What is a common finding on a biopsy of rapidly progressive crescentic glomerulonephritis?

In rapidly progressive crescentic glomerulonephritis (RPGN), a hallmark finding on biopsy is the presence of crescents in Bowman's capsule. These crescents are composed of epithelial cells, macrophages, fibrin, and often other inflammatory cells that accumulate in response to severe injury to the glomeruli. The formation of these crescents indicates a rapid loss of kidney function and is a critical feature in the diagnosis of RPGN, signaling a severe and typically progressive form of kidney injury.

Crescents reflect a pattern of damage caused by a variety of underlying mechanisms, including autoimmune diseases, infections, and vasculitis. The inflammation leads to the proliferation of glomerular cells and infiltration of inflammatory cells, which collectively create the crescent shape within the Bowman's space.

The correct identification of crescents on a biopsy can guide clinicians in determining the underlying etiology of the RPGN and the appropriate treatment strategy. This finding is integral to establishing the diagnosis and is commonly discussed in the context of both the pathology and clinical management of rapidly progressive glomerulonephritis.