IgA nephropathy has remained one of the most common forms of idiopathic glomerulonephritis since it was first described by Berger and Hinglais in 1968. Also known as Berger's disease, IgA nephropathy’s pathogenesis has remained incompletely understood. Also known as IgA nephritis, it often leads to chronic kidney disease (CKD).
Definition & Facts
IgA nephropathy is a disease that affects the kidneys. It occurs when the kidneys accumulate an antibody known as immunoglobulin A (IgA). Over time, the deposits of this antibody build up, causing inflammation which affects the ability of the kidney to filter wastes from the blood.
At the moment, there is no cure for IgA nephropathy; however, it can be controlled through the use of certain medications. The progression of the disease can be greatly slowed when cholesterol levels are reduced and blood pressure is under control, which medications can achieve.
Symptoms & Complaints
The most common symptom of IgA nephropathy is hematuria (blood in the urine) which is a sign of damaged glomeruli. Other signs and symptoms of IgA nephropathy that can be observed when kidney function is impaired include:
- High blood pressure
- Edema: This refers to swelling in the hands and feet.
- Pain below the ribs by the sides of the back (flank pain).
- Feelings of tiredness, drowsiness, numbness, headaches, vomiting and muscle cramps.
- In some cases, there may be little or no urination at all
- Some people experience repeated episodes of tea or cola-colored urine which may be accompanied with visible blood. This is usually the case when the patient is experiencing an upper respiratory tract infection or after other types of infections.
- Unexplained weight loss, nausea, itching, darkened and dry skin.
IgA nephropathy is believed to be an autoimmune disease of the kidneys, i.e. a disease that occurs as a result of the harm caused by a destructive response from the body’s immune system upon the kidneys.
The main function of the kidneys is to filter excess water, blood, and other substances that pass through them before re-entering the bloodstream, in the process producing urine that then travels to the bladder. By fighting infections and attacking invading pathogens, immunoglobin A (IgA) is an antibody that plays a vital role. However, in the case of IgA nephropathy, this antibody forms excessive clumps that deposit in the glomeruli, causing inflammation (or glomerulonephritis) which in turn gradually affect the filtering ability of the kidneys. It is unknown what exactly causes IgA nephropathy, but it has been associated with the following conditions:
- Infections such as HIV and other viral infections as well as some bacterial infections.
- Dermatitis herpetiformis- an itchy, blistering skin disease that occurs as a result of gluten intolerance.
- Genetic factors – research has shown that IgA nephropathy runs in families and is more common among certain ethnic groups.
- Celiac disease, an unusual kind of digestive problem that is caused by consuming gluten, a protein found in grains.
Diagnosis & Tests
When a routine test shows the presence of protein or blood in the urine or the patient has physically noticed blood in the urine, then IgA nephropathy may be the culprit. Typically, kidney disease is diagnosed with a physical examination, a medical history and family history, and blood tests and clinical urine tests so as to be able to really identify the problem. Some tests that may be performed include:
- Kidney biopsy. This is the only way through which a diagnosis of IgA nephropathy can be confirmed. Usually, a special kind of needle is used to extract small kidney tissue pieces (biopsy) which are then examined under the microscope in order to detect the presence of IgA deposits in the glomeruli.
- A blood test may reveal increased levels of waste product in the blood, indicating the dysfunction of the kidneys.
- Urine test. As part of a routine checkup, a urine test may reveal the presence of blood or protein in the urine which is usually a first sign of IgA nephropathy.
- Iothalamate clearance test. An iothalamate clearance test may be recommended by doctors so as to be able to track the efficiency of the kidneys in waste filtration.
Treatment & Therapy
Although researchers have yet to discover a cure for IgA nephropathy, the objective of current IgA nephropathy treatments is to delay or avoid the occurrence of end-stage kidney disease. The kidneys cannot be repaired once they are scarred, so it is important to prevent or delay IgA from becoming a chronic, irreversible disease. To this end, medications may be prescribed to lower a person’s cholesterol levels and control the person’s immune system to prevent it from attacking the kidneys. There are also certain medications that can help to remove extra fluid from a person’s blood.
In a bid to slow the progression of the disease, a health care provider may prescribe medications such as angiotensin receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitor. These medications can significantly slow the progression of kidney disease among people suffering from IgA nephropathy as they tend to lower blood pressure.
Removing extra fluid from the blood can also help control blood pressure. To this end, a diuretic can be prescribed by a health care provider. Sometimes, medications are prescribed or administered by health care providers to suppress the immune system and reduce inflammation. Cyclophosphamide is an immunosuppressive drug that is prescribed to diminish the autoimmune response, and corticosteroids may be prescribed by a health care provider to reduce inflammation.
Prevention & Prophylaxis
Excessive consumption of protein may cause the kidney to malfunction and even make it decline faster. Protein may strain the kidneys more than other foods by forcing the kidneys to work harder to filter out their waste products. Although the benefits for people with kidney disease of reducing protein in the diet have yet to be decisively proved, people with kidney disease may be advised by their doctors to eat moderate or reduced amounts of protein. A low sodium diet and reducing consumption of saturated fats and foods with high cholesterol may also assist in preventing damage to the kidneys.