Urinary Tract Infections: Symptoms, Causes, Diagnosis, and Treatment

Bacterial infections of the urinary tract (UTI) are not always simple and easy to treat. In some cases, they may recur, be associated with an abnormal structure or function of the urinary tract and can cause permanent injury to the kidneys.

Key takeaways:
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    Predisposition for UTI can result from poor genital hygiene, chronic incomplete bladder emptying, infrequent urination, kidney stones, and anatomical abnormalities of the urinary tract.
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    Females are at particular risk for UTI, largely because of the short distance between the urethral opening and the anus.
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    The frequency of UTIs increases in sexually active women, during pregnancy, and after menopause.
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    Prevention of UTI includes increasing your daily fluid intake, more frequent voiding, other healthy behavioral changes of voiding habits, and, possibly, the use of cranberry products.
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    Additional preventive measures may include long-term, low dose antibiotics and topical estrogen products in postmenopausal women.

Urinary tract infections (UTI) are common in females. Overall, 40% to 60% of women will experience at least one UTI in her lifetime. These occur more frequently in sexually active women, during pregnancy, and in the elderly. Although estimates vary, men are at least five to ten times less likely to develop a UTI, the majority of which occur after age 50.

Types of UTIs

UTIs are often referred to as bladder infections when, in fact, they may occur in any location within the urinary system: the urethra, bladder, ureter, and the kidneys. The medical term for infections of the kidneys is pyelonephritis. These are generally more serious than other types and often require more aggressive therapy. Although the vast majority of infections are bacterial, fungal, and viral causes may also occur.

UTI causes and risk factors

  1. Many conditions can predispose you to UTIs, including gender-specific risks, inadequate emptying of the bladder, and infrequent urination.
  2. When your bladder does not empty completely for any reason, bacteria that are normally “flushed out” in the urine will have the opportunity to multiply and cause an infection. Infrequent urination does the same. Several of the more important reasons for incomplete or abnormal bladder emptying are:
    1. Holding the urine long after you feel the urge to go.
    2. Overactive bladder and dysfunctional voiding that cause incomplete bladder emptying due to abnormal bladder muscle activity and coordination. These conditions are most common in children and recurring UTIs often occur. Symptoms often include a sudden, urgent need to go to the bathroom, unavoidable urination often with daytime wetting, squirming, pressing on the urethra, and constipation.
    3. A poor fluid intake that requires less frequent visits to the bathroom.
    4. Partial blockage of urine passing through the urinary system and exiting the bladder. Kidney stones can impair urine flow. Poor bladder emptying is common in middle-aged to older men with enlarging prostate glands that press on the urethra, making it difficult to completely empty.
    5. Any structural abnormality of your urinary system that interferes with normal bladder emptying.
  3. There also is a predisposition to UTI in individuals with vesicoureteral reflux. This is a condition where contraction of the bladder not only pushes urine out but also back into the upper urinary system.
  4. UTI in females. Several factors that contribute to the greater vulnerability of women to UTI are:
    1. The short distance between the urethra and the anus makes it easier for bacterial spread into the urethra. Moreover, once the bacteria reach the urethra, it is only a short distance to travel into the bladder.
    2. Almost all types of sexual activity involving the female genitals can also introduce bacteria into the urethra.
    3. As the uterus enlarges during pregnancy, it may press on the bladder and interfere with complete emptying.
    4. Menopause is one of the conditions associated with more frequent UTI. Decreased estrogen after menopause results in changes of the normal vaginal lining and growth of “bad” bacteria that can cause UTI.
    5. Diabetes also is associated with at least a twofold higher risk of UTI.
  5. UTI in males. The lower risk of UTI in men is largely due to the comparatively greater distance that bacteria must travel through the urethra to reach the bladder. Still, UTI may arise from irritation of the urethra from trauma to the penis, excessively vigorous masturbation, or sexually-transmitted infection. A prostate gland infection may also mimic UTI. The prostate gland surrounds the upper part of the urethra just below the bladder. Benign enlargement of the prostate can cause a weak urine stream, discomfort from an overfilled bladder, and frequent trips to the bathroom. This is called benign prostatic hypertrophy (BPH). Your doctor may want to check for other causes of prostate enlargement.

Symptoms of UTI

Symptoms often vary according to the site of infection:

Urethra (urethritis)

Has symptoms similar to a bladder infection. Of importance is that the bacteria and viruses causing urethritis are frequently different from those causing common UTI.

  • A burning sensation when urinating.
  • Painful sexual activity.
  • A discharge from the urethral opening.

Bladder (cystitis)

  • Frequent strong urge to urinate with only small amounts of urine.
  • A burning sensation when urinating.
  • Urine that is cloudy, has red or brownish discoloration, or is foul-smelling.
  • Pain in the pelvis or lower abdomen.

Kidneys (pyelonephritis)

  • High fever and chills.
  • Back or flank pain.
  • Nausea and vomiting.


The diagnosis of a UTI, regardless of origin, is based on urine culture. With pyelonephritis, blood cultures also can be helpful. Initial screening using a urinalysis will often show:

  • A positive reaction to leukocyte esterase on urine dipstick. When negative despite symptoms, a microscopic examination for white blood cells can be done. You also can screen yourself at home using over-the-counter urine dipsticks.
  • A positive nitrite reaction on urine dipstick is very specific for bladder infections but is positive in only about 25% of cases.
  • Microscopic blood or small amounts of protein.
  • The laboratory should be notified when a sexually transmitted urine infection is suspected; the urine culture may require different methods.

Prevention of UTI

Among numerous non-drug measures to prevent UTI, many are common sense remedies. The goal is to prevent the bacteria from establishing a presence in your urinary system.

  • Drink plenty of water with a goal of two-and-a-half to three quarts a day. Your urine should be pale yellow in color.
  • Empty your bladder frequently, around every four hours during the day. Bacteria will also be eliminated. Increased fluid intake will encourage frequent urination. In post-menopausal women the frequency of UTI was decreased by nearly half in those with high water intakes compared to who drank less.
  • Take showers rather than baths. Sudsy bathwater can irritate the urethral opening and surrounding tissue, and bacteria in the bathwater can enter the urethra.
  • Minimize the spread of bacteria from the area around the anus into the urethra by wiping front to back. Do not use the same tissue twice.
  • Empty your bladder after intercourse.
  • Cranberry products also may decrease the risk of UTI. In the lab, substances in cranberries have been shown to weaken the ability of certain bacteria to initiate an infection. However, in humans there have been inconsistent results. Be sure to check the recommended dosage since the recommended doses of cranberry products differ.

Treatment of UTI

For uncomplicated UTI, the first line of treatment for an acute bacterial UTI is an oral antibiotic, generally for around seven to ten days. The selected antibiotic may change based on the type of bacteria found on culture. Women who receive multiple antibiotic treatments for recurrent acute UTI are at risk for developing bacterial antibiotic resistance. Pyelonephritis is a serious condition that merits more intense treatment, including a more prolonged course of antibiotics and even hospitalization for intravenous antibiotics.

Recurrent UTIs are common. Repeated UTIs may prompt additional studies of your urinary system, including radiology tests and a cystoscopy. Continuous low dose antibiotics for recurrent UTIs can reduce the number of infections by more than 80%.

Post-menopausal women with frequent UTIs may also benefit from treatment with estrogen creams applied into the vagina and surrounding areas.

Using the UTI preventive measures already mentioned are of equal importance in those with recurrent UTI.

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