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APS Mesenteric Thrombosis — SCE Rheumatology MCQ

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HardRheumatology EmergenciesAPS Mesenteric ThrombosisSCE Rheumatology

A 30-year-old woman with SLE controlled on hydroxychloroquine presents with sudden severe abdominal pain out of proportion to the initial examination. CT angiography demonstrates segmental small-bowel ischaemia and an occlusive thrombus in the superior mesenteric artery. Her complement concentrations and anti-dsDNA titre are unchanged from baseline. Lupus anticoagulant, high-titre IgG anticardiolipin and IgG anti-beta-2-glycoprotein I antibodies have each been positive on two samples taken 16 weeks apart. Echocardiography shows no intracardiac thrombus or valvular vegetation. Which diagnosis best explains the intestinal ischaemia?

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Correct answer: B — Antiphospholipid syndrome-related superior mesenteric arterial thrombosis

The diagnosis is APS-related superior mesenteric arterial thrombosis. She has an objectively confirmed macrovascular arterial thrombotic event together with a persistent high-risk, triple-positive antiphospholipid-antibody profile. Stable complement and anti-dsDNA results argue against an inflammatory SLE flare, making lupus mesenteric vasculitis less likely. Libman–Sacks endocarditis can cause arterial emboli, but echocardiography shows no cardiac source. Non-occlusive mesenteric ischaemia occurs in profound low-flow states and would not explain an occlusive arterial thrombus. Atherosclerotic thrombosis is improbable in this young patient without supporting vascular disease. Thrombotic APS associated with SLE requires long-term vitamin K antagonist anticoagulation after an arterial event; EULAR permits an INR target of either 2–3 or 3–4 after individual assessment, so a universal target of 2–3 should not be stated.

Reference: Barbhaiya M, Zuily S, et al. The 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria (clinical domain: macrovascular arterial thrombosis; laboratory domains: LA, aCL, anti-β2GPI). Arthritis Rheumatol. 2023;75(10):1687–1702. https://pubmed.ncbi.nlm.nih.gov/37635643/