Kidney infection 


What do our kidneys do?

The kidneys filter waste products from the blood before turning it to urine. This video explains in detail how the kidneys function.

Media last reviewed: 15/11/2013

Next review due: 15/11/2015

The urinary tract

The urinary tract is made up of the:

  • kidneys, which extract waste materials from the blood and convert it into urine
  • ureters, the tubes that run from the kidney to the bladder
  • bladder, the organ that stores urine
  • urethra, the tube that carries urine out of the body

The kidneys 

The kidneys are two bean-shaped organs roughly four inches in length. They are found towards the back of the abdomen on either side of the spine.

They remove waste products from the blood. The clean blood is then transferred back into the body and the waste products are passed out of the body as urine.

An infection that develops inside the urinary tract is known as a urinary tract infection (UTI). As the parts of the urinary tract are all connected, a UTI that develops in one section can spread to another.

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A kidney infection is a painful and unpleasant illness that usually happens when bacteria travel up from your bladder into one or both of your kidneys.

The medical name for a kidney infection is pyelonephritis. It's more serious and different from cystitis, which is a common infection of the bladder that makes urinating painful.

If treated promptly, a kidney infection doesn't cause serious harm but it will make you feel very unwell. If a kidney infection isn't treated, it can get worse and cause permanent kidney damage.

Often the symptoms of a kidney infection come on quickly within a few hours. You can feel feverish, shivery, sick and have a pain in your back or side.

Read more about the symptoms of a kidney infection.

When to see your GP

You should 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.

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 vulnerable to the effects of an infection, for example if you have a pre-existing health condition or are pregnant, you may be admitted to hospital as a precaution and be treated with antibiotics through an intravenous drip.

Antibiotic treatment is usually a very effective way of treating a kidney infection and you should feel completely better after about two weeks.

In rare cases, a kidney infection can cause further problems. These include blood poisoning (sepsis) and a build-up of pus in the kidney called an abscess.

Read more about treating a kidney infection and the complications of a kidney infection.

What causes a kidney infection?

A kidney infection usually happens when bacteria – often a type called E. coli – gets into the urethra (the tube which urine passes through) from the anus and travels up through the bladder into one or both of the kidneys.

Read more about the causes of a kidney infection.

Who's at risk?

Kidney infections are relatively rare. It's estimated that one in every 830 people develops a kidney infection each year in the UK.

They can happen at any age, but are much more common in women. In fact, women are six times more likely to get a kidney infection than men. 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.

Younger children are also vulnerable to developing kidney infections because they may be born with an abnormality of the urinary tract or have a condition called vesico-ureteric reflux, where there is a backflow of urine from the bladder up to the kidneys.

Can kidney infections be prevented?

You can reduce your chances of developing a kidney infection by keeping your bladder and urethra free from bacteria. This can be achieved with simple measures such as drinking plenty of fluids and practicing good genital hygiene.

Read more about preventing a kidney infection.

Page last reviewed: 11/12/2012

Next review due: 11/12/2014


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The 14 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Splash16 said on 24 April 2014

About a month ago, I had a water infection. I had them in the past so I thought there was nothing to worry about so I took some cystitis relief from over the counter which got rid of it in the past. Anyway it didn't. I left it 4 days and my mum told me to go to the doctors so I did and they couldn't find what was wrong with me. (Having no clue if I had a water infection) so never gave me any antibiotics although I was very bad pain when urinating and constant burning, stomach ache and cramps in my back. A couple of days later I was sick (blood) twice one morning. My dad took me straight to A&E and they referred me to hospital. I was in hospital for a week. They put me on a drip. They discharged me still no clue as to what's wrong even though I knew and so did my mum and dad. Now I've just had a scan to see if it's a kidney infection. And since being out of the hospital 4 weeks I've had another 4 infections with all the same pain. I'm 16 and this has not been easy. I hope the results are positive

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LAMB23 said on 30 September 2013

Hi, Just wondering if anybody lse has experianced any of the following. My husband is in the Armed forces and we are Based overseas, Medical care is excellent but language barrier is unhelpful at times..
It started back in Jan 2013 i saw my GP due to Incontience and was referred to have a bladder repair, there was tests to do on the way to see the severty of the Incontience. And the 1st test was a urine sample which shown Blood hey then catheritised me to take another sample incase my original had been cross contanimated, it hadnt and there was blood n the urine naked to te eye. I was then sent to have the Dye in my arm and a series of xrays and a lockage shown up on one of my kidneys, they then sent me for a Cystosocopy & a retrograde xray, there blockage? or whatever it is was still there and they said i would need to be refferred to a nerphrologist?.
They carried on with the ingoing incontience problem i had and i had a TVT tape placed in May.. but i still hadnt heard about what was happening with them finding the blood in urine which is still there?. I ended up going bk to my GP to get the referal, Im worried about what the porblems could possibly be, or what tests i will need again? if any. I suffer from low back ache, and have had numerous urine infection over the years i am a female and am 47yrs old. I have an appointment for begining of Oct, then today the hospital have foned me, asking why i am going to General Meds andNot Gynecology?this has confused me as i would presume it would be Urology i would be seeing..? so again iv foned my GP and they also had the same fone call from the Hospital. This has been ongoing since Feb 2013. and any Information iv read about any kidney problems, all say early treatment is necessary?. iv not taken any antibiotics or anything iv basicaly been left to worry.. thanks

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Bekka_boo13 said on 12 August 2013

I was feeling ill a few weeks ago & it didnt click it could be a UTI went to the docs had to do a urine sample wasnt given anything then an hour later the doctors called to say to pick up my priscription...been taking Macrodantin (Nitrofurantoin) as i'm allergic to penicillien...been taking them a week tomorrow when the meds i feel even worse, Ive been sick, a cough, small pain in my stomach & in my left lower back also my neck is hurting & my legs & arms are a bit stiff & becoming sore...I have suffered with UTI & Kidney infections in the passed & was in hospital in 2007 cause of a kidney infection...any advise...been trying to drink more aswell...i feel awful aswell x

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1moore said on 03 March 2013

my mum has ecoli bug in her kidney. Her infections starts in her bladder the go up to her kidney. Her lft kidney is the weaker kidney as it has been damaged from passed infections. Mum get very ill wear she can pass out , she has been hospitalized and get several infections yearly. The specalist said the only pill that can kill the super bug is Trimethoprim .This tablet gives mum bad asthma and coughing, so she cant take it. I have started making colidal silver will this kill the bug and what would be the best treatment for mum. Please help thanks

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girlthatsparkles said on 31 August 2012

Heya folks. I was admitted to hospit via a&e as i was misdiagnosed by a gp as a bad urine infection. Had been shivering and vomitting for 48hrs and had pains in stomack and lower back, loss of control with urine and diahrrohea had swews of 5 and was admitted with kidney infection and sepsis. Was a nasty shock to the system and only with mum dragging me to gospital saved my life. Was life threatning and was given i.v antibiotics for 5 days - sepsis protocall. Went to infectuous disease ward and was treated by some of the best nhs drs and nurses i have ever encounterd. Was in hospital for a week. Had bladder scans too. And a bladder scan 4 weeks since being home. Im now a renal outpatient as since having kidney infection i have regular symptoms such as pain lower back and stomack, sore when going to toilet, sometimes diahrrhoea and im lack of energy. Currently waiting to have c.t scan for kidneys. They didnt find any kidney stones but have unexplained lumps and clumps in kidneys they not sure if sepsis have set things off. But i must insist to all those that are unsure of symptoms or if there change og symptoms that come on quickly. Please get in touch with g.p or a&e as it may just save your life. So glad to mum that takes no for an answer. If unsure get a 2nd opinion. Xx

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Vanessa3 said on 27 August 2012

Me again! So i finished my course of antibiotics and finally began to feel better after a week. Appeared to have made a full recovery. Then yesterday I started having symptoms of a very painful water infection, pain when passing urine and horrible cramps in my lower stomach, cloudy urine. I drank about 3 litres of water and took pain killers and went to the loo about once every 15 minutes! then i got slight diarrhoea. Went to bed and woke up today not feeling so bad pains in tummy gone, no diarrhoea just moderate pain when I urinate so I continued drinking well all day. Now for about 3 hours... pain in my lower right tummy and in my right side and back in the exact place as last time only a couple of weeks ago!! It's not as intense at the moment but enough to be stopping me from sleeping. Is this normal? should I be worried ? is it normal to have another infection in such short notice, i havent seen a doctor yet to confirm it but I'm at least 90% sure this is yet another kidney infection. My temperature is still normal at the moment.

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Vanessa3 said on 09 August 2012

I've just been told I have a kidney infection. been in absolute agony for 3days now and when its at it's worst it's hard to walk. I feel really really ill and especially at night get horrendous fever like symptoms including shivering uncontrollably and having a very high temp. Been given antibiotics and pain killers which i started yesterday im taking erythromycin and diclofenac. I'm allergic to penecillin so i think it's a different antibiotic to the ones people usually get. however they make me feel ill when i take them and last night i threw up twice. it was just bile that smelt strongly of medication. im worried about continuing taking them but i need to get some relief soon im in so much pain! i have no appetite and i have to battle with myslef to keep hydrated as the water makes me feel sick again. i feel so weak and struggle to look after myself im dizzy when i stand up out of bed and cant really do much for myself. kidney infecctions are horrid!

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chen2011 said on 22 October 2011

We should protect our kidneys. Now more and more people have kidney disease. So I should pay attention to our kidney.

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KidneyResearchUK said on 18 May 2011

Watch our video about kidney disease here:

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suze_87 said on 20 December 2010

in october i had a UTI symptoms such as burning pain when going to the loo and i went to the doctors have a urinaylsis done and comfirmed a UIT. I was given 4 days worth of antibiotics which wasnt doing anything. By the 5th day i woke up in the night with colic pain in my right back. it felt like my kidney squeezing and cramping up so painful and i couldnt walk. in the morning i went back to the doctors who said i may have a kidney stone and gave me some pain killers. over the weekend the pain got worse and i was being sick even when only drinking water i was sick. so i went to the doctors then A&E for an IVU and there were no stones. the SHO said i have either passed them and they also gave me a kidney infection. after being on more antibiotics the GP requested a urine sample which i sent off and came back that the infection was resistant to the original antibiotics. so i was prescribed Augmentin and 6 weeks or more later i still have blood in my urine and sometimes my right back aches but not as bad as before and i also feel that my bladder has weaken due to the infection. It was a horrible experience

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suzielindsay09 said on 29 August 2010

Since having kidney stones when I was a child I have faced infections all through life but now I seem to have a sore bladder if pressed in or when laughing to hard. I know when I have an infection as I get a pain in my lower back which I have also been getting. Should I be worries about the sore bladder and take further action..?

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beckys said on 26 January 2010

I am still waiting for my last lot of lipotripsy, I spent 2 weeks in hospital nearly four years ago when one was stuck in my bladder tube and also had stents put in, I had three stones and even now I am still getting infections and waiting for my final lot of treatment but since having them I seem to get run down more easily and the first thing that happens is my kidney starts to ache, I am hoping after this last session that I will feel better!

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amos9000 said on 23 January 2010

the kidneys create a hormone that tells your bones to make red blood cells, if they have been infected then it may not have done this and you might have become a bit anemic which might be why you are feeling week. as for the thickened arms and legs im not certian it could be that your kidneys are having trouble getting rid of excess fluid causing it to build up.
I had a kidney infection years ago and thought i was fine so i left it. untill about 2 months ago i felt completly fine then started getting tired and week with swelling in my legs and was found to have end stage kidney failure. So i would get it checked out just to be sure theres nothing goin on,.

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PAULA L said on 21 January 2010

i was found to have kidney stones last april, after many months of continually complaining to my doctor. i was at last sent for a ct scan where it was found i had 3 largish ones in my left and a huge one stuck in my ureter. it had been there for some time and had caused blockage and infection of the kidney. after stents being placed in both and lithotripsy on the smaller ones , spending a few days in hospital on 3 occasions with intravenous anti-biotics, various x-rays and blood tests , we at last think the worst is over. my question is , why do i still feel so unwell. i'm always tired and i'm so weak i still cant carry on in my usual capacity. i also have thickened arms and legs , not puffy or swollen but larger than usual and slightly numb; ,and the pain !!!!!!!! has anyone else had these problems as nothing has been properly explained to me ?

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