Acute Glomerulonephritis

Acute glomerulonephritis is a sudden kidney problem that occurs when tiny filters inside your kidneys become inflamed and cannot work properly. Many people have no warning signs, while others may notice blood in their urine or swelling in their face and legs.

Table of contents

• What is acute glomerulonephritis?
• What causes acute glomerulonephritis?
• Signs and symptoms
• How is it diagnosed?
• Treatment approaches
• What to expect

What is acute glomerulonephritis?

Acute glomerulonephritis is a type of kidney disease that develops suddenly over a short time. The condition affects the glomeruli, which are tiny filtering units made of blood vessels inside your kidneys. Each kidney contains almost a million of these filters, and their job is to remove waste and extra fluid from your blood.^[1]

When you have acute glomerulonephritis, these filters become swollen and irritated. This swelling prevents your kidneys from working properly, which means waste and fluid cannot be removed from your body as they should. The damage to the glomeruli can cause blood cells and protein to leak into your urine.^[3]

The condition is called “acute” because it comes on suddenly, often after an infection. This is different from chronic glomerulonephritis, which develops slowly over many months or years. Some people can have an acute attack and then develop a chronic condition years later.^[1]

• Kidneys
• Glomeruli
• Blood vessels

What causes acute glomerulonephritis?

Acute glomerulonephritis most often occurs as a complication after an infection. The most common type is poststreptococcal glomerulonephritis, which develops after a throat or skin infection with streptococcus bacteria, such as strep throat. This form typically develops in children between the ages of 2 and 10 years, usually more than one week after recovery from the infection.^[7]

Other infections can also trigger acute glomerulonephritis. These include infections with other types of bacteria like staphylococcus and pneumococcus, viral infections such as chickenpox, hepatitis B, hepatitis C, and HIV, as well as parasitic infections like malaria.^[7] In recent decades, the incidence of poststreptococcal glomerulonephritis has fallen in developed countries, while glomerulonephritis associated with staphylococcal infection has risen.^[3]

Sometimes the cause is related to problems with your immune system. Conditions that involve an abnormal immune response can lead to acute glomerulonephritis. These include lupus (systemic lupus erythematosus), IgA nephropathy, granulomatosis with polyangiitis, microscopic polyangiitis, and Goodpasture syndrome (also called anti-GBM disease).^[1]

In some cases, the reason glomerulonephritis appears is unknown. Other possible causes include certain medications, exposure to specific toxins, hereditary conditions that run in families, and certain types of cancer.^[1]

Signs and symptoms

About half of people with acute glomerulonephritis have no symptoms at all. When there are no obvious warning signs, the first indication that something is wrong might come from the results of a routine urine test.^[7]

When symptoms do occur, they often come on suddenly. The most common signs include:^[1][2]

• Blood in your urine, which may make it look brown, pink, or red
• Urine that appears foamy or bubbly due to protein in the urine
• Swelling in your legs, face, or around your eyes (edema), which is often first noticed as puffiness in the morning
• Producing less urine than usual
• High blood pressure
• Shortness of breath
• Nausea
• Rash
• Pain in your joints or abdomen
• Weight loss or loss of appetite

The swelling occurs because your kidneys cannot remove excess fluid from your body. This fluid buildup can also affect your lungs, causing difficulty breathing.^[7]

You should contact a healthcare provider if you have one or more of these symptoms. Many other health conditions can cause similar symptoms, so proper evaluation is important to determine if glomerulonephritis is the cause.^[1]

How is it diagnosed?

Glomerulonephritis may be identified during routine testing or when you visit a doctor because of symptoms. Several tests can help diagnose the condition and determine its cause.^[11]

A urinalysis is one of the most important tests. This urine test can reveal signs that your kidneys are not working properly, such as red blood cells and proteins that should not be in urine, or white blood cells that indicate inflammation. There may also be a lack of the expected levels of waste products.^[11]

Blood tests are also used to assess kidney function. Analysis of blood samples can reveal higher than expected levels of waste products in the bloodstream, the presence of antibodies that may indicate an immune system disorder, or signs of bacterial or viral infection. Tests may also measure complement levels, which are proteins involved in your immune response.^[3]

If you had a streptococcal infection, your doctor may order a special test to detect antibodies against streptococcal bacteria. Blood and tissue cultures may be performed if an infection is suspected.^[3]

Imaging tests may be recommended if your doctor detects evidence of kidney damage. These tests may show an irregularity in the shape or size of the kidney. An ultrasound, X-ray, or CT scan might be used for this purpose.^[11]

A kidney biopsy is considered the gold standard for diagnosing glomerulonephritis. This procedure involves using a special needle to extract small pieces of kidney tissue to look at under a microscope. A biopsy is used to confirm a diagnosis and to assess the degree and nature of tissue damage.^[3][11]

Treatment approaches

Treatment for acute glomerulonephritis depends on what is causing it and how severe your symptoms are. In many cases, treatment is mainly supportive, because there is no specific therapy for the kidney disease itself. If you have severe glomerulonephritis, you will usually be referred to a kidney specialist called a nephrologist.^[9][10]

When acute glomerulonephritis is caused by an infection, antibiotics may be used. Penicillin is commonly prescribed to control symptoms and prevent spread of infection to others. Antibiotic treatment of close contacts of the patient may help prevent development of the disease. Although older studies suggested that antibiotics do not prevent glomerulonephritis after an infection, more recent reviews suggest there may be possible benefits.^[9][15]

Medications may be needed to manage symptoms and complications. Loop diuretics may be required if you are swollen and have high blood pressure, to help remove excess fluid from your body. If you have severe high blood pressure, medicines called vasodilators (such as nitroprusside, nifedipine, hydralazine, or diazoxide) may be used.^[9]

If glomerulonephritis is caused by problems with your immune system, medicines called immunosuppressants may be recommended. Steroids such as prednisolone are used to reduce swelling and suppress your immune system. Once your kidneys have started to recover, your dose of steroids will usually be lowered.^[10]

Changes to your diet may be advised. A dietitian can help you make an eating plan with the right amounts of salt, potassium, and protein. You may also need to limit how much fluid you drink each day. Reducing the amount of salt, fat, protein, and potassium in your diet can help control your blood pressure and ensure the amount of fluid in your body is regulated.^[10][20]

Bed rest is recommended until signs of kidney inflammation and fluid buildup subside. However, prolonged inactivity is not beneficial for recovery.^[9]

In severe cases where the kidneys cannot work properly despite other treatments, dialysis may be needed. This is a treatment that does the work of your kidneys to filter waste from your blood. In very rare cases where glomerulonephritis leads to complete kidney failure, a kidney transplant may be necessary.^[10][20]

What to expect

The outlook for acute glomerulonephritis varies depending on the cause and how quickly treatment begins. Many mild cases get better on their own without treatment. Sometimes, glomerulonephritis is mild and goes away without serious complications.^[1]

Most people, especially children, recover completely from acute poststreptococcal glomerulonephritis. Long-term studies on children show few chronic problems after the acute illness resolves. The condition generally improves with supportive treatment.^[9]

However, in about 1% of children and 10% of adults who have acute glomerulonephritis, the condition can evolve into a more serious form called rapidly progressive glomerulonephritis. In this situation, most of the filtering units in the kidneys are destroyed, which can result in kidney failure.^[7]

Without timely treatment, acute glomerulonephritis can progress to chronic glomerulonephritis. This is characterized by ongoing kidney damage and reduced kidney function that can lead to chronic kidney disease and eventually end-stage renal disease. About 30% of adults with acute glomerulonephritis may progress to chronic kidney disease.^[3][4]

Follow-up care is very important. Regular monitoring should include checking your blood pressure, the levels of salt and protein in your urine, and how well your kidneys are working. If you are on medications, your doctor will carefully monitor for side effects and adjust doses as needed.^[9][10]

Because glomerulonephritis can make you more vulnerable to infections, it is a good idea to protect yourself by having a seasonal flu vaccine and a pneumonia vaccine. Smoking may make kidney disease caused by glomerulonephritis worse and increases the risk of complications like heart disease and stroke, so stopping smoking is strongly recommended.^[10]