- IgA nephropathy
- Berger's nephropathy
Berger's disease or Immunoglobulin A nephropathy is a kidney disease the affects the part of the kidney that filters blood to make urine (the glomerulus). It may lead to serious kidney damage and kidney failure requiring dialysis and/or kidney transplant. At this time, Berger's is considered to be "idiopathic" meaning that its exact cause is unknown.
What is going on in the body?
The job of the kidneys is to make urine by filtering the blood and then reabsorbing some components (salt and water), while excreting others (waste products) in the urine. In Berger's disease, or Immunolglobulin A nephropathy, the filtering parts of the kidney, called the glomeruli, become damaged.
The damage appears to be a result of deposits of proteins called immunoglobulin A class antibodies. Antibodies are normally made by the immune system to fight infections. For some unknown reason, people with Berger's disease have either increased production or reduced clearance of IgA antibodies that may be different than healthy immunoglobulin A. The higher level of antibodies injure the kidney after getting caught in the glomeruli and inciting inflammation.
What are the causes and risks of the disease?
Berger's disease probably results from some combination of genetic and environmental factors. For example, it is more common in Asians. However, the exact gene(s) responsible have not been discovered.
Since immunoglobulin A plays a role in fighting upper respiratory tract infections, it is reasonable to suppose that something in the environment triggers IgA production in at-risk individuals.
Berger's disease usually occurs in people between the ages of 15 and 35, but because it takes up to 25 years to lead to damage in some individuals, it may not be diagnosed until middle age. It is more common in Native Americans and Caucasians and rare in African-Americans.
Berger's disease is a leading cause of chronic kidney disease involving the glomeruli (glomerulonephritis) in young people in the United States, Europe, and Japan. As many as a third or more of patients with this disease will suffer serious progressive kidney damage.
What can be done to prevent the disease?
There are no known ways to prevent Berger's disease.
How is the disease diagnosed?
Diagnosis of Berger's disease begins with a medical history and physical exam. Some patients seek care when they notice blood in the urine right after a sore throat begins. A test called a urinalysis may show blood and protein in the urine. This often makes the healthcare professional suspect Berger's disease.
A blood test can be done to measure the level of IgA antibodies, which is higher than normal in about half of people with this condition.
A kidney biopsy is usually needed to confirm the diagnosis and determine its severity. This involves inserting a special needle through the skin of the back and into the kidney under local anesthetic and sedation. A small piece of kidney is removed with the needle and sent to the laboratory. There, a pathologist can identify the immunoglobulin A deposits in the glomeruli and exclude other possible diagnoses such as lupus.
Long Term Effects
What are the long-term effects of the disease?
Some people with Berger's disease suffer no long-term effects or kidney damage. In a few people, Berger's presents as sudden kidney failure that may not get better. In other cases, the disease slowly gets worse over time. A person may develop high blood pressure due to the kidney damage.
Roughly 50% of people with Berger's disease will gradually lose kidney function over a period of 20 or more years. Ultimately, these individuals reach the point where they need dialysis and/or a kidney transplant to survive.
Dialysis is a procedure that usually requires a person to be hooked up to a special blood-filtering machine for several hours three times a week. Once a person is placed on dialysis, he or she must continue with it for life or until he or she receives a kidney transplant.
What are the risks to others?
Berger's disease is not contagious and poses no risks to others
What are the treatments for the disease?
Treatment of Berger's disease usually focuses on carefully controlling high blood pressure and reducing protein loss in the urine. If a kidney biopsy demonstrates rapidly progressing disease, more aggressive treatment with steroids and immunosuppressive medications like azathioprine may be required.
Blood pressure control medications called angiotensin converting enzyme (ACE) inhibitors (such as enalapril or captopril) and angiotensin II receptor blockers (ARBs, such as valsartan or candesartan) may be used together to get optimum blood pressure readings (<120/80) and simultaneously decrease protein losses in the urine.
If urinary protein levels are high, corticosteroids such as prednisone may help slow down the kidney damage. Any conditions that damage the kidneys, such as infections and obstructions, should be treated promptly. Dietary modifications are important as kidney failure progresses. Individuals should follow the dietary guidelines prescribed by a healthcare professional. These generally focus on limiting sodium, protein, and fluid. A person who develops kidney failure will need dialysis and/or a kidney transplant.
What are the side effects of the treatments?
ACE inhibitor medications may cause cough. ACE inhibitor and ARB medications may cause potassium imbalances, and kidney problems in some cases. Medication of both these classes given together may raise the blood potassium level significantly. Corticosteroids can cause osteoporosis (softening of the bones) and an increased risk of infection.
Both dialysis and kidney transplant require surgery. Any surgery can be complicated by bleeding, infection, or a reaction to the anesthetic. Dialysis has many possible side effects, including infection, salt imbalances, rapid changes in blood pressure, bone problems, and even death.
After a kidney transplant, the person must take powerful medications to prevent rejection. Because these medications suppress normal immune system function, they can increase the risk for infections and for some forms of cancer. On occasion, they may also damage the transplanted kidney.
What happens after treatment for the disease?
Treatment does not cure Berger's disease. Aggressive blood pressure control can help slow further damage. Affected people, especially children, may go into remission and need no further treatment. Others will have occasional flare-ups of the disease, requiring closer monitoring and possibly treatment like steroids. Kidney failure from Berger's disease is not reversible. A person with kidney failure needs treatment for life.
How is the disease monitored?
The healthcare professional will order regular kidney function tests and check the person's blood pressure periodically. The person can watch for blood in the urine at home. Any new or worsening symptoms such as blood in the urine, a rising blood pressure, or swelling with fluid should be reported to the healthcare professional.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.