Rosh Internal Medicine Boost Practice Exam

Which condition involves weakness of proximal muscles without pain?

1. Polymyalgia rheumatica

2. Myasthenia gravis

3. Polymyositis

4. Guillain-Barré syndrome

The correct answer is: Polymyositis

The condition characterized by weakness of proximal muscles without pain is polymyositis. This autoimmune disease primarily affects skeletal muscles, leading to muscle weakness, particularly in the proximal muscles such as those in the shoulders and hips. While it often results in significant impairment in muscle strength, it typically does not present with pain, distinguishing it from other conditions that might involve muscle symptoms. Polymyalgia rheumatica, for example, is associated with pain and stiffness in the shoulder and pelvic girdle areas, making it distinct from polymyositis. Myasthenia gravis involves fluctuating muscle weakness that is typically worsened with activity and improves with rest, and it primarily affects facial and ocular muscles in many patients. Guillain-Barré syndrome can present with weakness as well, but it usually starts distally and progresses proximally, often accompanied by pain or sensory changes. Thus, polymyositis is the correct answer as it specifically presents with muscle weakness in proximal areas without an accompanying pain phenomenon.