Diabetes & The Body

Kidney Disease: A cause of concern for diabetics

Diabetes mellitus, usually called diabetes, is a disease in which body does not make enough insulin or cannot use normal amounts of insulin properly. Insulin is a hormone that regulates the amount of sugar in the blood. A high blood sugar level can cause problems in many parts of the human body.

Each year a large number of people are diagnosed with kidney failure, a serious condition in which the kidneys fail to get rid the body of wastes. Kidney failure is the final stage of a slow deterioration of the kidneys, a process known as nephropathy.

The kidneys are the master chemists of the body. Normally, there are two of them, one on either side of the spine under the lower ribs. They are reddish brown in colour and shaped like kidney beans. Each kidney is about the size of clenched fist.

Diabetes is the most common cause of kidney failure. However, it's also true that most people with diabetes don't go on to have end-stage kidney disease (ESRD). There are many things one can do to control diabetes and minimize the risk of kidney failure including stopping smoking and keeping blood pressure under control.

People with kidney failure undergo either dialysis, which substitutes for some of the filtering functions of the kidneys, or transplantation to receive a healthy donor kidney.

With diabetes, the small blood vessels in the body are injured. When the blood vessels in the kidneys are injured, the kidneys cannot clean blood properly. Hence, human body will retain more water and salt than it should, which can result in weight gain and ankle swelling. Also one might have protein in urine and waste materials will build up in blood.

Diabetes also may cause damage to nerves in the body. This can cause difficulty in emptying the bladder. The pressure that results from full bladder can back up and injure the kidneys. Also, if urine stays in the bladder for a long time, subjects might get an infection. This is because bacteria grow rapidly in urine that has a high sugar level.

About 30 percent of patients with Type I (juvenile onset) diabetes and 10 to 40 percent of those with Type II (adult onset) diabetes will eventually have kidney failure.

Signs

The earliest sign of diabetic kidney disease is an increased excretion of albumin in the urine. This is present long before the usual tests done in a doctor's office show evidence of kidney disease. Thus, it is important for subjects to have this test on a yearly basis. Subjects might be using the bathroom more at night and blood pressure may get too high. As a person with diabetes, one should have blood, urine and blood pressure checked at least once a year by the doctor. This will lead to better control of the disease and early treatment of high blood pressure and kidney disease. Keeping good control of your diabetes can lower the risk of having severe kidney disease.

At a latter stage as the kidneys fail, people will have a rise in blood urea nitrogen (BUN) and creatinine blood tests. Subjects might also have nausea, vomiting, a loss of appetite, weakness, increasing tiredness, itching, muscle cramps (especially in legs) and anemia (a low blood count). One might find the need to use less insulin. This is because diseased kidneys cause less breakdown of insulin. One should call the doctor as soon as he/she finds any of these signs.

Also there is end stage renal failure, or kidney failure. This is the time when kidneys are no longer able to support people in a reasonably healthy state, and dialysis or transplantation is needed. This happens when the kidney function is about 10 to 15 percent of normal. The usual time between the beginning of diabetic kidney injury and kidney failure is about five to seven years.

Actually there are five stages of diabetic kidney disease with the last stage being kidney failure. On average it takes a person with diabetes over 20 years to progress to the end stage. Both types of diabetes, Type 1 and Type 2, can lead to kidney disease. Type 1 is more likely to lead to end-stage kidney failure.

Stage I – The flow of blood through the kidneys increases and the kidneys get bigger. People can stay in this stage indefinitely or advance to Stage II after many years.

Stage II - Small amounts of blood protein known as albumin leak into the urine. This is called microalbuminuria.

Stage III - The loss of albumin and other proteins speeds up. Some patients develop high blood pressure. The kidneys continue to lose the ability to filter waste. Many people are first diagnosed with kidney disease at this stage.

Stage IV - In this stage large amounts of urine are passed through the kidneys and high blood pressure almost always occurs.

Stage V - The ability of the kidneys to filter waste almost stops. Kidney dialysis or transplants are treatment options.

High blood pressure, or hypertension, is a major factor in the development of kidney problems in people with diabetes. Both a family history of hypertension and the presence of hypertension appear to increase chances of developing kidney disease. Hypertension also accelerates the progress of kidney disease where it already exists.

Hypertension can be seen not only as a cause of kidney disease, but also as a result of damage created by the disease. As kidney disease proceeds, physical changes in the kidneys lead to increased blood pressure. Therefore, a dangerous spiral, involving rising blood pressure and factors that raise blood pressure, occurs. Early detection and treatment of even mild hypertension are essential for people with diabetes.

Treatment and Prevention

Keeping good control of diabetes can lower the risk of having severe kidney disease. This means having blood pressure and urine albumin excretion checked at least once a year and taking blood pressure medicine if the doctor orders it. One needs to get enough sleep -- usually about eight hours, follow the diabetic diet and get regular exercise. Subjects should avoid alcohol and cigarettes; see the doctor as often as told.

Scientists have made great progress in developing methods that slow the onset and progression of kidney disease in people with diabetes. Drugs used to lower blood pressure (antihypertensive drugs) can slow the progression of kidney disease significantly. One kind of drug, angiotensin-converting enzyme (ACE) inhibitors, has proven effective in preventing progression to stages IV and V.1 Diuretics, beta-blockers, adrenergic nervous system modulators, and calcium channel blockers also may enhance blood pressure control in patients with diabetes mellitus.

A diet containing reduced amounts of protein may benefit people with kidney disease of diabetes. In people with diabetes, excessive consumption of protein may be harmful. Experts recommend that most patients with stage III or stage IV nephropathy consume limited amounts of protein.

Three types of treatment can be used once the kidneys have failed.

• Kidney transplantation,
• Hemodialysis and
• Peritoneal dialysis.

The kidney doctor (nephrologist) will plan the treatment with the subjects and his/her family and the dietitian.

A kidney transplant can come from one of the relatives of the subject, living-related transplant or from a dead person, cadaver transplant. After getting a new kidney, one might need to use a higher dose of insulin. This is because subjects will be eating more, and the new kidney will break down insulin better than the injured one. If even this new kidney fails, dialysis treatment can be started and subjects can wait for another new kidney.

Currently, the survival of kidneys transplanted into patients with diabetes is about the same as survival of transplants in people without diabetes. Dialysis for people with diabetes also works well in the short run. Even so, people with diabetes who receive transplants or dialysis experience higher morbidity and mortality because of coexisting complications of the diabetes, such as damage to the heart, eyes, and nerves.

Discovery of better anti-rejection drugs will improve results of kidney transplantation in patients with diabetes who develop kidney failure. For some people with type 1 diabetes, advances in transplantation, especially transplantation of insulin-producing cells of the pancreas, could lead to a cure for both diabetes and the kidney disease of diabetes.