Pyelonephritis: A-to-Z Guide from Diagnosis to Treatment to Prevention

UTIs can occur in the bladder (cystitis) or in the kidney (pyelonephritis). Classic symptoms of pyelonephritis include fever, flank pain, and/ or vomiting.

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.

What is it?

Urinary tract infections can occur in the bladder (cystitis) or in the kidney (pyelonephritis). Stool bacteria are the most likely to cause urinary tract infections. Usually these bacteria come up through the urinary tract from the outside. Sometimes bacteria in the bloodstream settle into the kidney, causing an infection.

Viruses such as adenovirus can also cause urinary tract infections.

Who gets it?

In boys, urinary tract infections are most common in the first year of life. Uncircumcised boys are much more likely to have these infections than circumcised boys. After the first year or two of life, girls are far more likely to have urinary tract infections than boys. In girls, the peak time occurs during toilet training.

Children with vesicoureteral reflux, or other urinary tract problems, are more likely to have pyelonephritis. Constipation, pinworms, labial adhesions, and neurologic problems, such as spina bifida, are among the other factors that can lead to these infections.

What are the symptoms?

Classic symptoms of pyelonephritis include fever, flank pain, and/ or vomiting. Diarrhea is sometimes present as well. Young babies with pyelonephritis may be irritable, jaundiced, and feeding poorly.

Is it contagious?

Pyelonephritis is not directly contagious, although the bacteria in stool that can lead to pyelonephritis can be spread by touch.

How long does it last?

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

How is it diagnosed?

An infection of the urinary tract is generally diagnosed with a urine culture. The location of the infection in the urinary tract is usually determined based on the history and the physical examination. If the diagnosis is not clear, imaging studies such as a renal scan can solve the puzzle.

How is it treated?

Antibiotics are used to treat pyelonephritis. Prompt and adequate treatment is important. Depending on the child’s age and ability to tolerate medications by mouth, the antibiotics may be given either orally or intravenously.

How can it be prevented?

Avoiding wiping from back to front and avoiding tight-fitting underwear can prevent some urinary tract infections.

Children who have had pyelonephritis once (and most young children who have had any urinary tract infection) should have imaging studies of the urinary tract to identify specific ways to prevent further infections. Depending on the situation, preventive antibiotics or even surgery might be wise.

Kidney infection, Urinary tract infection – pyelonephritis

Last medical review on: October 29, 2013
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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