Overlap of Granulomatosis With Polyangiitis and IgA Nephropathy.

Acute glomerulonephritis is a constellation of renal disorders which are precipitated by an immunologic mechanism triggering inflammation and proliferation of glomerular tissue resulting in damage to the basement membrane, mesangium, or capillary endothelium. Two of the most well-known manifestations of glomerulonephritis are granulomatosis with polyangiitis (GPA) and IgA nephropathy (IgAN). To our knowledge, these diseases are often found separately and are rarely diagnosed in the same patient. Here, we discuss a case of a 35-year-old male who presented and was diagnosed with simultaneous GPA and IgAN. His renal biopsy was significant for extensive, crescentic, and necrotizing glomerulonephritis and IgA staining on immunofluorescence indicating severe renal damage. Despite full immunosuppressive therapy, our patient failed to recover his renal function. In our case, we hope to raise awareness of these disorders and early recognition of the clinical features. We believe that this case would prompt providers to pursue diagnostic workups to detect these diseases early on, especially when symptoms progressively worsen and become systemic. As demonstrated in our patient, delay in diagnosis can lead to irreversible damage to a patient's renal function, especially when two types of glomerulonephritis are present.