Alternative Names diabetic kidney disease, diabetic sclerosis, diabetic glomerulosclerosis
Definition Diabetic nephropathy is a description of the damage to a person's kidneys that can occur due to diabetes mellitus. This condition decreases kidney function.
What is going on in the body? The kidney is made up of several million filtering units. Each filtering unit contains a 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 signs and symptoms of the condition? If people with diabetes are not screened for this condition, 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 this condition start only after severe kidney damage has occurred and include:
swelling in the legs
nausea and vomiting
a generalised or whole body ill feeling
fatigue
headache
itching
frequent hiccups
unintended weight loss
swelling of the face
unintended weight gain due to fluid build up
What are the causes and risks of the condition? Diabetes mellitus causes this condition. It can occur in people whether or not they take insulin for their DM. However, this condition occurs in a greater percentage of people with insulin-dependent diabetes mellitus, or type I 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.
What can be done to prevent the condition? Three primary methods are advised to prevent or at least delay the onset of this condition:
close or tight control of blood sugar levels.
control of blood pressure. People with diabetes may even benefit from having a blood pressure that is lower than normal.
the use of drugs known as angiotensin converting enzyme (ACE) inhibitors, which are also used to treat high blood pressure.
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 non-steroidal anti-inflammatory drugs, such as ibuprofen. Any urinary tract infections should be treated with antibiotics. People should also be careful to keep themselves properly hydrated (drink lots of fluids, preferably water).
How is the condition diagnosed? Usually, a test of the urine is done in healthy people with diabetes to screen for this condition. This test 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 measure 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 laboratory can then examine the tissue.
Other special blood or urine tests may be done in some cases.
What are the long-term effects of the condition? Long-term, gradual worsening of the condition 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 this condition is kidney failure. In this setting a person will require dialysis or a kidney transplant. Dialysis usually involves hooking a person up to a machine to filter their blood. Once dialysis is begun, it must be continued for life unless a kidney transplant is received.
In Australia, diabetes is the number one cause of permanent kidney failure.
What are the risks to others? This condition is not contagious and poses no risk to others.
What are the treatments for the condition? The best treatment 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 drugs can also help limit the amount of kidney damage.
Dialysis or a kidney transplant is the treatment for people who develop kidney failure.
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 drugs used to control blood pressure have bothersome side effects. These include impotence, swelling in the legs, headaches, and low blood pressure. ACE inhibitor drugs 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, and rarely, death.
What happens after treatment for the condition? This condition does not go away and treatment does not end. As the condition gets worse, more intense treatment is needed until the kidneys fail.
How is the condition monitored? A doctor can help monitor the condition by checking protein levels in the urine early in the course of DM. 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 high levels to their doctor.
Author: Michael Curiel, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
