It is a urinary tract infection that affects the pelvis, parenchyma and renal calyces. It originates in the urinary tracts and rises up to the kidneys. It is mostly women who suffer from this condition.

If appropriate treatment is not carried out in its first phase, it can develop into serious complications that permanently affect the kidney and even septicaemia (blood poisoning which can be fatal).

There are two types:

Acute pyelonephritis.- Infection of the upper urinary tract without the tissues in the kidney being destroyed.

Chronic pyelonephritis.- The tissues in the kidney are destroyed, which is why the presence of lesions in the renal calyces, renal parenchyma and renal pelvis is characteristic. It usually occurs in people who have anatomical anomalies of the kidney.



The causes that can lead to the original infection include the following:

  • Blockages in the urinary tract which can cause vesicoureteral reflux.
  • Kidney stones
  • Urinary catheter- prolonged use of this must be avoided as far as possible.
  • Weak autoimmune system- As in other infections, if the defences are low they will not be able to counteract attacks from microorganisms.
  • Diabetes


  • Abdominal and back pain.
  • Pain or stinging when urinating (dysuria).
  • Haematuria.- Presence of blood in the urine.
  • Fever and chills.


In order to diagnose pyelonephritis, a blood and urine test which confirms the infection will need to be carried out, as well as an ultrasound scan or other tests that the doctor deems appropriate.



  • Antibiotics: to fight the infection, which can be administered either through the oral or intravenous route.
  • Painkillers and antipyretics: to control pain and temperature.
  • Drink a lot of water: with the aim of flushing out the greatest number of bacteria via urine.
  • Apply heat to the lower back
  • Surgery: In the case of chronic pyelonephritis, an operation may be required to correct anatomical problems, and thereby prevent future infections.
  • Urology