Goodpasture's Syndrome
Goodpasture's Syndrome
Definition
An uncommon and life-threatening hypersensitivity disorder believed to be an autoimmune process related to antibody formation in the body. Goodpasture's syndrome is characterized by renal (kidney) disease and lung hemorrhage.
Description
The disorder is characterized by autoimmune reaction which deposits of antibodies in the membranes of both the lung and kidneys, causing both inflammation of kidney (glomerulonephritis ) and lung bleeding. It is typically a disease of young males.
Causes and symptoms
The exact cause is unknown. It is an autoimmune disorder; that is, the immune system is fighting the body's own normal tissues through creating antibodies that attack the lungs and kidneys. Sometimes the disorder is triggered by a viral infection, or by the inhalation of gasoline or other hydrocarbon solvents. An association also exists between cigarette smoking and the syndrome. The target antigen of the Goodpasture's antibodies has been localized to a protein chain (type IV collagen).
Symptoms include foamy, bloody, or dark colored urine, decreased urine output, cough with bloody sputum, difficulty breathing after exertion, weakness, fatigue, nausea or vomiting, weight loss, nonspecific chest pain and/or pale skin.
Diagnosis
The clinician will perform a battery of tests to confirm a diagnosis. These tests include a complete blood count (CBC) to confirm anemia, iron levels to check for blood loss and blood urea nitrogen (BUN) and creatinine levels to test the kidney function. A urinalysis will be done to check for damage to the kidneys. A sputum test will be done to look for specific antibodies. A chest x ray will be done to assess the amount of fluid in the lung tissues. A lung needle biopsy and a kidney biopsy will show immune system deposits. The kidney biopsy can also show the presence of the harmful antibodies that attack the lungs and kidneys.
Treatment
Treatment is focused on slowing the progression of the disease. Treatment is most effective when begun early, before kidney function has deteriorated to a point where the kidney is permanently damaged, and dialysis is necessary. Corticosteroids, such as prednisone, or other anti-inflammatory medications may be used to reduce the immune response. Immune suppressants such as cyclophosphamide or azathioprine are used aggressively to reduce immune system effects.
A procedure whereby blood plasma, which contains antibodies, is removed from the body and replaced with fluids or donated plasma (plasmapheresis ) may be performed daily for two or more weeks to remove circulating antibodies. It is fairly effective in slowing or reversing the disorder. Dialysis to clean the blood of wastes may be required if kidney function is poor. A kidney transplant may be successful, especially if performed after circulating antibodies have been absent for several months.
Prognosis
The probable outcome is variable. Most cases progress to severe renal failure and end-stage renal disease within months. Early diagnosis and treatment makes the probable outcome more favorable.
Prevention
No known prevention of Goodpasture's syndrome exists. People should avoid glue sniffing and the siphoning gasoline. Stopping smoking, if a family history of renal failure exists, may prevent some cases. Early diagnosis and treatment may slow progression of the disorder.
Resources
BOOKS
Tierney, Lawrence, et. al. Current Medical Diagnosis and Treatment. Los Altos: Lange Medical Publications, 2001.
ORGANIZATIONS
American Kidney Fund. 6110 Executive Boulevard, Suite 1010, Rockville, MD 20852. (800) 638-8299. 〈http://www.akfinc.org〉.
National Kidney Foundation. 30 East 33rd Street, New York, NY 10016. (800) 622-9010. 〈http://www.kidney.org〉.
KEY TERMS
Antibody— A protein molecule produced by the immune system in response to a protein that is not recognized as belonging in the body.
Antigen— Any substance that, as a result of coming in contact with appropriate cells, induces a state of sensitivity and/or immune responsiveness after a period of time and that reacts in a demonstrable way with antibodies.
Autoimmune disorder— An abnormality within the body whereby the immune system incorrectly attacks the body's normal tissues, thereby causing disease or organ dysfunction.
Blood urea nitrogen (BUN)— A test used to measure the blood level of urea nitrogen, a waste that is normally filtered from the kidneys.
Creatinine— A test used to measure the blood level of creatinine, a waste product filtered out of the blood by the kidneys. Higher than usual levels of this substance may indicate kidney disease.
Glomerulus (glomeruli)— A small tuft of blood capillaries in the kidney, responsible for filtering out waste products.