Pyelonephritis (from
Greek πύελο|ς
pýelo|s, "basin" + νεφρ|ός
nepʰrós, "
kidney" + suffix
-itis suggesting "
inflammation") is an inflammation of the kidney
tissue,
calyces, and
renal pelvis. It is commonly caused by bacterial infection that has spread up the
urinary tract or travelled through the bloodstream to the kidneys.