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Urinary Tract Infection

Written by Ada’s Medical Knowledge Team

Updated on

This article contains self-care information for the selected condition. If you have questions or need more comprehensive treatment advice, please consult a medical professional.

What is a urinary tract infection?

A urinary tract infection, often referred to as a UTI or urine infection, is an infection of the urinary system. Usually, a urinary tract infection is caused by bacteria from the anal or genital region spreading to the bladder. 1 If left untreated, the infection can continue to spread, eventually reaching the kidneys in the upper urinary tract.

UTIs are a very common condition, mostly affecting women, although men can also develop UTIs. Symptoms can include frequent and painful urination, an odd smell to the urine, the presence of blood in the urine and pain in the lower abdomen. Fever, nausea and upper abdominal pain may be a sign that the infection has reached the upper levels of the urinary tract.

With prompt antibiotic treatment, most people recover quickly. However, if left untreated, a urinary tract infection can develop into a serious condition with a number of complications. 2

Types of urinary tract infection

Urinary tract infections can occur anywhere within the urinary tract, which includes the: 3

  • Urethra, the tube that passes urine out of the body from the bladder. Infection of the urethra is also known as urethritis
  • Bladder, the organ that collects and stores urine. Infection of the bladder is also known as cystitis
  • Ureters, the tubes that carry urine from the kidneys to the bladder
  • Kidneys, the organs that filter blood, eliminating waste via the urine. Infection of one or both kidneys is also known as pyelonephritis

The majority of UTIs affect the bladder and/or the urethra. These are known as lower urinary tract infections.

However, the infection can also travel up the urinary tract to reach the kidneys. In rare cases, the ureters may also become infected. These are called upper urinary tract infections. They are less common than lower tract infections and tend to be more severe. 2

Symptoms of a urinary tract infection

Signs and symptoms of a urinary tract infection often vary from person to person. Factors such as age, gender and the type of UTI may determine precisely which symptoms are experienced and to what degree. 4 However, there are some common symptoms to look out for as an indication of a urinary tract infection.

Lower urinary tract infection symptoms

Common symptoms of a lower urinary tract infection include: 1 3 4 5

  • Frequent and urgent need to urinate
  • Burning or painful sensation while urinating
  • Strong-smelling urine
  • Urine that is bloody and/or cloudy in color
  • Lower abdominal pain

Good to know: Lower urinary tract infections present similar symptoms in both men and women. However, men may also experience rectal pain, while women may experience pelvic pain. 6

Upper urinary tract infection symptoms

In addition to the symptoms above, the presence of the following symptoms may indicate that the affected person is suffering from an upper urinary tract infection: 1 3 4 5

  • Fever
  • Chills
  • Nausea and vomiting
  • Pain and/or aches between the upper abdomen and the back, known as flank pain
  • Signs of confusion, disorientation and/or agitation may occur, especially in elderly patients

Good to know: Upper urinary tract infection symptoms are similar in both men and women.

If you are experiencing possible symptoms of a urinary tract infection, carry out a symptom assessment with the free Ada app.

Symptoms in the elderly

Most people who develop a urinary tract infection will exhibit symptoms, such as those listed above. However, elderly people are less likely to display classic symptoms specific to the genital and urinary regions. This may be due to changes in immune function as age increases, as well as the possibility of additional diseases and disorders affecting usual bodily responses. 7

Additionally, a urinary tract infection may cause certain behavioral changes in an elderly adult, such as confusion, agitation or disorientation. Such symptoms are often categorized as delirium. People with age-related issues such as delirium or dementia are especially at risk of developing a more severe UTI because they may not be able to communicate their symptoms and receive prompt treatment. 8

Although this connection between UTIs and delirium has been established, the reason why delirium may occur in elderly adults with a UTI is not yet known. 9

Good to know: If a urinary tract infection is suspected in an elderly person, always contact a doctor as a simple urine analysis test is usually enough to confirm the diagnosis.

Causes of urinary tract infections

Urinary tract infections are almost always caused by a bacterial infection. The infection most commonly occurs when bacteria from the anal or genital region enter the urinary tract and ascend through the urethra to the bladder and/or kidneys. It is believed that over 85 percent of UTIs are caused by bacteria from the bowel or vagina. 10

80 percent of UTIs are reportedly caused by the E. coli bacteria which is present in human and animal intestines. 1 Most E. coli strains are a natural part of healthy, human digestion. However, some can cause illness when carried outside of the intestinal tract. 11

Usually, any bacteria that enter the urinary tract are flushed out by urine. In some cases, small amounts of bacteria remain in the system, and this can lead to a urinary tract infection. It is also possible to develop a UTI when a bacterial infection from elsewhere in the body spreads through the bloodstream, reaching the kidneys. 10 However, this is much less common.

In rare cases, urinary tract infections can also be caused by viruses, fungi and parasites. 10

Read also our article about COVID-19 and UTI here >>

Risk factors for developing urinary tract infections

Urinary tract infections are a very common condition, especially in women, and account for between 1 to 3 percent of all general practice (GP) consultations. 2

Gender is a primary risk factor for urinary tract infections. UTIs are much more common in women than men, and it is believed that roughly half of all women will experience a UTI in their lifetime. 2 Conversely, under the age of 50, only five to eight men out of every 10,000 report experiencing a UTI. 3

Although there are a number of risk factors specific to either men or women, the majority of risk factors are not gender-specific, including: 1 5 10 12

  • Age. The likelihood of a UTI increases with age. Over the age of 50, incidences of UTIs increase for both genders, with less disparity between the number of cases in men and women
  • Urinary catheters can cause bacteria to enter the urinary tract
  • Family history of UTIs
  • Urinary tract blockages and conditions which may impair urine flow, such as kidney stones, chronic constipation or abnormal urinary function/structure
  • Diabetes, specifically diabetes mellitus or type two diabetes, due to high urine glucose levels increasing the risk of infection
  • Poor personal hygiene may increase the presence of bacteria in the urinary area
  • Reduced mobility may result in longer gaps between urinations, resulting in a higher risk of infection
  • A weakened immune system reduces the body’s ability to defend against infection

Risk factors in women

Women are particularly susceptible to urinary tract infections because their urethra is shorter, meaning the infection can spread throughout the urinary tract more easily. Additionally, the anal and urinary openings of a woman are in closer proximity, increasing the risk of bacteria spreading between the two. 1

In addition to the above, women are also susceptible to the following risk factors for UTIs: 13 14 15 16

  • Sexual intercourse can contribute to the spread of genital or anal bacteria, especially with a new sexual partner when the rate of sexual activity is typically higher. However, UTIs are not a sexually transmitted disease
  • Spermicides and birth control methods which use spermicides can affect the natural balance of healthy bacteria within the vagina
  • Antibiotics can also alter the natural bacterial balance within the vagina
  • Diaphragms can place pressure on a woman’s urethra, resulting in the possibility of the bladder not emptying properly
  • Pregnancy. As the uterus grows in pregnancy, it can put added weight on the bladder, leading to the possibility of the bladder not emptying properly
  • Menopause can cause hormonal changes which affect the vagina’s natural bacterial balance

Risk factors in men

While urinary tract infections are much less common in men than women, there are a couple of risk factors that are unique to men, such as: 1 10 17 18

  • Enlarged or infected prostate, which can obstruct the bladder from emptying properly
  • Uncircumcised men may be more likely to experience a UTI than circumcised men
  • Anal sex. It is commonly accepted that sexual intercourse increases the risk of a UTI in women, but seems to be less of a risk factor in men. However, if a man participates in anal intercourse, the risk of a UTI increases

Diagnosis of a urinary tract infection

Diagnosis of a urinary tract infection usually begins with a consultation based on the symptoms and a physical examination. It is usual for a doctor to also ask about sexual history, medical history and any instances of previous UTIs. 19

A sample of urine might be requested in order to confirm a diagnosis of a urinary tract infection. Dipstick analysis may be done first to indicate the presence of bacteria in the urine. This quick test entails dipping a small chemical strip into a urine sample, then looking for certain color changes on the strip which may indicate abnormal levels of blood, sugar or bacteria in the urine. Looking at the urine sample under a microscope can usually confirm the diagnosis, as well as which bacteria has caused the infection. 1

If an upper urinary tract infection is suspected, a doctor may also recommend blood tests in order to check the infection hasn’t spread to the bloodstream. 20

People suffering from recurring or chronic urinary tract infections may be given additional tests to determine if there are any obstructions or abnormalities causing the repeat of the condition. Such tests can include: 1 21

  • An ultrasound scan of the bladder and kidneys, which uses painless soundwaves to generate an image of the urinary tract
  • A CT scan or MRI scan for a more detailed analysis of the urinary tract
  • A cystoscopy, in which a small camera is inserted through the urethra to see inside the urethra and bladder

When to see a doctor for a urinary tract infection

Urinary tract infections usually require a visit to the doctor to confirm diagnosis and receive treatment. If a UTI is suspected, a doctor’s appointment is always recommended for the following groups of people: 2 9 22 23

  • Children
  • The elderly
  • Men
  • Pregnant women
  • Anyone who has not had a UTI before
  • Anyone with blood in their urine
  • Anyone with symptoms of an upper urinary tract infection
  • Anyone whose symptoms have returned after treatment

Some people who experience UTIs on a frequent basis might be offered different management options by their doctor, such as long-term, low-dose antibiotics. 24 In these special cases, the onset of UTI symptoms may be managed at home, and a visit to the doctor is not always necessary.

In very mild cases, a bladder infection/cystitis may clear on its own without the need for medical treatment. However, other conditions such as genital herpes or vaginal thrush can be mistaken for cystitis, so people who are unsure whether they have cystitis should still see a doctor. 25

Feeling unwell? People experiencing symptoms that may be linked to a urinary tract infection can carry out a symptom assessment using the free Ada app now.

Treatment of urinary tract infections

With prompt treatment, the majority of people with a urinary tract infection make a full recovery. Medication is usually required to fight the infection. There are also a number of home remedies which may help alleviate discomfort.

Medical treatment of urinary tract infections

Because urinary tract infections are most often bacterial, they can be treated with antibiotics. As a guideline, antibiotic treatment for UTIs is usually split into two categories: 1 26

  • Uncomplicated UTI, which is an infection that occurs in an otherwise healthy person with normal kidney function
  • Complicated UTI, which usually occurs in people who have a medical or anatomical predisposition to urinary tract infections or treatment failure

The type of antibiotic used and the length of treatment differs, depending on the severity of the infection and medical history of the person with the condition. Symptoms from uncomplicated UTIs usually clear within three days of antibiotic treatment, whereas people with a complicated UTI may require antibiotics for up to two weeks. 3

Whatever the cause, it is important to complete the entire course of antibiotics prescribed in full, even if symptoms appear to have cleared. This can help to prevent antibiotic resistance developing.

In the rare cases where a urinary tract infection is caused by a virus or fungi, this can be treated with antiviral or antifungal medication respectively. 10

Home remedies for urinary tract infections

It is generally not recommended to treat urinary tract infections with home remedies alone, because antibiotic treatment is usually required to clear the infection. It is only in very mild cases of cystitis that the infection may clear without medical intervention. 25 However, it is possible to use certain natural methods at home alongside antibiotic treatment to alleviate pain and help clear the infection quicker. Such remedies can include: 3 5 27

  • Drinking plenty of water, ideally at least 1.5 liters a day, to help flush the bacteria out of the body
  • Placing a hot water bottle or heating pad against the abdomen or lower back to ease pain in those areas; make sure to wrap the heating device in a clean cloth or towel before application to avoid burns from direct contact with the skin
  • Taking pain-relief medications, such as paracetamol/acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen

Drinking cranberry juice has been cited in the past as a successful treatment method for urinary tract infections. Although not harmful, recent studies indicate the benefit of cranberry juice for treating UTIs is limited. 13

Preventing urinary tract infections

Urinary tract infections are most often caused by bacteria spreading from the anal or genital region and entering the urinary tract. Because of this, there are a number of preventative methods that can minimize the risk of experiencing a UTI: 1 5 28

  • Regular urination
  • Emptying the bladder after sexual intercourse
  • Drinking lots of water, ideally at least 1.5 liters a day. Avoid alcohol and caffeine, which can irritate the bladder
  • Wiping from front to back after using the toilet to avoid spreading bacteria from the anal region
  • Maintaining good personal hygiene and keeping the genital area clean and dry
  • Taking showers instead of baths

Prevention methods for women

In addition to the above prevention methods, women can also: 3 29 30 31

  • Avoid contraceptive methods that contain spermicide
  • Avoid using a diaphragm as a birth control method
  • Avoid the use of feminine products on genital regions, such as deodorant sprays and douches, which have the potential to irritate the urethra
  • Receive vaccination against certain E. coli strains

Prevention through antibiotics

For people that encounter recurring cases of urinary tract infections, doctors may choose to prescribe long-term, low-dose antibiotics. 1 This preventive treatment method is known as antibiotic prophylaxis, and it is administered to reduce the risk of the condition returning.

Prophylactic measures may also be suggested to people with urinary catheters, spinal cord injuries, as well as to renal transplant patients and pregnant women. 32

Complications of urinary tract infections

Urinary tract infections are an extremely common condition, and most people recover quickly with antibiotic treatment. However, if left untreated the infection can spread throughout the urinary tract system, increasing in severity and causing complications. 2

In some cases, the infection can reach the kidneys in the upper urinary tract, an infection known as pyelonephritis. Without medical intervention, this can lead to permanent kidney damage. 33 Possible complications from untreated UTIs include: 34 35

  • Formation of abscesses within or around the kidneys
  • Swelling of the kidneys, also known as hydronephrosis
  • Sepsis, also known as blood poisoning
  • Prostatitis in men

All of these complications are serious and require immediate medical attention.

Pregnancy and urinary tract infections

Pregnant women with a UTI that develops into a kidney infection are at higher risk of developing additional complications, which may affect both them and the fetus. Such complications include anemia, premature labor, low birth weight and, in very rare cases, stillbirth. 22 34

Fortunately, early medical intervention means that urinary tract infections in pregnant women can usually be treated successfully. If the affected person has a lower urinary tract infection, a course of oral antibiotics is the most common treatment method. If an upper urinary tract infection is suspected, the doctor may recommend administering antibiotics intravenously in hospital instead. 22

Once the infection has cleared, a doctor may choose to prescribe low-level, prophylactic antibiotics for the remainder of the pregnancy to reduce the risk of a UTI returning. 22

Pregnancy can increase the likelihood of developing a UTI. This is due to numerous factors, including hormonal changes and the increased weight of the uterus putting pressure on the bladder. 1

Urinary tract infection FAQs

Q: What causes a urinary tract infection?
A: Urinary tract infections are very common, especially in women, and are most often caused when bacteria from the bowel or genital region enter the body through the urethra. This can lead to an infection of the urethra, bladder, ureters or kidneys. Over 85 percent of UTIs are caused in this way.

UTIs can also be caused by viral, fungal or parasitic infections, but these are much less common causes.

Q: Can men develop a urinary tract infection?
A: Yes, although they are rare in men under 50 years of age. 35 Men are less likely than women to develop a UTI because the male urinary tract has more natural defences to infection, such as a longer urethra and further distance between the urethra and the anus.

For this reason, urinary tract infections in men are more likely to be due to a medical cause or an anatomical predisposition to UTIs.{^33]

Q: Can children develop a urinary tract infection?
A: Yes, urinary tract infections are a common condition in babies, toddlers and children. In fact, it is the most common bacterial infection in children under two years of age. 36 The usual cause of UTIs in children is similar to adults: bacteria from the anal region entering the urinary tract through the urethra. Some children may be at added risk of developing a UTI due to not having developed effective personal hygiene methods, such as wiping from front to back after using the toilet. 37Read more about Pediatric Urinary Tract Infection ».

Q: Does a urinary tract infection require medical treatment?
A: Yes, a urinary tract infection usually requires a course of antibiotics to clear the infection. If the UTI has been caused by a virus or fungus, antiviral or antifungal medication may be prescribed instead. With prompt treatment, a urinary tract infection usually clears within a matter of days. Without any medical treatment, a UTI can often develop into a much more serious infection with numerous complications, so a doctor’s appointment is typically recommended.

Very mild cases of bladder infection/cystitis may clear on its own in a few days without medical treatment. However, a doctor’s appointment is still recommended if the affected person has any other medical conditions, is pregnant or is not sure if they have cystitis. If symptoms worsen, always seek medical help.

Q: What home remedies are there for urinary tract infections?
A: Urinary tract infections typically require medical treatment. However, there are a number of home remedies which can help alleviate discomfort and may help clear the infection faster when used in combination with medical treatment. These include:

  • Drinking lots of water, ideally at least 1.5 liters a day. This aids frequent urination and may help to flush the bacteria out of the body
  • Placing a hot water bottle against the abdomen or lower back to help ease pain in those areas
  • Taking pain-relief medication such as paracetamol/acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen

Q: Is drinking cranberry juice good for a urinary tract infection?
A: Research into whether ingesting cranberry products can help prevent a urinary tract infection has had mixed results. One study suggests that certain components found in cranberries can help prevent E. coli bacteria from sticking to the urinary tract walls and thereby limit the risk of infection. 38 However, other studies have shown limited benefits. 39 Therefore, while likely not harmful, cranberry products are not a proven treatment method for UTIs and should not replace medical treatment under any circumstances.

Q: What are the risks of a urinary tract infection during pregnancy?
A: UTIs can be common during pregnancy due to hormonal changes and increased pressure on the bladder due to the growing uterus. The symptoms are similar in pregnant and non-pregnant women. However, if left untreated in pregnancy, a UTI can potentially cause complications such as premature labor, low birth weight and, in very rare cases, stillbirth.

Treatment of a bacterial UTI is typically through antibiotics. As certain antibiotics have side effects which may affect the development of a fetus, the doctor will prescribe different antibiotics that are safe to use during pregnancy. With medical intervention, most pregnant women make a full recovery with no further complications.