The symptoms of an infection in your upper urinary tract (kidney and ureters) are different from symptoms of infection in your lower urinary tract (bladder and urethra).

However, in some cases you may notice the symptoms of both, as one can spread to the other.

Symptoms of a UTI are similar to those of many other conditions and don't necessarily mean you have an infection.

Symptoms of a lower UTI can include:

• urethral syndrome – this includes needing to urinate more often, a constant, dull pain in the pubic region, and pain when urinating (dysuria)
• cloudy urine or blood in your urine (haematuria)
• urine that smells unusually unpleasant
• back pain
• a general sense of feeling unwell

Symptoms of an upper UTI can include: 

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

With an upper UTI you may also notice pain in your side, back or groin. The pain can range from moderate to severe, and it is often worse when you're urinating.

When to seek medical advice

There is a higher risk of complications with an upper UTI, so see your GP if you notice any of the symptoms.

Although many lower UTIs are mild and get better within a few days, speak to your GP if your symptoms are causing you a lot of pain and discomfort or if they last more than five days.

Increased risk of complications

There are some risk factors that increase your risk of more serious complications from a UTI. These include:

• kidney disease
• type 1 diabetes or type 2 diabetes
• a weakened immune system caused by treatment such as chemotherapy or a health condition such as HIV
• an object in your urinary tract, such as a kidney stone or catheter (a thin tube inserted by a health professional into the urethra to drain the bladder)
• being pregnant
• being over 65 years old

See your GP if any of these apply to you and you notice symptoms of a UTI.

Find out more about complications of a UTI.

UTIs and dementia

If an elderly person with dementia develops a UTI, it may lead to a noticeable change in their behaviour within a few days, known as delirium.

Signs of delirium may include:

• agitation or restlessness
• difficulty concentrating
• hallucinations or delusions
• becoming unusually sleepy or withdrawn

As the person with dementia may not be able to communicate the problem, it's important for family and carers to be aware of the signs of a UTI. Seek medical help if you notice these signs so they can be assessed and treated as soon as possible.