Crescentic glomerulonephritis

Definition

Rapidly progressive glomerulonephritis is a form of kidney disease that causes damage to the internal structures of the kidneys and rapid loss of function, with crescent-shaped abnormalities showing on a biopsy of the kidney.

Alternative Names

Causes

The glomeruli are small structures inside the kidneys. They are the area where blood flows through very small capillaries and is filtered through membranes to form urine.

Rapidly progressive glomerulonephritis includes any type of glomerulonephritis (inflammation of the glomerulus) in which progressive loss of kidney function occurs over weeks to months. Most pathologists define crescentic glomerulonephritis when 50% or more glomeruli reveal crescents on kidney biopsy. It may show up as an acute nephritic syndrome or unexplained renal (kidney) failure. It often worsens rapidly to renal failure and end-stage renal disease.

The disorder is more common in certain geographic areas. Mini-epidemics of this disorder have also occurred. It is most common in people aged 40-60, and slightly more common in men but, depending on the cause, occurs in both sexes and at any age. It is unusual in preschool children, and slightly more common in later childhood.

Many conditions are known to cause or increase the risk for developing this syndrome. These include vascular (blood vessel) diseases such as vasculitis or polyarteritis, abscess of any internal organ, collagen vascular disease such as lupus nephritis and Henoch-Schonlein purpura, Goodpasture's syndrome, IgA nephropathy, membranoproliferative GN, anti-glomerular basement membrane antibody disease

Symptoms

Common symptoms include the following:

• Edema (swelling)
  • face
  • eyes
  • ankles, feet, extremities
  • abdomen
  • generalized
• Dark or smoke-colored urine
• Blood in the urine
• Decreased urine volume

• Fever
• Myalgia (muscle aches)
• Arthralgia (joint aches)
• Shortness of breath
• Cough
• Malaise (a general ill feeling)
• Abdominal pain
• Loss of appetite
• Diarrhea

Exams and Tests

An examination reveals edema (swelling). Circulatory overload, with associated abnormal heart and lung sounds, may be present. The blood pressure may be elevated. Rapid, worsening loss of kidney function may be present.

• Urinalysis may be abnormal, showing blood in the urine, urine protein, white blood cells, casts, or other abnormalities.
• The BUN and creatinine may rise rapidly.
• The creatinine clearance decreases.
• Anti-glomerular basement membrane antibody tests may be positive in some cases.
• Antineutrophil cytoplasmic antibodies (ANCAs) may be present.
• Complement levels may be decreased in some cases.
• Other tests for suspected causes may be performed.
• A kidney biopsy confirms crescentic glomerulonephritis.

Treatment

The treatment varies with the suspected cause. The treatment goals may be a cure of the causative disorder, the control of symptoms, or the treatment of kidney failure.

Corticosteroids may relieve symptoms in some cases. Other medications may include immunosuppressive agents including cyclophosphamide, azathioprine, and others depending on the cause of the disorder.

Plasmapheresis may relieve the symptoms in some cases. The blood plasma (the fluid portion of blood) containing antibodies is removed and replaced with intravenous fluids or donated plasma (without antibodies). The removal of antibodies may reduce inflammation in the kidney tissues.

Observation for a progression to renal failure, and the treatment of renal failure if it is present, should be ongoing. Dialysis or a kidney transplant may ultimately be necessary.

Outlook (Prognosis)

Without treatment, crescentic glomerulonephritis often progresses to kidney failure and end-stage renal (kidney) disease in 6 months or less, although a few cases may just go away on their own.

Treated patients may recover some or rarely all of their original kidney function. The extent of recovery is related to the degree of kidney function at diagnosis and degree of crescent formation. The disorder may recur. If the disease occurs in childhood, it is likely that renal failure will eventually develop.

Possible Complications

• Congestive heart failure
• Pulmonary edema
• Hyperkalemia
• Acute renal failure
• Chronic renal failure
• End-stage renal disease

When to Contact a Medical Professional

Call your health care provider if symptoms indicate rapidly progressive glomerulonephritis may be present.

If you have this disorder, call if new symptoms develop, especially irregular heartbeat, difficulty breathing, increased edema, or decreased urine production.

Prevention

The prompt treatment of causative disorders may prevent the development of rapidly progressive glomerulonephritis.