acute poststreptococcal glomerulonephritis


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Acute Poststreptococcal Glomerulonephritis

 

Definition

Acute poststreptococcal glomerulonephritis (APSGN) is an inflammation of the kidney tubules (glomeruli) that filter waste products from the blood, following a streptococcal infection such as strep throat. APSGN is also called postinfectious glomerulonephritis.

Description

APSGN develops after certain streptococcal bacteria (group A beta-hemolytic streptococci) have infected the skin or throat. Antigens from the dead streptococci clump together with the antibodies that killed them. These clumps are trapped in the kidney tubules, cause the tubules to become inflamed, and impair that organs' ability to filter and eliminate body wastes. The onset of APSGN usually occurs one to six weeks (average two weeks) after the streptococcal infection.
APSGN is a relatively uncommon disease affecting about one of every 10,000 people, although four or five times that many may actually be affected by it but show no symptoms. APSGN is most prevalent among boys between the ages of 3 and 7, but it can occur at any age.

Causes and symptoms

Frequent sore throats and a history of streptococcal infection increase the risk of acquiring APSGN. Symptoms of APSGN include:
  • fluid accumulation and tissue swelling (edema) initially in the face and around the eyes, later in the legs
  • low urine output (oliguria)
  • blood in the urine (hematuria)
  • protein in the urine (proteinuria)
  • high blood pressure
  • joint pain or stiffness

Diagnosis

Diagnosis of APSGN is made by taking the patient's history, assessing his/her symptoms, and performing certain laboratory tests. Urinalysis usually shows blood and protein in the urine. Concentrations of urea and creatinine (two waste products normally filtered out of the blood by the kidneys) in the blood are often high, indicating impaired kidney function. A reliable, inexpensive blood test called the anti-streptolysin-O test can confirm that a patient has or has had a streptococcal infection. A throat culture may also show the presence of group A beta-hemolytic streptococci.

Key terms

Streptococcus — A gram-positive, round or oval bacteria in the genus Streptococcus. Group A streptococci cause a number of human diseases including strep throat, impetigo, and ASPGN.

Treatment

Treatment of ASPGN is designed to relieve the symptoms and prevent complications. Some patients are advised to stay in bed until they feel better and to restrict fluid and salt intake. Antibiotics may be prescribed to kill any lingering streptococcal bacteria, if their presence is confirmed. Antihypertensives may be given to help control high blood pressure and diuretics may be used to reduce fluid retention and swelling. Kidney dialysis is rarely needed.

Prognosis

Most children (up to 95%) fully recover from APSGN in a matter of weeks or months. Most adults (up to 70%) also recover fully. In those who do not recover fully, chronic or progressive problems of kidney function may occur. Kidney failure may result in some patients.

Prevention

Receiving prompt treatment for streptococcal infections may prevent APSGN.

Resources

Books

Fauci, Anthony S., et al., editors. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 1997.

Organizations

American Kidney Fund (AKF). Suite 1010, 6110 Executive Boulevard, Rockville, MD 20852. (800) 638-8299. http://216.248.130.102/Default.htm.
National Kidney Foundation. 30 East 33rd St., New York, NY 10016. (800) 622-9010. http://www.kidney.org.

a·cute glo·mer·u·lo·ne·phri·tis

glomerulonephritis that frequently occurs as a late complication of pharyngitis or skin infection, due to a nephritogenic strain of β-hemolytic streptococci, characterized by abrupt onset of hematuria, edema of the face, oliguria, and variable azotemia and hypertension; the renal glomeruli usually show cellular proliferation or infiltration by polymorphonuclear leukocytes.

acute poststreptococcal glomerulonephritis

Glomerular inflammation which follows infection—e.g., pyodermatitis with streptococci M types 47, 49, 55, 2, 60, and 57 and throat infection with streptococci M types 1, 2, 4, 3, 25, 49, and 12.

Epidemiology
More common in males age 3 to 7.
 
Clinical findings
Acute onset of oedema, hematuria, proteinuria, and hypertension.

Pathogenesis
Lysed bacteria plug renal tubules causing inflammation.
 
Lab
Haematuria, proteinuria, increased ASO.
 
Management
Symptomatic; bed rest, antibiotics; antihypertensives.

Paediatric Nephrologist should be consulted for:
Severe hypertension;
Severe oliguria;
Severe oedema;
Nephrotic-range proteinuria;
Azotemia if moderate or sever;
Recurrent episodes of gross haematuria;
Persistently depressed C3 (past 8-10 week).

acute poststreptococcal glomerulonephritis

Post-infectious glomerulonephritis Nephrology Glomerular inflammation which follows streptococcal infection–eg strep throat with group A beta-hemolytic streptococci Epidemiology More common in ♂ age 3 to 7 Clinical Edema of face, extremities, oliguria, proteinuria, HTN, joint pain Lab Hematuria, proteinuria, ↑ ASO Management Symptomatic; bed rest, antibiotics; antihypertensives. See Strep throat.
References in periodicals archive ?
Pathogenic mechanism of acute poststreptococcal glomerulonephritis.
Thrombocytopenia in patients with acute poststreptococcal glomerulonephritis.
Outbreaks of acute poststreptococcal glomerulonephritis (APSGN) are also common (13).

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