National Physical Therapy Examination (NPTE) Practice Exam

In patients with myasthenia gravis, what common symptom distinguishes it from other conditions?

1. Facial weakness

2. Fatigue that worsens throughout the day

3. Sudden onset of paralysis

4. Intense, stabbing facial pain

The correct answer is: Fatigue that worsens throughout the day

In myasthenia gravis, a hallmark symptom is fatigue that worsens throughout the day, known as "fatigable weakness." This symptom is particularly distinctive because it differs from other neuromuscular disorders where weakness might remain consistent or improve throughout activity. In myasthenia gravis, a patient may initially display strength in muscle movements but will often experience a noticeable decrease in strength with repeated use, resulting in exacerbated fatigue. This condition is characterized by autoantibodies that disrupt communication between nerves and muscles, leading to muscle weakness that is variable and gets worse with exertion, making it a defining feature of myasthenia gravis. Recognizing this symptom is critical for differentiation from other conditions that might present with weakness, as those may not exhibit the same pattern of fatigability.