Glomerulonephritis refers to a range of kidney conditions which cause inflammation in the very small blood vessels in the kidneys, known as glomeruli. It can be acute, which means it starts suddenly, or chronic, when the onset is gradual.The consequences can be fatal.
Kidney disease, including glomerulonephritis, also known as glomerular nephritis (GN) or glomerular disease, affects 4.9 million Americans, or 1.9 percent of the population.
The glomeruli are tiny filters in the kidneys. Each kidney contains millions of glomeruli.
If the glomeruli become damaged, the kidney can no longer remove waste and excess fluids efficiently. Blood and protein cannot be filtered, and are excreted in the urine.
Contents of this article:
What are the symptoms of glomerulonephritis?
Acute glomerulonephritis may appear suddenly, following a throat or skin infection.
Glomerulonephritis affects the kidneys.
- Puffiness of the face on waking up
- Urine that is brown or contains traces of blood
- Decreased urination
- Fluid in the lungs leading to coughing and shortness of breath
- High blood pressure.
Chronic glomerulonephritis develops over the years, often without apparent symptoms. But complete kidney failure can result.
Patients may experience:
- Blood or protein in the urine
- High blood pressure
- Swollen ankles or face, because of water retention
- Urinating often during the night
- Bubbles or foam in the urine, caused by excess protein
A person with kidney failure may have a poor appetite, nausea and vomiting. They may feel tired, and have difficulty sleeping, with muscle cramps during the night. Their skin may be dry and itchy.
Some patients have intense kidney pain in the upper back, behind the ribs.
A healthy adult urinates around 2 to 3 pints daily. People with severe glomerulonephritis may not urinate for 2 or 3 days.
What causes glomerulonephritis?
The glomerulus is a tiny, ball-shaped structure, and it is part of the nephron. A nephron consists of one glomerulus and a small fluid-collecting tube, or tubule. Both are key structures in the kidney.
Glomerulonephritis involves an inflammation of the glomeruli
The glomerulus is made up of capillary blood vessels, or glomeruli. These are tiny filters that remove waste from the blood. The waste is urine.
Each glomerulus attaches to the opening of a tubule.
Impure blood enters the nephron, and the urine is filtered out. Filtered blood returns to the bloodstream. Urine which contains the impurities from the blood is excreted to the bladder.
The tubules retain substances that are needed, such as protein.
The urine passes from the kidney to the bladder through a tube called the ureter, and then out of the body through urination.
When the glomeruli are inflamed, the patient has glomerulonephritis.
The damage caused by glomerulonephritis reduces the kidneys' ability to filter blood properly. Waste collects in the blood stream, and eventually the kidneys can fail.
There is also a lack of protein in the blood, because it gets expelled from the body in urine, instead of entering the bloodstream.
What are the risk factors?
Often, the cause is unclear, but here are some possible risk factors.
Post-streptococcal glomerulonephritis can result from streptococcal infections of the throat or, more rarely, impetigo, a skin infection. Improved treatments for most streptococcal infections means this is now less common.
Diseases such as tuberculosis (TB) and syphilis can lead to glomerulonephritis, as can bacterial endocarditis, an infection of the heart valves. Viral infections such as HIV, hepatitis B, and hepatitis C also increase the risk.
Acute glomerulonephritis may develop into chronic, or long-term, glomerulonephritis.
Genetic factors can play a role, but patients with glomerulonephritis do not normally have a family member with it.
People with Hodgkin's and sickle cell disease and those with systemic diseases, especially diabetes, and some autoimmune diseases, such as lupus, are at higher risk.
Scarring of the glomeruli
Scarring of the glomeruli can also lead to glomerulonephritis.
Conditions such as lupus and diabetes may cause scarring of the glomeruli, also called glomerulosclerosis or sclerosis of the glomeruli.
Scarring happens when growth factors activate the glomerular cells to produce scar material.
The growth factors may be produced by the glomerular cells, or carried by circulating blood.
This can lead to protein in the urine and eventually kidney failure.
Hypertension, or high blood pressure, can damage the kidneys and stop them from functioning normally. At the same time, the kidneys play an important part in regulating blood pressure. Glomerulonephritis can cause hypertension because of the damage to kidney function.
Diabetic nephropathy, or diabetic kidney disease, is the main cause of kidney failure in the United States. Anyone with diabetes can develop it. High glucose levels are thought to make the blood flow faster into the kidney, putting strain on the filtering process, and raising blood pressure. The capillaries in the glomerulus collapse, and the glomeruli may be scarred.
To reduce the risk of kidney damage, people with diabetes should control their glucose intake by eating healthily, and keep their blood pressure below 140/90 mm Hg, for example, by using medications such as ACE inhibitors.
Focal segmental glomerulosclerosis (FSGS) is scarring in scattered regions of the kidney, either because of a systemic disorder or as a disease in itself, without a known cause. It normally progresses to kidney failure over 5 to 20 years, earlier in some cases.
Diagnosis of FSGS is difficult, especially in the early stages, when lesions are scattered. The patient may have a urine test to detect excess protein, or one or more biopsies. Treatment is difficult, because the cause is unknown.
Steroids may help, and controlling cholesterol and blood pressure can reduce scarring.
Diagnosis of glomerulonephritis
As many people have no symptoms, it may take a routine check-up or tests linked to hypertension or fatigue to reveal glomerulonephritis.
Tests include a urine test to detect blood or protein in the urine, testing for antigens and antibodies in the blood, or a throat swab.
Renal, or kidney, function tests, include tests of blood and urine samples that show the levels of certain substances released by the kidneys, such as sodium, chloride, potassium and urea, as well as whether the patient is producing less urine than usual.
A kidney biopsy involves using a small needle to take a sample of kidney tissue. This will show how serious the condition is.
What is the treatment for glomerulonephritis?
Treatment depends on whether the condition is acute or chronic, the underlying cause, and the severity of symptoms.
In dialysis, a machine takes over when the kidneys no longer function adequately.
Glomerulonephritis after a strep infection usually clears up without treatment, but the doctor may prescribe antibiotics for the infection.
The patient will probably have to reduce fluid intake, and avoid drinks or food containing alcohol or high levels of protein, salt or potassium.
Diuretics can help to reduce hypertension, and slow kidney function decline, and blood pressure medication relaxes the blood vessels.
Corticosteroids and immune-suppressing drugs control inflammation.
Temporary dialysis may be necessary in cases of acute glomerulonephritis.
In dialysis, a machine does the kidney's job of filtering out waste products from the body. Dialysis also helps to control hypertension and to remove surplus fluid.
A person with immune problems may undergo plasmapheresis, a mechanical process that removes plasma with antibodies from the blood, and replaces it with other fluid or donated plasma.
Kidney transplant may be possible, if the patient's health allows it. Otherwise, dialysis may be the only option.
What are the complications of glomerulonephritis?
Without treatment, the kidneys may fail completely. Waste products accumulate quickly, making emergency dialysis necessary.
When the kidneys function at under 10% of their normal capacity, the patient has end-stage kidney disease, and will require regular dialysis or a kidney transplant to stay alive.
Most forms of glomerulonephritis cannot be prevented, but there are some ways to reduce the risk:
- Seek medical attention for a strep infection that causes a sore throat or impetigo
- Keep diabetes and blood pressure under control
- Practice safe sex and avoid illegal intravenous drug use.
The risk of glomerulonephritis, like many health conditions, can be reduced by choosing a healthy lifestyle with plenty of exercise, quality sleep and a healthy diet. These will reduce the risk of infections and hypertension.