Critical limb Ischaemia in granulomatosis with polyangiitis: a rare but severe complication.

Granulomatosis with polyangiitis (GPA) is a small-to-medium vessel vasculitis usually presenting with upper airway, pulmonary, and renal involvement. Critical limb ischaemia (CLI) and arterial thrombosis are rare but severe complications of GPA, often resulting in poor prognosis and limb loss. We describe a 34-year-old woman presenting with right upper limb CLI on a background of GPA, manifesting as fever, purpura with upper airway, pulmonary, and renal involvement. Investigations confirmed proteinase-3 anti-neutrophil cytoplasmic antibody positivity, elevated inflammatory markers, proteinuria with active urinary sediment, and imaging revealed pulmonary infiltrates with sinus involvement. She received IV steroids and rituximab but developed acute limb-threatening ischaemia due to brachial artery thrombosis. Immediate thrombectomy with thrombolysis restored blood flow and prevented amputation. Available literature highlights the extreme rarity of CLI in GPA (<1%), with most reported cases resulting in limb loss despite immunosuppression. Prompt diagnosis using Doppler/angiogram and urgent surgical intervention, in conjunction with immunosuppression, is critical for limb salvage. This case underscores the importance of early recognition and combined surgical-medical management in GPA presenting with arterial thrombosis and CLI, which can successfully preserve limb function and improve outcomes.