Pyelonephritis

Alternative names: Kidney Infection, Urinary Tract Infection (UTI)

Pyelonephritis affects either one or both kidneys.  Possible scarring of the kidneys is an important reason to recognize, treat and, when possible, to prevent urinary tract infections.  Scarring can lead to serious kidney problems years down the road.

Urinary Tract Infections (UTI). Undiscovered infections of the kidney during childhood or later may remain for years without causing noticeable symptoms.  Such an infection can cause scarring of the kidney which in turn distorts and destroys parts of the kidney.  For most children, teenagers and women the infection does not progress and it is eradicated by the body.  The damage done does not affect the ability of the kidneys to do their job.  However, in a few people, the continuous destruction of the kidney leads to chronic renal failure which will require treatment.

Incidence; Causes and Development

The infection occurs more frequently in women than in men simply because the opening of the urethra in women is closer to the anus and the bacteria from the bowel.

Pyelonephritis is caused by bacteria, most often from the bowel, entering the urinary system from the outside, up the urethra, into the bladder and then up one or both ureters to the kidneys.  Prostatism and kidney stones can also cause infection as they prevent efficient flow of urine from the bladder.

Reflux Nephropathy
For some children and adults the problem is caused by a condition called reflux nephropathy.  This is a combination of two problems that make infection more likely to occur.

Firstly, there are little valves at the ends of the two ureters where they join the bladder.  These are supposed to prevent urine that has drained from the kidneys being allowed back up the ureters to the kidneys.  These valves do not always work properly.  When the bladder contracts to push the urine out of the body through the urethra, they allow some urine to escape up into the kidneys again.

Secondly, the bladder may not empty properly each time a person (a child especially) goes to the toilet.  With the stale urine that has not emptied out going up into to the kidneys, the chances of infection (i.e. pyelonephritis) are increased.

Signs and Symptoms

As well as those listed below, symptoms of kidney infection include a desire to pass urine frequently and urgently, pain or burning when passing urine, feeling sick and fever.

Diagnosis and Tests

A doctor must find out exactly which bacteria are causing the infection in order to kill it and stop further damage.  A urine specimen is sent to a laboratory which identifies the bacteria, allowing the doctor to prescribe the right antibiotic.  Prompt and adequate antibiotic treatment is important.

The doctor should try to discover why the infection occurred, in order to reduce the risk of another and to assess how much damage has been caused.  Once treatment has started, the doctor will want the patient to undertake a couple of tests in order to find out why the infection happened, and to ascertain what damage has occurred.  The patient is usually sent for an ultrasound scan or an X-ray of the kidneys.  Ultrasound is a painless procedure that uses sound waves to build up a picture of your kidneys.  The X-ray involves injecting a special dye into a vein in the arm; the body naturally removes the dye from the blood through the kidneys into the urine.  While this is happening, the dye shows up the structure of the kidney on an X-ray.

Treatment and Prevention

Wiping 'front to back' during toilet visits and avoiding tight-fitting underwear can prevent some urinary tract infections.

Prognosis; Complications

Pyelonephritis may last until treated.  Once appropriate treatment is begun, improvement is often rapid.  The infection is generally cleared within 2 weeks.

Left untreated, infection can sometimes resolve on its own but, if it persists, it may lead to scarring and damage of the kidneys.  Damaged kidneys can cause other conditions, such as high blood pressure or even chronic renal failure, requiring frequent medical attention for the rest of one's life.