UTIs are considered to be the most common microbial infections in the USA. The 1997 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, state that UTIs account for nearly 7 million office visits and 1 million emergency department visits, resulting in 100,000 hospitalizations. Despite this, it remains difficult to accurately assess the incidence of UTIs, because they are not reportable diseases in the United States. This situation is further complicated by the fact that accurate diagnosis depends on both the presence of symptoms and a positive urine culture, although in most outpatient settings this diagnosis is made without the benefit of a urine culture.
Women are significantly more likely to experience UTIs than men. Nearly 1 in 3 women will have had at least 1 episode of a UTI requiring antimicrobial therapy by the age of 24 years. 50 60% of all women will experience 1 UTI during their lifetime. Specific subpopulations at increased risk of UTIs include infants, pregnant women, the elderly, patients with spinal cord injuries and/or catheters, patients with diabetes or multiple sclerosis, patients with acquired immunodeficiency disease syndrome/human immunodeficiency virus, and patients with underlying urologic abnormalities. A catheter-associated UTI is the most common nosocomial infection, accounting for >1 million cases in hospitals and nursing homes. The risk of UTIs increases with increasing duration of catheterization. In non-institutionalized elderly populations, UTIs are the second most common form of infection, accounting for nearly 25% of all infections.
There are important medical and financial implications associated with UTIs. In the non-obstructed, non-pregnant female adult, acute uncomplicated UTI is believed to be a benign illness with no long-term medical consequences. However, a UTI elevates the risk of pyelonephritis, premature delivery, and fetal mortality among pregnant women, and is associated with impaired renal function and end-stage renal disease among pediatric patients. Financially, the estimated annual cost of a community-acquired UTI is significant, at approximately $1.6 billion.
The urinary system can simply be described as the bodys drainage system for filtering and eliminating wastes from the body, as well as, maintaining the homeostasis of water, ions, pH, blood pressure, calcium and red blood cells.
The organs of the urinary system (Fig. 1) are the kidneys which secrete the urine; the ureters or tubes that convey the urine to the bladder where it is temporarily stored; and the urethra, through which the urine is discharged from the body.
Figure 1. Organs of the Urinary System
The kidneys are paired organs lying along the posterior wall of the abdominal cavity on either side of the vertebral column and behind the peritoneum. They are often described as bean-shaped each about the size of a fist. The left kidney is located slightly higher than the right kidney because it is displaced upwards by the liver. The kidneys, unlike the other organs of the abdominal cavity, are located posterior to the peritoneum and touch the muscles of the back. The kidneys are surrounded by a layer of adipose tissue that holds them in place and protects them from physical damage.
The kidneys are responsible for regulating the acid-base balance in the blood and hence in the body as a whole, maintaining the water balance in the body and excreting the waste products of metabolism from the blood. Their excretory activities conserve the proper concentration of essential organic and inorganic substances in the blood. Essentially the kidneys role of excretion keeps the bodys internal environment within physiological limits. The kidneys filter about 3 ounces of blood every minute. The waste products of metabolism along with extra water make up approximately the 1 to 2 quarts of urine a person produces each day.
The ureters are a pair of tubes that carry urine from the kidneys to the urinary bladder. Each is about 10 to 12 inches long and run along the left and right sides of the body parallel to the vertebral column. They descend beneath the peritoneum on the posterior abdominal wall and cross the pelvic floor to reach the bladder. Gravity and peristalsis of smooth muscle tissue in the walls of the ureters move urine toward the urinary bladder. The ends of the ureters extend slightly into the urinary bladder and are sealed at the point of entry to the bladder by the ureterovesical valves. These valves prevent urine from flowing back upwards to the kidneys.
The urinary bladder is pear shaped, becoming more oval as it fills with urine. This muscular sac lays midline at the inferior end of the pelvis behind the symphysis pubis, in front of the rectum in the male and in front of the vagina and uterus in the female. When empty the bladder inside is arranged in folds (called rugae), which disappear as the bladder expands with urine. Urine entering the urinary bladder from the ureters slowly fills the hollow space of the bladder and stretches its elastic walls. The walls of the bladder allow it to stretch to hold anywhere from 500 to 800 milliliters of urine. After emptying, the bladder may still retain about 50 cc residual volume. At about 150 cc of volume, stretch receptors in the detrusor muscle begin signaling the central nervous system via afferent nerves; at 400 cc we are "seeking" an appropriate toilet.
The bladder thusly serves as a reservoir in which the urine is stored until it is eliminated from the body. There are three openings on the floor of the bladder: one in front for the urethra and two at the sides for the ureters (called urethral openings).
At the base of the bladder is the bladder neck, which opens into the urethra, through which urine is expelled to the external environment. The bladder neck and the proximal urethra (nearest part) are supported by pubourethral ligaments and the levator ani muscles of the pelvic floor. The anatomy of the male urethra and female urethra vary considerably in both length and structure. The female urethra is around 2 inches long and ends inferior to the clitoris and superior to the vaginal opening. In males, the urethra is around 8 to 10 inches long and ends at the tip of the penis. The urethra is also an organ of the male reproductive system as it propels sperm out of the body through the penis. The first 3-4 cm of the male urethra passes through the prostate gland, which lies below the bladder and is attached to its base.
The flow of urine through the urethra is controlled by the internal and external urethral sphincter muscles. The internal urethral sphincter is made of smooth muscle and opens involuntarily when the bladder reaches a certain set level of distention. The opening of the internal sphincter results in the sensation of needing to urinate. The external urethral sphincter is made of skeletal muscle and may be opened to allow urine to pass through the urethra or may be held closed to delay urination.
Micturition is the process by which urine is expelled from the bladder. It can simply be broken down into 5 basic steps:
Beyond those 5 steps there are elaborate layers of neurologic control (Fig. 2). Figure 2 below illustrates the micturition process.
Figure 2. Neurologic Innervation of Urinary System
The bladder is composed of bands of interlaced smooth muscle called the detrusor muscle. The innervation of the body of the bladder is different from that of the bladder neck. The body of the bladder is rich in beta adrenergic receptors which are stimulated by the sympathetic component of the autonomic nervous system (ANS). Beta stimulation, via fibers of the hypogastric nerve, suppress contraction of the detrusor muscle i.e. allows the detrusor muscle to relax (the bladder fills with urine). Conversely, parasympathetic stimulation, by fibers in the pelvic nerve causes the detrusor muscle to contract (the bladder empties). Sympathetic stimulation is predominant during bladder filling, and the parasympathetic causes emptying.
The ureters pass between the layers of the detrusor muscle and enter the bladder through the trigone. The ureters propel urine into the bladder. The bladder passively expands to accept urine. As the bladder expands and intravesicular pressure increases, the ureters are compressed between the layers of muscle, creating a valve mechanism. This valve mechanism limits the backflow of urine up towards the kidneys.
Two sphincters control the bladder outlet:
Under normal circumstances, we are able to control where and when we urinate. This is largely because the cerebrum is able to suppress the sacral micturition reflex. If the sacral reflex is unrestrained, parasympathetic stimulation via the pelvic nerve causes detrusor muscle contraction. Detrusor muscle contraction is suppressed by alpha and beta sympathetic stimulation via the hypogastric nerve. In response to afferent stimulation, the cerebrum becomes aware of the need to void. If it is appropriate, the cerebrum relaxes the external sphincter, blocks sympathetic inhibition, the bladder contracts and urine is expelled.
Infection does not always occur when microorganisms are introduced into the bladder. A number of defense systems protect the urinary tract against infection-causing microorganisms:
UTIs are generally classified as: (1) Uncomplicated or complicated, depending on the factors that trigger the infections; (2) Primary or recurrent, depending on whether the infection is occurring for the first time or is a repeat event; (3) Asymptomatic UTI (Asymptomatic Bacteriuria).
Uncomplicated UTIs are usually due to microbial infections including fungi, viruses and bacteria. The most common bacterial infection is Escherichia coli (E. coli) which causes the vast majority of UTIs. Microbial infections affect women much more often than men.
Urethritis. Urethritis is an infection or inflammation of the lining of the urethra.
Cystitis. Cystitis, or bladder infection, is the most common UTI. It occurs in the lower urinary tract (the bladder and urethra) and nearly always in women. In most cases, the infection is brief and acute and only the surface of the bladder is infected. Deeper layers of the bladder may be harmed if the infection becomes persistent, or chronic, or if the urinary tract is structurally abnormal.
Pyelonephritis (Kidney Infection). Sometimes the infection spreads to the upper urinary tract (the ureters and kidneys). This is called pyelonephritis, or more commonly, a kidney infection.
Complicated UTIs, which occur in men and women of any age, are also caused by microorganisms but they tend to be more severe, more difficult to treat, and recurrent. Most often, they are the result of:
Recurrences can occur in up to 50 60% of patients with a complicated UTI if the underlying structural or anatomical abnormalities are not corrected.
Recurrence is often categorized as either reinfection or relapse:
Reinfection. About 80% of recurring UTIs are reinfections. A reinfection occurs several weeks after antibiotic treatment has cleared up the initial episode and can be caused by the same microbial strain that caused the original episode or a different one. The infecting organism is usually introduced through fecal bacteria and moves up through the urinary tract.
Relapse. Relapse is the less common form of recurrent UTI. It is diagnosed when a UTI recurs within 2 weeks of treatment of the first episode and is due to treatment failure. Relapse usually occurs in kidney infection (pyelonephritis) or is associated with obstructions such as kidney stones, structural abnormalities or, in men, chronic prostatitis.
Most women who have had an uncomplicated UTI have occasional recurrences. About 25 - 50% of these women can expect another infection within a year of the previous one. Between 3 - 5% of women have ongoing, recurrent UTIs, which follow the resolution of a previous treated or untreated episode.
Many women suffer from frequent UTIs. About 20 percent of young women with a first UTI will have a recurrent infection. With each UTI, the risk that a woman will continue having recurrent UTIs increases. Some women have three or more UTIs a year. However, very few women will have frequent infections throughout their lives. More typically, a woman will have a period of 1 or 2 years with frequent infections, after which recurring infections cease.
Men are less likely than women to have a first UTI. But once a man has a UTI, he is likely to have another because microbes can hide deep inside prostate tissue. Anyone who has diabetes or a problem that makes it hard to urinate may have repeat infections.
Research funded by the National Institutes of Health (NIH) suggests that one factor behind recurrent UTIs may be the ability of bacteria to attach to cells lining the urinary tract. One NIH-funded study found that bacteria formed a protective film on the inner lining of the bladder in mice. If a similar process can be demonstrated in humans, the discovery may lead to new treatments to prevent recurrent UTIs. Another line of research has indicated that women who are nonsecretors of certain blood group antigens may be more prone to recurrent UTIs because the cells lining the vagina and urethra may allow bacteria to attach more easily. A nonsecretor is a person with an A, B, or AB blood type who does not secrete the normal antigens for that blood type in bodily fluids, such as fluids that line the bladder wall.
When a person has no symptoms of infection but significant numbers of bacteria have colonized the urinary tract, the condition is called asymptomatic UTI (also called asymptomatic bacteriuria). The condition is harmless in most people and rarely persists, although it does increase the risk for developing symptomatic UTIs.
Screening for asymptomatic bacteriuria is not necessary during most routine medical examinations, with the following exceptions:
The bacterial strains that cause UTIs include:
The bacteria that cause kidney infections (pyelonephritis) are generally the same bacteria that cause cystitis. There is some evidence, however, the E. coli strains in pyelonephritis are more virulent (able to spread and cause illness).
Complicated UTIs that are related to underlying physical or structural abnormalities of the urinary tract are apt to be caused by a wider range of bacteria. E. coli is still the most common bacteria, but others include Klebsiella, P. mirabilis, and Citrobacter.
Other bacteria associated with complicated or severe infection include Pseudomonas aeruginosa, Enterobacter, and Serratia species gram-positive organisms (including Enterococcus species).
Fungal organisms, such as Candida species can cause complicated UTIs. Candida albicans causes the "yeast infections" that also occur in the mouth, digestive tract, and vagina.
Recurring infections are often caused by different bacteria than those that caused a previous or first infection.
Structure of the Female Urinary Tract. In general, the higher risk in women is mostly due to the shortness of the female urethra which is 1.5 inches compared to 8 inches in men. This anatomical difference allows microbes quicker access to the bladder. Also, a womans urethral opening is near sources of microbes from the anus and vagina. For women, the lifetime risk of having a UTI is greater than 50 percent.
Sexual Behavior. Sexually active women tend to have more UTIs than do women who are not sexually active. Sexual activity can move microbes from the bowel or vaginal cavity to the urethral opening. If these microbes have special characteristics that allow them to live in the urinary tract, it is harder for the body to remove them quickly enough to prevent infection. Following sexual intercourse, most women have a significant number of bacteria in their urine, but the body normally clears them within 24 hours. Nearly 80% of all UTIs in premenopausal women occur within 24 hours of intercourse. UTIs are very rare in celibate women. However, UTIs are not sexually transmitted infections. In general, the physical act of intercourse itself produces the conditions that increase susceptibility to developing a UTI.
Types of Contraceptives. Women who use diaphragms for birth control tend to develop UTIs. The spring-rim of the diaphragm can bruise the area near the bladder making it susceptible to bacteria. Using a diaphragm may slow urinary flow and allow bacteria to multiply. In some women, spermicidal foam or gel used with diaphragms, as well as, spermicidal condoms, may irritate the skin, increasing the risk of bacteria invading surrounding tissues. Most spermicides contain nonoxynol-9, a chemical that is associated with increased UTI risk. Condom use is also associated with increased risk of UTIs, possibly because of the increased trauma that occurs to the vagina during sexual activity.
Pregnancy. In pregnant women, the presence of asymptomatic bacteriuria is associated with increased risk of kidney infection, which can cause early labor and other serious pregnancy complications. For this reason, pregnant women should be screened and treated for asymptomatic bacteriuria. Pregnant women are more susceptible to kidney infections because as the uterus enlarges it compresses the ureters and bladder. This causes urine to back up into the kidneys, increasing the risk of bacterial infection.
Menopause. The risk for UTIs, both symptomatic and asymptomatic, is highest in women after menopause. This is primarily due to the decrease in estrogen, which thins the walls of the urinary tract and reduces its ability to resist bacteria. Estrogen loss can also reduce certain immune factors in the vagina that help block E. coli from adhering to vaginal cells. For some women, topical estrogen therapy helps restore healthy bacteria and reduce the risk of recurrent UTIs. Oral hormone replacement therapy is not helpful in the prevention of UTIs.
Other age-related urinary conditions, such as urinary incontinence, can increase the risk for recurrent UTIs.
Allergies. Women who have skin allergies to ingredients in soaps, vaginal creams, bubble baths, or other chemicals that are used in the genital area are at increased risk for developing UTIs. In such cases, the allergies may cause small injuries that can introduce bacteria.
Antibiotic Use. Antibiotics often eliminate lactobacilli, the protective bacteria, along with harmful bacteria. This can cause an overgrowth of E. coli in the vagina.
Prostate Problems. Men become more susceptible to UTIs after age 50, when they begin to develop prostate problems. Benign prostatic hyperplasia (BPH), enlargement of the prostate gland, can result in obstruction in the urinary tract and increase the risk for infection. In men, recurrent UTIs are also associated with prostatitis, an infection of the prostate gland. Although only about 20% of UTIs occur in men, these infections can cause more serious problems than they do in women. Men with UTIs are far more likely to require hospitalization than women.
Diabetes. Diabetes puts women at significantly higher risk for asymptomatic bacteriuria. The longer a woman has diabetes, the higher the risk. Control of blood sugar does not affect this condition. The risk for UTI complications, and fungal-related UTIs, is also higher in people with diabetes.
Kidney Problems. Nearly any kidney disorder, including kidney stones, increases the risk for complicated UTIs.
Neurogenic Bladder. A number of brain and nerve disorders can affect the nerves of the bladder and cause problems with the ability to empty the bladder and control urine leakage. Multiple sclerosis, stroke, spinal cord injury, and diabetic neuropathy are common examples.
Sickle-Cell Anemia. Patients with sickle-cell anemia are particularly susceptible to kidney damage from their disease, and UTIs put them at even greater risk.
Immune System Problems. People with immunocompromised systems, such as those who have HIV/AIDS or who are undergoing treatment for cancer, are at increased risk for all types of infections, including UTIs and pyelonephritis.
Urinary Tract Abnormalities. Some people have structural abnormalities of the urinary tract that cause urine to stagnate or flow upwards into the upper urinary tract. A prolapsed bladder (cystocele) can result in incomplete urination so that urine collects in the bladder creating a breeding ground for bacteria. Tiny pockets called diverticula sometimes develop inside the urethral wall and can collect urine and debris, further increasing the risk for infection.
Elderly Adults. All older adults who are immobilized, catheterized or dehydrated are at increased risk for UTIs. Nursing home residents especially those who are incontinent are at very high risk.
Hospitalizations. About 40% of all infections that develop in patients while in the hospital are in the urinary tract. The organisms that cause infections in hospitals (called nosocomial infections) are often different from those that commonly cause UTIs. They are also more likely to be resistant to standard antibiotics. Hospitalized patients at highest risk for such infections are those with in-dwelling urinary catheters, patients undergoing urinary procedures, long-stay elderly men, and patients with severe medical conditions.
Catheters. About 80% of UTIs in the hospital are due to catheters. The longer any urinary catheter is in place, the higher the risk for growth of bacteria and an infection. In most cases of catheter-induced UTIs, there are no symptoms. Because of the risk for wider infection, however, anyone requiring a catheter should be screened for infection. Catheters should be used only when necessary and should be removed as soon as possible.
Nursing Homes. All older adults who are immobilized, catheterized or dehydrated are at increased risk for UTIs. Nursing home residents, particularly those who are incontinent, are at very high risk. Symptoms of UTIs in patients and nursing home residents are often subtle.
In most cases, UTIs are annoyances that cause urinary discomfort. However, if left untreated, UTIs can develop into very serious and potentially life-threatening kidney infections (pyelonephritis) that can permanently scar or damage the kidneys. The infection may also spread into the bloodstream (called sepsis) and then elsewhere in the body.
UTIs in pregnant women pose serious health risks for both mother and child. UTIs that occur during pregnancy pose a higher than average risk of developing into kidney infections. Any pregnant woman who suspects she has a UTI should immediately contact her primary care physician (PCP). Many PCPs recommend that women receive periodic urine testing throughout their pregnancies to check for signs of infection.
In some adults, recurrent UTIs may cause scarring in the kidneys, which over time can lead to renal hypertension and eventual kidney failure. Most of these adults with kidney damage have other predisposing diseases or structural abnormalities. Recurrent UTIs, even in the kidney, almost never lead to progressive kidney damage in otherwise healthy women.
Symptoms of lower UTIs in adults do not always cause signs and symptoms, but when they do they may include:
Symptoms of Severe Infection in the Kidney (Pyelonephritis) tend to affect the whole body and be more severe than those of cystitis (inflammation of the bladder). These symptoms may include:
The classic lower UTI symptoms of pain, frequency, or urgency and upper UTI symptoms of flank pain, chills, and tenderness may be absent or altered in older patients. Older women and men are more likely to be tired, shaky, and weak and have muscle aches. Other symptoms of a kidney infection include pain in the back or side below the ribs.
Symptoms of UTIs that may occur in seniors but not in younger adults may include mental changes or confusion, nausea or vomiting, abdominal pain, or cough and shortness of breath. Concomitant illness may further confuse the picture and make diagnosis difficult.
UTIs may be overlooked or mistaken for other conditions in older adults.
A PCP can confirm if the patient has a UTI by testing a sample of urine. For some younger women who are at low risk of complications, the PCP may not order a urine test and may diagnose a UTI based on the description of symptoms.
Urinalysis (UA). A urinalysis is an evaluation of various components of a urine sample. It involves looking at the urine color and clarity, using a special dipstick to do different chemical testing, and possibly inspecting some of the urine underneath a microscope. A urinalysis usually provides enough information for a PCP to start treatment.
Urine Culture (UC). If necessary, the PCP may order a urine culture, which involves incubating and growing the bacteria contained in the urine. A urine culture can help identify the specific microorganism causing the infection, and determine which type of antibiotics to use for treatment. A urine culture may be ordered if the urinalysis does not show signs of infection but the PCP still suspects a UTI is causing the symptoms. It may also be ordered if the PCP suspects complications from the infection.
Urine Clean-Catch Sample. To obtain an untainted urine sample, PCPs usually request a so-called midstream, or clean-catch, urine sample. To ensure the best possible collection of the urine sample, the patient must be directed to:
The sample is generally given to the PCP or sent to the laboratory for analysis.
Collection with a Catheter. Some patients especially the elderly, immobilized or confused cannot provide a urine sample. In such cases, a catheter may be inserted into the bladder to collect urine. This is the best method for providing a contaminant-free sample.
If the UTI does not respond to treatment, the PCP may order other tests to determine what is causing the symptoms. Imaging tests can help identify:
Kidney and Bladder Ultrasound. Ultrasound is a noninvasive imaging test that uses a device, called a transducer that bounces safe, painless sound waves off organs to create an image of their structure. The procedure is performed in a PCPs office, outpatient center, or hospital by a specially trained technician. The images are interpreted by a radiologist. Anesthesia is not needed. The images can be used to screen for hydronephrosis (obstructions of the flow of urine), kidney stones that predispose to infection, and kidney abscesses. In men, ultrasound can detect enlargement or abscesses of the prostate and is an accurate method for detecting incomplete emptying of the bladder, a common cause of UTIs in men over age 50. However, this test cannot reveal all important urinary abnormalities or measure how well the kidneys work.
Special Types of X-Rays. Special x-rays can be used to screen for structural abnormalities, urethral narrowing, or incomplete emptying of the bladder, which can cause stagnation of urine and predispose to infection. Due to the possible risks to the fetus, x-rays are not performed on pregnant women.
Magnetic Resonance Imaging (MRI). MRI machines use radio waves and magnets to produce detailed pictures of the bodys internal organs and soft tissues without using x-rays. An MRI may include an injection of contrast medium. With most MRI machines, the patient lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end. Some newer machines are designed to allow the patient to lie in a more open space. The procedure is performed in an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist. Anesthesia is not needed though light sedation may be used for patients with a fear of confined spaces. Like CT scans, MRIs can provide clearer, more detailed images.
Radionuclide scan is an imaging technique that relies on the detection of small amounts of radiation after injection of radioactive chemicals. Because the dose of the radioactive chemicals is small, the risk of causing damage to cells is low. Special cameras and computers are used to create images of the radioactive chemicals as they pass through the kidneys. Radionuclide scans are performed in a PCPs office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist. Anesthesia is not needed. Radioactive chemicals injected into the blood can provide information about kidney function. Radioactive chemicals can also be put into the fluids used to fill the bladder and urethra for x-ray, MRI, and CT imaging.
Cystoscopy is used to detect structural abnormalities, interstitial cystitis, or masses that might not show up on x-rays during an IVP. The patient is given a light anesthetic, and the bladder is filled with water. The procedure uses a cystoscope, a flexible, tube-like instrument that the urologist inserts through the urethra into the bladder. Cystoscopy is performed by an urologist in his/her office, outpatient facility, or hospital with local anesthesia. However, in some cases, sedation and regional or general anesthesia are needed.
Urodynamics. Urodynamic testing is a procedure that looks at how well the bladder, sphincters, and urethra are storing and releasing urine. Most of these tests are performed in an urologists office by an urologist, physician assistant, or nurse practitioner. Some procedures may require light sedation to keep a patient calm. Most urodynamic tests focus on the bladders ability to hold urine and empty steadily and completely. Urodynamic tests can also show whether the bladder is having abnormal contractions that cause leakage. A PCP may order these tests if there is evidence that the patient has some kind of nerve damage.
Blood Cultures. If symptoms are severe, the PCP will order blood cultures to determine if the infection is in the bloodstream and threatening other parts of the body.
About half of women with symptoms of a UTI actually have some other condition, such as irritation of the urethra, vaginitis, interstitial cystitis, or sexually transmitted diseases (STDs). Some of these problems may also accompany or lead to UTIs.
Vaginitis. Vaginitis is a common vaginal infection that can be caused by a fungus (candidiasis) or bacteria. Occasionally, the infection causes frequent urination, mimicking cystitis. The typical symptoms of vaginitis are itching and an abnormal vaginal discharge.
Sexually Transmitted Diseases. Women with painful urination whose urine does not exhibit signs of bacterial growth in culture may have a sexually transmitted disease. The most common microorganism is Chlamydia trachomatis. Other STDs that may be responsible include gonorrhea and genital herpes.
Interstitial Cystitis. Interstitial cystitis (IC) is an inflammation of the bladder wall that occurs almost predominantly in women. The average age of patients with IC is 40 years old, but 25% of cases occur in women under age 30. Symptoms are very similar to cystitis, but no bacteria are present. Pain during sex is a very common complaint in these patients, and stress may intensify symptoms.
Kidney Stones. The pain of kidney stones along with blood in the urine can resemble the symptoms of pyelonephritis. There are no bacteria present in the urine with kidney stones, however.
Thinning Urethral and Vaginal Walls. After menopause, the vaginal and urethral walls become dry and fragile; causing pain and irritation that can mimic a UTI.
Prostate Conditions in Men. Prostate conditions, including prostatitis (inflammation of the prostate) and benign prostatic hyperplasia, can cause symptoms similar to urinary tract infections.
Antibiotics are the main treatment for all UTIs. A variety of antibiotics are available, and choices depend on many factors, including whether the infection is complicated or uncomplicated, primary or recurrent. Treatment decisions are also based on the type of patient (man or woman, a pregnant or nonpregnant woman, hospitalized or nonhospitalized patient, patient with diabetes etc.). Treatment should not necessarily be based on the actual bacterial count. For example, if a woman has symptoms, even if bacterial count is low or normal, infection is probably present, and the PCP should consider antibiotic treatment.
UTIs in low-risk women can often be successfully treated over the phone. In such cases, a PCP provides the patients with a 3-day antibiotic regimen without requiring an office urine test. This course is recommended only for women at low risk for recurrent infection, who do not have symptoms (such as vaginitis) suggesting other problems.
Antibiotic Regimen. Oral antibiotic treatment cures 94% of uncomplicated UTIs, although the rate of recurrence remains high. The following antibiotics are commonly used for uncomplicated UTIs:
After a week of antibiotic treatment, most patients are free of infection. If the symptoms do not clear up within the first few days of therapy, PCPs generally suggest that women discontinue their antibiotic and provide a urine sample for culturing in order to identify the specific organism causing the condition.
Although antibiotics can cure most UTIs, severe symptoms can persist for several days until treatment effectively eliminates the bacteria. A number of options are available for relieving symptoms until the antibiotics take effect.
A relapsing infection caused by treatment failure usually occurs within 3 weeks in about 10% of women. Relapse is treated similarly to a first infection, but the antibiotics are usually continued for 7 - 14 days. Relapsing infections may be due to structural abnormalities, abscesses, or other problems that may require surgery, and such conditions should be ruled out.
Women who have two or more symptomatic UTIs within 6 months or three or more over the course of a year may need preventive antibiotics. A woman's own perception of discomfort can generally guide her decisions on whether or not to use preventive antibiotics. All women should use lifestyle measures to prevent recurrences.
Intermittent Self Treatment. Many, if not most, women with recurrent UTIs can effectively self-treat without going to a PCP. In general, this requires the following steps:
A woman should consult her PCP under the following circumstances:
Women who are not good candidates for self-treatment are those with impaired immune systems, previous kidney infections, structural abnormalities of the urinary tract, or a history of infection with antibiotic-resistant bacteria.
Postcoital Antibiotics. If recurrent infections are clearly related to sexual activity and episodes recur more than two times within a 6-month period, a single preventive dose taken immediately after intercourse is effective. Antibiotics for such cases include TMP-SMX, nitrofurantoin, cephalexin, or a fluoroquinolone (such as ciprofloxacin). Fluoroquinolones are not appropriate during pregnancy.
Continuous Preventive Antibiotics (Prophylaxis). Continuous preventive (prophylactic) antibiotics are an option for some women who do not respond to other measures. With this approach, low-dose antibiotics are taken continuously for 6 months or longer.
Patients with uncomplicated kidney infections (pyelonephritis) may be treated at home with oral antibiotics. Patients with moderate-to-severe acute kidney infection and those with severe symptoms or other complications may need to be hospitalized. In such cases, antibiotics are usually given intravenously for several days. Chronic pyelonephritis may require long-term antibiotic treatment.
Treating Pregnant Women. Pregnant women seem no more prone to UTIs than other women. However, when a UTI does occur in a pregnant woman, it is more likely to travel to the kidneys. According to some reports, about 4 to 5 percent of pregnant women develop a UTI. Scientists think that hormonal changes and shifts in the position of the urinary tract during pregnancy make it easier for microbes to travel up the ureters to the kidneys and cause infection. For this reason, PCPs routinely screen pregnant women for microbes in the urine during the first 3 months of pregnancy.
The antibiotics used during pregnancy include amoxicillin, ampicillin, nitrofurantoin, and cephalosporin. Fosfomycin (Monurol) is not as effective as others but may be used during pregnancy. Pregnant women should not take fluoroquinolones or tetracyclines.
Pregnant women with asymptomatic bacteriuria (evidence of infection but no symptoms) have a 30% risk for acute pyelonephritis in their second or third trimester. They need screening and treatment for this condition. In such cases, they should be treated with a short course of antibiotics (3 - 5 days). For an uncomplicated UTI, pregnant women may need longer-term antibiotics (7 - 10 days).
Catheter-induced UTIs are very common, and preventive measures are extremely important. Catheters should not be used unless absolutely necessary and they should be removed as soon as possible. Reducing the risk for infections during long-term catheter use, however, remains problematic.
Intermittent Use of Urinary Catheters. If a urinary catheter is required for long periods, it is best to use it intermittently if possible (as opposed to an indwelling catheter). Some PCPs recommend replacing an indwelling urinary catheter every 2 weeks to reduce the risk of infection and irrigating the bladder with antibiotics between replacements.
Daily Hygiene. A typical indwelling urinary catheter is one that has been preconnected and sealed and uses a drainage bag system. To prevent infection, some of the following tips may be helpful:
Antibiotics for Catheter-Induced Infections. Patients using catheters who develop UTIs with symptoms should be treated for each episode with antibiotics and the catheter should be removed, if possible, or changed. A major problem in treating catheter-related UTIs is that the organisms involved are constantly changing. Because there are likely to be multiple species of microorganisms, PCPs generally recommend an antibiotic that is effective against a wide variety of microorganisms.
Although high bacterial counts in the urine (bacteriuria) occur in most catheterized patients, administering antibiotics to prevent a UTI is rarely recommended. Many catheterized patients do not develop symptomatic UTIs even with high bacterial counts. If bacteriuria occurs without symptoms, antibiotic therapy has little benefit if the catheter is to remain in place for a long period.
Making some lifestyle changes may help a patient prevent or lessen the symptoms of recurrent UTIs.
Water. Drinking a lot of fluids can help flush microorganisms from the system by diluting the urine. Water helps flush out the microorganisms. Water is best. Most people should try for six to eight, 8-ounce glasses a day. A person who has kidney failure should not drink this much fluid. In this case consulting the PCP to learn how much fluid is advisable is recommended.
Avoid Drinks that may Irritate the Bladder. Avoid coffee, alcohol and soft drinks that contain citrus juices and caffeine until the UTI has resolved. These may irritate the bladder and tend to aggravate the frequent or urgent need to urinate.
Perineal Care and Hygiene. The following are some good hygiene tips:
Avoid Potentially Irritating Feminine Products. Avoid bath oils, feminine hygiene sprays, douches, and powders in the genital area which can irritate the urethra. As a general rule, do not use any product containing perfumes or other possible allergens near the genital area. Douching is never recommended as it may irritate the vagina and urethra and increase the risk of sexually transmitted diseases.
Sexual Precautions. The following recommendations may reduce the risks of developing a UTI from sexual activity:
Birth Control. For women, using a diaphragm or spermicide for birth control can lead to UTIs by increasing microbial growth. A woman who has trouble with UTIs should try switching to a new form of birth control. Unlubricated condoms or spermicidal condoms increase irritation, which may help microbes grow. Switching to lubricated condoms without spermicide or using a nonspermicidal lubricant may help prevent UTIs.
Clothing. Cotton-crotch underwear and loose-fitting clothes should be worn and changed at least once a day so air can keep the area around the urethra dry. Tight-fitting jeans and nylon underwear should be avoided because they can trap moisture and help microbes grow. Mild detergents are best for washing underwear.
Urinate often. A person should urinate often and when the urge arises. Microorganisms can grow when urine stays in the bladder too long.
Scientists are working on developing a vaccine that can prevent UTIs from coming back. Researchers are testing injected and oral vaccines to see which works best. Another method being considered for women is to apply the vaccine directly as a suppository in the vagina. Other scientists are working on identifying ways to prevent UTIs using probiotics.
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.
Anderson GG, Palermo JJ, Schilling JD, et al. Intracellular bacterial biofilm-like pods in urinary tract infections. Science. 2003;301:105107.
Colgan R, Williams M. Diagnosis and treatment of acute uncomplicated cystitis. Am Fam Physician. 2011 Oct 1;84(7):771-6.
Colgan R, Nicolle LE, McGlone A, Hooton TM. Asymptomatic bacteriuria in adults. Am Fam Physician. 2006 Sep 15;74(6):985-90.
Cranberry. Natural Medicines Comprehensive Database. Accessed July 19, 2012.
Foster RT Sr. Uncomplicated urinary tract infections in women. Obstet Gynecol Clin North Am. 2008 Jun;35(2):235-48, viii.
Foxman B. (2002) Epidemiology of urinary tract infections: incidence, morbidity, and economic costs. Am J. Med 2002 Jul 8; 113 Suppl 1A: 5S-13S. Retrieved March 20, 2014 from Schappert SM, Rechtsteiner EA. Ambulatory medical care utilization estimates for 2006. National health statistics reports; no 8. Hyattsville, MD: National Center for Health Statistics; 2008.
Griebling TL. Urinary tract infection in women. In: Litwin MS, Saigal CS, eds. Urologic Diseases in America. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Washington, D.C.: GPO; 2007. NIH publication 075512:587619.
Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, 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 Mar;52(5):e103-20.
Gupta K, Trautner B. In the clinic. Urinary tract infection. Ann Intern Med. 2012 Mar 6;156(5):ITC3-1-ITC3-15.
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 Mar 1;50(5):625-63.
Hooton TM. Recurrent urinary tract infection in women. UpToDate.com. Accessed July 19, 2012.
Hooton TM. Clinical practice. Uncomplicated urinary tract infection. N Engl J Med. 2012 Mar 15;366(11):1028-37.
Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews. 2012;10:CD001321. DOI: 10.1002/14651858.CD001321.pub5.
Lentz GM, et al. Comprehensive Gynecology. 6th ed. Philadelphia, Pa.: Mosby Elsevier; 2012. mdconsult.com Accessed July 19, 2012.
Lin K, Fajardo K; U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: evidence for the U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2008 Jul 1;149(1):W20-4.
Little P, Merriman R, Turner S, Rumsby K, Warner G, Lowes JA, et al. Presentation, pattern, and natural course of severe symptoms, and role of antibiotics and antibiotic resistance among patients presenting with suspected uncomplicated urinary tract infection in primary care: observational study. BMJ. 2010 Feb 5;340:b5633. doi: 10.1136/bmj.b5633.
Little P, Moore MV, Turner S, Rumsby K, Warner G, Lowes JA, et al. Effectiveness of five different approaches in management of urinary tract infection: randomized controlled trial. BMJ. 2010 Feb 5;340:c199. doi: 10.1136/bmj.c199.
Litwin MS, Saigal CS, editors. Urologic Diseases in America. US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Washington, DC: US Government Printing Office, 2007; NIH Publication No. 07-5512.
McPherson RA, et al. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa.: Saunders Elsevier; 2011. mdconsult.com Accessed July 19, 2012.
Moore KN, Fader M, Getliffe K. Long-term bladder management by intermittent catheterization in adults and children. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD006008.
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: Saunders Elsevier; 2011:chap 36.
Norrby SR. Approach to the patient with urinary tract infection. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap.306.
Perrotta C, Aznar M, Mejia R, Albert X, Ng CW. Oestrogens for preventing recurrent urinary tract infection in postmenopausal women. Cochrane Database Syst Rev. 2008 Apr 16;(2):CD005131.
Peterson J, Kaul S, Khashab M, Fisher AC, Kahn JB. A double-blind, randomized comparison of levofloxacin 750 mg once-daily for five days with ciprofloxacin 400/500 mg twice-daily for 10 days for the treatment of complicated urinary tract infections and acute pyelonephritis. Urology. 2008 Jan;71(1):17-22.
Pohl A. Modes of administration of antibiotics for symptomatic severe urinary tract infections. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003237.
Schaeffer AJ. Infections of the urinary tract. In: Walsh PC, Retik AB, Vaughan ED, Wein AJ, eds. Campbell's Urology. 8th ed. Vol. 1. Philadelphia: Saunders; 2002: 515602.
Sharma JB, Aggarwal S, Singhal S, Kumar S, Roy KK. Prevalence of urinary incontinence and other urological problems during pregnancy: a questionnaire based study. Archives of Gynecology and Obstetrics. 2009;279(6):845851.
Stapleton AE, Nudelman E, Clausen H, Hakomori S, Stamm WE. Binding of uropathogenic Escherichia coli R45 to glycolipids extracted from vaginal epithelial cells is dependent on histo-blood group secretor status. Journal of Clinical Investigation. 1992;90;965972.
Tolkoff-Rubin NE, Cotran RS, Rubin RH. Urinary tract infection, pyelonephritis, and reflux nephropathy. In: Brenner BM, ed. Brenner & Rector's The Kidney. 8th ed. Vol. 2. Philadelphia: Saunders; 2008: 12031238.
Vazquez JC, Abalos E. Treatments for symptomatic urinary tract infections during pregnancy. Cochrane Database Syst Rev. 2011 Jan 19;(1):CD002256.
Wang CH, Fang CC, Chen NC, Liu SS, Yu PH, Wu TY, et al. Cranberry-containing products for prevention of urinary tract infections in susceptible populations: a systematic review and meta-analysis of randomized controlled trials. Arch Intern Med. 2012 Jul 9;172(13):988-96.
Wein AJ, et al. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. mdconsult.com. Accessed July 19, 2012.
U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2008 Jul 1;149(1):43-7. Ann Intern Med. 2008 Jul 1;149(1):W20-4.