IgA nephropathy in association with Crohn's disease: a case report and brief review of the literature.

A case of immunoglobulin A nephropathy (IgAN) complicating a 10-year history of biopsy-proven Crohn's disease in a 31-year-old man is described. The patient presented with mild proteinuria and impaired renal function in the setting of an exacerbation of Crohn's disease. Renal biopsy showed IgAN. The patient responded to steroid treatment with clinical remission of the bowel disease and improvement of renal function, while proteinuria remained unchanged. IgA glomerulonephritis is rarely associated with Crohn's disease with only a few previously described cases. We briefly review these cases together with an overview of potential pathophysiological connections between these two diseases.