Urinary System

WHAT CAN GO WRONG WITH THE URINARY SYSTEMMost urinary system problems are associated with age. As individuals grow older, the functioning of their kidneys declines. An average seventy-five-year-old person has half the original number of nephrons in their kidneys. Because of this, the kidneys lose some of their ability to concentrate urine. The urinary bladder also shrinks with age, leading to a need to urinate more frequently. In some older people, the ability to control urination is lost, a condition known as urinary incontinence (see discussion below). KIDNEY DIALYSISDialysis is a process by which small molecules in a solution are separated from large molecules. The process has come to play a crucial role in the health of humans. For some people, the term dialysis refers to a specific kind of medical treatment in which a machine (the dialysis machine) takes on the functions of a human kidney. Dialysis machines have made possible the survival of thousands of people who would otherwise have died as a result of kidney failure.

The kidney dialysis machine was invented by Dutch-American surgeon Willem Johan Kolff in 1945. Since that time, many improvements have been made to the machine and to the procedure of removing wastes from the blood of people whose kidneys have ceased to function.

The most common dialysis treatment prescribed in the United States is known as hemodialysis (he-moe-die-AL-i-sis). In short, during this procedure, two needles atached to tubes are inserted into veins in an individual's arm. Blood is drawn out of the person's body through one tube and pumped through the dialysis machine.

Inside the machine, the blood is circulated on one side of a semipermeable membrane. This means that the membrane allows the passage of certain sized molecules (such as waste products) across it, but prevents the passage of other, larger molecules (such as blood cells). A special dialysis fluid containing mineral ions and other substances necessary to the body circulates on the other side of the membrane.

As blood circulates in the machine, wastes and other unneeded substances in the blood are drawn out through the membrane. At the same time, the mineral ions and other chemicals in the dialysis fluid cross the membrane into the blood. The "cleansed" and chemically-balanced blood is then returned to the person's body through the second tube.

Most hemodialysis patients require treatment two to three times a week, and each treatment can last several hours.

Disorders and diseases of the urinary system do not affect only the elderly, however. The systems in children and adults through late middle age can also be affected, mainly by bacterial infections that cause inflammation. If not treated properly, many of these infections can lead to serious, even life-threatening, conditions.

Infections and diseases that strike elsewhere in the body can eventually impair the functioning of the kidneys. Acute (short-term) kidney failure appears most frequently as a complication of a serious illness such as heart failure, liver failure, dehydration, severe burns, and excessive bleeding. Acute kidney failure is a temporary condition that can be reversed with proper and timely treatment. Chronic kidney failure, which is long-term and irreversible, can be triggered by diabetes, hypertension, glomerulonephritis (see below), and sickle cell anemia, among other conditions. Without proper treatment to remove wastes from the bloodstream, chronic kidney failure is fatal.

The following are just a few of the many diseases and disorders that can affect the urinary system or its parts.

Bladder cancerBladder cancer develops when cells lining the urinary bladder become abnormal and grow uncontrollably, forming tumors. It is the fifth most common cancer in the United States. The disease is three times more common in men than woman. Most cases of bladder cancer are found in people who are fifty to seventy years old.

The exact cause of bladder cancer is unknown. However, smokers are twice as likely as nonsmokers to get the disease. Workers who are exposed to certain chemicals in the dye, rubber, leather, textile, and paint industries are also believed to be at a higher risk for developing bladder cancer.

One of the first warning signs of bladder cancer is blood in the urine. Painful urination, increased frequency of urination, and a feeling of having to urinate but not being able to are additional signs of bladder cancer.

URINARY SYSTEM DISORDERSCystitis (sis-TIE-tis): Inflammation of the urinary bladder caused by a bacterial infection.

Glomerulonephritis (glah-mer-u-lo-ne-FRY-tis): Inflammation of the glomeruli in the renal corpuscles of the kidneys.

Kidney stones: Large accumulations of calcium salt crystals from urine that may form in the kidneys.

Pyelonephritis (pie-e-low-ne-FRY-tis): Inflammation of the kidneys caused by a bacterial infection.

Urethritis (yer-i-THRY-tis): Inflammation of the urethra caused by a bacterial infection.

Urinary incontinence (YER-i-nair-ee in-KON-tinence): Involuntary and unintentional passage or urine.

If bladder cancer is diagnosed, the three standard methods of treatment are surgery, radiation therapy, and chemotherapy. During surgery, surgeons may remove the tumor, part of the bladder containing the tumor, or the entire bladder and adjoining organs (the prostate gland in men; the uterus, ovaries, and fallopian tubes in women). Radiation therapy (using X rays or other high-energy rays to kill any remaining cancer cells and shrink any tumors) is generally used after surgery. Chemotherapy (using a combination of drugs to kill any remaining cancer cells and shrink any tumors) may also be given after surgery.

When detected early and treated appropriately, bladder cancer can be cured. In those people who have sought early treatment, at least 94 percent survive five years or more. However, when the disease has spread to nearby tissues, the survival rate drops below 50 percent.

GlomerulonephritisGlomerulonephritis is the inflammation of the glomeruli in the renal corpuscles. It is generally caused by a bacterial infection elsewhere in the body, mostly in the throat or skin. In children, it is mostly associated with an upper respiratory infection, tonsillitis, or scarlet fever.

During a bacterial infection, the body produces antibodies or substances that help protect the body against foreign invaders. Glomerulonephritis develops when antibodies and the bacteria they attach to accumulate in the glomeruli, producing inflammation. If left untreated, the glomeruli are soon replaced by fibrous tissue and waste products cannot be effectively filtered from the blood. The kidneys become enlarged, fatty, and congested.

Bladder cancer cells. Bladder cancer develops when cells lining the urinary bladder become abnormal and grow uncontrollably, forming tumors. (Photograph by Nancy Kedersha . Reproduced by permission of Photo Researchers, Inc. )

Symptoms of severe cases of glomerulonephritis include fatigue, nausea, vomiting, shortness of breath, high blood pressure, blood in the urine, and swelling in the face, hands, feet, and ankles.

Treatment for glomerulonephritis includes bed rest to maintain adequate blood flow to the kidneys and antibiotics to rid the body of the infection. If too much fluid has accumulated in the body, diuretics may be given to increase urine output. Sodium and protein intake may also be decreased to help rest the kidneys. Symptoms of glomerulonephritis usually disappear in two weeks to several months. Ninety percent of children recover without complications. Adults often recover more slowly.

Kidney cancerKidney cancer develops when cells in certain tissues in the kidneys become abnormal and grow uncontrollably, forming tumors. Kidney cancer accounts for 3 percent of cancer cases in the United States. The disease occurs most often in men over the age of forty. Men are twice as likely as women to suffer from this type of cancer.

The exact causes of kidney cancer are unknown. However, there is a strong connection between cigarette smoking and kidney cancer; smokers are twice as likely as nonsmokers to get the disease. Obesity may be another risk for kidney cancer.

The most common symptom of kidney cancer is blood in the urine. Other symptoms include painful urination, pain in the lower back or sides, abdominal pain, a lump or hard mass that can be felt in the kidney area, unexplained weight loss, fever, weakness, and high blood pressure.

The primary treatment for kidney cancer that has not spread to other parts of the body is surgical removal of the diseased kidney. Because most cancers affect only one kidney, an individual can function well on the one remaining. Radiation therapy (using X rays or other high-energy rays to kill cancer cells and shrink any tumors) may be used when the cancer is inoperable, but it is has not proven to be of much use in destroying kidney cancer cells. Chemotherapy (using a combination of drugs to kill any cancer cells and shrink any tumors) has also not produced good results.

Because kidney cancer is often caught early and sometimes progresses slowly, the chances of a surgical cure are good.

Kidney stonesKidney stones are solid accumulations or material that form in the tubal system of the kidneys. Kidney stones cause problems when they block the flow of urine through or out of the kidneys. When the stones move along the ureter, they cause severe pain.

Kidney stones are most common among white males over the age of thirty. The stones can be composed of a variety of substances, but the majority (about 80 percent) are formed from calcium salts that have separated from the urine to form crystals that combine to form larger stones. Some may grow as big as golf balls.

Increased blood levels of calcium caused by a diet heavy in meat, fish, and poultry can lead to the formation of kidney stones. Certain diseases-hyperthyroidism and some types of cancer-can also increased blood calcium levels.

A patient undergoes lithotripsy, a treatment for eliminating kidney stones. In this process, physicians use a machine called a lithotriptor to generate sound waves through the body and shatter the stones. (Reproduced by permission of Photo Researchers, Inc. )

Individuals who have kidneys stones usually do not have symptoms until the stones pass into the ureter. Prior to this, some people may notice blood in their urine. Once the stone is in the ureter, however, most people will experience severe bouts of crampy pain that usually begins in the area between the lower ribs and the hip bone. Nausea, vomiting, and extremely frequent and painful urination may then occur.

Although most kidney stones will pass out of the body on their own, some will not. If a stone is too large to pass or is causing a serious obstruction, surgical removal of the stone may be necessary. In the past, open surgery to remove the stone was common. Now, however, physicians may use a machine to aim shock waves at the stone, either from outside or inside the body. The shock waves often crush the stone into smaller fragments, which may then pass on their own or may be removed surgically. In most cases, individuals with uncomplicated kidney stones will recover very well.

Urinary incontinenceUrinary incontinence is the involuntary and unintentional passage of urine. Approximately 13 million Americans suffer from this disorder. Women are affected more frequently than men; approximately one out of every ten women under the age of sixty-five are affected. Older people, too, are more prone to the condition. Twenty percent of Americans over the age of sixty-five are incontinent.

The inability to control urination can be caused by a wide variety of physical conditions. Any blockage at the bladder outlet that permits only small amounts of urine to pass; irritation of the bladder due to an infection; undue pressure placed on the bladder (such as in obese individuals); and the loss of muscle tone in the pelvic muscles, the bladder, or the urethral sphincter muscles-these are all just a few of the many causes of urinary incontinence.

Left untreated, incontinence can cause physical and emotional harm. Those people with long-term incontinence suffer from urinary tract infections and skin rashes. Incontinence can also affect their self-esteem, causing depression and so cial withdrawal.

There are numerous treatment options for urinary incontinence, depending on the cause. The condition may not be stopped, but it can at least be improved. If weakened pelvic muscles are to blame, exercises to tone them can be performed. In certain people, especially older women, medications may help tighten pelvic muscle tone or the urethral sphincters. A balloonlike device may be inserted into a woman's urethra and inflated to prevent urine leakage. Surgery to raise and support the bladder neck and urethra may also be undertaken.

Urinary tract infectionsUrinary tract infections (UTIs) are inflammations of the urinary tract caused by a bacterial infection. UTIs have specific names, depending on the location of the inflammation. Inflammation of the urethra is known as urethritis. Inflammation of the urinary bladder is known as cystitis. When the bacterial infection spreads to the kidneys, the condition is known as pyelonephritis.

UTIs are much more common in women than in men, probably due to anatomy. In women, bacteria from fecal matter and vaginal discharges can enter the urethra because its opening is very close to the vaginal opening and the anus. Once an infection occurs in the urethra of a woman, the relative shortness of the urethra makes it easy for bacteria to gain entry to the bladder and multiply. In men who are not circumcised, the foreskin can harbor bacteria that can enter the urethra and cause UTIs. UTIs can also be sexually transmitted.

Sometimes, a UTI has no symptoms. When symptoms appear, they include pain or a burning sensation when urinating, frequent urination, or blood in the urine. In pyelonephritis, additional symptoms include fever and chills, aching pain on one or both sides of the lower back or abdomen, fatigue, nausea, vomiting, and diarrhea. If left untreated, pyelonephritis can last for months or years. Scarring of the kidneys and the possible loss of kidney function may result.

Typical treatment for all three types of UTIs is a course of antibiotics. An individual suffering from pyelonephritis may also require hospitalization if the disorder is severe. Given the appropriate antibiotic, UTIs usually go away quickly. Drinking plenty of fluids at the first sign of a UTI may help ward it off by diluting the bacteria present and flushing the urinary system. Drinking unsweetened cranberry juice may also help. The juice seems to contain a compound that can prevent bacteria from sticking to and thus growing in the urinary tract.