An Overiew of Albuminuria in Diabetes

Albuminuria, also called proteinuria, is a condition in which albumin—a type of protein found in blood plasma—leaches into the urine. Although very small amounts of protein in urine can be normal, high levels of albumin is one of several indicators of chronic kidney disease (CKD), a common complication of both type 1 and type 2 diabetes. Because albuminuria doesn't cause noticeable symptoms, people at risk of kidney disease typically are advised to be tested regularly for protein in their urine in order to detect the condition. This way measures can be taken right away to reduce the amount of protein in urine and protect the kidneys from further damage.

The only outward signs of excess protein in urine are those that develop in conjunction with chronic kidney disease. There are many symptoms of CKD that can be mistaken for other problems, which is why screening is vital.

Common symptoms of CKD include:

• Intolerance to cold
• Fatigue
• DIzziness
• The scent of ammonia on the breath (uremia fetor)
• Dysgeusia (a metallic taste in the mouth)
• Dyspnea (shortness of breath)
• Easy bruising
• Edema (swelling) of the face
• Trouble concentrating
• Pruritus (Itching)
• Loss of appetite
• Foamy urine
• Difficult or frequent urination (including at night)
• Pain in the kidneys, legs, or upper back

There are two reasons a person with diabetes might develop proteinuria. The first is long-term hyperglycemia—higher-than-normal levels of glucose (sugar) in the blood. Excess glucose can damage capillaries in the kidneys called glomeruli. These tiny blood vessels are bundled together to form the glomerular membrane, the structure that filters waste from the blood into the urine while at the same time preventing vital substances such as albumin and blood cells from leaking out.

Why this happens isn't completely understood, although preliminary research in animals suggests large amounts of glucose may lower the levels of nitric oxide in blood vessels, a substance that plays a key role in allowing them to dilate.

Albuminuria in diabetes also can result from hypertension—high blood pressure that's a common complication of diabetes.

Although albuminuria alone does not cause symptoms, diagnosing it is a simple matter of a urine test (urinalysis) that typically is part of a routine health checkup. For this familiar test, a patient is asked to provide a small sample of urine by peeing into a clean specimen cup.

Only a couple of tablespoons of urine are necessary. Usually, it will be tested right away using a small plastic dipstick that will change colors in response to the presence of protein. (This initial test also can detect other suspicious substances in urine, such as bacteria, glucose, and blood cells—any of which can be a sign of a medical problem.)

A dipstick test isn't sensitive enough to detect very small amounts of protein in urine that could indicate the beginning stages of kidney disease—a condition known as microalbuminuria. Therefore, the urine sample will be sent to a lab for further analysis—an ACR (albumin-to-creatinine ratio) test.

Most doctors do a urinalysis as part of regular checkups, but it's especially important that people with diabetes have their urine checked frequently—ideally at least once a year, according to the American Diabetes Association (ADA).

Because albuminuria is not a disease itself but rather a side effect (of diabetes or hypertension, for instance) or a symptom (of kidney disease), there's no treatment per se for the condition. Rather, dealing with the excess protein in urine will depend on the specific situation.

In the case of diabetes, that means following a treatment protocol designed by a doctor. For most people, managing diabetes involves a combination of adhering to a medically-approved diet, embarking on a regular exercise routine, taking medication to help control blood sugar, and self-testing glucose levels regularly.

Treatment for chronic kidney disease associated with diabetes also includes controlling blood glucose levels, as well as taking measures to lower blood pressure, such as losing weight, eating less salt, cutting out alcohol, quitting smoking, and increasing activity levels. Medication is sometimes necessary to treat hypertension; according to the ADA, ACE inhibitors are the safest choice for treating hypertension in people with diabetes.

The ADA also says that a low-protein diet is sometimes effective for treating kidney disease. If these measures do not head off kidney failure, dialysis or a kidney transplant will be necessary.

If you have diabetes and your urinalysis reveals you have protein in your urine, you have reason to be concerned. However, you also should feel empowered by the fact that you've caught what may be the beginning of chronic kidney disease well before it has progressed to the point of causing symptoms of end-stage kidney disease. With your doctor's guidance, you can make lifestyle changes and take other measures to keep your kidneys healthy and functioning normally.