py·​elo·​ne·​phri·​tis ˌpī-(ə-)lō-ni-ˈfrī-təs How to pronounce pyelonephritis (audio)
: inflammation of both the lining of the renal pelvis and the parenchyma of the kidney especially due to bacterial infection
pyelonephritic adjective

Example Sentences

Recent Examples on the Web Kidney infection Kidney infection (or pyelonephritis) is a type of UTI that generally begins in your urethra or bladder and travels to one or both of your kidneys. Samantha Lauriello,, 9 Sep. 2019 The least common type of UTI, a kidney infection (acute pyelonephritis), can cause flank pain, fever, chills, nausea, and vomiting. Carolyn L. Todd, SELF, 9 Mar. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pyelonephritis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


New Latin

First Known Use

1839, in the meaning defined above

Time Traveler
The first known use of pyelonephritis was in 1839

Dictionary Entries Near pyelonephritis

Cite this Entry

“Pyelonephritis.” Dictionary, Merriam-Webster, Accessed 24 Mar. 2023.

Medical Definition


py·​elo·​ne·​phri·​tis ˌpī-(ə-)lō-ni-ˈfrīt-əs How to pronounce pyelonephritis (audio)
plural pyelonephritides -ˈfrit-ə-ˌdēz How to pronounce pyelonephritis (audio)
: inflammation of both the parenchyma of a kidney and the lining of its renal pelvis especially due to bacterial infection
pyelonephritic adjective

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