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Pyelonephritis (kidney infection)

Understanding the kidneys and urinary tract

There are two kidneys, one on each side of the abdomen. They make urine which drains down the ureters into the bladder. Urine is stored in the bladder and is passed out through the urethra each time we urinate.

Common cause of Pyelonephritis:

  • Most kidney infections develop as a complication of cystitis (bladder infection). Bacteria causing cystitis can sometimes travel up to infect a kidney. The bacteria are usually those which live in the bowel. They can travel from the anus, up the urethra into the bladder. However, most people with cystitis do not develop a kidney infection.
  • Some kidney infections develop without a bladder infection. This is due to other problems in the kidney, such as, kidney stones or an abnormality of the kidney.

It is usually one kidney that develops an infection. The incidence of kidney infection is more common in women. This is because women are at more risk of developing a bladder infection, which can spread to the kidneys.

In women, the urethra is closer to the anus which makes it easier for bacteria to travel from the bowel up to the urethra. The urethra is also shorter in women than in men; it measures 3.5mm in women and 15mm in men.

Symptoms of a kidney infection

  • Pain in the side of the abdomen or back area over the kidney (loin pain)
  • High temperature (38 degrees centigrade), with rigors (shivers)
  • Feeling nausea, vomiting and or diarrhoea
  • Blood in your urine (haematuria)
  • Pain on urinating and frequency

Treatment for a kidney infection

  • Antibiotics- to clear the infection
  • Analgesia- Non-steroidal anti-inflammatory painkillers will not be recommended as they can cause an increased risk of problems with the kidney function during a kidney infection
  • Increase fluid intake to prevent dehydration