Written by Ada’s Medical Knowledge Team
What is post-streptococcal glomerulonephritis?
Post-streptococcal glomerulonephritis (PSGN) is a disease of the kidneys which occurs after infection with certain strains of a bacterium called group A streptococcus (GAS). Streptococcal bacteria can cause a number of different conditions. Symptoms of these conditions often affect the skin and throat, such as in scarlet fever and tonsillitis.
The most common symptom of PSGN is swelling around the eyes. This swelling can also affect other parts of the body, such as the hands and feet. Dark or rusty colored urine is a possible early sign of the condition. However, approximately half of people affected by PSGN will display no symptoms.
PSGN is a knock-on effect of the infection in the kidneys. As a response to the infection, blood vessels in the kidneys become inflamed. This makes it harder for the kidneys to filter urine.
The disease is now very rare in high income countries such as the U.S. and the U.K. Children are the age group most affected by the condition worldwide, but when it does occur in high income countries such as the U.S., it is usually the elderly that are most affected.
PSGN usually resolves itself after a few weeks or months. Treatment is directed at controlling symptoms through medication and removing any infection left in the body with antibiotics such as penicillin. A low-salt diet may be recommended to control swelling.
The vast majority of people affected by PSGN will recover with no complications. However, in rare cases the condition can lead to long-term kidney damage, such as kidney failure. This is far more common in adults than in children.
The severity of symptoms varies from person to person. Approximately half of people affected by PSGN display no signs of the illness. When symptoms do occur, it is usually between seven and 21 days after the group A streptococcal infection begins.
Another symptom of the condition is dark-colored urine, sometimes described as rust-colored or cola-colored. This dark coloration is due to blood being present in the urine.
High blood pressure, also known as hypertension, is a common effect of PSGN. However, this can often cause no observable symptoms.
- Less need to urinate than usual
- Protein in the urine. This may not be visible, but, when it is, the urine has a frothy appearance
- Increased tiredness, due to anemia
- Abdominal pain
- A loss of appetite
If you are experiencing possible symptoms of post-streptococcal glomerulonephritis, try using the free Ada app to carry out a symptom assessment.
The kidneys are two organs that sit underneath the ribs in the back of the abdomen and that are responsible for filtering toxins from the blood. If the small filtration units of the kidney, known as the glomeruli, become inflamed and swollen, this is called glomerulonephritis. There are several other possible causes for this, besides infection with GAS bacteria. These include autoimmune disorders - when the immune system mistakenly begins to attack the healthy body tissues - and various other medical conditions, including diabetes and some cancers.
PSGN is not an infection and is thought to be the immune system’s reaction to the GAS infection. In other words, PSGN itself cannot be caught from other people.
Most group A streptococcal infections that lead to PSGN primarily affect the skin or the throat. These include:
Children between two and 12 are the age group most at risk of developing PSGN. Six or seven years old is the age when the infection is most likely. Males are more likely to be affected than females, and the condition often occurs after a large outbreak of an infection, otherwise known as an epidemic.
PSGN is most common in tropical countries where skin infections are a regular occurence. PSGN is now very rare in high-income countries such as the U.S. and the U.K. In these countries, it primarily affects those over 50, particularly men. The following are risk factors for developing the condition later in life:
- Diabetes mellitus
- High consumption of alcohol
- HIV infection
- Tumors and cancers
The diagnosis may be suspected based on the symptoms affecting a person who has recently been unwell with a bacterial infection. Several tests may be carried out to help with the diagnosis, including blood tests and urine tests for the following purposes:
- To help confirm the diagnosis of PSGN
- To check on how well the kidney is functioning
- To find out if the group A streptococcal infection is still present
An ultrasound, which is when sound waves are used to create an image inside of the body, may be carried out on the kidney. The organ is often visible in an ultrasound as slightly enlarged in people affected by PSGN.
In rare cases - usually where a person is not showing the typical signs of PSGN, or if serious complications are suspected - a kidney biopsy may be recommended. This is when a special needle is used to remove a few very small pieces of the kidney so that they can be laboratory tested.
PSGN usually resolves itself in a few weeks or months. By the time post-streptococcal glomerulonephritis is diagnosed in most children, the body has already begun to recover from the inflammation.. Medication and lifestyle changes can give some relief from the symptoms and address any complications that the condition may cause.
Diet and exercise
One of the first recommendations a doctor may give will usually be to restrict salt in the diet and to drink less water. Temporarily eating less protein, i.e. cutting out meat and plant-based protein products, may be recommended.
Penicillin may be recommended if there is any remaining evidence of group A streptococcal infection. Erythromycin may be given instead if the person affected is allergic to penicillin.
Loop diuretics, which increase urine production, may be recommended to reduce swelling and control blood pressure. Other blood pressure medications, including angiotensin-converting enzyme inhibitors and calcium-channel blockers, may also be used as part of treatment for PSGN.
The best means of preventing PSGN is to prevent the spread of group A streptococcal infection. At present, there is no vaccine available to prevent group A streptococcal infection. As a result, practicing good hygiene and ensuring that anybody affected by GAS or PSGN is treated are the best ways to prevent the condition. This includes:
- Washing the hands thoroughly before eating or preparing food
- Covering the mouth or nose before coughing or sneezing
- Staying at home until after being treated with antibiotics for GAS infection or until after fever stops completely
Most people affected by PSGN recover in a few weeks. However, there are several possible complications that may occur because of the condition. These complications are generally more common in adults than in children. They include:
- High blood pressure, also known as hypertension
- Renal failure
- Pulmonary edema, a buildup of fluid in the lungs
- Hyperkalemia, an abnormally high level of potassium in the blood
Heart failure is a rare, but possible complication of PSGN.
Q: Is post streptococcal glomerulonephritis contagious?
A: PSGN itself is not contagious. However, it develops in some people as a response to being infected with a bacterium called group A streptococcus, which can be caught from others. Practicing good hygiene and encouraging those around you to practice it, too, is currently the best way to avoid being affected by PSGN.
Q: Do antibiotics stop post streptococcal glomerulonephritis?
A: Antibiotics cannot be used to treat PSGN itself, but penicillin may be prescribed to treat any underlying group A streptococcal infection that remains in the affected person’s body at the time of diagnosis (see causes for more information). Treatment with antibiotics significantly reduces the risk of passing a group A streptococcal infection onto others.
Q: How long does post streptococcal glomerulonephritis last?
A: Most people recover from the symptoms of PSGN after a few weeks.
Other names for post-streptococcal Glomerulonephritis
- Poststreptococcal glomerulonephritis
- Postinfectious glomerulonephritis
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“Acute Poststreptococcal Glomerulonephritis Treatment & Management: Approach Considerations.” Medscape. 05 December, 2018. Accessed: 28 January, 2019. ↩ ↩ ↩ ↩
“Current Approaches to Group A Streptococcal Vaccine Development.” Streptococcus pyogenes : Basic Biology to Clinical Manifestations. 10 February, 2016. Accessed: 08 February, 2019. ↩
“Acute Poststreptococcal Glomerulonephritis: Prognosis.” 05 December, 2018. Accessed: 08 February, 2019. ↩