Diabetic glomerulosclerosis

Definition

Diabetic nephropathy is a complication of diabetes. If you have this condition, your kidney loses its ability to function properly. The condition is characterized by high protein levels in the urine.

Alternative Names

Causes

Each kidney is made of hundreds of thousands of units called nephrons. Each nephron has a cluster of blood vessels called a glomerulus. The glomerulus filters blood and forms urine, which drains down into the ureter.

The earliest detectable change in the course of diabetic nephropathy is a thickening in the glomerulus. At this stage, the kidney may start allowing more albumin (protein) than normal in the urine, and this can be detected by sensitive tests for albumin. This stage is called "microalbuminuria" (micro refers to the small amounts of albumin).

As diabetic nephropathy progresses, increasing numbers of glomeruli are destroyed. Now the amounts of albumin being excreted in the urine increases, and may be detected by ordinary urinalysis techniques. At this stage, a kidney biopsy clearly shows diabetic nephropathy.

Protein may appear in the urine for 5 to 10 years before other symptoms develop. High blood pressure often accompanies diabetic nephropathy. Over time, the kidney's ability to function starts to decline. Diabetic nephropathy may eventually lead to chronic kidney failure. The disorder continues to progress toward end-stage kidney disease, often within 2 to 6 years after the appearance of high protein in the urine (proteinuria).

Diabetic nephropathy is the most common cause of chronic kidney failure and end-stage kidney disease in the United States. People with both type 1 and type 2 diabetes are at risk. The risk is higher if blood-glucose levels are poorly controlled. However, once nephropathy develops, the greatest rate of progression is seen in patients with poor control of their blood pressure.

Diabetic nephropathy generally goes along with other diabetes complications including hypertension, retinopathy, and blood vessel changes, although these may not be obvious during the early stages of nephropathy. Nephropathy may be present for many years before high protein in the urine or chronic kidney failure develop.

Symptoms

Early stage diabetic nephropathy has no symptoms. Symptoms develop late in the disease and may be a result of kidney failure or eliminating high amounts of protein in the urine.

Symptoms may include:

• Fatigue
• Foamy appearance or excessive frothing of the urine
• Frequent hiccups
• General ill feeling
• Generalized itching
• Headache
• Nausea and vomiting
• Poor appetite
• Swelling of the legs
• Swelling, usually around the eyes in the mornings; general body swelling may occur with late-stage disease
• Unintentional weight gain (from fluid build up)

Exams and Tests

The first laboratory abnormality is a positive microalbuminuria test. This often means you have at least some damage to the kidney from diabetes. Damage at this stage may be reversible.

Most often, the diagnosis is suspected when a routine urinalysis shows too much protein in the urine (proteinuria) of someone with diabetes. This test may also show glucose in the urine, especially if blood sugar is poorly controlled.

High blood pressure may be present or develop rapidly. It may be difficult to control. Serum creatinine and BUN eventually may increase as kidney damage gets worse.

A kidney biopsy confirms the diagnosis. However, this test is not done if you have shown increasing protein in the urine over time and the presence of diabetic retinopathy

This disease may also alter the results of the following tests:

• 24-hour urine protein
• Blood levels of phosphorus, calcium, bicarbonate, and potassium
• Hemoglobin
• Hematocrit
• Protein electrophoresis - urine
• Red blood cell (RBC) count

Treatment

The goals of treatment are to slow the progression of kidney damage and control related complications.

The main treatment, once proteinuria is diagnosed, is keeping blood pressure under control (to levels less than 130/80.) If possible, a type of blood pressure medicine, either angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs), should be used. These drugs reduce urine protein levels and slow down the diabetic nephropathy. Many studies have suggested that a combination of these two types of drugs may be best.

Uncontrolled high blood pressure will worsen kidney, eye, and blood vessel damage in the body. Controlling your high blood pressure is the most effective way of slowing kidney damage from diabetic nephropathy. It is also very important to control lipid levels, maintain a healthy weight, and engage in regular physical activity.

Blood glucose levels should be closely monitored and controlled. This may slow the progression of the disease especially in the very early stages. Your can change your diet to help control your blood sugar. See: Diet for people with diabetes

Medications to manage diabetes include hypoglycemic pills and insulin injections. Your blood glucose must be monitored and the dose of insulin adjusted as needed. As kidney failure progresses, less insulin is excreted, so smaller doses may be needed to control glucose levels.

Contrast dyes that contain iodine, such as those used during some imaging tests, are excreted through the kidney. These dyes may worsen kidney function, and should be avoided if possible. If they must be used, fluids should be given through an IV line for several hours before the test. This allows for rapid removal of the dyes from the body.

Commonly used nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen, naproxen, and prescription Cox-2 inhibitors such as celecoxib (Celebrex), may injure the weakened kidney. You should always talk to your health care provider before using any drugs.

Urinary tract and other infections are common and can be treated with appropriate antibiotics.

Dialysis may be necessary once end-stage renal disease develops. At this stage, a kidney transplant must be considered. Another option for type 1 diabetes patients is a combined kidney-pancreas transplant.

Outlook (Prognosis)

Once large amounts of protein begin to appear in the urine or the serum creatinine begins to rise, diabetic nephropathy typically continues to slowly worsen.

Complications of chronic kidney failure are more likely to occur earlier, and progress more rapidly, when it is caused by diabetes than other causes. Even after dialysis or transplantation, people with diabetes tend to do worse than those without diabetes.

Possible Complications

Possible complications include:

• Anemia
• Chronic kidney failure (rapidly gets worse)
• Dialysis complications
• End-stage kidney disease
• Hyperkalemia
• Severe hypertension
• Hypoglycemia
• Infections
• Kidney transplant complications
• Peritonitis (if peritoneal dialysis used)

When to Contact a Medical Professional

Call your health care provider if your health care provider if you have diabetes and a routine urinalysis shows protein.

Call your health care provider if you develop symptoms of diabetic nephropathy, or if new symptoms develop, including little or no urine output.

Prevention

Blood glucose levels should be controlled as closely as possible in people with diabetes. Controlling blood pressure, cholesterol, and weight is just as important.