Rapidly progressive glomerulonephritis

Crescentic glomerulonephritis (2)

Rapidly Progressive Glomerulonephritis (RPGN) is a severe form of glomerulonephritis characterized by rapid loss of kidney function, typically over days to weeks. RPGN is a medical emergency that requires prompt diagnosis and treatment to prevent irreversible kidney failure. The condition is also known as crescentic glomerulonephritis due to the crescent-shaped formations observed in the glomeruli during histological examination.

Causes

RPGN can be caused by a variety of underlying diseases, which are broadly classified into three categories based on the presence of certain antibodies and the pattern of immune deposits seen on kidney biopsy:

• Type I RPGN: Primarily caused by anti-glomerular basement membrane (anti-GBM) antibodies, as seen in Goodpasture's syndrome.
• Type II RPGN: Results from immune complex deposition in the glomeruli, associated with diseases such as Lupus nephritis, IgA nephropathy, and post-infectious glomerulonephritis.
• Type III RPGN: Linked to pauci-immune conditions, where there are few or no immune deposits, most commonly associated with ANCA-associated vasculitis, including granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis) and microscopic polyangiitis.

Symptoms

The symptoms of RPGN are often severe and can include:

• Hematuria (blood in the urine)
• Proteinuria (protein in the urine)
• Edema (swelling), particularly in the legs and feet
• Hypertension (high blood pressure)
• Oliguria (reduced urine output)
• Fatigue and weakness
• Loss of appetite and weight loss

Diagnosis

Diagnosis of RPGN involves a combination of clinical evaluation, laboratory tests, and kidney biopsy. Laboratory tests may show elevated levels of creatinine and urea, indicating reduced kidney function. Urinalysis typically reveals hematuria and proteinuria. A kidney biopsy is essential for confirming the diagnosis, determining the underlying cause, and guiding treatment.

Treatment

Treatment of RPGN aims to control the symptoms, prevent further kidney damage, and treat the underlying cause. It may include:

• High doses of corticosteroids to reduce inflammation
• Cytotoxic drugs to suppress the immune system
• Plasmapheresis to remove antibodies from the blood (particularly in cases caused by anti-GBM antibodies)
• Management of complications such as hypertension and edema

Prognosis

The prognosis of RPGN varies depending on the underlying cause, the severity of kidney damage at the time of diagnosis, and the response to treatment. Early and aggressive treatment can improve outcomes, but some patients may progress to chronic kidney disease or end-stage renal disease, requiring dialysis or kidney transplantation.