Urinary Tract Infection Causes, Types, Symptoms, Risks and FAQs

Urinary Tract Infection

Urinary tract infections (UTIs) are very common – particularly in women, babies and older people. Around one in two women and one in 20 men will get a UTI in their lifetime.

The kidneys control the amount of water in the blood and filter out waste products to form urine. Each kidney has a tube called a ureter, which joins the kidney to the bladder.
The urine leaves the kidneys through the ureters and enters the bladder. The bladder ‘signals’ the urge to urinate and urine leaves the body through a tube called the urethra.
The urinary system is designed to minimize the risk of serious infection in the kidneys. It does this by preventing the urine from flowing back up into the kidneys from the bladder. Most urinary infections are confined to the bladder and, while causing symptoms, are not serious or life-threatening.

Types of urinary tract infections (UTIs)

UTIs are caused by micro-organisms or germs, usually bacteria. The different types of UTI can include:
  • urethritis – infection of the urethra
  • cystitis – infection of the bladder
  • pyelonephritis – infection of the kidneys
  • vaginitis – infection of the vagina.

Symptoms of UTIs

Some of the symptoms of UTIs include:

  • wanting to urinate more often and urgently, if only a few drops
  • burning pain or a ‘scalding’ sensation when urinating
  • a feeling that the bladder is still full after urinating
  • pain above the pubic bone
  • cloudy, bloody or very smelly urine.

Symptoms of kidney infections

If the infection reaches the kidneys, prompt medical attention is needed. In addition to the general symptoms of UTIs, a person with a kidney infection can also experience:

  • chills
  • fever
  • loin (lower abdominal) pain
  • pain in the back
  • vomiting.

Causes of UTIs

When bacteria enter the urinary tract and multiply, they can cause a UTI. To infect the urinary system, a micro-organism usually has to enter through the urethra or, rarely, through the bloodstream. The most common bacterium to cause UTIs is Escherichia coli (E. coli). It is usually spread to the urethra from the anus.

Other micro-organisms, such as mycoplasma and chlamydia, can cause urethritis in both men and women. These micro-organisms are sexually transmitted so when these infections are detected, both partners need medical treatment to avoid re-infection.

Risk factors for developing UTIs

Some people are at greater risk than others of developing UTIs. These include:

  • women – sexually active women are vulnerable, in part because the urethra is only four centimeters long and bacteria have only this short distance to travel from the outside to the inside of the bladder
  • people with urinary catheters – such as people who are critically ill, who can’t empty their own bladder
  • people with diabetes – changes to the immune system make a person with diabetes more vulnerable to infection
  • men with prostate problems – such as an enlarged prostate gland that can cause the bladder to only partially empty
  • babies – especially those born with physical problems (congenital abnormalities) of the urinary system

Urinary infections in children

A urinary infection in a child needs to be investigated as it may indicate a more serious condition.

The most common urinary system condition is urinary reflux. With this condition, the bladder valve isn’t working properly and allows urine to flow back to the kidneys, increasing the risk of a kidney infection.

Urinary reflux and the associated infections can scar or permanently damage the kidney, and can also lead to:

  • high blood pressure
  • toxaemia in pregnancy
  • kidney failure.

Urinary reflux tends to run in families, so it’s important to screen children as early as possible if a close relative is known to have the problem.

Prevention of UTIs

Although not always backed up by clinical research, some women have found some suggestions useful in reducing their risk of developing urinary tract infections, including:

  • Drink plenty of water and other fluids to flush the urinary system.
  • Treat vaginal infections such as thrush or trichomonas quickly.
  • Avoid using spermicide-containing products, particularly with a diaphragm contraceptive device.
  • Go to the toilet as soon as you feel the urge to urinate, rather than holding on.
  • Wipe yourself from front to back (urethra to anus) after going to the toilet.
  • Empty your bladder after sex.
  • Avoid constipation.

Cranberries (usually as cranberry juice) have been used to prevent UTIs. Cranberries contain a substance that can prevent E. coli bacteria from sticking to the urinary tract lining cells. However, recent research has shown that cranberry juice does not have a significant benefit in preventing UTIs, and most people are unable to continue drinking the juice on a long-term basis.

Let your doctor know if you are having cranberry juice as it can alter the effectiveness of some antibiotics.

Seek medical attention for UTIs

It is important to seek medical attention if you think you may have a UTI – particularly if you think you may have a bladder or kidney infection, both of which are very serious conditions. Early treatment of urinary infection can help to prevent infection spreading to the bladder or kidneys.

Your doctor will test your urine to check which micro-organism is present. Urinary tract infections usually respond quickly and well to antibiotics.

Frequently Asked Questions About Urinary Tract Infections (UTIs)

How much urine does the average adult pass each day?

An average adult passes about 6 cups of urine daily. This amount varies depending on how much you eat and drink and how active you are. During the night, your body produces about half the volume of urine that is produced during the day.

What is the most common cause of a urinary tract infection (UTI)?

The most common cause of a urinary tract infection (UTI) is the bacterium Escherichia coli (E. coli</i>), which is typically found in the colon. In women, sexual intercourse can cause these bacteria to be introduced into the urinary tract and lead to a bladder infection (cystitis). Other bacteria including Chlamydia, Mycoplasma, and Gonorrhea, as well as the herpes virus,  can cause infections of the urethra (urethritis).

What is a common UTI risk factor in adults?

Risk factors for UTIs in adults include:

  • Enlarged prostate in men
  • Catheters placed in the urethra and bladder
  • Diabetes
  • Spinal cord injury or another nerve injury around the bladder
  • Sexual intercourse, including anal intercourse
  • Condom use
  • Pregnancy
  • Not drinking enough fluids
  • Kidney or urinary stones

What are the signs and symptoms of a UTI in adults?

Urinary tract infections are infections that involve the bladder (most common) or the kidneys. Symptoms of a bladder infection include:

  • Pain or burning when urinating
  • Frequent urge to urinate
  • Sudden urge to urinate
  • Blood in the urine

Symptoms of a kidney infection are the same as those for a bladder infection, as well as:

  • Fever
  • Back pain
  • Nausea or vomiting

How many people in the U.S. visit the doctor each year to be treated for a UTI?

Each year, about 8.1 million people see a doctor about a urinary tract infection. Women tend to be more prone to UTIs than men, for two reasons: their urethra is shorter, allowing easier access for bacteria to get into the bladder, and a woman’s urethral opening is close to the anus and vagina which are sources of bacteria.

To prevent urinary tract infections, some doctors recommend that people drink which liquid?

Cranberry juice has long been touted as a home remedy of choice to prevent urinary tract infections.

The active ingredient in cranberries, A-type proanthocyanidins (PACs), has been shown to block bacteria from adhering to the wall of the bladder. However, it takes an extremely large concentration of cranberry to accomplish this, a concentration not found in typical juices we drink. Further, any concentration of these PACs is long gone by the time it reaches the bladder. Drinking cranberry juice may help hydrate you, which can help wash bacteria from your body, but water can accomplish the same thing. Drinking cranberry juice won’t hurt, but it probably won’t help either.

On average, what percentage of pregnant women develops UTIs?

About 1.5% of women in the U.S. develop a urinary tract infection during pregnancy.

It is believed hormonal changes combined with the increased weight of a growing uterus blocking urine from passing out of the bladder contributes to a greater incidence of UTIs in pregnancy. UTIs in pregnant women involve the kidneys more often than the bladder.

Which antibiotics are used in the treatment of uncomplicated UTIs?

The treatment of choice for urinary tract infections is antibiotics.

Most courses last three to seven days, though if you have a kidney infection you may need to take antibiotics for up to two weeks. The most commonly used medications for treating UTIs include:

  • trimethoprim/sulfamethoxazole (Bactrim, Septra, Cotrim)
  • nitrofurantoin (Macrodantin, Furadantin)
  • fosfomycin (Monurol)
  • ciprofloxacin (Cipro)
  • levofloxacin (Levaquin)
  • cephalexin (Keflex)
  • trimethoprim (Trimpex)
  • amoxicillin (Amoxil, Trimox, Wymox)
  • ampicillin (Omnipen, Polycillin, Principen, Totacillin)

In some cases, medications to numb the bladder such as phenazopyridine (Pyridium) may be prescribed if the UTI is especially painful.

How can women prevent urinary tract infections?

Women can take steps to prevent urinary tract infections.

  • Urinate when you feel you need to
  • Always wipe from front to back after using the bathroom to prevent spreading bacteria from the anus or vagina into the urethra
  • Do not use douches or feminine hygiene sprays, which can irritate the urethra
  • Take showers rather than sitting in baths
  • Wear cotton underwear and avoid tight-fitting garments
  • Drink more water
  • Empty the bladder after sexual activity
  • Do not use spermicides
  • Use tampons instead of pads during menstrual periods

A pregnant woman who develops a UTI needs prompt treatment. True or False?

True. A pregnant woman who develops a UTI must get prompt treatment to prevent a kidney infection. A kidney infection during pregnancy can cause high blood pressure, early labor, premature delivery, and low birth weight.

What causes UTIs in men?

Urinary stones or an enlarged prostate can obstruct the flow of urine and cause a urinary tract infection in men. Catheters placed in the urethra or bladder can introduce bacteria into the urinary tract and cause a UTI.

Drinking water may provide some relief from UTI pain. True or False?

True. Urinary tract infections can be painful. Some home remedies that may provide pain relief include using a heating pad and drinking plenty of water to help flush the urinary tract and rid it of bacteria.

What percentage of women who have a UTI will have another?

In general, about 20%-30% of women that develop a UTI will develop a second UTI.

Urinary tract infections are more common in women than in men; up to 20% of women will experience at least one UTI in their lifetime. About 20% percent of women will have a second UTI, and up to 30 percent of those women will have a third. Of those women who have a third UTI, about 80% of them will have recurrent UTIs.

What is the urinary system?

The main organs of the urinary system include two kidneys, two ureters, the bladder, and the urethra.

Excess liquid and waste in the blood pass through the kidneys and form urine. Salts and other substances in the Waste and extra fluids in the body are filtered by the kidneys and passed on through tubes called ureters into the bladder. The bladder holds urine until it is full, and then signals are sent to your brain that it is time to urinate, and urine passes out of the body through a tube called the urethra.

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