A urinary tract infection (UTI) occurs when bacteria enter the urinary tract. Many UTIs resolve without treatment, and early, effective treatment can help prevent complications.
UTIs can affect any part of the urinary tract, including:
- urethra, which is the tube that carries urine from the bladder out of the body
- ureters, which are the two tubes that carry urine from the kidney to the bladder
Signs and symptoms of UTIs include:
- a frequent urge to urinate, even without much urine to pass
- a burning sensation when urinating
- urine that is foul smelling, cloudy, or contains blood
- abdominal pain
- a feeling of tiredness and overall lack of energy
- confusion or agitation in older people
Additional signs and symptoms of upper UTIs may include:
- severe deep pain in the back near the ribs
- pain in the lower abdomen
- nausea or vomiting
- feeling hot and cold
The symptoms of upper and lower UTIs can overlap, and lower UTIs can often spread to the kidneys.
Uncomplicated UTIs can clear up by themselves. However, a person can help relieve their symptoms by:
- drinking plenty of liquids, especially water
- using a heating pad over the bladder
- urinating as often as possible
People who may have kidney infections should immediately seek advice from a doctor. Kidney infections can be serious, and they can cause permanent kidney damage.
A healthcare professional may prescribe antibiotics for a UTI. Males and children are more likely to need treatment. Occasionally, people with severe infections may require hospital treatment and further investigation.
It is a good idea to get medical advice for a UTI, especially for:
- pregnant people
- anyone with upper UTI symptoms or a history of kidney infections
- individuals with risk factors for complications
Urine flows through the urinary tract in one direction, from the kidneys down through the bladder to the outside. Bacteria are often present but pass out with the urine.
Most UTIs occur when bacteria that live in the bowel spread into the bladder. Sometimes, the bacteria travel up to the kidneys, causing more severe infections.
The bacterium Escherichia coli causes the majority of uncomplicated UTIs.
Risk factors for lower UTIs, which are more common in females, include:
- not drinking enough water
- not urinating when a person feels the need to
- having had a UTI before
- having diabetes
- being sexually active
- having a vaginal infection
- having obesity
- practicing poor personal hygiene
Females have much shorter urethras than males, making it easier for the bacteria to travel up to the bladder. This is why female UTIs are four times as common as male ones. Between 40 and 60% of females have at least one UTI in their lifetime, and recurrence is common.
Risk factors for complicated UTIs include:
- some anatomical or neurological conditions
- kidney failure or transplantation
- the presence of foreign bodies, such as kidney or bladder stones
- having a urinary catheter
- infection with certain organisms
- some other health conditions, such as being immunosuppressed
Uncomplicated UTIs are typically lower UTIs in healthy females with no structural abnormalities. The main complication is if the infection spreads upward. Doctors often consider any UTI in a male complicated because they do not occur often.
Complicated UTIs usually affect people whose ability to fight infection is compromised or whose urinary tract does not function properly.
The presence of a urinary catheter, which carries urine from the bladder down the urethra, is a significant risk factor for UTIs. Catheter-associated UTIs (CAUTIs) are a particular issue in hospitals.
According to the Centers for Disease Control and Prevention (CDC), UTIs are the most common type of healthcare-associated infections. About three-quarters of UTIs people pick up in hospitals are associated with a urinary catheter.
Overall, perhaps 1 million complicated UTIs a year in the United States are associated with indwelling catheters, which are catheters that stay in the bladder. People at a higher risk of CAUTI include:
- older people
- people with diabetes
- people who have had a catheter for a long time
Doctors may use a range of tests to diagnose UTIs:
- Urinalysis: People with suspected UTIs provide a urine sample, which is tested for the presence of bacteria or white blood cells, which indicate an infection.
- Urine culture: If a UTI is complicated or recurrent, a urine sample can also be cultured to establish which bacteria are causing the infection.
- Scans and imaging: These can also be helpful if UTIs are complicated or recurrent.
People without UTIs can also have bacteria in their urine, so doctors base a diagnosis on all the available information.
A person may prevent UTIs by:
- urinating frequently and after sex
- trying to empty the bladder fully
- wiping from front to back when going to the toilet
- wearing loose cotton underwear
- taking showers rather than baths
- avoiding using scented products around the genital area
- drinking plenty of liquids, especially water
- avoiding using spermicide
Cranberry juice and other cranberry products may help prevent recurrent UTIs and decrease the use of antibiotics. However, a review by the National Institute for Health and Care Excellence (NICE) in 2018 found mixed evidence of the effectiveness of these products in alleviating active infections.
According to NICE, about 1 in 10 girls and 1 in 30 boys will have had a UTI by age 16.
Children with UTIs have similar symptoms to adults but may also seem just overall ill and not themselves. They often try to hold in their urine because of the burning sensation and may wet themselves. They may cry when they urinate.
Symptoms of a UTI in babies may include:
- having a fever
- being irritable
- not feeding properly
Children with UTIs may need antibiotics and should stay well hydrated. Helping them learn proper toilet habits, and preventing constipation may help fend off further UTIs.
Lower UTIs are common, especially in females. However, if the infection spreads upward to the kidneys, it can be severe.
Some people are more vulnerable to complicated UTIs.
The primary treatment for UTIs is antibiotics. People can take several precautions to help prevent UTIs.