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Kidney Infections: Symptoms and Treatments

Most urinary tract infections (UTIs) involve only the bladder and urethra (the lower urinary system). Pyelonephritis results when a UTI progresses to involve the upper urinary system (the kidneys and ureters).

The kidneys filter the blood to produce urine. Two tubes called the ureters carry urine from the kidneys down to the bladder. Urine travels from the bladder out of the body through the urethra.

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Urethritis is inflammation of the urethra. That's the tube that carries urine from the bladder to outside the body. Pain with urination is the main symptom of urethritis. Urethritis is commonly due to infection by bacteria. It can typically be cured with antibiotics.

Read the Urethritis article > >

Most cases of pyelonephritis are complications of common bladder infections. Bacteria enter the body from the skin around the urethra. They then travel up the urethra to the bladder.

Sometimes, bacteria escape the bladder and urethra, traveling up the ureters to one or both kidneys.

Pyelonephritis is a potentially serious kidney infection that can spread to the blood, causing severe illness. Fortunately, pyelonephritis is almost always curable with antibiotics.

The urethra is much shorter in women than in men, which is one reason why women are more vulnerable to UTIs and pyelonephritis.

Symptoms of Pyelonephritis

At least half of women have experienced the discomfort with urination caused by a urinary tract infection: painful, urgent, or frequent urination.

Pyelonephritis may start with similar symptoms. However, once the infection has spread to the kidney, signs of more severe illness usually result. They include:

  • Back pain or flank pain
  • Fever (usually present) or chills
  • Feeling sick (malaise)
  • Nausea and vomiting
  • Confusion (especially in the elderly)

Pyelonephritis may cause noticeable changes in the urine, such as:

  • Blood in the urine (hematuria)
  • Cloudy or foul-smelling urine
  • Pain when urinating
  • Increased frequency or urgency of urination

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