Diffuse alveolar hemorrhage in IgA nephropathy: case series and systematic review of the literature.

Objectives: To describe the spectrum of pulmonary involvement in immunoglobulin A nephropathy (IgAN).

Methods: We describe two patients with pulmonary renal syndrome related to IgAN and a systematic review of previously reported cases of IgAN and lung involvement.

Results: We identified 23 reports of IgAN-related pulmonary disease, including 19 reports of alveolar hemorrhage and two cases of organizing pneumonia. Dyspnea (84%), hemoptysis (74%), cough (53%) and fever (47%) were common presenting complaints. Simultaneous involvement of kidneys and lung was the most common presentation (42%) but alveolar hemorrhage occurred independent of renal disease in one-fifth (21%). Azotemia was seen in 55.5% at presentation. Mesangio-proliferative glomerulonephritis was the most common biopsy finding and crescentic glomerulonephritis was seen in 27.7%. Among patients undergoing lung biopsy, capillaritis was seen in 72.7%; 37.5% of these had IgA deposits. Steroids with cyclophosphamide, followed by maintenance with methotrexate or azathioprine was used in 44%. Mechanical ventilation, dialysis and plasmapheresis were other adjunctive therapies used. IgAN-related alveolar hemorrhage was associated with a mortality of 26.3% and significant morbidity, with 52.7% having end-stage kidney disease despite immunosuppression. Organizing pneumonia with pulmonary IgA deposition is a well-described association of IgAN.

Conclusion: These findings are similar to our previous observations of Henoch-Schonlein purpura (HSP)-related alveolar hemorrhage, highlighting the similarities of these related syndromes. Multicentric studies of IgAN and HSP-related pulmonary renal syndrome with a standard protocol are needed to define their similarities and differences, optimum suppression and its role in preventing renal progression in this setting.