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Urinary tract infection

What is a urinary tract infection?

Urine is usually sterile: that is, it contains no micro-organisms. Urinary tract infection (UTI) is the general term given to infection of the urinary system, with bacteria and pus cells being present in the urine. Inflammation in the bladder is called 'cystitis', whether or not it is caused by infection. If one or both kidneys are involved then the condition is called 'nephritis'.

What causes a urinary tract infection and who is at risk?

The bacteria that cause UTI are usually the individual's own normal intestinal organisms which, in certain circumstances, are able to pass from the area around the anus into the urethra (the tube connecting the bladder with the outside of the body) and so into the bladder. Nephritis is usually caused by the same kinds of bacteria managing to spread from the bladder into the ureters (the tubes connecting the kidneys to the bladder) and up to the kidneys. UTI can also be caused by other bacteria, including tuberculosis, reaching the kidneys via the bloodstream.

A number of factors increase the risk of developing UTI:

• Being female: the female urethra is shorter than the male's, and this, together with the antibacterial actions of some secretions of the male's prostate gland, probably accounts for why women are more likely than men to develop UTI.
• Sexual position: Some women find that they are liable to develop a UTI if, during sexual intercourse, their partner enters their vagina from behind. This is simply because in this position it is more likely that bacteria from around the anus may be pushed forward towards the urethra
• Failure to completely empty the bladder: The most important causes of this are obstruction caused by prostate enlargement in men or neurological diseases in either sex
• Abnormal structure of the bladder: This can be something that you are born with or that develops later in life
• 'Vesico-ureteric reflux': This is a condition that some children are born with, in which urine flows back into the ureters or kidney during urination
• Being pregnant
• Being diabetic
• A tumour in the urinary tract
• Stones in the urinary tract
• 'Foreign body' in the urinary tract: Urinary catheters, nephrostomy tubes (a tube inserted into the kidney to drain urine to the abdominal surface) and ureteric stents (a wire tube fitted in the urethra to keep the passage open) all tend to increase the likelihood of infection.

What are the common symptoms and complications of a urinary tract infection?

Symptoms of UTI include:

• A burning sensation on passing urine
• Needing to pass urine more frequently than usual
• Needing to hurry to get to the toilet in time to pass urine (sometimes incontinence may occur)
• Having the sensation of needing to pass urine but being unable to do so
• Having cloudy urine, which may be foul smelling
• Having blood present in the urine
• Feeling unwell
• Having a fever

If there is infection of the kidneys themselves, the illness is usually more severe, with lower back pain on one or both sides, high fevers and chills.

Some people, usually women rather than men, have recurrent symptoms suggestive of UTI but without infection being present. This condition is not serious but can be troublesome. The symptoms sometimes can be caused by chemical irritation such as bath additives and washing powders. Therefore, they may disappear if toiletries and washing powder are changed.

How do doctors recognise a urinary tract infection?

Your doctor may be able to determine that you have a UTI by a 'dipstick test'. This test involves dipping a special plastic strip into a sample of fresh urine and gives a result within a minute or two.

Often, however, a sample of urine will need to be sent away for 'culture' testing. This will confirm that infection is present, identify the kind of bacteria causing the infection and check that the antibiotic prescribed by the doctor is appropriate for the type of infection.

In women, no further investigations would usually be required, unless the UTI was a recurring problem. In men and children, additional investigations may be carried out to identify any underlying cause. These examinations may include an ultrasound scan of the bladder and kidneys and/or cystourethroscopy (examination of the inside of the bladder using a flexible telescope inserted into the bladder via the urethra).

What is the treatment for a urinary tract infection?

Self-care action plan

People who are prone to getting UTIs usually find that drinking plenty of fluids throughout the day is helpful. UTI in women sometimes can be prevented by avoiding sexual intercourse 'from behind' and/or passing urine immediately after intercourse.

Someone who has symptoms of UTI and is pregnant or diabetic should see their doctor promptly.

Medicines

UTI is normally treated with an antibiotic. Generally, an antibiotic is prescribed as soon as a UTI is diagnosed, without waiting for the results of a urine 'culture' test. A five-day course of tablets is usually given, but sometimes a single large dose is used. Symptoms usually start to improve within 24 hours, but the full course of antibiotics prescribed should be taken to ensure the infection is cleared up completely.

Occasionally, the 'culture' test result may make it necessary to change to a different antibiotic. Nephritis generally requires hospital admission, where antibiotics will be given by drip into a vein. Some people with recurrent UTIs need to take continuous low doses of antibiotics.

Surgery

Surgery is sometimes needed to correct an abnormality of the urinary tract that increases the likelihood of an individual having an infection. Children with vesico-ureteric reflux, in which urine can pass backwards from the bladder to the ureter, may require preventative antibiotics for a period of time, but the condition usually improves without surgery as they grow older. If UTI is caused by the presence of renal stones, these will need to be removed, often by 'lithotripsy'- an external shock wave therapy that breaks the stones into small pieces which are then passed in the urine.

What is the outcome of a urinary tract infection?

UTI rapidly responds to appropriate antibiotic treatment. If left untreated however, it can eventually cause permanent kidney damage.

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