Poststreptococcal glomerulonephritis (PSGN) is a type of kidney inflammation. It is caused by a reaction to an infection with certain strains of bacteria called Streptococcus.
Poststreptococcal glomerulonephritis mostly affects children, who are prone to Streptococcus infections. These bacteria are a common cause of sore throat, sometimes called strep throat. They can also cause skin infections known as impetigo. When a person has one of these infections, the immune system can sometimes react abnormally. This reaction can cause inflammation and even damage in the kidneys. It is not known why this occurs. Most people recover from PSGN and have no long-term effects. Some, however, get permanent kidney failure from PSGN.
PSGN is caused by an infection with certain strains of Streptococcus bacteria. When the infection is in the throat, it's called pharyngitis. When it's in the skin, it's often called impetigo. Children between 4 and 10 years old are most commonly affected. Males are more likely to be affected than females. Adults with PSGN usually have more serious kidney inflammation than children and are less likely to have a full recovery.
Symptoms of poststreptococcal glomerulonephritis usually occur 1 to 3 weeks after the strep infection. They may include:
Diagnosis of PSGN begins with the history and physical exam. A history of recent sore throat or skin infection and kidney problems suggests PSGN.
A urine test called a urinalysis is usually done. This test can show abnormal blood or protein in the urine. A blood test called an antibody titer may also be done. This test helps to confirm that a recent strep infection has occurred. Another blood test called a complement level is often abnormal in this condition. This test measures the activity of part of the immune system.
A person with unusual, prolonged, or severe symptoms may need a kidney biopsy. This procedure can help figure out the amount and type of kidney damage. It can also help make sure that there are no other conditions causing kidney damage.
The only known way to prevent PSGN is to avoid strep infections. This is very difficult to do. Treating the infection with antibiotics clears up the infection but does not appear to reduce the risk of PSGN.
Most people with PSGN, especially children, recover within a few weeks and have no long-term effects. However, some people develop permanent kidney damage and even kidney failure. Those with kidney failure need dialysis or a kidney transplant to survive. Dialysis is a procedure to filter the blood when the kidneys no longer work. Usually this must continue for the rest of the person's life or until a kidney transplant can be done.
Poststreptococcal glomerulonephritis is not contagious. However, the strep infection that causes this condition is contagious. Those who catch the infection may or may not develop PSGN.
Treatment is usually directed at the symptoms. Many people can be treated at home. Those with more severe symptoms need to stay in the hospital. Limiting fluid and salt intake can help with skin swelling. Medications called diuretics, such as furosemide, may also be needed for swelling or breathing trouble. Blood pressure medications, such as amlodipine, may be needed for high blood pressure. Those who develop kidney failure will often need dialysis or a kidney transplant.
Diuretics may cause allergic reactions, stomach upset, and salt imbalances. Dialysis requires surgery to get the person ready to be hooked up to the blood-filtering machine. Dialysis can cause salt imbalances and even death. Surgery may cause infections, bleeding, or allergic reactions to anesthesia.
Most people with PSGN recover completely and need no further treatment. Those who have severe kidney damage may need monitoring and treatment for many years, or even life.
Many people can be watched by caregivers at home. Any change in symptoms or response to treatment can be reported to the healthcare provider. Those with more serious kidney damage need closer monitoring with blood and urine tests. Blood pressure may also need to be monitored in those with high blood pressure.
Author:Crystal R. Martin, MD
Editor:Duff, Ellen, BA
Reviewer:Adam Brochert, MD
Harrison's Principles of Internal Medicine, Fauci et al, 1998