Post-streptococcal glomerulonephritis (GN)

Also known as: Glomerulonephritis - post-streptococcal and Post-infectious glomerulonephritis

Definition

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

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 stiffness or swelling

Signs and tests

• Abnormal sounds may be heard when listening to the heart and lungs with a stethoscope (auscultation).
• Anti-DNase B test may be abnormal.
• Blood pressure is often high.
• Kidney biopsy confirms 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.
• Urinalysis shows 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.

See also:

• Disease

  Acute kidney failure

  

  Acute (sudden) kidney failure is the sudden loss of the ability of the kidneys to remove waste and concentrate urine without losing .

• Special Topic

  Antibody

  

  An antibody is a protein produced by the body’s immune system when it detects harmful substances, called antigens. Examples of antigens include microorganisms (such as bacteria, fungi, parasites, and viruses) and chemicals. Antibodies are also produced when the immune system mistakenly ...

• Disease

  Impetigo

  

  Impetigo is a common skin infection.

• Test

  Complement

  Complement is a blood test that measures the activity of certain proteins in the liquid portion of your blood. The complement system is a group of proteins that move freely through your bloodstream. The proteins work with your immune system and play a role in the development of inflammation. ...

• Symptoms

  Sore throat

  

  A sore throat is discomfort, pain, or scratchiness in the throat. A sore throat often makes it painful to swallow.

• Special Topic

  Antigen

  

  An antigen is any substance that causes your immune system to produce against it. An antigen may be a foreign substance from the environment such as chemicals, bacteria, viruses, or pollen. An antigen may also be formed within the body, as with bacterial or tissue cells.

• Disease

  Hyperkalemia

  

  Hyperkalemia is higher-than-normal levels of potassium in the blood.

• Disease

  End-stage kidney disease

  

  End-stage kidney disease is the complete, or almost complete failure of the kidneys to function. The main function of the kidneys is to remove wastes and excess water from the body.

• Disease

  Pulmonary edema

  

  Pulmonary edema is an abnormal build up of fluid in the air sacs of the lungs, which leads to shortness of breath

• Disease

  Glomerulonephritis

  

  Glomerulonephritis is a type of in which the part of your kidneys that helps filter waste and fluids from the blood is damaged.

• Disease

  Chronic glomerulonephritis

  

  Chronic glomerulonephritis is the advanced stage of a group of kidney disorders, resulting in inflammation and slowly worsening destruction of internal kidney structures called glomeruli.

• Disease

  Heart failure

  

  Heart failure, also called congestive heart failure, is a condition in which the heart can no longer pump enough blood to the rest of the body.

• Disease

  Strep throat

  

  Strep throat is caused by Group A Streptococcus bacteria. It is the most common bacterial infection of the throat.

• Disease

  Hypertension

  

  Hypertension is the term used to describe high blood pressure. Blood pressure is a measurement of the force against the walls of your arteries as the heart pumps blood through the body. Blood pressure readings are measured in millimeters of mercury (mmHg) and usually given as two numbers — ...

Review date:

November 30, 2009

Reviewed by:

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.

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