Granulomatosis With Polyangiitis Presenting With Diffuse Alveolar Hemorrhage: A Systematic Review

Granulomatosis with polyangiitis (GPA) is a systemic disease that has variable clinical expression. GPA is the most common antineutrophilic cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Diffuse alveolar hemorrhage (DAH) is one of the least common pulmonary manifestations in patients with GPA. DAH is clinically marked by hemoptysis, anemia, and diffuse alveolar infiltrates on imaging as well as hypoxemic respiratory failure. The diagnosis and treatment are challenging. Recommendations for ANCA-associated vasculitis, in general, are already established; however, there is a knowledge gap that addresses the association of GPA and DAH. The aim of this systematic review is to focus on the main clinical aspects and treatment of patients with GPA who present with DAH. Thorough research of available literature was performed, including studies published in the last 10 years, following the Preferred Items for Systematic Review and Meta-Analysis (PRISMA) 2020 recommendations. The following databases were included: PubMed, Medline, Embase, ClinicalTrials.com, Google Scholar, and Prospero. The search terms included: [granulomatosis] AND [polyangiitis] AND [diffuse alveolar hemorrhage] OR [diffuse pulmonary hemorrhage] NOT [microscopic polyangiitis] NOT [eosinophilic granulomatosis]. NOS was used to assess the internal validity of the study in four domains, including selection, ascertainment, causality, and reporting. Our initial search identified 8989 studies. After excluding duplicated data and using our predetermined inclusion and exclusion criteria, we were able to retrieve 18 studies. Twelve out of 18 (67%) studies were case reports. Five were retrospective cohorts and one controlled trial. The average age of patients with GPA with DAH was 49.55 ± 17.54 years (18 - 76). Male individuals had a slight predominance (59%) in comparison to female individuals (41%). The hemoglobin level at the time of presentation was 8.86 mg/dL ± 1.43. The majority of patients (61.5%) reported hemoptysis. Renal involvement was present in 66.7%. Patients who required mechanical ventilation represented 61.5%. Plasmapheresis was used in 71.4%. Mortality was 20%, and gender was not associated with mortality (p = 0.822). Hemoptysis was not associated with the need for mechanical ventilation (p = 0.928). Renal impairment was not a predictor of mechanical ventilation (p = 0.207). In summary, patients with GPA and DAH were severely ill, frequently had renal impairment upon admission, and frequently required mechanical ventilation. Steroids, rituximab, and cyclophosphamide are the first-line treatment, and plasmapheresis is still in use. Eventually, extracorporeal membrane oxygenation (ECMO) can be the salvage therapy. Randomized controlled clinical trials (RCTs) are needed to address the best therapeutic options for this population.