Rapidly progr neph synd w diffus mesangial prolif glomrlneph

This code signifies a severe and rapidly worsening form of kidney inflammation characterized by the rapid decline of renal function, often leading to kidney failure within weeks or months. Histologically, it involves the proliferation of mesangial cells throughout the glomeruli, contributing to the rapid progression of kidney damage.

Apply this code when documentation clearly indicates a diagnosis of rapidly progressive nephritic syndrome (RPGN) with biopsy-confirmed diffuse mesangial proliferative glomerulonephritis. This typically presents with acute renal failure, hematuria, proteinuria, and red blood cell casts. Supporting documentation will include pathology reports confirming the specific glomerular lesion.

• Ensure the documentation explicitly states "rapidly progressive" and specifies "diffuse mesangial proliferative" glomerulonephritis.
• Do not use this code for other forms of glomerulonephritis without the rapid progression and specific histological findings.
• Code any underlying systemic diseases (e.g., lupus, vasculitis) as primary diagnoses if they are the cause of the glomerulonephritis, with this code as a secondary diagnosis.