Early VV-ECMO enabling immunosuppressive therapy in severe diffuse alveolar hemorrhage due to ANCA-associated vasculitis.

Background: Diffuse alveolar hemorrhage (DAH) is a catastrophic manifestation of ANCA-associated vasculitis (AAV) that can rapidly progress to severe hypoxemic respiratory failure. The optimal sequencing of immunosuppression and extracorporeal support remains unclear, particularly in the setting of active pulmonary bleeding, where anticoagulation during extracorporeal membrane oxygenation (ECMO) presents a major clinical challenge. Case presentation: A 62-year-old previously healthy woman presented with hemoptysis and rapidly progressive hypoxemia. Despite high-flow oxygen therapy and mechanical ventilation, oxygenation continued to deteriorate, prompting initiation of venovenous ECMO with minimized anticoagulation due to ongoing DAH. High-dose methylprednisolone pulse therapy (1 g/day for 3 days) was initiated immediately, followed by intravenous cyclophosphamide (500 mg) based on chest computed tomography findings consistent with pulmonary capillaritis. Oxygenation improved following initiation of immunosuppressive therapy, allowing discontinuation of ECMO within 11 days and extubation within 3 weeks. Renal function also improved without the need for dialysis, despite a peak serum creatinine level of 5.5 mg/dL and nephritic-range proteinuria (urine protein-to-creatinine ratio 4708 mg/g). MPO-ANCA positivity was confirmed prior to the second cyclophosphamide dose. Outcome: No thrombotic complications occurred despite minimized anticoagulation during ECMO support. Follow-up imaging and inflammatory markers demonstrated sustained improvement. The patient continued recovery with tapering glucocorticoids and azathioprine maintenance therapy. Conclusion: This case suggests that venovenous ECMO with individualized anticoagulation may serve as a bridge to definitive immunosuppression in fulminant AAV-associated DAH. Early cyclophosphamide administration timed to worsening organ involvement may help limit multi-organ injury and avert the need for renal replacement therapy.