Urinary tract infection (UTI)

Definition

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  Female urinary system
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  Male urinary system

A urinary tract infection (UTI) is an infection in any part of your urinary system — your kidneys, ureters, bladder and urethra. Most infections involve the lower urinary tract — the bladder and the urethra.

Women are at greater risk of developing a UTI than men are. Infection limited to your bladder can be painful and annoying. However, serious consequences can occur if a UTI spreads to your kidneys.

Doctors typically treat urinary tract infections with antibiotics. But you can take steps to reduce your chances of getting a UTI in the first place.

Symptoms

Urinary tract infections don't always cause signs and symptoms, but when they do they may include:

• A strong, persistent urge to urinate
• A burning sensation when urinating
• Passing frequent, small amounts of urine
• Urine that appears cloudy
• Urine that appears red, bright pink or cola-colored — a sign of blood in the urine
• Strong-smelling urine
• Pelvic pain, in women — especially in the center of the pelvis and around the area of the pubic bone

UTIs may be overlooked or mistaken for other conditions in older adults.

Types of urinary tract infection

Each type of UTI may result in more-specific signs and symptoms, depending on which part of your urinary tract is infected.

Part of urinary tract affected	Signs and symptoms
Kidneys (acute pyelonephritis)	Upper back and side (flank) pain High fever Shaking and chills Nausea Vomiting
Bladder (cystitis)	Pelvic pressure Lower abdomen discomfort Frequent, painful urination Blood in urine
Urethra (urethritis)	Burning with urination Discharge

When to see a doctor

Contact your doctor if you have signs and symptoms of a UTI.

Risk factors

Urinary tract infections are common in women, and many women experience more than one infection during their lifetimes. Risk factors specific to women for UTIs include:

• Female anatomy. A woman has a shorter urethra than a man does, which shortens the distance that bacteria must travel to reach the bladder. 
• Sexual activity. Sexually active women tend to have more UTIs than do women who aren't sexually active. Having a new sexual partner also increases your risk.
• Certain types of birth control. Women who use diaphragms for birth control may be at higher risk, as well as women who use spermicidal agents.
• Menopause. After menopause, a decline in circulating estrogen causes changes in the urinary tract that make you more vulnerable to infection.

Other risk factors for UTIs include:

• Urinary tract abnormalities. Babies born with urinary tract abnormalities that don't allow urine to leave the body normally or cause urine to back up in the urethra have an increased risk of UTIs.
• Blockages in the urinary tract. Kidney stones or an enlarged prostate can trap urine in the bladder and increase the risk of UTIs.
• A suppressed immune system. Diabetes and other diseases that impair the immune system — the body's defense against germs — can increase the risk of UTIs.
• Catheter use. People who can't urinate on their own and use a tube (catheter) to urinate have an increased risk of UTIs. This may include people who are hospitalized, people with neurological problems that make it difficult to control their ability to urinate and people who are paralyzed.
• A recent urinary procedure. Urinary surgery or an exam of your urinary tract that involves medical instruments can both increase your risk of developing a urinary tract infection.

Tests and diagnosis

Analyzing a urine sample.Your doctor may ask for a urine sample for lab analysis to look for white blood cells, red blood cells or bacteria. To avoid potential contamination of the sample, you may be instructed to first wipe your genital area with an antiseptic pad and to collect the urine midstream.Tests and procedures used to diagnose urinary tract infections include:
• Growing urinary tract bacteria in a lab. Lab analysis of the urine is sometimes followed by a urine culture. This test tells your doctor what bacteria are causing your infection and which medications will be most effective.
• Creating images of your urinary tract. If you are having frequent infections that your doctor thinks may be caused by an abnormality in your urinary tract, you may have an ultrasound, a computerized tomography (CT) scan or magnetic resonance imaging (MRI). Your doctor may also use a contrast dye to highlight structures in your urinary tract.
• Using a scope to see inside your bladder. If you have recurrent UTIs, your doctor may perform a cystoscopy, using a long, thin tube with a lens (cystoscope) to see inside your urethra and bladder. The cystoscope is inserted in your urethra and passed through to your bladder.

• Simple infection

  Drugs commonly recommended for simple UTIs include:
  • Trimethoprim/sulfamethoxazole (Bactrim, Septra, others)
  • Fosfomycin (Monurol)
  • Nitrofurantoin (Macrodantin, Macrobid)
  • Ciprofloxacin (Cipro)
  • Levofloxacin (Levaquin)
  • Cephalexin (Keflex)
  • Ceftriaxone (Rocephin)
  • Azithromycin (Zithromax, Zmax)
  • Doxycycline (Monodox, Vibramycin, others)
  Often, symptoms clear up within a few days of treatment. But you may need to continue antibiotics for a week or more. Take the entire course of antibiotics as prescribed.
  For an uncomplicated UTI that occurs when you're otherwise healthy, your doctor may recommend a shorter course of treatment, such as taking an antibiotic for one to three days. But whether this short course of treatment is enough to treat your infection depends on your particular symptoms and medical history.
  Your doctor may also prescribe a pain medication (analgesic) that numbs your bladder and urethra to relieve burning while urinating, but pain usually is relieved soon after starting an antibiotic. One common side effect of urinary tract analgesics is discolored urine — orange or red.

  Frequent infections

  If you have frequent UTIs, your doctor may make certain treatment recommendations, such as:
  • Low dose antibiotics, initially for six months but sometimes longer
  • Self-diagnosis and treatment, if you stay in touch with your doctor
  • A single dose of antibiotic after sexual intercourse if your infections are related to sexual activity
  • Vaginal estrogen therapy if you're postmenopausal

  Severe infection

  For a severe UTI, you may need treatment with intravenous antibiotics in a hospital.