Correct Answer: B. Takayasu arteritis
Takayasu arteritis is a large-vessel vasculitis that classically presents with claudication (limb ischemia), ocular manifestations (transient vision loss, retinal haemorrhages), and abdominal pain from visceral ischemia. The weak femoral pulses indicate aortic arch and descending aorta involvement—the hallmark of Takayasu. This disease predominantly affects young women in Asia (especially India), with a female-to-male ratio of 8:1. The clinical triad of limb claudication + ocular symptoms + visceral pain, combined with diminished pulses, is pathognomonic. Takayasu causes granulomatous inflammation of large elastic arteries (aorta and its branches), leading to progressive stenosis and occlusion. Retinal haemorrhages occur due to retinal artery involvement or secondary hypertension from renal artery stenosis. The weak femoral pulses reflect aortic arch syndrome (Type I Takayasu). Indian guidelines and epidemiology make Takayasu the leading diagnosis in a young Indian woman with this constellation.
Why the other options are wrong
A. Thromboangiitis obliterans — Thromboangiitis obliterans (Buerger disease) affects small and medium vessels of limbs, causing claudication and gangrene, but does NOT cause ocular manifestations or weak femoral pulses. It is also predominantly a disease of male smokers in India, not young women. Absence of ocular involvement and normal proximal pulses rule this out. C. Microscopic polyangiitis — Microscopic polyangiitis is a small-vessel vasculitis (ANCA-associated) that presents with glomerulonephritis, pulmonary haemorrhage, and neuropathy—not large-vessel claudication or weak femoral pulses. Retinal haemorrhages in MPA are rare and secondary to hypertension, not primary vasculitis. The clinical pattern of large-vessel ischemia is absent. D. Polyarteritis nodosa — Polyarteritis nodosa affects medium-sized muscular arteries and presents with constitutional symptoms, peripheral neuropathy, and coronary/mesenteric infarction, but NOT with large-vessel claudication or weak femoral pulses. PAN does not cause aortic arch syndrome. The absence of neuropathy and the presence of proximal large-vessel disease favour Takayasu over PAN.
High-Yield Facts
- Takayasu arteritis is a large-vessel granulomatous vasculitis affecting the aorta and its branches, predominantly in young Asian women (female:male = 8:1).
- Type I Takayasu (aortic arch involvement) presents with weak upper limb pulses, claudication, and ocular symptoms; Type II involves descending thoracic aorta; Type III involves descending thoracic and abdominal aorta.
- Ocular manifestations include amaurosis fugax (transient vision loss), retinal haemorrhages, and retinal artery occlusion due to direct arterial involvement or secondary hypertension.
- Weak femoral pulses indicate aortic arch or proximal aortic involvement; this finding is absent in small-vessel vasculitides (MPA, PAN).
- Diagnosis relies on elevated ESR/CRP, angiography (CT/MR showing concentric narrowing and wall thickening), and clinical criteria; ANCA is typically negative.
- Indian DOC: Corticosteroids (prednisolone 1 mg/kg) ± methotrexate or azathioprine; TNF-α inhibitors (infliximab) for refractory cases per RNTCP guidelines.
Mnemonics
TAKAYASU = Large Vessel + Young Woman + Asia Thoracic aorta, Arch involvement, Key: young women, Asian origin, Young age, Aortic arch syndrome, Stenosis/occlusion, Upper limb claudication. Remember: Takayasu = aorta + young Asian female. Ocular + Claudication + Weak Pulses = TAKAYASU When you see the triad of transient vision loss (ocular), limb ischemia (claudication), and diminished proximal pulses in a young woman, think Takayasu first. This combination is rare in other vasculitides.
NBE Trap
NBE may lure students into choosing PAN or MPA by listing "abdominal pain" and "retinal haemorrhages" without emphasizing that weak femoral pulses indicate large-vessel disease—a feature unique to Takayasu among the options. The trap is conflating small-vessel vasculitis (PAN, MPA) with large-vessel vasculitis based on non-specific symptoms.
Clinical Pearl
In Indian clinical practice, Takayasu arteritis is the leading cause of aortic arch syndrome in young women presenting with claudication and ocular symptoms. Early recognition and aggressive immunosuppression prevent irreversible vascular damage and complications like stroke or myocardial infarction. Always check for weak pulses and blood pressure differential between limbs in young women with claudication.
_Reference: Robbins & Cotran Pathologic Basis of Disease, Ch. 11 (Blood Vessels); Harrison's Principles of Internal Medicine, Ch. 378 (Vasculitis); Park's Textbook of Preventive and Social Medicine (epidemiology in India)_