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Kidney infections (pyelonephritis)

Kidney infections are known medically as pyelonephritis and can cause considerable pain and discomfort.

Kidney infections are usually caused by bladder infections spreading up from the bladder into a kidney or both kidneys.

Always seek medical advice for a kidney infection - as without treatment it can result in lasting damage to the kidneys.

Symptoms of kidney infection

Kidney infection symptoms can come on over some days - or a matter of hours.

Symptoms may include:

  • Pain on the side or sides, lower back and around the genital area
  • Abdominal pain
  • Discomfort
  • High temperature/fever
  • Shivering
  • Chills
  • Weakness
  • Feeling tired
  • Lost appetite
  • Nausea
  • Vomiting
  • Diarrhoea
  • Urinating more often, wanting to wee more
  • Burning feeling when urinating
  • Smelly urine, cloudy urine, blood in urine.

A child with a kidney infection may also show signs of:

  • Being irritable
  • Blood in pee
  • Smelly pee
  • Wetting the bed after being dry
  • Not growing at the usual rate if there is a long-term infection.

As well as the kidney infection symptoms, there may also be a bladder infection, cystitis or urethra infection in a child or adult. Symptoms of these infections may include:

  • Pain when peeing, burning feeling
  • An urge to get to the toilet quickly to pee
  • A feeling that the bladder is not fully empty after using the toilet
  • Blood in pee
  • Smelly or cloudy pee
  • Lower abdominal pain.

Kidney infection causes

Bacteria cause kidney infections, usually this is E. coli bacteria. The infection is thought to spread from the bottom (anus) through the penis or vagina area to the urethra tubes, bladder and kidneys.

Kidney infections are more likely to affect women and girls because of the risk of spreading infection when wiping the bottom.

In rare cases the bacteria can spread through the blood if a person's immune system is weakened by a health condition or cancer treatment.

It isn't always known why a person gets a kidney infection, but the chances are higher with:

  • Kidney stones or blockages
  • Enlarged prostate, prostate gland infection in men ( prostatitis)
  • Having urinary tract abnormalities
  • Having problems emptying the bladder completely
  • Use of a catheter to drain urine
  • Having sex, including anal sex
  • Pregnancy
  • Being a victim of female genital mutilation (FGM).

Kidney infection diagnosis

A doctor will diagnose a kidney infection based on the symptoms - especially fever and pain around the sides - the person's medical history and a physical examination.

A urine test may be arranged to check for infection, but this won't tell the doctor where in the urinary tract, including the kidney, the infection is.

Further tests may be arranged, or a referral to a specialist, if the infection isn't helped with treatment, if symptoms worsen quickly, or if there is a risk of complications.

Hospital scans to check the kidneys include:

  • Ultrasound
  • CT scan
  • Isotope scan - where special dye is injected before X-rays are taken to get a better image.

WebMD Medical Reference

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