What is this?

It is a bacterial urinary tract infection of the renal parenchyma and excretory tract intra-renal.

It is common in women.

Contamination mechanism and germ involved:

There are two mechanisms of contamination:

  • The ascending pathway: Acute pyelonephritis occurs when germs rise from the bladder to the kidneys through the ureters. The germs involved are the same than for cystitis.
  • The hematogenous route: the kidney is infected by the germs carried by the blood during of sepsis. The most common germ involved is staphylococcus.


Typically, the clinical picture associates signs of cystitis (voiding burns, urge to urinate and pollakiuria) with signs of renal parenchymal involvement:

fever, lower back pain radiating to the pubis and external genitalia.

Physical examination finds pain on palpation of the lumbar fossa.


ECBU: positive

Biological inflammatory syndrome: leukocytosis, high CRP.


Renal ultrasound is essential in the search for pyelocalicular dilation posing thus the diagnosis of acute obstructive pyelonephritis.


In the case of acute non-obstructive pyelonephritis, treatment is based on antibiotic therapy for 15 days associated with analgesic treatment and hyperdiuresis.

In obstructive forms the treatment is medico-surgical combining treatment antibiotic and urine drainage either by a double J catheter or by a percutaneous nephrostomy.