Proteinuria—also called albuminuria or urine albumin—is a condition in which urine contains an abnormal amount of protein. Albumin is the main protein in the blood. Proteins are the building blocks for all body parts, including muscles, bones, hair, and nails. Proteins in the blood also perform a number of important functions. They protect the body from infection, help blood clot, and keep the right amount of fluid circulating throughout the body.
As blood passes through healthy kidneys, they filter out the waste products and leave in the things the body needs, like albumin and other proteins. Most proteins are too big to pass through the kidneys’ filters into the urine. However, proteins from the blood can leak into the urine when the filters of the kidney, called glomeruli, are damaged.
Proteinuria is a sign of chronic kidney disease (CKD), which can result from diabetes, high blood pressure, and diseases that cause inflammation in the kidneys. For this reason, testing for albumin in the urine is part of a routine medical assessment for everyone. Kidney disease is sometimes called renal disease. If CKD progresses, it can lead to end-stage renal disease (ESRD), when the kidneys fail completely. A person with ESRD must receive a kidney transplant or regular blood-cleansing treatments called dialysis.
Causes Of Proteinuria
You may develop proteinuria as a result of:
- Chemotherapy drugs such as: Streptozocin
- Biologic therapies such as: Interleukin-2
- Certain diseases or conditions -
Multiple myeloma will cause you to have a special kind of protein in your urine, called the "M-protein", "myeloma protein", or Bence-Jones protein. These are all terms for the same kind of protein. If Protienuria is among your symptoms of kidney problems, your doctor or healthcare provider will monitor your urine proteins periodically - either monthly, or yearly, depending on the severity and activity of your disease.
Systemic lupus erythematosis (SLE) - you may develop a "glomerulonephritis", or lupus nephritis, from your disease.
Diabetes - with diabetes, the protein that you will have in your urine is called albumin. If you have sustained long-term damage to your kidneys from poor blood sugar control, your kidneys may fail.
Long-standing high blood pressure (Hypertension) - long-standing hypertension may cause your kidney failure.
Infection - Inflammation in the kidneys (Nephritis) may cause protein in your urine
The following five types of proteinuria are distinguished by milligrams (mg) of protein measured during a 24-hour urine collection:
- Microalbuminuria (30–150 mg)
- Mild (150–500 mg)
- Moderate (500–1000 mg)
- Heavy (1000–3000 mg)
- Nephrotic range (more than 3500 mg)
Hypertensive people who develop proteinuria stand a significant chance for kidney failure. African Americans are 20 times more likely than Caucasians to develop hypertensive-related kidney failure. Proteinuria in people with diabetes may be a sign that kidney disease is worsening. Microalbuminuria is often cited as a risk for coronary artery disease (CAD) and is often diagnostic of it and related cardiovascular conditions.
How Is Proteinuria Treated ?
If you have diabetes, hypertension, or both, the first goal of treatment will be to control your blood glucose and blood pressure. If you have 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.
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, restricting dietary salt and protein intake is recommended. Your doctor may refer you to a dietitian to help you develop and follow a healthy eating plan.