Correct Answer: B. Arterial disease with aortoiliac involvement
Intermittent claudication affecting both thigh and buttock regions is the classic presentation of aortoiliac disease (Leriche syndrome when complete occlusion occurs). The key discriminator is the bilateral buttock and thigh pain, which indicates proximal arterial involvement above the inguinal ligament. Aortoiliac disease causes claudication in the buttocks, hips, thighs, and calves due to compromised blood supply to the lower limbs via the iliac arteries. The patient's chronic smoking history is a major risk factor for atherosclerotic disease. In Indian vascular surgery practice, aortoiliac occlusive disease is increasingly common in smokers aged 40–60 years. The walking distance of 500 m before symptom onset indicates moderate-to-severe stenosis. Aortoiliac disease typically presents with claudication in proximal muscle groups (buttocks and hip flexors), whereas distal arterial disease (superficial femoral or profunda femoris) causes calf claudication. The bilateral nature further supports proximal disease affecting both iliac systems. Diagnosis is confirmed by ankle-brachial index (ABI <0.9), duplex ultrasound, or CT/MR angiography. Management includes risk factor modification (smoking cessation, statins, antiplatelet therapy) and revascularization (aortofemoral bypass or endovascular intervention) if claudication is disabling.
Why the other options are wrong
A. Femoral venous insufficiency — Venous insufficiency causes heaviness, swelling, and skin changes (pigmentation, ulceration), not true claudication pain. Claudication is a hallmark of arterial disease, not venous disease. Venous symptoms worsen with prolonged standing and improve with leg elevation, opposite to arterial claudication. This is a common NBE trap pairing vascular symptoms without distinguishing arterial vs. venous pathology. C. Arterial disease involving the profunda femoris artery — Profunda femoris disease causes claudication in the thigh and calf, but typically spares the buttocks because the profunda arises distal to the inguinal ligament. Buttock claudication specifically indicates proximal (aortoiliac) disease. Profunda femoris occlusion alone rarely causes significant claudication due to collateral circulation from the profunda system itself. D. Arterial disease involving the superficial femoral artery — Superficial femoral artery (SFA) disease causes calf and thigh claudication but characteristically spares the buttocks. SFA occlusion is the most common cause of claudication in Indian populations, but it does not explain buttock pain. The bilateral buttock involvement is the key finding that excludes unilateral SFA disease and points to proximal aortoiliac involvement.
High-Yield Facts
- Buttock + thigh claudication = aortoiliac disease; calf claudication = femoropopliteal disease.
- Leriche syndrome = complete aortoiliac occlusion presenting with buttock claudication, erectile dysfunction, and absent femoral pulses.
- Smoking is the strongest modifiable risk factor for aortoiliac occlusive disease in Indian males aged 40–60 years.
- Ankle-brachial index (ABI) <0.9 confirms arterial disease; ABI 0.4–0.9 suggests claudication; ABI <0.4 suggests critical limb ischemia.
- Aortofemoral bypass and endovascular stenting are standard revascularization options; choice depends on anatomy and patient fitness.
Mnemonics
CLAUDICATION LOCATION RULE BUTTOCK = Aortoiliac; THIGH = Iliac/Profunda; CALF = Femoropopliteal/Tibial. Use this to map claudication site to arterial segment. LERICHE = AORTOILIAC Leriche syndrome = Aortoiliac occlusion + buttock claudication + erectile dysfunction + absent femoral pulses. Remember: Leriche = proximal.
NBE Trap
NBE pairs "arterial disease" with multiple distal options (SFA, profunda) to trap students who recognize claudication but miss the proximal location clue (bilateral buttock pain). The buttock symptom is the discriminator that must be recognized to exclude distal disease.
Clinical Pearl
In Indian vascular clinics, aortoiliac disease is increasingly seen in smokers presenting with "hip pain on walking." Always ask: "Does the pain start in the buttock or calf?" Buttock onset = think proximal; calf onset = think distal. This single question often clinches the diagnosis before imaging.
_Reference: Bailey & Love Ch. 51 (Arterial Disease); Harrison Ch. 243 (Peripheral Arterial Disease)_