Overview, Causes, & Risk Factors

Diabetic nephropathy is a description of the damage to a person's kidneys that can occur due to diabetes mellitus, more commonly called diabetes. The damage to the kidneys interferes with normal kidney function.

What is going on in the body?

The kidney is made up of several million filtering units. Each filtering unit contains a membrane to filter the blood, which is how urine is made. Diabetes, which is a condition that causes high blood sugar levels, can slowly damage these filtering membranes. The exact mechanism of this kidney damage is unknown. As this condition gets worse over time, kidney failure may occur.

What are the causes and risks of the condition?

Diabetes mellitus, or diabetes, causes this condition. It can occur in people whether or not they take insulin for their diabetes. However, this condition occurs in a greater percentage of people with type 1 diabetes. Tight control of the blood sugar can help people delay or avoid the onset of kidney damage and slow its progression. The more out of control the blood sugar is over time, the more likely kidney damage is to occur.

Symptoms & Signs

What are the signs and symptoms of the condition?

If people with diabetes are not screened for diabetic nephropathy, many years may pass before symptoms develop. The earliest sign of this condition is usually an abnormally high level of protein in the urine. This occurs without symptoms.

Symptoms of diabetic nephropathy start only after severe kidney damage has occurred and include:

Diagnosis & Tests

How is the condition diagnosed?

Urine testing is done in healthy people with diabetes to screen for diabetic nephropathy. These tests generally shows increased amounts of protein in the urine if diabetes has damaged the kidneys. Sometimes, the urine is collected over a 24-hour period to get a more exact measurement of the amount of kidney damage. If kidney damage is severe, blood tests will show decreased kidney function.

A kidney biopsy may be done to evaluate the amount of kidney damage. This involves inserting a special needle through the skin and into the kidney. A small piece of tissue can be taken from the kidney with the needle. The lab can then examine the tissue.

Other special blood or urine tests may be done in some cases.

Prevention & Expectations

What can be done to prevent the condition?

Three primary methods are recommended to prevent or at least delay the onset of diabetic nephropathy:

In addition, materials that can damage the kidneys should be avoided if possible. These materials include contrast dyes that are injected into a vein during some X-ray tests and nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. Any urinary tract infections should be treated with antibiotics. People should also be careful to keep themselves properly hydrated by drinking enough fluids.

What are the long-term effects of the condition?

Long-term, gradual worsening of diabetic nephropathy is expected. The greater the control over blood sugar levels, the slower the condition will progress and the less severe it will become. However, this condition progresses despite the tightest control.

The most serious long-term effect of diabetic nephropathy is kidney failure leading to end-stage renal disease. In this situation, a person will require dialysis or a kidney transplant. Dialysis usually involves hooking a person up to a machine to filter his or her blood. Once dialysis is begun, it must be continued for life unless a kidney transplant is received.

What are the risks to others?

Diabetic nephropathy is not contagious and poses no risk to others.

Treatment & Monitoring

What are the treatments for the condition?

The best treatment for diabetic nephropathy is prevention. Control of blood sugar levels is the most important way to prevent the onset and worsening of this condition. Control of blood pressure and the use of ACE inhibitor medications can also help limit the amount of kidney damage.

Dialysis or a kidney transplant is the treatment for people who develop end-stage renal disease.

What are the side effects of the treatments?

Tight control of the blood sugar with insulin may cause blood sugars that are too low. This could cause a coma or even death, though this is very rare. If pills are used to control diabetes, liver damage, stomach upset, and other side effects may occur.

Many medications used to control high blood pressure have bothersome side effects. These include erectile dysfunction, swelling in the legs, headaches, and low blood pressure. ACE inhibitor medications can cause a chronic cough and allergic reactions.

Dialysis is time-consuming and may cause infections, salt imbalances, and, rarely, death. A kidney transplant requires surgery, which may cause infection, bleeding, allergic reaction to anesthesia, and, rarely, death.

What happens after treatment for the condition?

Treatment of diabetic nephropathy is lifelong. As the condition gets worse, more intense treatment is needed until the kidneys fail completely.

How is the condition monitored?

A healthcare provider can help monitor the condition by checking protein levels in the urine early in the course of diabetes. This helps detect the condition at an early stage so aggressive treatment can begin. Blood tests are also used to monitor a person's diabetes and kidney function.

Those with diabetes should monitor their blood sugar levels at home every day and report abnormal levels to their healthcare provider. Any new or worsening symptoms should also be reported to the healthcare provider.