Glomerular diseases

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 2, 2016
StartDiseasesGlomerular diseases

Glomerular disease can be defined as any medical condition that impairs the ability of the glomeruli to properly function. Glomeruli are a network of blood vessels in the kidneys. They perform a vital function by removing waste from the blood. There are approximately one million glomeruli in each kidney. Together they filter between 120 and 150 quarts of blood every single day and produce about one to two quarts of urine.

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Definition & Facts

According to the National Institute of Diabetes and Digestive and Kidney Diseases, glomerular disease generally falls into two broad categories. Glomerulonephritis is an inflammatory condition that affects the ability of the kidneys to separate waste from the blood. Glomerulosclerosis is a disease that hardens the blood vessels within the glomerulus.

Although both types of glomerular disease have distinct causes and treatments, the symptoms are generally similar. Glomerular disease can manifest as either an acute or chronic case. An acute case can lead to a rapid deterioration in kidney function within a matter of weeks; kidney function usually returns once the cause is treated. A chronic case can lead to a long-run deterioration in kidney function and is more likely to result in permanent kidney damage.

Symptoms & Complaints

The most common symptom associated with glomerular disease is an excessive amount of protein in the urine (at least 3.5 grams per day) which is called proteinuria or low protein levels in the blood (hypoproteinemia). It is also associated with swelling in parts of the body, especially the hands and ankles (edema).

These symptoms are collectively known as nephrotic syndrome, which occurs when damaged glomeruli are unable to filter out protein and blood from the kidneys. People with nephrotic syndrome may notice that their urine appears foamy. In other cases, urine may have blood in it (hematuria), with a slight pink or light brown discoloration. This is because of red blood cells leaking into the urine.

People with glomerular disease may also experience high blood pressure (hypertension) and increased blood clotting. Symptoms can vary in length and intensity, but usually develop only gradually.

People with the disease may not even know they have it at first. After many months or years, glomeruli damage can progress to chronic kidney disease. If left untreated, the kidneys may stop working altogether, leading to kidney failure.

Causes

Glomerular disease describes only the damage to the glomerulus itself, but the cause of that damage can vary widely. Some people have a genetic predisposition to glomerular disease. A genetic link is easier to detect because it will generally run in the family.

More often, glomerular disease is caused by another disease or a drug. For example, one of the most common causes of glomeruli damage is an autoimmune disease, in which the immune system attacks the body's own tissue and provokes an inflammatory response. Glomerular disease may also be caused by a viral infection, such as HIV, hepatitis B, or hepatitis C (about five to 10 percent of people with HIV eventually experience kidney failure).

In most cases, however, the leading cause of both glomerular disease and chronic kidney disease in the United States is diabetic nephropathy, in which elevated levels of blood glucose damage the kidneys and place a strain on the kidney's filtration system. Diabetic nephropathy can affect anyone with diabetes, but it might not develop for years. In cases of scarring, the damage to the kidneys is generally irreversible.

Diagnosis & Tests

Because the signs of symptoms of glomerular disease do not always manifest quickly, patients might go months or years without realizing they are at risk of a kidney disease. The best way to detect it is through an analysis of the patient's urine and kidney function. Tests to assess kidney function include:

  • Urine tests to check for protein and blood in the urine
  • Blood tests to measure the level of protein, cholesterol, and waste in the blood
  • A kidney biopsy in which a small piece of the kidney is removed from the patient's body and then examined for signs of inflammation or damage
  • An imaging test such as an X-ray or an ultrasound, to check for abnormalities in the kidney, although the imaging data may not detect any cellular damage.

In some cases, a genetic test might be an effective way to find out whether the patient has a genetic predisposition to kidney disease. However, genetic testing cannot catch all risk factors related to kidney disease.

Treatment & Therapy

Glomerular disease can be stopped in the majority of cases by treating the underlying condition. Doctors may prescribe one of the following medications or treatments: corticosteroids or calcineurin inhibitors to reduce inflammation in the kidneys; diuretics or ACE inhibitors to reduce blood pressure and the amount of protein in the urine; or blood-thinning drugs to prevent blood clots.

Treatment focuses on preventing further damage. People with kidney disease can also improve their outlook by making a few changes to their lifestyle:

The prognosis for people with glomerular disease, if detected in time, is generally good. However, chronic kidney disease cannot be cured; it can only be controlled or slowed down. The only way to treat end-stage renal disease is with kidney dialysis or kidney transplant. That is why early intervention for a kidney problem is critical; it should be diagnosed and treated as soon as possible, before long-term damage has already set in.

Prevention & Prophylaxis

Because glomerular disease is typically caused by another underlying condition, it might be difficult to take specific steps to prevent it.

Nevertheless, there are a few general guidelines for reducing the risk of kidney disease in some cases. One should always seek immediate medical treatment for an infection. Keeping one's blood pressure within reasonable limits can reduce the strain on one's kidneys. Controlling one's blood sugar can help prevent diabetes.