Mediclinic Al Sufouh

Knowledge Village - Dubai

Mediclinic Dubal Mall

Fashion Avenue - Dubai


Kidney infection

Table of Contents

Pyelonephritis is an acute UTI (Urinary Tract Infection) of the kidney.

It originates from the complication o cystitis. The bacteria from the bladder can spread to the kidney through the ureter. It is the cause of kidney infection.

Symptoms are lumbar pain and high fever.

The diagnosis and treatment must be immediate to have a full recovery. Delay may result in unpredictable progression.

Chronic pyelonephritis is less common and is a complication of dysfunctions like reflux of urine from the bladder to the kidney or chronic kidney obstructions.

We define uncomplicated pyelonephritis as when it occurs in non-pregnant, pre-menopausal women without relevant urologic abnormalities or other chronic diseases.

Causes of pyelonephritis

Acute pyelonephritis is a complication of lower UTI (urinary tract infection), usually cystitis. The bacterial count increases in the bladder and can spread up through the ureter into the kidney.

The risk of kidney infection increases:

  • In females: UTIs are more frequent in women;
  • During pregnancy;
  • In obstructed urinary tract (stone, prostate enlargement);
  • If the immune system is weak;
  • In bladder voiding dysfunction (neurologic)
  • In chronic bladder catheterization;
  • In vesicoureteral reflux.


 Cystitis usually precedes fever and lumbar pain. Other possible symptoms are:
  • Abdominal pain
  • Nausea and vomiting
  • Pus or blood in the urine (hematuria)
  • Urine that smells bad or is cloudy


It is essential to differentiate as soon as possible between uncomplicated and primarily complicated obstructive kidney infection, as the latter can rapidly lead to spreading infection in the blood. An immediate US scan helps in this regard.
Treatment of pyelonephritis

Usually requires immediate IV antibiotic treatment. Complicated infection often requires kidney drainage to decrease the back-pressure related to obstruction (insertion of a tube in the skin of the lumbar area, directly into the kidney; insertion of an internal conduit in the ureter).

Final recommendations

Uncomplicated kidney infection regards non-pregnant, pre-menopausal women with no chronic diseases and urological abnormalities.

It requires prompt IV antibiotic treatment, and the prognosis is always good with complete recovery.

The infection in pregnancy requires careful attention, complex antibiotic treatment and possible drainage of the affected kidney.

Kidney infection with obstruction and renal back-pressure is an emergency. We must treat it with a combination of antibiotic therapy and renal drainage.

The treatment must be prompt because of the risk of a life-threatening, generalized blood infection (sepsis).