URINARY TRACT INFECTIONS - A REVIEW

The urinary tract makes and stores urine, one of the body's liquid waste products. The kidneys produce 1.5 to 2 quarts of urine every day by removing waste and water from the blood. The urine travels from the kidneys down two narrow tubes, the ureters. It is then stored in a balloon-like container called the bladder.

In an adult, the bladder can hold 10 to 20 ounces of urine (about as much liquid as in one can of soft drink). When the bladder is about half full, the need to empty it by urinating maybe felt. Urine is carried out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the vagina in women.

Normal urine contains no bacteria, but bacteria do cover the skin and are present in large numbers in the rectal area and in bowel movements. Bacteria may, at times, get into the urinary tract (and the urine) and may travel up the urethra into the bladder. When this happens, the bacteria cause infection and inflammation of the bladder by multiplying, so that they cause irritation, swelling, and pain. Bladder infection, also called cystitis, is the most common urinary tract infection.

If the bacteria travel upward from the bladder through the ureters and reach the kidneys, a kidney infection may develop, also known as pyelonephritis. Kidney infections are much less common, but often more serious, than bladder infections.

Prevalence

Every year, between eight and ten million visits to doctors occur because of urinary tract infections.

Women are usually more prone to urinary tract infections than men or children. One to two per cent of children develop urinary tract infections. The risk of kidney damage due to urinary tract infections is greatest among young children.

Causes

Some people, mainly women, develop urinary tract infections because they are prone to such infections, the way other people are prone to getting coughs or colds. Urinary tract infections are much less common in men and children than in adult women. A number of factors may increase a person's risk of getting a urinary tract infection. Some of these factors include:

• having certain diseases (such as diabetes) or an abnormal urinary system
• recently having had a medical instrument inserted into the urethra
• sexual contact

A urinary tract infection in a man or child may be the sign of an abnormal urinary tract. For this reason, when men or children are found to have a urinary tract infection, they may be referred to a urologist (a specialist in diseases of the urinary system and the male reproductive system) for additional tests and x-rays.

Symptoms

A urinary tract infection irritates the lining of the bladder and urethra (akin to the irritation caused to the inside of the nose or throat by a cold). This irritation can cause pain in the abdomen and pelvic area, and may result in a constant urge to empty the bladder.

However, an attempt to urinate may produce only a few drops of urine. In addition, there may be a burning sensation as the urine comes out. It may even be hard to control, and some urine may leak onto the clothing. The urine may have an unpleasant odour or a cloudy look. At times, bladder infections may also cause low back pain, fever, or chills.

Kidney infections produce fever and back pain much more commonly than do bladder infections. If a kidney infection is not treated promptly, the bacteria may spread to the bloodstream and cause a life-threatening infection.

In an infant or young child, the signs of a urinary tract infection may not be clear, especially if the child is too young to tell just how he or she feels. Instead, the child may be irritable, not eat as much as usual, have a fever or loose bowel movements, or just not seem healthy. If the symptoms last more than a day, they may signal the need to see a doctor.

Diagnosis

If a urinary tract infection is suspected, then consult a doctor, especially if blood is present in the urine. Because bloody urine is not normally caused by an infection, it may mean that there is a different urinary tract problem.

The doctor will examine urine samples under a microscope. If an infection is present, the physician may also perform a urine culture, a process in which bacteria from infected urine are grown in a laboratory. The germs can then be identified and tested to see which drugs will provide the most effective treatment. It often takes a day or two to complete this testing.

Treatment

Urinary tract infections are treated with antibiotics (infection-fighting drugs), which are generally taken by mouth. However, once the test results are in, the physician may switch to another antibiotic, one that is more effective against the particular bacteria found in the urine.

The length and frequency of dosage depends in part on the type of infection and its severity. The medicine must usually be taken for at least two to three days, and possibly for several weeks. The daily treatment schedule recommended depends on the specific drug prescribed. It may call for a single dose each day, or up to four daily doses.

A few doses of the antibiotic may relieve the need to urinate often, as well as most of the pain from a bladder infection. It may be several days, however, before the bladder infection and its symptoms vanish completely. In any case, it is important to take the medicines as prescribed and not to stop them simply because the symptoms have gone away. Unless urinary tract infections are fully treated, they frequently return. In addition, it is important to drink fluids whenever feeling thirsty - not necessarily large amounts, but enough to ensure that the body has the liquid it needs.

If the urinary tract infection is severe, it may involve the kidneys. In that case, antibiotic drugs may have to be injected. Hospital treatment with medication given intravenously (injected directly into the bloodstream) is sometimes necessary.

Additional tests

Once the infection has cleared, the doctor may recommend additional tests. Their purpose is to ensure that there are no abnormalities in the urinary tract that might result in kidney damage from urinary tract infections. Certain types of patients are most likely to need the tests; these types include:

• young children
• men
• people who have urinary tract infections that are frequent, or that will not respond to treatment
• people who have had fever with the infection
• people who have had blood in the urine

Referral

The symptoms of a urinary tract infection may resemble those of other urinary tract diseases. If no infection can be found or the infection does not respond to treatment, then the doctor may decide upon referral to a urologist to discover the reason. Other problems that the urologist may look for are:

• urethritis, which may be either an inflammation or an infection of the urethra; when infection is present in the urethra, the condition often is due to bacteria passed by sexual contact
• interstitial cystitis, which is a bladder irritation found mainly in adult women; its cause is not known
• urinary stones sometimes develop in the bladder, irritating it and causing symptoms similar to those of a urinary tract infection; sometimes the stones have bacteria inside that trigger hard-to-cure infections
• bladder tumours (cancerous or non-cancerous growths) which, when present, may irritate the bladder; the symptoms often include a frequent need to urinate and possibly blood in the urine
• prostatitis, which is an inflammation or infection of the male gland (the prostate), which surrounds the urethra just below the bladder; in adult males, prostate disorders may cause symptoms that resemble those of urinary tract infections

Long-term effects

Urinary tract infections in most adults can be successfully treated without causing long-term problems.

Young children are most at risk of kidney damage from urinary tract infections. Such damage may lead to poor kidney function, high blood pressure, and other problems. For this reason, it is important that children with urinary tract infections receive prompt treatment and careful check-ups.

Pregnant women with a history of repeated urinary tract infections should have their urine tested often. Urinary tract infections during pregnancy can cause serious kidney infections in the mother, and possible risks for the baby.

Self-help

The following are steps that can be taken to reduce the risk of getting a urinary tract infection:

• urinate when the urge is felt
• take time when urinating to empty the bladder completely
• respond to the body's signals of thirst by drinking enough water or other liquids every day
• urinate after having sex (using condoms during intercourse is wise for many reasons)

Consult a doctor at the first sign of a problem. Urinary tract infections are very common, and they are easiest to treat if caught before they become severe, or spread beyond the bladder.