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Urinary tract infection, adults

Page last reviewed: 13/07/2011

A urinary tract infection (UTI) is a common type of infection that occurs in the urinary tract (see below). The symptoms of a UTI include:

  • pain or a burning sensation during urination (dysuria)
  • a frequent need to urinate
  • lower abdominal pain

The urinary tract

The urinary tract is made up of:

  • The kidneys, which extract waste materials from the blood and convert them into urine.
  • The ureters, which are tubes that run from the kidney to the bladder.
  • The bladder, which is a balloon-shaped organ that is used to store urine.
  • The urethra, which is the tube that passes from the bladder through the penis (in men) or vulva (in women), through which urine passes. In women, the urethra is located between the opening of the vagina and the clitoris.

Types of UTI

A UTI develops when part of the urinary tract becomes infected, usually by bacteria. Bacteria can enter the urinary system through the urethra or, more rarely, through the bloodstream.

There is usually no obvious reason why the urinary tract gets infected, although some women find that they develop a UTI after having sexual intercourse.

There are two types of UTI:

  • Lower UTI is an infection of the lower part of the urinary tract, which includes the bladder and the urethra. An infection of the bladder is called cystitis, and an infection of the urethra is known as urethritis.
  • Upper UTI is an infection of the upper part of the urinary tract, which includes the kidneys and the ureters. Upper UTIs are potentially more serious than lower UTIs because there is a risk of kidney damage.

How common are UTIs?

UTIs are a very common type of infection in women. It is estimated that one woman in three will have a UTI before the age of 24, and that half of all women will have at least one UTI during their lifetime.

UTIs are a lot less common in men. It is estimated that every year in otherwise healthy men, only one in every 2,000 will develop a UTI.


The outlook for most cases of UTI is excellent. The infections are usually mild and will usually resolve within four to five days. Antibiotics can be used to help speed up the recovery time.

However, some women find that they experience repeated UTIs, and that they require long-term treatment with antibiotics to prevent the infection returning.

Complications of a UTI are uncommon, but serious, and include:


  • kidney failure, where the kidneys lose almost all of their functioning capability
  • blood poisoning, also known as sepsis

These complications usually only affect people with a pre-existing health problem, such as diabetes, or a weakened immune system (the body's natural defence against infection).

Page last reviewed: 13/07/2011

Lower urinary tract infection

The symptoms of a lower urinary tract infection (UTI) include:

  • cloudy urine
  • a need to urinate more frequently, either during the day, or night, or both
  • pain or discomfort when passing urine
  • an urgent need to urinate (holding in your urine becomes more difficult)
  • unusually unpleasant smelling urine
  • blood in your urine (haematuria)
  • abdominal pain
  • a feeling of tenderness around your pelvis
  • back pain
  • a general sense of feeling unwell

Upper urinary tract infection

The symptoms of an upper UTI include:

  • a high temperature (fever) of 38ºC (100.4ºF) or above
  • uncontrollable shivering
  • nausea
  • vomiting
  • diarrhoea

You may also experience pain in your side, back or groin. The pain can range from moderate to severe, and it is often worse when you are urinating.

In addition, you may experience the symptoms of a lower UTI because the infection can spread from your kidneys to your lower urinary tract.

When to seek medical advice

An upper UTI has a higher risk of complications, so it is always recommended that you visit your GP if you suspect that you have an upper UTI.

You should also visit your GP if you think that you have a lower UTI and your symptoms do not improve or they suddenly get worse.

You should also visit your GP if you have a risk factor that increases the chances of the infection causing more serious complications. Risk factors that are linked to a higher chance of developing complications include:

  • a weakened immune system (immunocompromised) caused by treatment such as chemotherapy or a health condition such as HIV
  • kidney disease
  • type 1 or type 2diabetes kidney stone
  • a foreign body in your urinary tract, such as a , or an in-dwelling catheter (a tube that is used to drain the bladder)
  • being pregnant
  • being over 65 years of age

Page last reviewed: 13/07/2011

Most urinary tract infections (UTIs) are caused by bacteria that live in the digestive system.

It is thought that the bacteria can be spread via the anus (the opening through which stools are passed out of the body) to the urethra.

This can happen if, when wiping your anus after going to toilet, the toilet paper comes into contact with your genitals. The bacteria can then multiply and move through your urinary tract causing the following possible infections:

  • Infection of your urethra (urethritis). The urethra is the tube that runs from the penis or vagina up into the bladder, through which you urinate.
  • Infection of your bladder (cystitis). The bladder is a balloon-shaped organ used to store urine.
  • Infection of your ureters (ureteritis). The ureters are tubes that run from the bladder to the kidneys.
  • Infection of your kidneys (pyelonephritis). The kidneys are two bean-shaped organs that are used to remove waste products from your blood and convert them into urine.

Risk factors

Women are more likely to develop a UTI than men. This is because a woman's urethra is located closer to the anus than a man's, which makes it easier for bacteria from the anus to reach the urethra. The female urethra is also much shorter than the male urethra (which runs through the penis), making it easier for bacteria to reach the bladder.

You are also more likely to develop a UTI if:

  • You have a condition that obstructs or blocks your urinary tract, such as kidney stones.
  • You have a condition that prevents you from fully emptying your bladder. If urine stays for too long in the bladder it provides an environment that allows bacteria to thrive and multiply.
  • You have a weakened immune system, for example, because you have diabetes, or are undergoing chemotherapy (medication to treat cancer).
  • You are female and sexually active. Sexual intercourse can irritate the urethra, allowing bacteria to travel more easily through it and into your bladder.
  • You are male and have an enlarged prostate gland. If the prostate gland is enlarged, it can place pressure on the bladder and urethra, preventing the bladder from emptying fully.
  • You have a urinary catheter, which is a tube that is inserted into your bladder to drain away urine.
  • You use a diaphragm. Diaphragms (a barrier form of contraception that sits inside the vagina) can place pressure on the bladder, preventing it from emptying properly.
  • Your sexual partner uses condoms coated with spermicide. The chemicals in spermicide gel can irritate the vagina making it more vulnerable to infection.

Asymptomatic bacteriuria

The presence of bacteria in your urine does not necessarily mean that you will develop a urinary tract infection (UTI). For example, many people, particularly the elderly, have bacteria in their urine without having any ill effects. This is known as asymptomatic bacteriuria.

Page last reviewed: 13/07/2011

If you are a woman and you have the typical symptoms of a lower UTI, further testing is not usually required to confirm the diagnosis. This is because a lower UTI causes a distinctive pattern of symptoms, so a reasonably confident diagnosis can be made simply by asking you about your symptoms.

When testing is required

There are a number of circumstances where testing is usually recommended. These are:

  • In all cases of UTI in men. UTIs are uncommon in men, so it is important to rule out other possible causes of the symptoms.
  • In cases of a suspected upper UTI. These infections have a higher risk of complications, so a careful assessment of the state of the urinary tract needs to be made.
  • UTIs that occur in pregnant women. Pregnant women have a slightly higher risk of developing complications.
  • In cases where a person has blood in their urine. Although unlikely, this could be a symptom of bladder cancer, so it is important to rule out or confirm the diagnosis.
  • In cases where a person has a risk factor that makes them more vulnerable to developing serious complications, such as having a weakened immune system.

Initial testing involves taking a urine sample and testing it for the presence of bacteria. This can confirm the diagnosis and it is useful for deciding what the most effective antibiotic is to use for your treatment.

Further testing

Further testing for a UTI is only required if your symptoms fail to improve, or you experience repeated UTIs that could be caused by abnormalities in your urinary tract, such as a bladder stone.

Further testing may also be required to rule out a diagnosis of bladder cancer in cases where you have noticed blood in your urine.

Intravenous urogram (IVU)

One test that is used to assess the state of the urinary tract is called an intravenous urogram (IVU).

Before the IVU takes place, you will be injected with a special dye that shows up on an X-ray. The radiologist (a specialist in using medical imaging technology, such as X-rays) will study how the dye moves through your urinary system in order to see whether there are any problems.

You may experience a metallic taste in your mouth and flushed, itchy skin when the dye is injected. However, this is normal and these symptoms should pass after a few minutes.


Another test that is sometimes used is known as a cystoscopy. A cystoscopy is a procedure that uses a special instrument, called a cystoscope, to examine the inside of your bladder. A cystoscope is a thin, flexible telescope that is passed into your body so that the urologist (a specialist in treating conditions that affect the urinary tract) can look inside your bladder.

During a cystoscopy, a jelly-like substance that contains a local anaesthetic is squirted into the opening of your urethra (the tube that runs from the bladder to the penis, or vagina, through which urine passes). As well as working as a painkiller, the jelly helps the cystoscope to pass into the urethra more easily.

A cystoscopy usually takes between five and ten minutes to perform. The urologist will study the lining of your bladder and urethra in order to identify any abnormal areas that could be the result of bladder cancer.

Page last reviewed: 13/07/2011

Your treatment plan

Your recommended treatment plan will depend on whether you have a lower or an upper urinary tract infection (UTI). A lower UTI can usually be treated at home using antibiotics, as can cases of mild to moderate upper UTI. More serious cases of upper UTI, or cases that develop in people with pre-existing risk factors that increase the risk of complications, will require hospital treatment.

Lower UTI - treatment at home

Treatment at home for a lower UTI usually involves taking a three to seven day course of an antibiotic. The exact length of the course will depend on whether you have an increased risk of developing complications.

Trimethoprim is an antibiotic that is often used to treat cases of lower UTI. Side effects of trimethoprim are uncommon and they are usually mild. They include:

  • nausea
  • vomiting
  • skin rash
  • itchy skin

Over-the-counter (OTC) painkillers, such as paracetamol or ibuprofen, can be used to relieve symptoms of UTI such as abdominal pain.

Upper UTI - treatment at home

Treatment at home for an upper UTI usually involves taking a seven to fourteen day course of antibiotics. Again, the length of the course will depend on your risk of developing complications.

Antibiotics called co-amoxiclav or ciprofloxacin are usually used, unless you are pregnant, in which case an alternative antibiotic called cefalexin, which is known to be safe to be used during pregnancy, can be used instead.

These antibiotics can cause drowsiness, so while you are taking them avoid driving and operating complex or heavy machinery.

Make sure you drink plenty of fluids as this will help to relieve your symptoms of fever, and will also help to prevent dehydration.

Paracetamol can be used to treat the associated symptoms of an upper UTI. However, you should not use the non-steroidal anti-inflammatory drug (NSAID) type of painkiller, such as ibuprofen or naproxen, because they can increase the risk of developing kidney complications.

Treatment at hospital

You may be admitted to hospital if you have an upper UTI and:

  • you are pregnant
  • you are over 60 years of age
  • you have symptoms of severe vomiting
  • you have symptoms of severe pain
  • you are dehydrated
  • you are unable to pass urine, or the amount of urine you are passing is severely reduced
  • you have a blockage in your kidneys, such as a kidney stone
  • you have diabetes
  • you have been undergoing chemotherapy and/or radiotherapy
  • you have a previous history of kidney disease
  • you have a previous history of recurring upper UTIs
  • you have HIV
  • you have sickle-cell anaemia
  • you have cancer

If you are admitted to hospital with an upper UTI, you will probably be attached to a drip so that you can be given fluids to help keep you hydrated. Antibiotics can also be administered through the drip.

You will be given regular blood and urine tests so that your health can be carefully monitored, and to measure the effectiveness of the antibiotics at fighting off the infection.

Most people who are admitted to hospital to be treated for an upper UTI respond well to treatment and are able to leave hospital within three to seven days.

Treating recurring UTIs

If you have repeated and recurring UTIs, further treatment may be required to prevent permanent damage to your urinary tract.

If it is thought that the recurring UTIs are due to your urethra becoming irritated after sexual intercourse, you may be given antibiotic tablets. You should take a tablet after each time that you have sex, ideally in the first two hours after intercourse.

If you are using a diaphragm or spermicide-coated condom as your main method of contraception, you may want to consider using another method that does not increase your risk of developing UTIs, such as the contraceptive pill.

If the recurring UTIs are not thought to be linked to sexual intercourse, you may be given a low-dose antibiotic to take daily.

A medication called methenamine hippurate is an alternative to taking antibiotics. Methenamine hippurate works by changing the chemical composition of your urine, making it 'less attractive' to bacteria.

Side effects of methenamine hippurate are uncommon and include:

  • skin rashes
  • itchy skin
  • indigestion

Methenamine hippurate is not as effective as antibiotics in preventing the return of infection. Therefore, it tends to be used only when people are unable or unwilling to take antibiotics.

There are also some lifestyle changes that you can make to reduce the risk of UTIs. See UTI, adults - prevention for more information.


Page last reviewed: 13/07/2011

Women are more likely to develop urinary tract infections (UTIs) than men. This is because, in women, the urethra is located closer to the anus than in men, making it easier for bacteria from their anus to reach their urethra. The female urethra is also much shorter than the male urethra (which runs through the penis), making it easier for bacteria to reach the bladder.

You are also more likely to develop a UTI if:

  • you have a condition that obstructs or blocks your urinary tract, such as kidney stones
  • you have a condition that prevents you from emptying your bladder fully
  • you have a weakened immune system, for example, because you have diabetes, or you are undergoing chemotherapy
  • you are female and sexually active (this is because sexual intercourse can irritate the urethra, allowing bacteria to travel more easily through it and into your bladder)
  • you are male and have an enlarged prostate gland
  • you have a urinary catheter (a tube that is inserted into your bladder to drain away urine)

Page last reviewed: 13/07/2011

While not all cases of urinary tract infection (UTI) can be prevented, there are some steps you can take to reduce your risk of developing an infection. These are explained below.

Cranberry juice and capsules

Drinking cranberry juice may help to prevent UTIs. If you have had recurring UTIs, higher strength cranberry capsules are recommended. These are available from most pharmacists.

However, you should not consume cranberry juice or cranberry capsules if you are taking warfarin (a medicine that is used to prevent blood clots).

Treat constipation promptly

Constipation (where it is difficult to pass stools) can increase your chances of developing a UTI.

Recommended treatments for constipation include:

  • increasing the amount of fibre in your diet (20g to 30g of fibre a day)
  • using a mild laxative on a short-term basis
  • drinking plenty of fluids

You should see your GP if your symptoms do not improve after 14 days. Children should see their GP if their symptoms have not improved after seven days.

There is growing evidence that probiotics and the use of oestrogen supplements in post menopausal women may also help. Talk to you GP for further information.

Other useful advice

The following advice may be useful in helping you to keep your bladder and urethra free from bacteria:

  • go to the toilet as soon as you feel the need to urinate, rather than holding it in
  • wipe from front to back after going to the toilet
  • practise good hygiene by washing your genitals every day, and before having sex
  • empty your bladder after having sex

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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