Pyelonephritis is infection and inflammation of the urine collecting system (the pelvis) of the kidney. There may be small abscesses in the substance of the kidney

Symptoms

The condition causes sudden pain in the back, under the ribs (the loin), radiating to the lower quadrant of the abdomen on the same side. There is difficulty in passing urine, with a burning or scalding sensation as the urine passes out, accompanied by high fever, shivering, vomiting and, in children, sometimes convulsions.

Causes

The infection reaches the kidneys from the bladder. Often the urinary system has been damaged by urinary disorders in childhood, with urine flowing back up the ureters (the tubes that carry the urine from the kidneys to the bladder). Such damage may cause the valve at the lower end of a ureter to fail, so that urine infected by germs in the bladder can pass back up.
There may also be urinary stones in the tubes, causing partial blockage.

Diagnosis

This is made on the basis of the symptoms and CT or MRI scanning. The urine will be cultured for germs and examined under the microscope for pus cells.

Treatment

Pyelonephritis is treated with antibiotics.

Any underlying cause is investigated and, if possible, removed.
Taking plenty of fluids every day is important.
In severe cases the pus may have to be drained surgically.
Complications
Pyelonephritis may progress to a kidney abscess. This causes bulging of the back wall under the ribs and an acute worsening of the condition, and the abscess may burst through the wall of the back to the exterior.


Written by Medpages Editorial Team
Last Editorial Review: 19/1/2010