American Board of Internal Medicine (ABIM) Certification Practice Exam

What condition is characterized by progressive weakness, areflexia, and sensorimotor neuropathy that lasts longer than 8 weeks?

1. Guillain-Barré syndrome

2. Chronic inflammatory demyelinating polyradiculoneuropathy

3. Myasthenia gravis

4. Amyotrophic lateral sclerosis

The correct answer is: Chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is characterized by progressive weakness, areflexia, and sensorimotor neuropathy that persists for a duration longer than 8 weeks. This condition is an autoimmune disorder in which the body's immune system attacks the myelin sheath of peripheral nerves, leading to inflammation and subsequent damage. Unlike Guillain-Barré syndrome, which typically has a more acute onset and resolves over weeks to months, CIDP is chronic, and the symptoms can last for months to years if untreated. The presence of areflexia and progressive weakness, along with the duration exceeding 8 weeks, aligns with the clinical profile of CIDP. It is important to note that CIDP can be differentiated from other neuromuscular disorders because it can present with a relapsing course, and patients often experience recovery periods. In contrast, while Guillain-Barré syndrome also presents with weakness and areflexia, it typically follows an acute course, with a peak within 4 weeks. Myasthenia gravis primarily involves muscle weakness that fluctuates with activity and often improves with rest, rather than presenting with areflexia or neuropathic symptoms. Amyotrophic lateral sclerosis