|Print Date:||May 22, 2013, 9:10 pm|
|Text||Acute pyelonephritis is an infection of the upper urinary tract that usually occurs when colonic bacteria ascend from the lower urinary tract to invade the renal parenchyma. E. coli is the most frequent organism, with Proteus, Klebsiella, Staphylococcus saprophyticus, and Enterococcus being less common. The role of imaging is generally to define underlying pathology (obstruction, reflux, calculus) and rule out complications (abscess, emphysematous pyelonephritis, changes consistent with chronic infection).
IVP, CT, US, can be normal in up to 75% of cases. CT findings (when present) include: renal enlargement (edema); areas of decreased perfusion/enhancement; stranding of the perirenal fat; striated nephrogram with contrast enhanced studies. US findings are similar, with focal hyperechogenicity and enlargement.
Nuclear medicine DMSA findings include single or multiple areas of no or decreased radiotracer uptake.
|References:||Saunders Manual of Medical Practice. Primer of Diagnostic Imagaing, 3rd ed. Radiology Review Manual, 5th ed.|
|Contributor||Peter Vangeertruyden (National Capital Consortium)|
|Peer Reviewer||William R Carter, M.D. (National Naval Medical Center Bethesda)|
|Record Number||: 7736|
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