Post-streptococcal glomerulonephritis (GN)

Answer 1

Definition

Post-streptococcal glomerulonephritis (GN) is a disorder of the kidneys that occurs after infection with certain strains of Streptococcus bacteria.

Alternative Names

Glomerulonephritis - post-streptococcal; Post-infectious glomerulonephritis

Causes, incidence, and risk factors

Post-streptococcal GN is a form of glomerulonephritis. It is the result of an infection, not of the kidneys, but of a completely different area, such as the skin or throat, with a specific type of Group A beta hemolytic streptococcus bacteria.

The strep bacterial infection causes the tiny blood vessels called glomeruli in the kidneys to become inflamed, making the kidneys less able to filter and control the content of the urine.

Post-streptococcal GN is uncommon these days because infections that can lead to the disorder are commonly treated with antibiotics. The disorder may develop 1 - 2 weeks after an untreated throat infection, or 3 - 4 weeks after a skin infection.

It may occur in people of any age, but most often occurs in children ages 6 - 10. Although skin and throat infections are not uncommon in children, post-streptococcal glomerulonephritis is a rare complication of these infections.

Risk factors include:

• Strep throat
• Streptococcal skin infections (such as impetigo)

Symptoms

• Decreased urine output
• Edema (swelling)
  • Generalized swelling
  • Swelling of the abdomen
  • Swelling of the face or eyes
  • Swelling of the feet, ankles, extremities
• Rust-colored urine
• Visible blood in the urine

Other symptoms that may be associated with this disease:

• Joint pain
• Joint stiffnessor swelling

Signs and tests

• Abnormal sounds may be heard when listening to the heart and lungs with a stethoscope (auscultation).
• Anti-DNase Btest may be abnormal.
• Blood pressureis often high.
• Kidney biopsyconfirms post-streptococcal GN (although biopsy is not usually necessary).Physical examination shows swelling (edema), especially of the face
• Serum ASO may be raised.
• Serum complement levels usually decrease.
• Urinalysisshows protein and blood in the urine.

Treatment

There is no specific treatment for post-streptococcal glomerulonephritis. Treatment is focused on relieving symptoms.

Antibiotics, such as penicillin, should be used to destroy any streptococcal bacteria that remain in the body. Blood pressure medications and diuretic medications may be needed to control swelling and high blood pressure. Corticosteroids and other anti-inflammatory medications are generally not effective.

Dietary salt restriction may be necessary to control swelling and high blood pressure.

Expectations (prognosis)

Post-streptococcal glomerulonephritis usually goes away by itself after several weeks to months. In a minority of adults, it may progress to chronic kidney failure.

Complications

• Acute renal failure
• Chronic glomerulonephritis
• Chronic renal failure
• Congestive heart failure or pulmonary edema
• End-stage renal disease
• Hyperkalemia
• High blood pressure (hypertension)
• Nephrotic syndrome

Calling your health care provider

Call your health care provider if you have symptoms of post-streptococcal GN.

If you have experienced post-streptococcal GN, call your health care provider if you have decreased urine output or other new symptoms.

Prevention

Treating known streptococcal infections may prevent post-streptococcal GN.

References

Appel GB. Glomerular disorders and nephrotic syndromes. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 122.

Answer 2

Definition

Post-streptococcal glomerulonephritis (GN) is a disorder of the kidneys that occurs after infection with certain strains of Streptococcus bacteria.

Alternative Names

Glomerulonephritis - post-streptococcal; Post-infectious glomerulonephritis

Causes, incidence, and risk factors

Post-streptococcal GN is a form of glomerulonephritis. It is caused by an infection with a type of streptococcus bacteria. The infection does not occur in the kidneys, but in a different part of the body, such as the skin or throat.

The strep bacterial infection causes the tiny blood vessels in the filtering units of the kidneys (glomeruli) to become inflamed. This makes the kidneys less able to filter the urine.

Post-streptococcal GN is uncommon today because infections that can lead to the disorder are commonly treated with antibiotics. The disorder may develop 1 - 2 weeks after an untreated throat infection, or 3 - 4 weeks after a skin infection.

It may occur in people of any age, but it most often occurs in children ages 6 - 10. Although skin and throat infections are common in children, post-streptococcal glomerulonephritis is a rare complication of these infections.

Risk factors include:

• Strep throat
• Streptococcal skin infections (such as impetigo)

Symptoms

• Decreased urine output
• Rust-colored urine
• Swelling (edema)
  • General swelling
  • Swelling of the abdomen
  • Swelling of the face or eyes
  • Swelling of the feet, ankles, hands
• Visible blood in the urine

Other symptoms that may occur with this disease:

• Joint pain
• Joint stiffnessor swelling

Signs and tests

A physical examination shows swelling (edema), especially in the face. Abnormal sounds may be heard when listening to the heart and lungs with a stethoscope (auscultation). Blood pressure is often high.

Other tests that may be done include:

• Anti-DNase B
• Kidney biopsy(this is usually not needed)
• Serum ASO (and streptolysin O)
• Serum complement levels
• Urinalysis

Treatment

There is no specific treatment for post-streptococcal glomerulonephritis. Treatment is focused on relieving symptoms.

• Antibiotics, such as penicillin, should be used to destroy any streptococcal bacteria that remain in the body.
• Blood pressure medications and diuretic medications may be needed to control swelling and high blood pressure.
• Corticosteroids and other anti-inflammatory medications are generally not effective.

You may need to limit salt in the diet to control swelling and high blood pressure.

Expectations (prognosis)

Post-streptococcal glomerulonephritis usually goes away by itself after several weeks to months.

In small number of adults, it may get worse and lead to chronic kidney failure. Sometimes it can progress to end-stage kidney disease, which requires dialysis and a kidney transplant.

Complications

• Acute renal failure
• Chronic glomerulonephritis
• Chronic renal disease
• Congestive heart failure or pulmonary edema
• End-stage renal disease
• Hyperkalemia
• High blood pressure (hypertension)
• Nephrotic syndrome

Calling your health care provider

Call your health care provider if:

• You have symptoms of post-streptococcal GN
• You have post-streptococcal GN, and you have decreased urine output or other new symptoms

Prevention

Treating known streptococcal infections may prevent post-streptococcal GN.

References

Appel GB. Glomerular disorders and nephrotic syndromes. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 122.

Nachman PH, Jennette JC, Falk RJ. Primary glomerular disease. In: Brenner BM, ed. Brenner and Rector's the Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 30.

Pan Cg, Avner Ed. Glomerulonephritis associated with infections. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, Behrman RE, eds. Nelson's Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 505.

Reviewed By

Review Date: 09/20/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Herbert Y. Lin, MD, PHD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.