choices do not accurately represent myasthenia gravis. While some disorders may affect multiple organ systems or involve muscle function, myasthenia gravis's specific characterization as an autoimmune disorder primarily affecting neuromuscular transmission distinguishes it from genetic disorders or cancers. Additionally, it is not an infectious disease; thus, it does not impair lung function through infectious processes but may lead to respiratory muscle weakness in severe cases.