Urinary Tract Infection (UTI)

Originally published on: April 6th, 2017. Last modified on August 16th, 2021

Urinary tract infections (UTI’s) are a common and usually mild infection that can affect the bladder, urethra, ureters and kidneys. UTI’s can occur at all ages, although women are particularly at risk and over 50% will experience at least one episode during their lifetime. 

Most of the time, a UTI will cause a short acute illness and can mostly be easily treated with a course of antibiotics. Occasionally however, depending on the site and type of infection they can develop into a serious, even life-threatening condition. If you think you have a Urinary Tract Infection be sure to contact your GP or Healthcare professional as early as possible.

The infection can occur in your lower urinary tract and affect your bladder and urethra, this type of infection is known as bacterial cystitis. The infection can also occur in your upper urinary tract and affect your kidneys and ureters, which is known as pyelonephritis or a kidney infection.

Symptoms Of A Urinary Tract Infection

Symptoms of a lower UTI include

  • Frequency and/ or urgency
  • Pain or discomfort when urinating (usually a burning sensation)
  • The feeling of being unable to empty your bladder fully
  • Cloudy and/or foul-smelling urine that may contain blood
  • Pain in your lower abdomen and pelvis
  • Feeling achy, tired and generally under-the-weather

Symptoms of an upper UTI include

  • A high temperature of 38°C (100°F)
  • Pain in your sides or back
  • Shivering or chills
  • Nausea or sickness
  • Confusion
  • Agitation or restlessness

Causes of Urinary Tract Infections

A UTI is caused by a bacterial infection in the urinary tract. The urinary tract is where our bodies make and expel urine and is made up of the kidneys, the ureters, the bladder and the urethra. You can get an infection in the lower (bladder & urethra) or upper (kidney & ureters) part of the urinary tract. Upper UTIs are potentially more serious because there is a risk of kidney damage and in acute cases can cause kidney failure or blood poisoning. Urinary tract infection is a term used to cover a variety of infections. 

The three main causes of UTI’s are: 

  • Cystitis – infection in the bladder
  • Urethritis – infection in the urethra
  • Pyelonephritis – infection in the kidney

Cystitis (lower UTI)

If bacteria reach the bladder, they can multiply and irritate the bladder lining, causing the symptoms of cystitis.

The main symptoms associated with bacterial cystitis include:

  • Pain when urinating
  • An urgent need to pass water but only passing small amounts
  • A constant feeling of the need to urinate even when the bladder is empty
  • Urine that can be cloudy and dark and strong smelling
  • Lower abdominal pain and/or a mile fever

It is important to see your GP if you think you have an infection. He or she will test a urine sample for bacteria and if present will prescribe antibiotics. 

You can help the treatment process with the following:

  • Drinking plenty of water (around 1.5 – 2 litres or 6-8 glasses every day). 
  • Painkillers, such as paracetamol or an anti-inflammatory such as ibuprofen can also be taken if needed. 
  • Drinking cranberry juice may also help reduce infections, one to two glasses a day can help whilst you have an infection or a glass every day as a maintenance dose if you suffer from recurrent infections (people taking Warfarin should avoid cranberry juice, and diabetics should check the sugar content) 

For more about the causes and symptoms, see Bacterial Cystitis, and the Treatments available.

Urethritis (lower UTI)

Urethritis is inflammation of the urethra – the tube from the bladder through which urine flows out of the body – which may be caused by an infection. Infections are usually caused by bacteria entering the urinary tract via the urethra and can generally be easily treated with antibiotics. Symptoms are similar to those for Cystitis and it is advisable to visit your GP if you think you may have an infection.
NSU can cause different symptoms in men and women. 

The symptoms of NSU in men can include:

  • a white or cloudy discharge from the tip of the penis
  • a burning or painful sensation when you urinate
  • the tip of your penis feeling irritated and sore
  • a frequent need to urinate

NSU tends to cause no noticeable symptoms in women unless the infection spreads to other parts of the female reproductive system. 

Pyelonephritis (Upper UTI)

A kidney infection is a painful, unpleasant illness that usually happens when bacteria travels up from your bladder into one or both of your kidneys. The kidneys and ureters are often both infected at the same time. Often the symptoms come on quickly, within a few hours, and they can make you feel feverish, shivery, sick and with a strong ache or pain in your back or side.

The symptoms may include those of a lower UTI (see Cystitis above) as well as:

  • High temperature (over 38°C or 101°F)
  • Nausea or vomiting
  • Shivering or chills (Rigours)
  • Pain in lower back (may only be one side)

If you have any of these symptoms you should seek medical advice as soon as possible.

How Is A Urinary Tract Infection Diagnosed?

Your GP will probably ask you to provide a urine sample and will do a simple dipstick test to look for signs of any infection.

Find out about Urinary Tract Infection Treatments.

Further Information

If you think you might have a UTI or are experiencing similar symptoms to those described in this article, it is most important to make an appointment to see your doctor straight away. You may also wish to seek advice from your local continence clinic. The clinics are run by the NHS and you don’t always need to be referred to a clinic by your GP, as some clinics will allow you to book an appointment yourself. 

To find your nearest continence clinic use our Healthcare Professional Finder.