Urinary Tract Infection

Urinary tract infections are among the most common bacterial infections people experience, affecting millions each year. While these infections can be uncomfortable and disruptive, understanding the symptoms, causes, and treatment options can help you recognize when to seek care and how to reduce your risk.

Table of contents

• What is a urinary tract infection?
• The urinary tract and affected areas
• How common are urinary tract infections?
• Signs and symptoms
• What causes urinary tract infections?
• Who is at risk?
• How doctors diagnose UTIs
• Treatment options
• How to prevent urinary tract infections
• When to seek medical care

• Kidneys
• Ureters
• Bladder
• Urethra

What is a urinary tract infection?

A urinary tract infection (UTI) is an infection in any part of your urinary system. UTIs are common infections that happen when bacteria, often from the skin or rectum, enter the urethra and infect the urinary tract.^[1][3]

UTIs can involve different parts of your urinary system, including your urethra (called urethritis), bladder (called cystitis), or kidneys (called pyelonephritis).^[1] Most infections affect the lower urinary tract, which includes the bladder and the urethra.^[2]

The urinary tract and affected areas

Your urinary tract is the system that makes and stores urine (pee). It includes several important parts that work together:^[1]

Kidneys are small, bean-shaped organs located on the back of your body, above your hips. Most people have two kidneys. They filter water and waste products from your blood, which becomes urine. Common wastes include urea and creatinine.^[1]

Ureters are thin tubes that carry urine from your kidneys down to your bladder.^[1]

Bladder is a balloon-like organ that stores urine before it leaves your body.^[1]

Urethra is a tube that carries urine from your bladder to the outside of your body.^[1]

Normally, urine moves through your urinary system without any contamination. However, bacteria can get into your urinary system, which can cause UTIs.^[1]

How common are urinary tract infections?

UTIs are very common, especially in females. About half of females will have a UTI at some point during their lives.^[1] Healthcare providers treat 8 million to 10 million people each year for UTIs.^[1]

Males can also get UTIs, as well as children, though they only affect 1% to 2% of children.^[1] About 60% of people assigned female at birth and 12% of people assigned male at birth will have at least one UTI in their lifetime.^[19]

Signs and symptoms

A UTI causes inflammation in the lining of your urinary tract. The inflammation is when the body’s tissues become swollen and irritated. This can cause several uncomfortable problems:^[1]

Common urinary symptoms include:

• Pain or burning when you urinate (called dysuria)^[1][3]
• Needing to urinate more often than usual^[3]
• Feeling the need to urinate despite having an empty bladder^[3]
• Needing to urinate suddenly or more urgently than usual^[6]
• Needing to urinate more often than usual during the night (called nocturia)^[6]
• Urinary incontinence (leaking urine)^[1]
• Blood in your urine (called hematuria), which may look bright pink, red, or dark brown^[1][3]
• Cloudy, foul-smelling, or milky urine^[1][5]

Other symptoms may include:

• Pain in your flank, abdomen, pelvic area, or lower back^[1]
• Pressure in the lower part of your pelvis or cramping in the groin or lower abdomen^[1][3]
• Feeling extremely tired (called fatigue)^[1]
• Fever^[1]
• Chills^[1]
• Nausea and vomiting^[1]
• Mental changes or confusion^[1]

Symptoms in children

Children with UTIs may also have a high temperature, appear generally unwell, wet the bed or wet themselves, or be sick. Babies and young children may be irritable and not feed, eat, or drink properly.^[6] While fever is the most common sign of UTI in infants and toddlers, most children with fever do not have a UTI.^[3]

Symptoms in older adults

In older, frail people who have problems with memory, learning, and concentration (such as dementia), and people with a urinary catheter, symptoms of a UTI may also include changes in behaviour (such as acting agitated or confused), leaking urine that is worse than usual, or new shivering or shaking.^[6]

What causes urinary tract infections?

Microorganisms—usually bacteria—cause urinary tract infections. They typically enter through your urethra and may infect your bladder. The infection can also travel up from your bladder through your ureters and eventually infect your kidneys.^[1]

E. coli bacteria cause more than 90% of bladder infections.^[1] E. coli typically exist in your lower intestines (large intestine).^[1] Urinary tract infections are caused by a range of pathogens, but most commonly by Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, and Staphylococcus saprophyticus.^[4]

It’s possible to get a UTI from your fingers. Your hands can pick up bacteria and other microorganisms whenever you touch a surface. You can accidentally introduce bacteria to your urethra when you go to the bathroom or during sexual acts, including masturbation or fingering. It’s a good idea to wash your hands before and after going to the bathroom.^[1]

Who is at risk?

Anyone can get a urinary tract infection, but you’re more likely to get a UTI if you don’t have a penis. This is because your urethra is shorter and closer to your anus, where E. coli bacteria are common.^[1] UTIs are more common in females because their urethras are shorter and closer to the rectum. This makes it easier for bacteria to enter the urinary tract.^[3]

Other risk factors include:

• A previous UTI^[3]
• Recent sexual activity^[3]
• Changes in the bacteria that live inside the vagina. For example, menopause or the use of spermicides can cause these bacterial changes^[3]
• Pregnancy^[3]
• Age—older adults and young children are more likely to get UTIs^[3]
• Structural problems in the urinary tract, such as enlarged prostate^[3]
• Poor hygiene, for example, in children who are potty-training^[3]
• Having diabetes^[6]
• Using a catheter^[6]
• Having a weakened immune system^[6]

How doctors diagnose UTIs

Your healthcare provider will determine if you have a UTI by asking about symptoms, doing a physical exam, and ordering urine tests if needed.^[3]

Urine tests are commonly used to diagnose UTIs. You may be asked for a urine sample. A lab can check the urine for white blood cells, red blood cells, or bacteria. You may need to first wipe your genital area with an antiseptic pad and then collect the urine midstream—a second or two after you start passing urine into the toilet. This helps prevent the sample from being contaminated.^[8]

Lab analysis of urine is sometimes followed by a urine culture. This test checks what bacteria are causing the infection. The culture results help your healthcare professional know what medicines will be most effective in treating your condition.^[8]

For UTIs that come back repeatedly, your healthcare provider may order additional tests. These can include imaging tests such as ultrasound, CT scan, or MRI to show the structures in the urinary tract, or using a scope to see inside the bladder.^[8]

Treatment options

Taking antibiotics, prescribed by a healthcare provider, at home can treat most UTIs.^[3] Antibiotics can cure most UTIs. If your doctor prescribes antibiotics, take the pills exactly as you are told. Do not stop taking them just because you feel better. You need to finish taking them all so that you don’t get sick again.^[11]

Your healthcare provider might also recommend medicine to help lessen the pain or discomfort.^[3] For symptoms such as pain or burning in a bladder infection, phenazopyridine is a medicine you can buy without a prescription. But it doesn’t treat the infection—you’ll still need an antibiotic.^[11]

Some cases may require treatment in a hospital. For kidney infections, oral antibiotics usually can treat them, but you may need a brief hospital stay and intravenous (IV) antibiotics if you are too ill or sick to your stomach to take medicine by mouth.^[11]

It’s important to take all the medicine you are prescribed, even if you start to feel better.^[6] Drink plenty of water or other fluids to help your body flush out bacteria.^[3]

Treatment for recurring UTIs

If your UTI comes back after treatment, or you have 2 UTIs in 6 months (or 3 within 12 months), you’ll need to see a healthcare provider. They may prescribe a different antibiotic or prescribe a low-dose antibiotic to take for up to 6 months.^[6] Women with recurrent bladder infections may be treated with preventive antibiotic therapy.^[11]

For women in perimenopause or those who have gone through menopause, doctors may prescribe a vaginal cream, gel, tablet, pessary, or ring containing oestrogen.^[6]

Side effects of antibiotics

Any time you take antibiotics, they can cause side effects. Side effects can include rash, dizziness, nausea, diarrhea, and yeast infections. More serious side effects can include antimicrobial-resistant infections or C. diff infection, which causes diarrhea that can lead to severe colon damage and death. Call your healthcare provider if you develop any side effects while taking your antibiotic.^[3]

How to prevent urinary tract infections

You can reduce your risk of UTIs by making several simple lifestyle changes:^[3]

• Urinate after sexual activity to help flush out bacteria^[3]
• Stay well hydrated by drinking plenty of water. Drinking at least 50 ounces (about 1.5 liters) daily helps dilute your urine and flush bacteria from your urinary tract^[18][19]
• Take showers instead of baths^[3]
• Minimize douching, sprays, or powders in the genital area^[3]
• Teach girls when potty training to wipe front to back to prevent bacteria from the anal region from reaching the urethra^[3]
• Urinate regularly—at least every two or three hours. When you hold your urine, bacteria can remain inside your body^[17]
• Wash your genital area with mild, unscented soaps and avoid harsh soaps or scented products^[18]

Some contraceptives, like spermicides and diaphragms, can increase your risk of UTIs. If you’re using these methods and experiencing recurrent infections, talk with your healthcare provider about alternative contraceptive methods.^[18]

When to seek medical care

You should seek medical care if you or your child have symptoms of a UTI or for any symptom that is severe or concerning.^[3]

Ask for an urgent appointment or get help if you or someone you care for:

• Are aged 65 or older^[6]
• Are aged 15 or younger^[6]
• Have a very high or low temperature, feel hot or cold, or are shivering^[6]
• Are a man or were assigned male at birth^[6]
• Have diabetes^[6]
• Have symptoms that get worse quickly or do not improve within 48 hours of starting treatment^[6]
• Keep getting UTIs^[6]
• Use a catheter^[6]
• Are pregnant^[6]
• Have pain in the lower tummy or in the back, just under the ribs^[6]
• Have blood in your urine^[6]
• Have a weakened immune system^[6]

Call emergency services immediately if you or your child are confused, drowsy, or have difficulty speaking.^[6] Some symptoms could indicate a kidney infection, which can be serious if it’s not treated as it could cause sepsis.^[6]

Talk to your healthcare provider right away if your child is younger than 3 months old and has a fever of 100.4°F (38°C) or higher.^[3]