Proteinuria

Proteinuria is a condition where there is too much protein in the urine. Some protein is normal in the urine, but most proteins do not make it from your blood to your urine unless there has been damage to the kidneys.

Who is at risk?

People with diabetes, high blood pressure, or certain family backgrounds are at risk for proteinuria.

Diabetes

Diabetes is the number one cause of End Stage Renal Disease (ESRD) in the United States – a condition where the kidneys are unable to function at a level necessary for day-to-day life. In both type 1 and type 2 diabetes, you may notice small amounts of protein (called albumin) in the urine as the kidney deteriorates. This is called microalbumniaria. As the kidneys worsen, more albumin in the blood appears, and microalbuminuria becomes full-fledged proteinuria.

High Blood Pressure

High blood pressure is the second leading cause of ESRD. Proteinuria in a person with high blood pressure indicates declining kidney function. If the high blood pressure is not regulated, the person can progress to full renal failure. African Americans are more likely than Caucasians to have high blood pressure and to develop kidney problems from it, even when their blood pressure is only mildly elevated. In fact, African Americans are six times more likely than Caucasians to develop hypertension-related kidney failure.

Heredity

Other groups at risk for proteinuria are American Indians, Hispanic/Latinos, Pacific Islander Americans, older people, and overweight people. These at risk groups and people who have a family history of kidney disease should have their urine tested regularly.

Symptoms

You may have proteinuria without noticing any signs or symptoms. Being tested by a physician is the only way to find out how much protein you have in your urine.

Other common symptoms include:

• Foamy urine
  
• Swelling in your hands, feet, stomach, or face
  
• Breathlessness due to water around the lungs
  

Diagnosis

To test for proteinuria, you will need to give a urine sample. You will also need a blood test to check for creatinine and urea nitrogen – waste products that healthy kidneys remove from the blood. High levels of creatinine and urea nitrogen in your blood indicate that kidney function is impaired. Your doctor may order a number of blood tests and possibly a kidney biopsy to help determine the cause of your proteinuria.

Treatment

If you have diabetes, hypertension, or both, the first goal of treatment will be to control your blood glucose and blood pressure.

With diabetes, you should test your blood glucose often, follow a healthy eating plan, take your medicines, and get plenty of exercise.

If you have diabetes and high blood pressure, your doctor may prescribe a medicine from a class of drugs called ACE (angiotensin-converting enzyme) inhibitors or a similar class called ARBs (angiotensin receptor blockers). These drugs have been found to protect kidney function even more than other drugs that provide the same level of blood pressure control. The American Diabetes Association recommends that people with diabetes keep their blood pressure below 130/80.

People who have high blood pressure and proteinuria, but not diabetes, also benefit from taking an ACE inhibitor or ARB. Their blood pressure should be maintained below 130/80. To maintain this target, you may need to take a combination of two or more blood pressure medicines. Your doctor may also prescribe a diuretic in addition to your ACE inhibitor or ARB. Diuretics are also called “water pills” because they help you urinate and get rid of excess fluid in your body.

In addition to blood glucose and blood pressure control, the National Kidney Foundation recommends restricting dietary salt and protein. Your doctor may refer you to a dietitian to help you develop and follow a healthy eating plan.

A less common cause of proteinuria is glomerulonephritis. There are a number of types of glomerulonephritis that cause proteinuria. The diagnosis is made by a kidney biopsy and treatment may include chemotherapeutic agents or other immunosuppressive medications.

Points to Remember

• Normally, protein should not be found in the urine. A person who has protein in the urine is said to have proteinuria.
  
• The term albuminuria is also often used because some tests measure this protein specifically and it is the major type of protein in the urine.
  
• Proteinuria may be a sign that your kidneys are damaged and that you are at risk for end stage renal disease.
  
• Several health organizations recommend that people be regularly checked for proteinuria so kidney disease can be detected and treated before it progresses.
  
• Groups at risk for proteinuria and kidney failure include African Americans, American Indians, Hispanic/Latinos, Pacific Islander Americans, people with diabetes or hypertension, and people who have a family history of kidney disease.
  
• If you have diabetes or high blood pressure, or both, the first goal of treatment will be to control your blood glucose and blood pressure.
  
• Most people have no signs or symptoms of proteinuria. Testing is the only way to find out how much protein you have in your urine.