What is a Urinary Tract Infection (UTI) in Adults?

A UTI is when bacteria gets into your urine and travels up to your bladder. UTIs cause more than 8.1 million visits to health care providers each year. About 10 in 25 women and 3 in 25 men will have symptoms of at least 1 UTI during their lifetime.

How Does the Urinary Tract Work?

Female Urinary Tract
Female Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

Male Urinary Tract
Male Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

The urinary tract makes and stores urine, one of the waste products of your body. Urine is made in the kidneys and travels down the ureters to the bladder. The bladder stores the urine until it is emptied through the urethra, a tube that connects the bladder to the skin, when you urinate. The opening of the urethra is at the end of the penis in a male and in front of the vagina in a female.

The kidneys are a pair of fist-sized organs in the back that filter liquid waste from the blood and remove it from the body in the form of urine. Kidneys balance the levels of many chemicals in the body (sodium, potassium, calcium, phosphorous and others) and check the blood's acidity. Certain hormones are also made in the kidneys. These hormones help control blood pressure, boost red blood cell production and help make strong bones. 

Normal urine has no bacteria in it, and the one-way flow helps prevent infections. Still, bacteria may get into the urine from the urethra and travel up into the bladder.



What are the Signs of a UTI?

When you have a UTI, the lining of the bladder and urethra become red and irritated just as your throat does when you have a cold. The irritation can cause pain in your belly and pelvic area and may make you feel like urinating more often. You may even try to urinate but only get a few drops and/or feel some burning as your urine comes out. At times, you may lose control and wet yourself. You may also find that your urine smells bad or is cloudy.

Kidney infections often cause fevers and back pain. These infections need to be treated at once because a kidney infection can quickly spread into the bloodstream and cause a life-threatening health issue.



What Causes a UTI?

Large numbers of bacteria live in the rectal area and also on your skin. Bacteria may get into the urine from the urethra and travel into the bladder. They may even travel up to the kidney. But no matter how far they go, bacteria in the urinary tract can cause problems.

Just as some people are more prone to colds, some people are more prone to UTIs. Men are less likely to get a UTI.

Some factors that can add to your chances of getting a UTI are:

Body Factors

Women who have gone through menopause have a change in the lining of the vagina and lose the protection of estrogen that lowers the chance of getting a UTI. Some women are genetically predisposed to UTIs and have urinary tracts that make it easier for bacteria to cling to them. Sexual intercourse can also affect how often you get UTIs.

Birth Control

Women who use diaphragms have also been found to have a higher risk when compared to those who use other forms of birth control. Using condoms with spermicidal foam is also known to be linked to greater risk of getting UTIs in women. Women are more prone to UTIs because they have shorter urethras than men, so bacteria have a shorter distance to travel to reach the bladder.

Abnormal Anatomy

You are more likely to get a UTI if your urinary tract has an abnormality or has recently had a device (such as a tube to drain fluid from the body) placed in it. If you are not able to urinate normally because of some type of block, you will also have a higher chance of a UTI.

Anatomical abnormalities in the urinary tract may also lead to UTIs. These abnormalities are often found in children at an early age but can still be found in adults. There may be structural abnormalities, such as outpouchings called diverticula, that harbor bacteria in the bladder or urethra or even blockages, such as an enlarged bladder, that keep the body from draining all the urine from the bladder.

Immune System

Issues such as diabetes (high blood sugar) also put people at higher risk for UTIs because the body is not able to fight off germs as well.

Can UTIs be Prevented?

There are steps women can take to avoid UTIs:

  • Urinating after sex may lower the risk of UTI by flushing out bacteria that may have gotten into the urinary tract during intercourse.
  • Certain forms of birth control, such as spermicidal foam and diaphragms, are known to increase the risk of UTIs in women. Check with your health care provider about other types of birth control.
  • Drink plenty of fluids to keep well hydrated.
  • Don't put off urinating when you need to and don't rush to finish. Holding in urine and not draining your bladder fully can increase your risk of UTIs.
  • Wipe from front to back to keep bacteria around the anus from getting into the vagina or urethra.


How are UTIs Diagnosed?

If you are worried about a UTI, then you should talk with your health care provider. UTIs can be found by analyzing a urine sample. The urine is examined under a microscope for bacteria or white blood cells, which are signs of infection. Your health care provider may also take a urine culture.

If you ever see blood in your urine, you should call your health care provider right away. Blood in the urine may be caused by a UTI but it may also be from another problem in the urinary tract.

If you are having fevers and symptoms of a UTI, or symptoms that won't go away despite therapy, then you should call a health care provider. You may need further tests, such as an ultrasound or CT scan, to check the urinary tract.



How are UTIs Treated?

There are two types of UTIs: simple and complicated. Simple UTIs are infections that happen in healthy people with normal urinary tracts.

Complicated UTIs happen in abnormal urinary tracts or when the bacteria causing the infection cannot be treated by many antibiotics. Most women have simple UTIs, while the UTIs in men and children should be thought of as complicated.

Simple UTI

A simple UTI can be treated with a short course of antibiotic meds. A 3-day course of antibiotics will often treat most uncomplicated UTIs. However, some infections may need to be treated for 5 days. Depending on the type of antibiotic used, you may take a single dose per day or up to 4 doses per day. Pain and the urge to urinate often go away after a few doses, but you should still take the full course of the meds even if you feel better. Unless UTIs are fully treated, they can often return. You should also drink plenty of liquids, especially around the time of a UTI.

Postmenopausal women with UTIs may be helped by topical (vaginal) hormone replacement (estrogen). Since some patients cannot take estrogen replacement, you should talk with your health care provider before starting any treatment.

Complicated UTI

If the UTI is a complicated UTI, then a longer course of antibiotics is given and is often started intravenously (IV) in the hospital. After a short period of IV antibiotics, the antibiotics are given by mouth for up to many weeks. Kidney infections are often treated as a complicated UTI.



After Treatment

Simple UTIs often improve with 3 days of antibiotics and you do not need a urine culture to prove that it is gone. If you have a complicated UTI, you should have a urine culture to show that the UTI is gone. If your symptoms don't go away even with meds, then you may need a longer course of meds, a different drug or different way of taking it.

About 1 in 5 young women who have a UTI will have another. Men are less likely to get a UTI in the first place. But if they get one, they are likely to have another because the bacteria tend to hide inside the prostate.

If you get UTIs often (3 or more per year), then you should see your health care provider. Your health care provider might want to do more tests (such as checking if the bladder empties) to find out why. You may also need an ultrasound or CT scan, which allow your health care provider to look for any abnormalities of the urinary tract. If you keep getting UTIs, a longer course of low-dose antibiotics or taking an antibiotic after sex may help. There are also methods of self-testing that your health care provider may arrange that let you diagnosis and treat your UTIs at home.



More Information

Frequently Asked Questions

Why do I get UTIs?

Most UTIs are single events that, if treated, will not come back. Some patients have anatomical and genetic predispositions that tend to make getting UTIs more likely.

When should I be worried?

If you are being treated for a UTI and are not getting better, or you have symptoms of a UTI along with upset stomach and throwing up, then you should call your health care provider. If you ever see blood in your urine, you should call your health care provider right away.

Will a UTI cause damage to the kidneys?

If the UTI is treated early, then there will likely be no lasting effect on your urinary tract. UTIs can cause harm if not found and treated quickly.

What if I am pregnant?

If you are pregnant and have symptoms of a UTI, then you should call your health care provider right away. UTIs during pregnancy can put both mother and baby at risk if not dealt with quickly and properly.