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Urinary tract infection - adults

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Definition

A urinary tract infection, or UTI, is an infection of the urinary tract. The infection can occur at different points in the urinary tract, including:

  • Bladder -- An infection in the bladder is also called cystitis or a bladder infection.
  • Kidneys -- An infection of one or both kidneys is called pyelonephritis or a kidney infection.
  • Ureters -- The tubes that take urine from each kidney to the bladder are rarely the only site of infection.
  • Urethra -- An infection of the tube that empties urine from the bladder to the outside is called urethritis.

Alternative Names

Bladder infection - adults; UTI - adults; Cystitis - bacterial - adults; Pyelonephritis - adults; Kidney infection - adults

Causes

Most UTIs are caused by bacteria that enter the urethra and then the bladder. The infection most commonly develops in the bladder, but can spread to the kidneys. Most of the time, your body can get rid of these bacteria. However, certain conditions increase the risk of having UTIs.

Women tend to get them more often because their urethra is shorter and closer to the anus than in men. Because of this, women are more likely to get an infection after sexual activity or when using a diaphragm for birth control. Menopause also increases the risk of a UTI.

Video: Urinary tract infection - adults

The following also increase your chances of developing a UTI:

Test Your Bladder Health Knowledge

The bladder's job is to hold urine.

The correct answer is true. The kidneys produce urine, which travels to the bladder through narrow tubes called the ureters. The bladder is located in the center of the lowest part of your abdomen. It holds your urine until you urinate. Most people make about one to two quarts of urine every day.

A healthy bladder can hold how much urine at a time?

The correct answer is more than two cups. You first feel the urge to urinate when your bladder is about half full, but your bladder continues to stretch until it's full. Don't wait too long to urinate after you feel the urge.

Men are more likely to have bladder infections than women.

The correct answer is false. Women are more likely to have bladder infections. This is because women have a shorter urethra (the tube where urine leaves the body,) and it's closer to the anus. Women are more likely to get an infection after sex or during and after menopause.

A fever is the most common sign of a bladder infection.

The correct answer is false. People with a bladder infection do not have a fever. More common symptoms include cloudy or bloody urine, pain or burning when you urinate, pressure or cramps in the lower stomach or back, or feeling like you need to urinate often. Call your doctor if you think you have a bladder infection.

An untreated bladder infection can spread to the kidneys.

The correct answer is true. The symptoms of a kidney infection include a high fever, chills, back pain, and a general sick feeling. If you have any signs of a kidney infection, call your doctor right away. A kidney infection can damage the kidneys if it's not treated.

Men with a bladder infection may have another health problem.

The correct answer is true. A bladder infection in a man could be a sign that he has a problem with his urinary system or another health condition. Your doctor may refer you to a urologist for more testing.

Only people over age 60 have urinary incontinence.

The correct answer is false. Urinary incontinence occurs if you leak urine or have trouble holding your urine. It is most common in older people, but men and women of any age can have it. If you have trouble with leaking urine or not getting to the bathroom on time, see your doctor. There are many treatments that can help.

Smoking increases your risk of bladder cancer.

The correct answer is true. Smoking can increase your risk of bladder cancer by two to three times. The most common symptom of bladder cancer is blood in the urine. See your doctor if you have blood in your urine, even if it goes away after a few days.

Interstitial cystitis (IC) is the same thing as cystitis.

The correct answer is false. Cystitis is another name for a bladder infection. IC is a painful condition caused by irritation of the bladder not due to an infection. Doctors don't know the cause, but it can feel like a bladder infection. Tell your doctor if you have symptoms of a bladder infection that don't get better with treatment.

Women are more likely to have IC than men.

The correct answer is true. Women are 10 times more likely to have IC than men. It's most common in women ages 30 to 40, but younger women can have it too. See your doctor if you have pelvic pain, pain while urinating, or pain during intercourse.

Symptoms

The symptoms of a bladder infection include:

  • Cloudy or bloody urine, which may have a foul or strong odor
  • Low fever in some people
  • Pain or burning with urination
  • Pressure or cramping in the lower abdomen or back
  • Strong need to urinate often, even right after the bladder has been emptied

If the infection spreads to your kidneys, symptoms may include:

  • Chills and shaking or night sweats
  • Fatigue and a general ill feeling
  • Fever above 101°F (38.3°C)
  • Pain in the side, back, or groin
  • Flushed, warm, or reddened skin
  • Mental changes or confusion (in older people, these symptoms often are the only signs of a UTI)
  • Nausea and vomiting
  • Very bad abdominal pain (sometimes)

Exams and Tests

Most of the time you will need to provide a urine sample for the following tests:

  • Urinalysis: This test is done to look for white blood cells, red blood cells, bacteria, and to test chemicals such as nitrites in the urine. This test can diagnose an infection most of the time.
  • Clean-catch urine culture: This test may be done to identify the bacteria and determine the best antibiotic for treatment.

Blood tests such as complete blood count (CBC) and a blood culture may be done as well.

You may also need the following tests to help rule out other problems in your urinary system:

Treatment

Your health care provider must first decide if the infection is just in the bladder, or if it has spread to the kidneys and how severe it is.

MILD BLADDER AND KIDNEY INFECTIONS

  • Most of the time you will need to take an antibiotic to prevent the infection from spreading to the kidneys.
  • For a simple bladder infection, you will take antibiotics for 3 days (women) or 7 to 14 days (men).
  • If you are pregnant or have diabetes, or have a mild kidney infection, you will most often take antibiotics for 7 to 14 days.
  • Finish all of the antibiotics, even if you feel better. If you do not finish the whole dose of medicine, the infection may return and be harder to treat later.
  • Always drink plenty of water when you have a bladder or kidney infection.
  • Tell your provider if you might be pregnant before taking these drugs.

RECURRENT BLADDER INFECTIONS

Some women have repeated bladder infections. Your provider may suggest that you:

  • Take a single dose of an antibiotic after sexual contact to prevent an infection.
  • Have a 3-day course of antibiotics at home to use if you develop an infection.
  • Take a single, daily dose of an antibiotic to prevent infections.

MORE SEVERE KIDNEY INFECTIONS

You may need to go into the hospital if you are very sick and cannot take medicines by mouth or drink enough fluids. You may also be admitted to the hospital if you:

  • Are an older adult
  • Have kidney stones or changes in the anatomy of your urinary tract
  • Have recently had urinary tract surgery
  • Have cancer, diabetes, multiple sclerosis, spinal cord injury, or other medical problems
  • Are pregnant and have a fever or are otherwise ill

At the hospital, you will receive fluids and antibiotics through a vein.

Some people have UTIs that do not go away with treatment or keep coming back. These are called chronic UTIs. If you have a chronic UTI, you may need stronger antibiotics or to take medicine for a longer time.

You may need surgery if the infection is caused by a problem with the structure of the urinary tract.

Outlook (Prognosis)

Most UTIs can be cured. Bladder infection symptoms most often go away within 24 to 48 hours after treatment begins. If you have a kidney infection, it may take 1 week or longer for symptoms to go away.

Possible Complications

Complications may include:

  • Life-threatening blood infection (sepsis). The risk is greater among the young, very old adults, and those whose bodies cannot fight infections (for example, due to HIV or cancer chemotherapy).
  • Kidney damage or scarring.
  • Kidney infection.

When to Contact a Medical Professional

Contact your provider if you have symptoms of a UTI. Call right away if you have signs of a possible kidney infection, such as:

  • Back or side pain
  • Chills
  • Fever
  • Vomiting

Also call if UTI symptoms come back shortly after you have been treated with antibiotics.

Prevention

Diet and lifestyle changes may help prevent some UTIs. After menopause, a woman may use estrogen cream around the vagina to reduce infections.

Prevention of cystitis

Prevention of cystitis

Images

Bladder catheterization, female
Bladder catheterization, male
Female urinary tract
Male urinary tract
Prevention of cystitis

References

Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011;52(5):e103-e120. PMID: 21292654 www.ncbi.nlm.nih.gov/pubmed/21292654.

Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(5):625-63. PMID: 20175247 www.ncbi.nlm.nih.gov/pubmed/20175247.

Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2012;10:CD001321. PMID: 23076891 www.ncbi.nlm.nih.gov/pubmed/23076891.

Little P, Moore MV, Turner S, et al. Effectiveness of five different approaches in management of urinary tract infection: randomised controlled trial. BMJ. 2010;340:c199. PMID: 20139214 www.ncbi.nlm.nih.gov/pubmed/20139214.

Nicolle LE. Urinary tract infection in adults. In: Taal MW, Chertow GM, Marsden PA, et al, eds. Brenner and Rector's The Kidney. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 36.

Sobel JD, Kaye D. Urinary tract infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 74.

Review Date: 
9/26/2015
Reviewed By: 
Daniel N. Sacks MD, FACOG, obstetrics & gynecology in private practice, West Palm Beach, FL. Review Provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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