Urinary Tract Infections
Urinary tract infections (UTIs) are among the most common bacterial infections reported in the United States, with 84% occurring in women. More than half of women have had at least one UTI by the age of 32, with a lifetime occurrence of up to 70%. Twenty to 30% of these women will experience a recurrence, and 10% of women over the age of 60 will have recurrent UTI’s. This condition results in tremendous cost to the healthcare system in the diagnosis and management of UTIs with an estimated $3.5 billion spent in 2000.
Symptoms of bladder infection.
Bladder infections can be miserable. Burning with urination, having to void frequently, & pain can ruin your day (& night). The urine may appear cloudy, smell strong, or may contain blood. Bladder infections can cause or worsen bladder spasms which can result in urgency, frequency, pain, &/or urine loss.
What causes bladder infections?
Bladder infections usually have nothing to do with hygiene. Bacteria get into the bladder from the vagina &, if they have time enough to start growing rather than getting flushed out, they can cause infection. Women are 4 times more likely than men to get infections because their urethra, or opening of the bladder, is only about an inch long. This is also why women are more likely to have incontinence. In younger women bladder infections are almost always related to sex. Intercourse pushes bacteria into the bladder. Most women will be able to flush them out, but some do not. Sexually transmitted diseases can cause infection of the urethra (urethritis) & vagina, but usually not cystitis.
Bacteria are normally present in a healthy vagina. Prior to menopause, the pH of the vagina is low & slightly acidic due to estrogen. This promotes the growth of a bacteria called “lactobacillus,” creating a healthy balance which inhibits the growth of bacteria which cause bladder infections. After menopause, falling estrogen levels cause pH levels to rise, & the balance of bacteria changes. Lower estrogen levels also lead to the urethral & vaginal tissues becoming thinner. This “atrophy” makes it easier for bacteria to get into the bladder. In women, 75-95% of bladder infections are due to E. Coli. Most other infections are caused by Enterococcus, Klebsiella, Proteus or Pseudomonas. Multiple studies have shown that using estrogen topically in the vagina can improve atrophy, & replacement of estrogen in the vagina is the most effective way to reduce infections. Using estrogen vaginally is much safer than using hormone pills because very little is absorbed into your bloodstream.
Weakness of the muscle surrounding the opening of the bladder may also make it easier for bacteria to get into the bladder. Other more rare causes of bladder infections include stones in the kidneys or bladder, diabetes, conditions which affect the immune system, neurologic conditions such as multiple sclerosis, spinal cord tumors, or impaired bladder emptying. Pelvic organ prolapse is also associated with bladder infections. Pregnancy increases the risk of bladder infection, & chronic urinary catheters are a major risk.
What happens if bladder infections are not treated?
Low grade bladder infections may resolve without antibiotics just by increasing fluid intake, or using some over the counter treatments noted below. Mild infections do not usually cause fever or abdominal pain. One of the most serious problems which can develop is for the infection to ascend from the bladder to the kidney, called “pyelonephritis”. This condition is more common in pregnancy, & may require intravenous antibiotics.
How is a bladder infection diagnosed?
A urine dip test can diagnose a bladder infection in a few minutes. This is done by collecting a “clean catch” urine specimen, & then dipping a chemical test strip. The presence of markers for white & red blood cells is up to 98% accurate in predicting infection.
For women with recurrent or relapsing infections, a specimen may be sent for culture to determine what type of bacteria is the culprit, & which antibiotic will be most effective. For women who get recurrent bladder infections, we may recommend getting test strips at a pharmacy to dip in your urine & confirm that there is a bladder infection.
For women with recurrent infections, it is advisable to get further evaluation. A basic exam can tell whether the vaginal tissues have enough estrogen. When indicated, we perform more complex bladder testing to make sure the bladder empties, assess that the lining of the bladder is healthy, & to see if there are bladder spasms which can be mistaken as infection. X-ray or ultrasound tests are usually not needed unless there is concern that a kidney stone may be contributing to infection.
Which antibiotics work?
Most bladder infections can be cured by taking oral antibiotics for 3-7 days. It may take a couple of days for your symptoms to improve. For recurrent infections, 7-10 days may be needed. The best antibiotic which works in over 90% of bladder infections is nitrofurantoin (brand name “Macrobid” or “Macrodantoin”). This antibiotic is great because it does not cause vaginal yeast infections by changing the bacteria in the area. Other antibiotics include the sulfa antibiotic “Bactrim” (or “Septra”), cephalexin (“Keflex,”) & fosfomycin (“Monurol”). Ciprofloxacin (“cipro”) also often works, but in 2011 infectious disease specialists recommend avoiding it as a first line agent unless the bacteria are resistant to the antibiotics above, or due to limitations with patient allergies.
Women with recurrent UTIs (2 or more in 6 months, 3 or more in a year) may go on a longer course of antibiotics. This is called antibiotic suppression, & consists of taking a low dose of an antibiotic (usually nitrofurantoin) every night for 3 months. For women with infections related to sex, a single dose of antibiotic prophylaxis after sex can help. Sometimes it is helpful to have a prescription for 3 days of antibiotics on hand for when you get the symptoms of a bladder infection on weekends, holidays, or while travelling.
What things besides antibiotics can help?
As mentioned above, vaginal estrogen is the most effective treatment to prevent bladder infections in women after menopause. Adequate hydration promotes urine production, & this may flush bacteria from the bladder. There is no magic number, because fluid requirements vary depending on activities & perspiration, but eight 8 ounce glasses per day is a good ballpark. Excess fluid intake will just make you have to void more often, & can contribute to incontinence. Voiding after sex can also help. Research has shown cranberries contain chemicals called proanthocyanidins which make it hard for bacteria to attach to the bladder wall. Not everyone likes cranberry juice, & many prefer to take caplets. Other dietary additives including blueberry extracts, herbs such as bearberry (uva ursi) or Indian coleus (forsokolin), or supplements which acidify the urine (vitamin C) have not been shown to prevent infection in clinical studies. In postmenopausal women lactobacilli vaginal suppositories (“Vivag,” “EcoVag;” & “Lactin-V” [ not available in the US]) may prevent bladder infections by improving the balance of bacteria in the vagina. These may help in women who chose not to use vaginal estrogen. Taking these “probiotics” orally does not seem to work, as they are broken down by stomach acid.
Other remedies for bladder infections include preparations which contain a number of substances which inhibit bacterial growth (methenamine, methylene blue, glycerophosphate), provide pain relief (pyridium , phenzopyridine, phenyl salicylate, butalbital), & reduce bladder spasms (hyoscyamine). Examples of these preparations include Azostandard, Cystospas, Cystex, Uristat, Urelief, & Hyophen. Some of these contain test strips. Since it may take a couple of days for antibiotics to work, you may want to try an over-the-counter preparation to get relief sooner.
Bacteria in the bladder without infection?
Older people sometimes have bacteria in the bladder without it being a true infection. This is called “asymptomatic bacteriuria,” & it appears to be related to reduced estrogen levels in women, & sometimes impaired emptying. It is very common in residents of nursing homes. In asymptomatic bacteriuria, bacteria colonize the bladder, & will grow when a urine culture is performed. In asymptomatic bacteriuria there is no inflammation of the bladder, & it is not an infection. Patients with asymptomatic bacteriuria do not have symptoms of infection, such as pain with urination & increasing frequency, & a urine test strip will not show markers of infection. Many studies have been done treating patients with asymptomatic bacteriuria, & most show no benefit using antibiotics, even in patients who are using bladder catheters. Patients with asymptomatic bacteriuria do not get sick, & the bacteria usually come back when the antibiotics are stopped. Infectious disease specialists do not recommend treating patients with asymptomatic bacteriuria unless they become symptomatic, & they do not recommend routine screening in elderly populations.