DPM DPM Vascular & Neurological Conditions of the Lower Extremity 2 — Questions and Answers
Question 1: What is the most common underlying cause of peripheral neuropathy in the United States?
- Alcoholism
- Vitamin B12 deficiency
- Diabetes mellitus (Correct answer)
- Hypothyroidism
Correct answer: Diabetes mellitus
Diabetic peripheral neuropathy is the most common cause of peripheral neuropathy in the US, affecting up to 50% of diabetic patients.
Question 2: Which type of nerve fiber is first affected in diabetic peripheral neuropathy?
- Large myelinated motor fibers
- Small unmyelinated C fibers and Aδ fibers (Correct answer)
- Proprioceptive Ia afferents
- Alpha motor neurons
Correct answer: Small unmyelinated C fibers and Aδ fibers
Small fiber neuropathy affects unmyelinated C fibers (pain, temperature) and thinly myelinated Aδ fibers first, causing burning pain before large-fiber deficits appear.
Question 3: Which clinical finding is characteristic of Raynaud's phenomenon in the feet?
- Pitting edema with brawny skin changes
- Triphasic color change: white → blue → red with cold exposure (Correct answer)
- Ulceration over the medial malleolus
- Bounding dorsalis pedis pulse
Correct answer: Triphasic color change: white → blue → red with cold exposure
Raynaud's phenomenon causes episodic vasospasm resulting in a classic triphasic color change (pallor → cyanosis → erythema) triggered by cold or emotional stress.
Question 4: An ABI value greater than 1.3 in a diabetic patient suggests:
- Normal arterial circulation
- Severe arterial occlusion
- Non-compressible calcified vessels giving falsely elevated readings (Correct answer)
- Venous hypertension
Correct answer: Non-compressible calcified vessels giving falsely elevated readings
In diabetic and elderly patients, medial arterial calcification can render vessels incompressible, producing falsely elevated ABI values above 1.3 that do not reflect true arterial perfusion.
Question 5: Which medication class is the cornerstone of medical management for symptomatic peripheral arterial disease?
- Antiplatelet agents (aspirin or clopidogrel) (Correct answer)
- Warfarin anticoagulation
- Calcium channel blockers
- Loop diuretics
Correct answer: Antiplatelet agents (aspirin or clopidogrel)
Antiplatelet therapy with aspirin or clopidogrel reduces cardiovascular events and is the cornerstone of medical management for PAD.
Question 6: Which monofilament test is the standard for screening loss of protective sensation in the diabetic foot?
- 2-point discrimination with a caliper
- 10-gram Semmes-Weinstein monofilament (Correct answer)
- 128-Hz tuning fork vibration test
- Sharp/dull discrimination with a pin
Correct answer: 10-gram Semmes-Weinstein monofilament
The 10-gram Semmes-Weinstein monofilament is the standard clinical tool for detecting loss of protective sensation in diabetic patients at risk for foot ulceration.
DPM DPM Vascular & Neurological Conditions of the Lower Extremity 2
What is the most common underlying cause of peripheral neuropathy in the United States?