Urinary Tract Infection
A urinary tract infection (UTI) can occur in any part of the urinary tract — the urethra, bladder, ureters, or kidneys — but most commonly affects the urethra or bladder.
Last Updated: October 20 2022
Urinary tract infections (UTIs) are the most common type of infection in women, occurring in up to 40% of women in the United States throughout their lifetime. Uncomplicated UTIs are localized to the bladder and can be called cystitis, referring to inflammation of the bladder in reaction to the infection (for this reason, it is also commonly referred to as a “bladder infection”). Complicated UTIs involve infection that spreads past the bladder to the kidneys or other urinary structures and will manifest with more serious symptoms like fever, back pain, and vomiting most commonly, and more commonly occur in people with diabetes, pregnancy, immunosuppression, old age, or abnormalities of the urinary tract. The most common bacteria involved in uncomplicated UTIs is Escherichia coli, followed by Klebsiella.
Common UTI signs and symptoms include the following:
- Pain/burning while urinating
- Fever, tiredness, or shakiness
- Frequent urges to urinate, or inability to start urination
- Lower stomach pressure or discomfort
- Urine that is bloody, smells bad, and/or appears cloudy
- Back pain or pain below the ribs
Usually, a medical professional identifies a UTI when there are both positive signs/symptoms and positive lab tests. When bacteria are found in the urine but there are no abnormal symptoms, this is usually not enough to diagnose a UTI; this is known as “asymptomatic bacteriuria” and almost never requires treatment, except in the case of pregnancy. Lab tests used to help with diagnosis include urinalysis (testing for nitrates, bacteria, and/or white blood cells) and urine pH. Notably, patients with certain comorbid conditions don’t always experience telltale UTI symptoms (e.g., those with spinal cord injury) or may not be able to communicate symptoms (e.g., those with cognitive impairment).
Uncomplicated UTIs can resolve without treatment in some healthy, nonpregnant women and may not have a high risk of becoming a complicated UTI (when infection spreads into the upper urinary tract). Often, UTIs are treated with antibiotics such as trimethoprim/sulfamethoxazole or fosfomycin, which are chosen based on community bacterial resistance and individual factors. Sometimes phenazopyridine is given in addition to antibiotics for symptom relief since it numbs the urinary tract. It is imperative that complicated UTIs are treated promptly to avoid damage to the kidneys — which can increase the risk of developing high blood pressure and other chronic diseases; and to prevent progression of complicated UTIs to more serious infections like sepsis.
A number of supplements have been studied for the prevention and treatment of UTIs. More high quality studies are needed to determine if these supplements really work. Commonly used supplements include vitamin C (to acidify the urine), cranberry, D-mannose, probiotics, and uva ursi.
Increasing hydration and consuming foods that acidify the urine can help prevent recurrent UTIs and contribute to the resolution of uncomplicated UTIs in healthy individuals. Some research suggests that increasing daily fluid consumption by more than 1 liter helps to prevent UTI recurrence.
There are a number of behavioral measures that are purported to help to prevent UTI. Some examples include increasing hydration (and subsequent frequent urination), as well as improving personal hygiene (e.g., wiping front to back, urinating after sex). Also, in postmenopausal women with atrophic vaginitis, regular use of vaginal estrogen cream can help to prevent recurrent UTIs.
UTIs are caused by bacterial colonization of the urinary tract and subsequent inflammation. Sexual intercourse, spermicides, and diaphragms may increase the risk for UTIs, especially when proper hygiene is not maintained. Other factors that increase the risk of developing a UTI include using a urinary catheter, urethral manipulation, frequent pelvic exams, anatomical abnormalities (e.g., urethral stricture, benign prostatic hyperplasia), kidney transplant, antibiotic use, and diabetes).