Which condition is characterized by weakness in extraocular muscles?

• A. Multiple sclerosis
• B. Myasthenia gravis
• C. Guillain-Barré syndrome
• D. ALS

Answer: (B)

Myasthenia gravis is characterized by weakness in extraocular muscles, which affects voluntary muscle control. This condition results from an autoimmune response against acetylcholine receptors at the neuromuscular junction, leading to muscle weakness and fatigue that often worsens with activity and improves with rest. The extraocular muscles, responsible for eye movement, are frequently affected, leading to symptoms such as diplopia (double vision) and ptosis (drooping eyelids).

While multiple sclerosis, Guillain-Barré syndrome, and amyotrophic lateral sclerosis (ALS) can involve muscle weakness, myasthenia gravis specifically presents with fluctuating muscle weakness that predominantly affects the extraocular muscles.