Glomerulonephritis is the name given to a range of conditions that can affect the kidney, specifically the glomeruli of the kidney. The glomeruli become damaged, commonly because of a problem with the body's immune system. Many people with glomerulonephritis may not notice any symptoms initially. However, salt and excess fluid can build up in the body if the glomeruli and kidneys are not working normally. This can lead to complications such as high blood pressure and, in some cases, chronic kidney disease, which may lead to end-stage kidney failure. Treatment will depend on the underlying cause as well as the severity of symptoms.
The kidneys clear waste materials from the body and maintain a normal balance of fluids and chemicals in the body.
The two kidneys lie to the sides of the upper abdomen, behind the intestines, and on either side of the spine. The kidneys are higher up in the body than people imagine - from behind they are actually partially protected by the lowest ribs. The kidneys move slightly with a change in body position and with movement of the diaphragm with breathing.
Each kidney is about the size of a large orange, but bean-shaped.
The word renal is a descriptive medical word, meaning related to the kidney. For example, a renal physician is a doctor who looks after people with kidney (renal) diseases.
. A large renal artery takes blood to each kidney. The artery divides into many tiny blood vessels (capillaries) throughout the kidney. In the outer part of the kidneys, tiny blood vessels cluster together to form structures called glomeruli.
Each glomerulus (the singular form of glomeruli) is like a filter. The structure of the glomerulus allows waste products and some water and salts to pass from the blood into a tiny channel called a tubule, while keeping blood cells and protein in the bloodstream. Each glomerulus and tubule is called a nephron. There are about one million nephrons in each kidney.
As the waste products, water and salts pass along the tubule there is a complex adjustment of the content. For example, some water and salts may be absorbed back into the bloodstream, depending on the current level of water and salts in your blood. Tiny blood vessels next to each tubule enable this fine tuning of the transfer of water and salts between the tubules and the blood.
The liquid that remains at the end of each tubule is called urine. This drains into larger channels (collecting ducts) which drain into the renal pelvis (the inner part of the kidney). From the renal pelvis the urine passes down a tube called the ureter which goes from each kidney to the bladder. Urine is stored in the bladder until it is passed out through another tube, called the urethra, when you go to the toilet. The cleaned (filtered) blood from each kidney collects into a large renal vein which takes the blood back towards the heart. The kidneys, ureters, bladder and urethra are, together, called the urinary tract.
Glomerulonephritis is the name given to a range of conditions that can affect the glomeruli of the kidney. Glomerulo refers to the glomeruli and nephritis means inflammation of the kidney. But, strictly speaking, there is not always inflammation present in some types of glomerulonephritis. In glomerulonephritis there is damage to the glomeruli. This damage interferes with the function of the glomeruli and it can interfere with the function of the kidneys as a whole. Salt and excess fluid can build up in the body if the kidneys are not working normally. This can lead to complications such as high blood pressure and, in some cases, kidney failure can occur.
Glomerulonephritis can vary in severity. It can be acute. That is, it can come on suddenly and last for a short period, requiring minimal treatment. Or it can be chronic. That is, it can last for a longer time and it can lead to irreversible damage to the glomeruli and kidneys, interfering with kidney function and leading to chronic kidney disease.
Glomerulonephritis is commonly due to a problem with the body's immune system. Usually, the immune system works to protect the body against things like infections by attacking and killing the germs causing them. However, sometimes the body's immune system can go wrong. Many cases of glomerulonephritis are caused by the body mistakenly attacking itself, causing damage to the glomeruli of the kidney. It is not always clear why this happens but, in some cases, a trigger can be identified, such as an infection. The infection triggers the problem with the immune system and the damage to the glomeruli.
Infection with certain types of streptococcal bacteria is the most common infection that can trigger glomerulonephritis. This can happen after an upper respiratory tract infection or a skin infection that was caused by those bacteria. Symptoms of glomerulonephritis typically develop between one and three weeks after the initial infection. Other bacteria, viruses, parasites, or fungi can also trigger glomerulonephritis. Glomerulonephritis that is triggered by a infection may occur at any age but it most commonly develops in children aged between 5 and 15 years.
Glomerulonephritis can also be triggered after taking certain medicines, including non-steroidal anti-inflammatory drugs (NSAIDs). In some people, it may be difficult to find a trigger for, or the exact cause of, glomerulonephritis.
As well as glomerulonephritis being either acute or chronic, there are various ways to classify the different types of glomerulonephritis that can occur. Broadly speaking, glomerulonephritis can be:
When a sample of tissue is taken from a kidney affected by glomerulonephritis (when a kidney biopsy is taken), the glomerulonephritis can be classified according to the changes that can be seen when the tissue sample is examined under a microscope. For example, glomerulonephritis can be:
In many people, glomerulonephritis does not cause any symptoms. It may be diagnosed after blood or urine tests are carried out for some other reason. However, in others, glomerulonephritis can cause symptoms that you may notice. These symptoms can develop slowly, or more quickly in acute glomerulonephritis.
Glomerulonephritis can lead to two main clinical syndromes (sets of symptoms and signs that occur together). These are nephrotic syndrome and nephritic syndrome. The type of glomerulonephritis that is seen when a sample of kidney tissue is examined under a microscope can often have little bearing on the symptoms of glomerulonephritis that can develop.
The main feature of nephrotic syndrome is that the kidneys leak a lot of protein because of damage to the glomeruli. This leads to proteinuria (the name given to an excess of protein in the urine). Excess protein in the urine can only be detected when the urine is tested using a urine testing strip dipped into the urine or by measuring the exact amount of protein in the urine in the laboratory. Also, urine may sometimes appear frothy when you go to the toilet if there is excess protein.
As protein is lost in the urine, this leads to low levels of protein in the blood. Protein and other chemicals in the blood exert an osmotic pressure which tends to pull fluid into the blood vessels. If the concentration of protein in the blood reduces, the osmotic pressure reduces, and fluid leaks out from the blood vessels into the tissues. This leads to oedema (fluid retention) which is the main symptom of nephrotic syndrome. When fluid leaks out of blood vessels into the body tissues, this causes swelling and puffiness of the affected tissues. The face, especially around the eyes, usually becomes puffy first. The ankles can also become puffy and swollen and as oedema becomes worse, the calves, then the thighs may become swollen. In severe cases, fluid can accumulate in the abdominal cavity (ascites) or in the chest between the lungs and the chest wall (pleural effusion). Ascites can cause abdominal pain and discomfort due to distension. Pleural effusions may cause chest pain and breathlessness.
Other symptoms that may develop include:
Symptoms of nephritic syndrome can include:
Complications of glomerulonephritis can include:
Various investigations may be suggested if glomerulonephritis is suspected. These may include:
The treatment will depend on the underlying cause as well as the symptoms that you have and how severe these symptoms are. In mild cases, no treatment may be needed, just regular and careful monitoring of your condition. In more severe cases, treatment may be suggested.
If you have glomerulonephritis, you will usually be treated and followed up by a specialist in kidney disease, a renal physician. They will be able to advise about treatment for your case. Treatment may include:
In many cases, glomerulonephritis can be a temporary problem that can completely resolve (get better). For example, in glomerulonephritis triggered by a streptococcal infection, the long-term outlook is generally very good: more than 98% of people have no symptoms at all five years afterwards.
However, in other cases, glomerulonephritis can get gradually worse over time, cause permanent damage to the glomeruli, and lead to chronic kidney disease. In some cases, this can progress to end-stage kidney (renal) failure. A kidney biopsy can help your doctors to predict the likely outcome in your individual case.
The Point, Coach Road, Shireoaks, Worksop, Nottinghamshire, S81 8BW
Helpline: 0845 601 0209 Web: www.kidney.org.uk
A national kidney charity run by patients, for patients.