Introduction

Kidney infection
Kidney infection
A kidney infection is a painful and unpleasant illness usually caused by cystitis, a common infection of the bladder.
 
Most people with cystitis won't get a kidney infection but, occasionally, the bacteria can travel up from the bladder into one or both kidneys.
 
If treated with antibiotics straightaway, a kidney infection doesn't cause serious harm, although you'll feel very unwell.  If a kidney infection isn't treated, it can get worse and sometimes cause permanent kidney damage.
 
Symptoms of kidney infection
 
Symptoms of a kidney infection often come on within a few hours.  You can feel feverish, shivery, sick and have a pain in your back or side.
 
In addition to feeling unwell like this, you may also have symptoms of a urinary tract infection (UTI) such as cystitis.  These include:
  • needing to pee suddenly, or more often than usual
  • pain or a burning sensation when peeing
  • smelly or cloudy pee
  • blood in your pee

When to see your GP

See your GP immediately if you think your child may have a kidney infrection.

If you can't get a GP appointment and you need urgent medical attention, go to your nearest Accident and Emergency department.

Diagnosing kidney infection

To work out if you have a kidney infection, your doctor will ask about your symptoms and recent medical history.

They will carry out a urine test to see if you have a UTI.

If you are a male with a confirmed UTI, your GP will refer you straight to a specialist (urologist) for further investigation.

Treatment of kidney infection

Most kidney infections need prompt treatment with antibiotics to stop the infection from damaging the kidneys or spreading to the bloodstream.  You may also need painkillers.

If you're especially vunerable to the effects of an infection - for example, if you have a long-term health condition or are pregnant - you may be admitted to hospital and treated with antibiotics through a drip.

After taking antibiotics, you should feel completely better after about 2 weeks.

Causes of kidney infection

A kidney infection usually happens when bacteria - often a type called E.coli - get into the tube that carries urine out of your body (urethra).  The bacteria travel up to your bladder, causing cystitis, and then end up in your kidneys.

E.coli bacteria normally live in your bowel, where they cause no harm.  They can be transferred from your bottom to your genitals during sex or if you're not careful when wiping your bottom after going to the loo.

A kidney infection can sometimes develop without a bladder infection - for example, if you have a problem with your kidney, such as kidney stones, or if you have diabetes or a weakened immune system.

Who's at risk?

Kidney infections can happen at any age and are much more common in women.  This is because a woman's urethra is shorter, making it easier for bacteria to reach the kidneys.

Younger women are most at risk because they tend to be more sexually active, and having frequent sex increases the chances of getting a kidney infection.

Preventing kidney infection

The best way to prevent a kidney infection is to keep your bladder and urethra free from bacteria by:

  • drinking plenty of fluids (plain water is best)
  • going to the loo as soon as you feel the need to, rather than holding it in
  • going to the loo after sex
  • wiping from front to back after going to the loo
  • washing your genitals every day, and before having sex if possible
  • treating any constipation - being constipated can increase your chance of developing a UTI
  • not using a diaphragm or condoms coated in spermicide if you're prone to getting UTI's - it's thought spermicide can increase your risk of getting a UTI

If you keep getting urine infections, your GP may prescribe you a low dose of antibiotics to take regularly.  This may help to prevent the infection returning or prebent any infection spreading to the kidneys.

 

 
^^ Back to top

Symptoms

The symptoms of a kidney infection usually develop quite quickly over a few hours or days.

Common symptoms include:

  • pain and discomfort in your side, lower back or around your genitals
  • high temperature – 38C (100.4F) or above; it may reach 39.5C (103.1F)
  • shivering or chills
  • feeling very weak or tired
  • loss of appetite
  • feeling sick or being sick
  • diarrhoea

You may have other symptoms if you also have a urinary tract infection (UTI) such as cystitis.

These additional symptoms may include:

  • pain or a burning sensation when peeing
  • need to pee suddenly or more often than usual
  • blood in your pee
  • smelly or cloudy pee
  • pain in your lower tummy
  • pain in your genitals

In older people, a kidney infection may cause confusion.

Symptoms in children

Children with a kidney infection may have the following symptoms:

  • smelly pee
  • blood in their pee
  • wetting the bed
  • a high temperature and feeling unwell (they may complain of tummy ache)
  • vomiting and/or not feeding well

A child younger than 2 with a kidney infection may only have a high temperature, without any other obvious symptoms.

When to seek medical advice

See your GP if you feel feverish and you have pain in your tummy, lower back or genitals that won't go away.

You should also see a GP if you have symptoms of a UTI that haven't improved after a few days, or if you have blood in your pee.

Contact your GP immediately if you think your child may have a kidney infection.

Kidney infections require prompt treatment with antibiotics.

^^ Back to top

Treatment

Most people with a kidney infection can be treated at home with a course of antibiotics, and paracetamol if needed.

See your GP if you have a fever and persistent tummy, lower back or genital pain, or if you notice a change to your usual pattern of urination.

You should also see a GP if you have symptoms of a UTI that haven't improved after a few days or if you have blood in your pee.

If you think your child has a UTI, even if it's just cystitis, make sure you see a GP or go to an out-of-hours emergency service.

Medication

Antibiotics

If you're being treated at home, you'll usually be prescribed a course of antibiotic tablets or capsules that lasts between 7 and 14 days.

For most people, apart from pregnant women, antibiotics called ciprofloxacin or co-amoxiclav are recommended. Other antibiotics, such as trimethoprim, may also be used.

Common side effects of ciprofloxacin include diarrhoea and feeling sick. Co-amoxiclav can make the contraceptive pill and contraceptive patch less effective, so you may need to use another form of contraception during the course of treatment.

A 14-day course of an antibiotic called cefalexin is recommended for pregnant women.

Usually, you'll start to feel better quite soon after treatment starts and should feel completely better after about 2 weeks.

If your symptoms show no sign of improvement 24 hours after treatment starts, contact your GP for advice.

Painkillers

Taking a painkiller such as paracetamol should help relieve symptoms of pain and a high temperature.

However, non-steroidal anti-inflammatories (NSAIDs) such as ibuprofen aren't normally recommended for a kidney infection – they may increase the risk of further kidney problems so shouldn't be taken unless advised by a doctor. A doctor may only prescribe these in certain circumstances.

Things you can try yourself

If you have a kidney infection, try not to "hover" over the toilet seat when you go to the loo because it can result in your bladder not being fully emptied.

It's also important for most people with a kidney infection to drink plenty of fluids (water is best) because this will help to flush out the bacteria from your kidneys. Aim to drink enough so that you're frequently passing pale-coloured urine.

If you have kidney failure, get advice from your doctor on how much to drink.

Make sure you get plenty of rest. A kidney infection can be physically draining, even if you're normally healthy and strong. It may take up to 2 weeks before you're fit enough to return to work.

Treatment at hospital

Your GP may refer you to hospital if you have an underlying problem that makes you vulnerable to kidney infections.

It's standard practice to further investigate all men with a kidney infection simply because the condition is much rarer in men. Women don't tend to be referred unless they've had 2 or more kidney infections.

Most children with a kidney infection will be treated in hospital.

Hospital treatment may also be needed if:

  • you're severely dehydrated
  • you're unable to swallow or keep down any fluids or medications
  • you have additional symptoms that suggest you may have blood poisoning, such as a rapid heartbeat and losing consciousness
  • you're pregnant and you also have a high temperature
  • you're particularly frail and your general health is poor
  • your symptoms fail to improve within 24 hours of starting treatment with antibiotics
  • you have a weakened immune system
  • you have something inside your urinary tract, such as a kidney stone or a urinary catheter
  • you have diabetes
  • you're over the age of 65
  • you have an underlying condition that affects the way your kidneys work, such as polycystic kidney disease or chronic kidney disease

If you're admitted to hospital with a kidney infection, you'll probably be attached to a drip so you can be given fluids to help keep you hydrated. Antibiotics can also be given through the drip.

You'll have regular blood and urine tests to monitor your health and how effectively the antibiotics are fighting off the infection.

Most people respond well to treatment. As long as there are no complications, you should typically be well enough to leave hospital in 3 to 7 days.

Treatment will usually switch to tablets or capsules after you stop receiving antibiotics through a drip.

You may need further investigations if you get more than one kidney infection. Your GP or hospital specialist would arrange these tests for you.

^^ Back to top


The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 18/06/2018 15:30:06