Kidney Infections: Symptoms and Treatments
Causes of Pyelonephritis
Most often, the bacteria that cause pyelonephritis are the same as those that cause ordinary urinary tract infections. Bacteria found in stool (such as E. coli or klebsiella) are most common. Uncommonly, bacteria from the skin or the environment cause pyelonephritis.
Conditions that create reduced urine flow make pyelonephritis more likely. When urine flow slows or stops, bacteria can more easily travel up the ureters. Some causes of urine obstruction include:
- Benign prostatic hypertrophy (BPH)
- Abdominal or pelvic masses (as from cancer)
- Stones in the bladder, ureters, or kidneys
Kidney stones contribute to pyelonephritis by providing a place for bacteria to grow while evading the body's defenses.
People with diabetes or conditions that impair the immune system are more likely to get pyelonephritis.
How Pyelonephritis Is Diagnosed
Doctors may rely on various tests to diagnose pyelonephritis:
History. Telling the story of your illness and specific symptoms helps a doctor make the diagnosis of pyelonephritis.
. A doctor notes a person's general appearance, vital signs, and presses over the kidneys to check for tenderness.
Urinalysis. In pyelonephritis, microscopic analysis of the urine virtually always shows signs of infection. This can include an excess of white blood cells and bacteria.
Urine culture. Within days, bacteria in urine may grow on a culture dish, allowing the best antibiotic to be chosen.
Blood cultures. If pyelonephritis has spread to the blood, blood cultures can detect this and guide treatment.
Computed tomography (CT scan). A scanner takes a rapid series of X-rays, and a computer creates detailed images of the abdomen and kidneys. A CT scan is not necessary to diagnose pyelonephritis, but sometimes helps.
Kidney ultrasound. A probe directs high-frequency sound waves through the skin, creating images of the kidneys and ureters. Ultrasound can help identify abscesses, stones, and blockages.
In addition to diagnosing pyelonephritis itself, doctors look for any conditions that make pyelonephritis more likely. For example, kidney stones or birth defects of the urinary tract can increase the chance of an infection. Both are potentially correctable, which will reduce the chances of future kidney infections.