Urinary Tract Infection: Causes, Symptoms and Treatments

What is a Urinary Tract Infection (UTI)?

A UTI is when bacteria gets into your urine and travels up to your bladder. UTIs cause more than 8.1 million visits to health care providers each year. About 10 in 25 women and 3 in 25 men will have symptoms of at least 1 UTI during their lifetime.

How Does the Urinary Tract Work?

The urinary tract makes and stores urine, one of the waste products of your body. Urine is made in the kidneys and travels down the ureters to the bladder. The bladder stores the urine until it is emptied through the urethra, a tube that connects the bladder to the skin, when you urinate. The opening of the urethra is at the end of the penis in a male and in front of the vagina in a female.

The kidneys are a pair of fist-sized organs in the back that filter liquid waste from the blood and remove it from the body in the form of urine. Kidneys balance the levels of many chemicals in the body (sodium, potassium, calcium, phosphorous and others) and check the blood’s acidity. Certain hormones are also made in the kidneys. These hormones help control blood pressure, boost red blood cell production and help make strong bones.

Normal urine has no bacteria in it, and the one-way flow helps prevent infections. Still, bacteria may get into the urine from the urethra and travel up into the bladder.

Fast facts on urinary tract infections

Here are some key points about urinary tract infection. 

  • Urinary tract infections are the 2nd most common infection in the body.
  • Women have a lifetime risk of over 50% of developing a urinary tract infection.
  • The majority of urinary tract infections are caused by the E. Coli bacterium.
  • Common symptoms include a strong, frequent urge to urinate and a painful and burning sensation when urinating.
  • Urinary tract infection diagnosis is usually made after a health care provider has examined the symptoms and a urine sample.
  • Urinary tract infections are commonly treated with antibiotics.
  • Uncomplicated urinary tract infections can be cured with 2-3 days of treatment.
  • Most young women with urinary tract infections have uncomplicated urinary tract infections.
  • Men with urinary tract infections should be presumed to have complicated urinary tract infections until it can be proven otherwise.
  • In severe cases, seriously ill patients with urinary tract infections may need to be hospitalized.

Causes of urinary tract infections

Urinary tract infections are caused when microbes manage to get past the body’s natural defenses.

The vast majority of UTI cases are caused by the bacterium Escherichia coli (E. coli), usually found in the digestive system. Chlamydia and Mycoplasma bacteria can infect the urethra but not the bladder.

People of any age and sex can develop a UTI; however, some people are more at risk than others.

The following factors can increase the likelihood of developing a UTI

  • Sexual intercourse
  • Diabetes
  • Poor personal care
  • Problems emptying the bladder completely
  • Having a urinary catheter
  • Bowel incontinence
  • Blocked flow of urine
  • Kidney stones
  • Some forms of contraception
  • Pregnancy
  • Menopause
  • Procedures involving the urinary tract
  • Suppressed immune system
  • Immobility for a long period.

Symptoms of urinary tract infections

The symptoms of a urinary tract infection can depend on age, gender, the presence of a catheter and what part of the urinary tract has been infected.

Common symptoms of urinary tract infection include:

  • Strong and frequent urge to urinate
  • Cloudy, bloody or strong smelling urine
  • Pain or burning sensation when urinating
  • Nausea and vomiting
  • Muscle aches and abdominal pains.
  • People with catheters may only have an otherwise undiagnosable fever as a symptom.

Acute pyelonephritis
If a person has a kidney infection, they could also experience upper back and side pain, high fever, shaking, chills, fatigue and mental changes.

If a person has a bladder infection, they could also experience low fever, and pressure and cramping in the abdomen and lower back.

Treatment of urinary tract infections

As urinary tract infections are normally caused by bacteria, they are most commonly treated with antibiotics or antimicrobials. The type of medication and length of treatment will depend on the patient’s symptoms and history.

The full course of treatment should always be completed for UTIs, in order to ensure that the infection is fully clear. UTI symptoms can disappear before the infection has completely gone.

Drinking lots of fluids, and frequently urinating are always recommended for people who have UTIs. Various pain relief medication is available to alleviate pain and may be prescribed. Applying a heating pad to the back or abdomen can also help.

An uncomplicated UTI is one that occurs in an otherwise healthy person with a normal clear urinary tract. These can usually be cured with 2-3 days of treatment.

A complicated UTI is one that occurs in a person who is weakened by another condition, such as pregnancy or heart transplant, or who has a urinary tract which is compromised either structurally or functionally, such as with an obstructive kidney stone or enlargement of the prostate. Complicated UTIs tend to require longer periods of antibiotics, usually between 7-14 days.

Curing UTIs that are caused by problems within the urinary system depend on the underlying problem being found and corrected. If left untreated, these infections can lead to kidney damage.

If the patient is seriously ill, they may need to be admitted to hospital to ensure that they can drink enough fluids and take the right medication.

Patients may also need to go to hospital if they:

  • Are pregnant and are otherwise ill
  • Are elderly
  • Have cancer, diabetes, multiple sclerosis, spinal cord injury or other medical problems
  • Have kidney stones or other changes in the anatomy of their urinary tract
  • Have recently undergone urinary tract surgery.
  • Recurrent infections in women

Women can be given different advice if they have recurrent bladder infections:

  • Take a single dose of an antibiotic after sexual contact
  • Take a single, daily dose of an antibiotic for at least 6 months
  • Take a short course – 2-3 days – of an antibiotic if symptoms reappear
  • Have vaginal estrogen therapy if postmenopausal.

Differences between the genders
Most young women with UTIs have uncomplicated UTIs. In comparison, men should be presumed to have complicated UTIs until proven otherwise. This is because men are more likely to develop a UTI as the result of an obstruction, such as an enlarged prostate.


There are several measures that can be taken in order to reduce the risk of developing a UTI:

  • Drink lots of water and urinate frequently
  • Avoid bladder irritating fluids such as alcohol and caffeine
  • Urinate shortly after sex
  • Wipe from front to back after urinating and bowel movement
  • Keep the genital area clean
  • Showers are preferred to baths. Avoid using oils
  • Sanitary pads are preferred to tampons
  • Avoid using a diaphragm or spermicide for birth control
  • Avoid using any products containing perfume in the genital area
  • Wear cotton underwear and loose fitting clothing to keep the area around the urethra dry.

It is advised that you contact your health care provider if you develop the symptoms of a UTI, especially if you have developed the symptoms of a potential kidney infection (acute pyelonephritis).

Urinary tract infection – children

The infection can affect different parts of the urinary tract, including the:

  • Bladder (cystitis)
  • Kidneys (pyelonephritis)
  • Urethra — the tube that empties urine from the bladder to the outside

UTIs are more common in girls. They may occur often around age 3, as children begin toilet training. Boys who are not circumcised have a slightly higher risk of UTIs before age 1.


Young children with UTIs may have a fever, poor appetite, vomiting, or no symptoms at all.

Most urinary tract infections in children only involve the bladder. If the infection spreads to the kidneys (called pyelonephritis), it may be more serious.

Symptoms of a bladder infection in children include:

  • Blood in the urine
  • Cloudy urine
  • Foul or strong urine odor
  • Frequent or urgent need to urinate
  • General ill feeling (malaise)
  • Pain or burning with urination
  • Pressure or pain in the lower pelvis or lower back
  • Wetting problems after the child has been toilet trained

Signs that the infection may have spread to the kidneys include:

  • Chills with shaking
  • Fever
  • Flushed, warm, or reddened skin
  • Nausea
  • Pain in the side (flank) or back
  • Severe pain in the belly area
  • Vomiting

Exams and Tests

A urine sample is needed to diagnose a UTI in a child. The sample is examined under a microscope and sent to a lab for a urine culture.

It may be hard to get a urine sample in a child who is not toilet trained. The test cannot be done using a wet diaper.

Ways to collect a urine sample in a very young child include:

  • Urine collection bag. A special plastic bag is placed over the child’s penis or vagina to catch the urine. This is not the best method because the sample may become contaminated.
  • Catheterized specimen urine culture. A plastic tube (catheter) placed into the tip of the penis in boys, or straight into the urethra in girls, collects urine right from the bladder.
  • Suprapubic urine collection. A needle is placed through the skin of the lower abdomen and muscles into the bladder. It is used to collect urine.

If this is your child’s first UTI, imaging tests may be done to find the cause of the infection or check for kidney damage. Tests may include:

  • Kidney ultrasound
  • X-ray taken while the child is urinating (voiding cystourethrogram)

These studies may be done while the child has an infection. Most often, they are done weeks to several months later.

Your health care provider will consider many things when deciding if and when a special study is needed, including:

  • The child’s age and history of other UTIs (infants and younger children usually need follow-up tests)
  • The severity of the infection and how well it responds to treatment
  • Other medical problems or physical defects the child may have


In children, UTIs should be treated quickly with antibiotics to protect the kidneys. Any child under 6 months old or who has other complications should see a specialist right away.

Younger infants will most often need to stay in the hospital and be given antibiotics through a vein. Older infants and children are treated with antibiotics by mouth. If this is not possible, they may need to get treated in the hospital.

Your child should drink plenty of fluids when being treated for a urinary tract infection.

Some children may be treated with antibiotics for periods as long as 6 months to 2 years. This treatment is more likely when the child has had repeat infections or vesicoureteral reflux.

After antibiotics are finished, your child’s health care provider may ask you to bring your child back to do another urine test. This may be needed to make sure that bacteria are no longer in the bladder.

Outlook (Prognosis)

Most children are cured with proper treatment. Most of the time, repeat infections can be prevented.

Repeated infections that involve the kidneys can lead to long-term damage to the kidneys.

When to Contact a Medical Professional

Call your health care provider if your child’s UTI symptoms continue after treatment, or come back more than twice in 6 months.

Call your health care provider if the child’s symptoms get worse. Also call if your child develops new symptoms, such as:

  • Back pain or flank pain
  • Bad-smelling, bloody, or discolored urine
  • Fever of 100.4°F (38°C) rectally in infants, or over 101°F (38.3°C) in children
  • Low back pain or abdominal pain below the belly button
  • Fever that does not go away
  • Very frequent urination, or need to urinate many times during the night
  • Vomiting
  • Prevention

Things you can do to prevent UTIs include:

  • Avoid giving your child bubble baths.
  • Have your child wear loose-fitting underpants and clothing.
  • Increase your child’s intake of fluids.
  • Keep your child’s genital area clean to prevent bacteria from entering through the urethra.
  • Teach your child to go the bathroom several times every day.
  • Teach your child to wipe the genital area from front to back to reduce the spread of bacteria.

To prevent recurrent UTIs, the health care provider may recommend low-dose antibiotics after the first symptoms have gone away.

Alternative Names

UTI – children; Cystitis – children; Bladder infection – children; Kidney infection – children; Pyelonephritis – children