Urinary Tract Infection: Symptoms and Risk Factors
Urinary tract infections (UTIs) are one of the most common infections. Millions of UTIs occur in the United States every year, most commonly in young, sexually active women.
A UTI can begin anywhere along the urinary tract, which includes the urethra, bladder, and kidneys. Normally, these structures are sterile. That is, they have no bacteria, viruses, or other microbes living in them. A UTI occurs when one or more of these organs become infected, usually by bacteria (E. coli is the most common, causing up to 90 percent of cases).
The simplest type of UTI is urethritis, in which the urethra alone is infected. In this case, symptoms usually include only a burning sensation in the vaginal area or penis. Patients may also feel the need to urinate frequently.
More commonly, the bladder is infected, in which case the disease is called cystitis. Symptoms of cystitis include dysuria (pain when urinating), urinary frequency (the feeling of needing to urinate frequently), and urinary urgency (a feeling of not being able to hold in the urine). In some cases, pain in the lower abdomen occurs. In others, bloody or cloudy urine occurs.
In severe cases, the kidneys become infected, a condition called pyelonephritis, which is a potentially deadly infection that usually requires immediate hospitalization and intravenous antibiotic treatment. Patients with pyelonephritis appear seriously ill, with fever, nausea, vomiting, and severe side or back pain.
Among the elderly, confusion and other changes in mental functioning may be the only signs of a urinary tract infection.
In young children, symptoms typically include irritability, changes in eating habits, incontinence, and diarrhea. Vomiting may be the only symptom in young girls.
- Gender: In women, the urethra is shorter than in men, which allows bacteria to more easily move up the urethra and into the bladder to cause a UTI. More than 50 percent of women will have a UTI during their lifetime, and 20 percent of these women will have at least two UTIs. In men, UTIs are rare (less than 0.1 percent), except in men who have abnormalities of the bladder.
- Sexual intercourse: A woman's risk of infection is associated with her frequency of intercourse. This is because bacteria are often forced into the urinary tract during intercourse. In addition, a new sexual partner and the use of spermicides are risk factors.
- Bladder catheterization, such as during a surgery or a hospital stay, increases the risk of UTI greatly.
- Urinary tract obstruction also increases the risk significantly: Some causes of urinary tract obstruction include kidney stones and enlargement of the prostate gland in men.
- Diabetes: Diabetic individuals are much more likely to have UTIs. This is partly due to increased sugar (glucose) in their urine, which fosters bacterial growth.
- Menopause: Menopause also increases the risk for UTI due to weakening (atrophy) of the vaginal walls.
- In most cases, urethritis and cystitis can be diagnosed by the typical symptoms and testing is not necessary.
- In some cases, urinalysis is useful to confirm the diagnosis. This test is especially useful to distinguish a UTI from vaginitis (inflammation of the vagina) in women. Patients with a UTI will have microscopic white blood cells and nitrites (a chemical produced by the invading bacteria) in their urine, and possibly also red blood cells.
- In cases of pyelonephritis, many tests are needed, including urine cultures, blood cultures, and other blood tests, and possibly other tests, such as X-rays and CT scans.
- In patients who have repeated UTIs, an in-depth investigation is needed to determine if an anatomic abnormality is contributing to the problem. Testing may include X-rays, CT scans, cystoscopy, or other diagnostic studies.
In general, UTIs are treated with antibiotics.
- Simple cases can be given a three to seven day course of oral antibiotics, which will usually cure the infection.
- In patients with diabetes or other diseases, and in patients with a history of multiple UTIs, a longer course of antibiotics may be necessary. In rare cases, patients may require treatment for six months or more.
- The most common antibiotics used are a combination of trimethoprim and sulfamethoxasole (sometimes abbreviated as "TMP/SMX"), and a group of antibiotics known as fluoroquinolones (such as ciprofloxacin).
- In more severe cases of UTI and in cases of pyelonephritis, hospitalization is often necessary in order to closely monitor the patient and to administer intravenous antibiotics.
- Women with recurrent UTIs who use spermicides and a diaphragm may benefit from alternate forms of contraception.
In children and elderly individuals, poor personal hygiene (such as persistently wet diapers or undergarments) may be a cause of UTIs and should be addressed appropriately.
Urinary Tract Infection: Nutritional Considerations
There are several nutritional strategies that may be effective in preventing UTIs:
- Breast-feeding: Infants who are breast-fed have fewer than half the number of UTIs as infants who are fed with formula. This is, in part, due to antibodies (such as Immunoglobin A) present in high concentrations in breast milk that help to prevent the growth of bacteria.
- Cranberry juice: Studies have shown that women who consume cranberry juices, which contain high levels of antioxidants known as flavonoids, have a 20 percent lower risk for developing UTIs. This may be because the nutrients in cranberries decrease the ability of bacteria to stick to the walls of the urinary tract cells.
- Probiotics, such as lactobacilli: There is some evidence that women who consume lactobacilli have a decreased risk for UTIs. Although this is still under investigation, taking a probiotics supplement is a simple, cheap practice that may have other positive effects, including decreasing allergies and abdominal pain.
- High-fiber diets: Although the reason for this benefit is not yet known, chronic constipation is associated with an increased risk of UTIs. Since high-fiber diets have many other positive benefits, people - especially children - are encouraged to increase fiber intake. The best way to increase fiber in the diet is to eat plenty of vegetables, fruits, beans, and whole grains.