In Myasthenia Gravis, which type of muscle weakness is characteristic?

In Myasthenia Gravis, the characteristic muscle weakness indeed worsens with repetition. This phenomenon occurs due to the nature of the disease, which involves an autoimmune attack on the acetylcholine receptors at the neuromuscular junction. As repeated activation of the muscle occurs, the available receptors become more depleted, leading to increased weakness with sustained or repeated contractions.

Patients often experience this pattern in activities such as climbing stairs, holding their arms overhead, or speaking, where muscle strength declines progressively throughout the task. This is in contrast to other neuromuscular disorders where weakness may improve with use or remain stable, thereby emphasizing the distinctiveness of Myasthenia Gravis' clinical presentation.

The other options do not accurately reflect the typical behavior of muscle weakness seen in this condition. For instance, muscle weakness that worsens with rest is not characteristic; instead, patients may experience temporary improvement after periods of rest. Consistent weakness throughout the day is also not typical, as individuals often notice fluctuations in their muscle strength that correlate with activity levels. Lastly, while weakness can occur in the lower limbs, it is not confined to that area and usually affects ocular muscles, leading to ptosis or diplopia, as well as bulbar and proximal