Pauci immune glomerulonephritis is a serious kidney condition affecting the tiny filters within the kidneys, called glomeruli. This disease causes inflammation and damage to these small blood vessels, which are responsible for filtering waste and excess fluids from the blood. When damaged, the kidneys cannot properly remove harmful substances, potentially leading to reduced kidney function and, in severe cases, kidney failure.
Understanding Pauci Immune Glomerulonephritis
The term “pauci immune” refers to the characteristic absence or scarcity of immune complex deposits in the affected glomeruli, distinguishing it from other forms of glomerulonephritis. Despite this lack of deposits, the immune system is involved, as this condition is considered an autoimmune disease.
Pauci immune glomerulonephritis often leads to rapid inflammation and damage to the glomeruli, causing a swift decline in kidney function over days or weeks. This rapid progression frequently classifies it as a form of rapidly progressive glomerulonephritis (RPGN), representing the most common cause of this syndrome. The underlying mechanism involves an immune response that directly attacks the small blood vessels, leading to their destruction and the formation of crescent-shaped scars within the glomeruli.
Identifying the Symptoms
Symptoms of pauci immune glomerulonephritis can be subtle in the early stages, making them easy to overlook. As kidney function declines, more noticeable signs emerge. One common symptom is fatigue, which can result from the accumulation of waste products in the body that the kidneys are no longer effectively filtering.
Swelling, or edema, particularly in the legs, ankles, or around the eyes, often occurs due to the kidneys’ inability to properly regulate fluid balance. Foamy urine, known as proteinuria, indicates that excessive protein is leaking from the damaged glomeruli into the urine. The presence of blood in the urine, or hematuria, is another frequent sign, reflecting damage to the tiny blood vessels in the kidneys. High blood pressure can also develop or worsen as the kidneys struggle to maintain proper fluid and electrolyte balance.
Confirming the Diagnosis
The diagnostic process for pauci immune glomerulonephritis begins with laboratory tests. Urine analysis is performed to detect abnormalities such as the presence of protein and blood, which indicate kidney damage. Blood tests are also conducted to measure markers of kidney function, including creatinine and blood urea nitrogen (BUN) levels, which rise as kidney function declines.
A significant step in diagnosis involves specific blood tests for autoantibodies, particularly anti-neutrophil cytoplasmic antibodies (ANCA). This condition is often associated with ANCA-associated vasculitis, where these antibodies mistakenly target components within certain white blood cells. Approximately 80-90% of pauci immune glomerulonephritis cases are ANCA-positive, with the antibodies targeting myeloperoxidase (MPO) or proteinase 3 (PR3).
While blood and urine tests provide strong indications, a kidney biopsy is the definitive diagnostic tool. During a biopsy, a small piece of kidney tissue is removed and examined under a microscope. This examination reveals characteristic features such as crescent formation and fibrinoid necrosis within the glomeruli. The biopsy also shows the absence of significant immune deposits, which distinguishes pauci immune glomerulonephritis from other kidney diseases.
Approaches to Treatment and Ongoing Care
The primary goals of treatment for pauci immune glomerulonephritis involve suppressing the immune system’s inflammatory response, preserving remaining kidney function, and preventing further damage. High-dose corticosteroids, such as prednisone, are administered initially to rapidly reduce inflammation. These are combined with other immunosuppressive drugs, such as cyclophosphamide or rituximab, to control the immune system and prevent it from attacking the kidneys.
In severe cases, particularly when there is a rapid decline in kidney function or significant lung involvement, plasma exchange (plasmapheresis) may be used. This procedure involves removing the patient’s blood, separating the plasma (which contains harmful antibodies), and returning the treated blood to the body. Long-term monitoring is important, including regular blood and urine tests, to assess kidney function and detect any signs of disease recurrence. Managing associated conditions, such as high blood pressure, is also part of comprehensive care to protect the kidneys. For individuals who progress to severe kidney failure, kidney replacement therapies like dialysis or kidney transplantation may become necessary to sustain life.