Rapidly progressive glomerulonephritis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Jogeet Singh Sekhon, M.D. [2]
Overview
Rapidly progressive glomerulonephritis (RPGN) is a disease of kidney which occurs following severe damage to the kidneys and it can lead to rapid deterioration of kidney function in a few days. It is characterized by the presence of crescents in the glomeruli and hence is also called crescentic glomerulonephritis. Patients with RPGN present with nephritic syndrome, but some may also have proteinuria.RPGN progresses to end stage renal disease if it is not treated in time. RPGN is classified into three types, all of which involve immune-mediated damage to the glomeruli. In type I RPGN,, injury is caused by antibodies directed against the glomerular basement membrane. Type II RPGN accountsory is characterized by the deposition of immune complexes in the glomerulus. are type III, or pauci-immune RPGN, which features antibodies directed against neutrophils (anti-neutrophil cytoplasmic antibodies, ANCA). Treatment depends on the underlying disease process. For example, plasmapheresis, corticosteroids, and cytotoxic drugs may promote recovery in Goodpasture syndrome, a cause of type I RPGN. Despite even early treatment, however, many patients with RPGN may ultimately require dialysis and possibly renal transplant.
Historical Perspective
1919 Ernst Goodpasture made case reports about glomerulnophritis and pulmonary haemorrhages. Stanton and Tait from Australia studied these case reports and then named the findings as Goodpasture syndrome in 1958. They gave the anti GBM antibodies classification and discovered RPGN in these cases. In 1960s electron microscopy and immunofluorescence helped to learn RPNG on immunological level.
Classification
Rapidly progressive glomerulonephritis can be classified on the basis of cause of glomerular injury.The immunoflourescent microspcopic findings are used in determining the cause of glomerular injury.
Pathophysiology
Rapidly progressive glomerulonephritis is a disease of the kidney in which the renal function deteriorates in a few days. Atleast 50% reduction in GFR occurs in RPGN in a few days to weeks. RPGN occurs from severe and fast damage to the GBM which results in crescent formation, the main pathological finding in RPGN. Injury can occur by anti GBM antibodies-type I RPGN, Immune complex- type II RPGN or pauci immune RPGN(ANCAs)-type III RPGN. Crescents are present in the Bowmans space. Light, immunofluoresnce and electron microscopy are used to diagnose RPGN.
Causes
Rapidly progressive glomerulonephritis can be caused by multiple factors.These include life threatening conditions such as sepsis and other pre existing renal diseases.Infections, drugs and some types of cancer also cause RPGN.
Differentiating rapildy progressive glomerulonephritis from Other Diseases
The various types of glomerulonephritides should be differentiated from each other based on associations, presence of pitting edema, hemeturia, hypertension, hemoptysis, oliguria, peri-orbital edema, hyperlipidemia, type of antibodies, light and electron microscopic features.
Epidemiology and Demographics
The incidence of RPGN is 1 per 1 million individuals per year and the incidence is affected by race and age.
Risk Factors
Common risk factors in the development of rapidly progressive glomerulonephritis may be occupational, environmental, genetic, and viral.
Screening
There is insufficient evidence to recommend routine screening for rapidly progressive glomerulonephritis.
Natural History, Complications, and Prognosis
Patients with RPGN present with flu like symptoms initially and then develop nephritic syndrome with proteinuria in some cases as well. In type III RPGN, systemic features of vasculitis are present in some cases.Pulmonary symptoms are also present in Goodpastures syndrome and Churg Strauss syndrome.The prognosis is usually poor due to rapid deterioration of renal function and is dependent on age, presence of pulmonary symptoms, serum creatinine levels and presence of ANCAs.
Diagnosis
Diagnostic Study of Choice
Determination of ANCAs can aid in the diagnosis, but positivity is not conclusive and negative ANCAs are not sufficient to reject the diagnosis. Cytoplasmic staining ANCAs that react with the enzyme proteinase 3 (cANCA) in neutrophils (a type of white blood cell) are associated with Granulomatosis with polyangiitis. If the patient has renal failure or cutaneous vasculitis, these are the most logical organs to obtain a biopsy from. Rarely, thoracoscopic lung biopsy is required.
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
X-ray
Echocardiography and Ultrasound
CT scan
MRI
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Treatment of RPGN depends on the underlying disease process. For example, plasmapheresis, corticosteroids, and cytotoxic drugs may promote recovery in Goodpasture syndrome, a cause of type I RPGN. Despite even early treatment, however, many patients with RPGN may ultimately require dialysis and possibly renal transplant.
Surgery
Surgery is not the first-line treatment option for patients with rapidly progressive glomerulonephritis. Renal transplantation is usually reserved for patients who present with undetectable circulating anti-glomerular basement antibodies in serum for 12 months and at least 6 months after stopping the use of cytotoxic agents.
Primary Prevention
There are no established measures for the primary prevention of Rapidly progressive glomerulonephritis.
Secondary Prevention
There are no established measures for the secondary prevention of Rapidly progressive glomerulonephritis.