What Is Glomerulonephritis? What Causes Glomerulonephritis?

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Main Category: Urology / Nephrology
Article Date: 14 Oct 2009 - 2:00 PDT

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Glomerulonephritis is also known as glomerular nephritis (GN) or glomerular disease. It is a disease of the kidney, characterized by inflammation of the glomeruli. Glomeruli are very small blood vessels in the kidneys that act as tiny little filters - there are about one million glomeruli in each kidney. The disease damages the kidneys' ability to remove waste and excess fluids from the body.

GN can be acute, meaning there is a sudden attack of inflammation, or chronic (long-term and coming on gradually).

People can develop glomerulonephritis on its own, in which case it is called primary glomerulonephritis. If it is caused by another disease, such as diabetes or lupus, infection, or drugs it is called secondary glomerulonephritis.

What are the signs and symptoms of glomerulonephritis?

A symptom is something the patient feels or reports, while a sign is something other people, including the doctor may detect. For example, a headache may be a symptom while a rash may be a sign.

Some patients may not show any clear symptoms. The type of signs and symptoms will usually depend on whether it is the acute or chronic form, and its cause. For some people, their first indication that something is not right is when the results of a urine or blood sample test come back.

• Urine - if the glomeruli are damaged there will be a small amount of blood and/or protein in the urine, which may be visible or will show up in a urine test.
  
  If symptoms are more severe the individual's urine will turn visibly red - sometimes it may be Coca-cola colored. If the urine is cloudy or frothy it means that excess protein is present (proterinuria).
  
  A healthy adult urinates between 1 to 1.5 liters per day. People with severe glomerulonephritis may spend two or three days without being able to urinate; and when they do, there may be blood and/or protein in the urine.


• Kidney damage - in the initial stage the inflammation of the kidneys may not be evident. Symptoms may suddenly appear, or come on about three weeks after infection. Patients with glomerulonephritis caused by kidney damage may have the following signs or symptoms:
  
  
  • An elevated body temperature (typically about 38C, 100.4F)
  • Breathing difficulties
  • Edema (swelling), especially in the hands, face, feet, ankles or abdomen
  • Loss of appetite
  • Nausea
  • Pallor
  • Vision problems
  • Vomiting
  
  The following signs or symptoms are also possible:
  
  
  • Hypertension (high blood pressure)
  • Fatigue


• Kidney pain - although pain in the kidneys is possible, it is unusual. When pain is felt, it is usually in the upper back, behind the ribs. Sometimes the pain may be intense. Kidney pain might be a symptom of kidney stones or a kidney infection, instead of glomerulonephritis.

What are the causes of glomerulonephritis?

What is a glomerulus (plural: glomeruli)?

The glomerulus is a tiny structure shaped like a ball; in the kidney. It is composed of capillary blood vessels and is actively involved in the filtration of the blood to form urine. The glomerulus is one of the structures that make up the nephron - a key functional unit of the kidney. The Latin word glumus means "a ball of yarn". Glomerulus in Latin means "a small ball of yarn". The glomerulus is literally a ball containing a yarn of blood vessels.

Put simply - the glomeruli are tiny filters in our kidneys that take waste out of our blood. The waste is urine.

Each kidney has about 1 million glomeruli, which attach to the opening of a small fluid-collecting tube (tubule). A nephron consists of one glomerulus and one tubule. Impure blood enters the nephron, waste (urine) is filtered out, and filtered blood returns to the bloodstream. The tubules modify what the glomerulus filters by saving substances that are needed, such as protein. The waste (urine) goes from the kidney to the bladder through a tube called the ureter. The urine is then passed out of the body when we go to the toilet (urinate).

When the glomeruli are inflamed the patient has glomerulonephritis. Glomerulonephritis can damage the kidneys. Sometimes the damage undermines the kidney's ability to filter blood properly, resulting in an accumulation of waste in the blood stream - kidney failure. The damage may also starve the blood of protein, which ends up being expelled from the body in urine, instead of entering the bloodstream.

In many cases the doctor never finds out what the cause of the glomerulonephritis was. Below is a list of known possible causes or risk factors:

• Post-streptococcal glomerulonephritis - strep infections of the throat and impetigo (a skin infection) may cause glomerulonephritis. Impetigo is a much less common cause than throat infection. As treatment for most streptococcal infections improve, this cause is becoming much less common.


• TB (tuberculosis) - glomerulonephritis can develop as a complication of tuberculosis.


• Syphilis - glomerulonephritis can develop as a complication of syphilis.


• Injecting illegal drugs - people who inject illegal drugs are at a much higher risk of developing glomerulonephritis.


• Bacterial endocarditis - this is an infection in at least one of the heart valves. Patients with a heart defect have a higher risk of developing bacterial endocarditis and eventually glomerulonephritis.


• Some viral infections - people infected with the HIV, hepatitis B and C viruses are more likely to develop glomerulonephritis compared to others.


• Lupus - this is a chronic inflammatory condition caused by an autoimmune disease (the body's immune system attacks itself, its own tissues). People with lupus are more likely to develop compared to people without it.


• Goodpasture's syndrome - this is also an autoimmune disease which causes lung and kidney disease. The patient may bleed in the lungs and develop glomerulonephritis.


• IgA nephropathy - immunoglobulin A (IgA) deposits appear in the glomeruli, eventually causing glomerulonephritis.


• Polyarteritis - this is an autoimmune disease in which the arteries become inflamed (arteritis). As the arteries are involved it can affect any organ in the body, including the kidneys.


• Wegener's granulomatosis - a rare kind of inflammation of the small arteries and veins (vasculitis) that typically involves the vessels that supply lung, sinus and kidney tissue.

The following conditions may cause scarring of the glomeruli:

• Hypertension (high blood pressure) - hypertension can damage the kidneys and subsequently their normal functioning. Glomerulonephritis itself can cause hypertension because kidney function is undermined - the kidneys play a vital role in regulating our blood pressure.


• Diabetic nephropathy (diabetic kidney disease) - any patient with diabetes has the potential to develop diabetic nephropathy. Kidney damage may be prevented, or at least significantly slowed down with good diabetes control.


• Focal segmental glomerulosclerosis - segmental collapse of glomerular capillaries (small vessels). There may be scattered scarring of some of the glomeruli.


• Acute glomerulonephritis - an attack of acute glomerulonephritis may develop into chronic (long-term) glomerulonephritis. If the patient has no history of kidney disease, the first indication of chronic glomerulonephritis will be chronic kidney failure.


• Genetic factors - there is a certain type of glomerulonephritis that runs in families. However, most people with glomerulonephritis do not have a family member who has/had the condition.


• Long-term medications - some medications, if taken over the long-term, may increase a patient's likelihood of developing glomerulonephritis. Examples include:
  
  
  • NSAIDs (non-steroidal anti-inflammatory drugs), such as ibuprofen and aspirin.
  • Gold injections, for the treatment of rheumatoid arthritis.
  • Lithium, for the treatment of depression.
  • Penicillamine, for the treatment of arthritis.


• Hodgkin's disease - this is a type of cancer which can result in glomeruli being damaged.


• Sickle cell disease - a genetic blood disease in which there is an abnormal form of hemoglobin.

Diagnosis of glomerulonephritis

It is not uncommon for a patient to have no signs and symptoms and find out he/she has glomerulonephritis after a check-up or tests linked to hypertension, or fatigue - or during routine antenatal check-ups.

• Urine test - if the doctor suspects possible glomerulonephritis a urine test may be ordered to check for blood or protein.


• Blood test - levels of antigens and antibodies in the blood may help doctors in their diagnosis.


• Throat swab - some cells from the back of the patient's throat are taken and sent to the lab.


• Renal function tests - patients who have kidney disease may have to undergo further tests to find out whether they have glomerulonephritis. Renal function tests are a range of tests, including blood and urine samples which are checked for certain substances released by the kidneys. This is also called a kidney function test. Blood levels of sodium, chloride, potassium and urea will be checked. The tests may also tell the doctor whether the patient is producing less urine that usual.


• Kidney biopsy - patients with chronic glomerulonephritis may need to have a small sample of kidney tissue removed for testing to find out how serious the condition is. The doctor extracts tissue samples using a small needle. The patient will normally receive a local anesthetic. A kidney biopsy has a small risk of bleeding.


• Imaging tests - if the doctor finds evidence of damage, diagnostic studies may be ordered so that the kidneys can be visualized. This may include a kidney X-ray, an ultrasound scan, or a CT (computerized tomography) scan.

What are the treatment options for glomerulonephritis?

The type of treatment the patient receives will depend on whether he/she has acute (sudden) or chronic (long-term, gradual progression) glomerulonephritis, what the underlying cause is, and how severe the signs and symptoms are.

Glomerulonephritis cases which follow a strep infection usually resolve themselves without treatment.

Diet and fluid intake - the patient will likely be advised to reduce fluid intake and refrain from consuming alcoholic drinks or those with a high salt or potassium content. The patient may be referred to a dietician who will give advice on potassium and salt intake, among other things.

Blood chemistry will need to be checked regularly to make sure levels of potassium, sodium, and chloride are right.

Hypertension - in order to treat the hypertension and halt or slow down kidney function decline, the doctor may prescribe diuretics, Angiotensin-converting enzyme (ACE) inhibitors, and Angiotensin-converting enzyme (ACE) inhibitors, which help to relax the blood vessels, reducing the workload of the heart. Hypertension can cause further kidney decline and other health problems and needs to be controlled.

The following medications may also be prescribed to treat possible underlying causes:

• Bacterial infections - a targeted antibiotic.


• Lupus or vasculitis - corticosteroids and immunosuppressants.


• IgA - possibly fish oil supplements.


• Goodpasture's syndrome - plasmapheresis is a procedure designed to reduce blood plasma levels without depleting the body of its blood cells. Antibodies are removed and donated plasma replaces the depleted plasma.

Acute glomerulonephritis and kidney failure - temporary dialysis can help control hypertension and remove surplus fluid. If kidney transplant is not possible, usually because the patient's poor health would not withstand the procedure, dialysis becomes the only available therapy. Kidney dialysis is when a machine is utilized to do the kidney's job of filtering out waste products from the body.

What are the possible complications of glomerulonephritis?

• Hypertension (high blood pressure)
  
  This is a common complication because our kidneys play a key role in blood pressure regulation. Untreated hypertension can lead to serious health problems, including heart failure and pulmonary edema.


• Other organs
  
  Although the kidneys are usually the only organs affected, the body's immune system can damage other parts of the body.


• Kidney disease or kidney failure
  
  The kidneys can become so damaged that they fail completely if the condition is left untreated. Loss of function of the filtering part of the nephron may result in accumulation of waste products - if this happens rapidly the patient can develop acute kidney failure and will need emergency dialysis. If the kidneys gradually lose function and continue to do so the patient will develop chronic (long-term) kidney failure. When the kidneys function at under 10% of their normal capacity the patient is in what is known as end-stage kidney disease, and will require regular dialysis or a kidney transplant to stay alive.

Prevention

Most forms of glomerulonephritis are not preventable. However, the following may help prevent complications of the disease itself or potential underlying causes:

• Make sure you get immediate treatment for a strep infection that causes a sore throat or impetigo.


• Take steps to prevent yourself from becoming infected by bacteria and viruses, such as HIV, which may raise your risk.


• If you have diabetes make sure you adhere to your treatment plan.


• Keep your blood pressure under control.


• Although keeping fit, getting at least 7 hours good sleep every night, and eating a well balanced diet high in fruit and vegetables has not been clinically proven to lower glomerulonephritis risk, it will lower your risk of developing an infection complication.

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today