Urinary tract infection
| Urinary tract infection | |
|---|---|
| Other names | Acute cystitis, simple cystitis, bladder infection, symptomatic bacteriuria |
| Multiple white cells seen in the urine of a person with a urinary tract infection using microscopy | |
| Specialty | Infectious disease Urology |
| Symptoms | Pain with urination, frequent urination, cloudy urine, feeling the urge to urinate despite having an empty bladder |
| Causes | Most often E. coli bacteria |
| Risk factors | Catheterisation (foley catheter), female anatomy, sexual intercourse, diabetes, obesity, family history |
| Diagnostic method | Based on symptoms, urine culture |
| Differential diagnosis | Vulvovaginitis, urethritis, pelvic inflammatory disease, interstitial cystitis, kidney stone disease |
| Treatment | Antibiotics |
| Frequency | 405 million (2019) |
| Deaths | 260,000 (2021) |
A urinary tract infection (UTI) is an infection that affects a part of the urinary tract, which includes the bladder, urethra and the kidney. Lower UTIs affect the bladder (cystitis) or urethra while upper UTIs affect the kidney (pyelonephritis). Symptoms from a lower UTI include burning or pain during urination, pain in the lower abdomen and the urge to urinate even when the bladder is empty. Symptoms of a kidney infection are more systemic and include fever or flank pain, usually in addition to the symptoms of a lower UTI. Rarely, the urine may appear bloody. Symptoms may be less clear in very young or old people.
The most common cause of infection is E. coli, though other bacteria or fungi may sometimes be the cause. Risk factors include being female, sexual intercourse, diabetes, using a catheter, and family history. Kidney infections usually occurs when a bladder infection spreads, but may also come from bacteria in the blood. Diagnosis in young healthy women can be based on symptoms alone. In those with vague symptoms, diagnosis can be harder because bacteria may be present even if there is no infection.
In uncomplicated cases, UTIs are usually treated with a short course of antibiotics. Resistance to many of the antibiotics used to treat this condition is increasing. In complicated cases, a longer course or intravenous antibiotics may be needed. If symptoms do not improve in two or three days, further diagnostic testing may be needed. People with bacteria or white blood cells in their urine but no symptoms usually do not need antibiotics. For people with recurrent infections, methenamine may be prescribed. Postmenopausal women may also be offered vaginal estrogen replacement. If these do not work, preventative antibiotics can be considered.
Approximately 400 million UTI cases occur each year. They are more common in women than men, and are the most common bacterial infection in women. Up to 10% of women have a urinary tract infection in a given year, and half of women have at least one infection at some point in their lifetime. They occur most frequently between the ages of 16 and 35 years. Recurrences are common. Urinary tract infections have been described since ancient times with the first documented description in the Ebers Papyrus dated to c. 1550 BC.