What does hydronephrosis mean?
Hydronephrosis is the medical term for swelling of the kidney's internal collecting system when urine accumulates and fails to drain normally. It most often results from an obstruction, such as a kidney stone, enlarged prostate, stricture, or tumor, although urinary flow can also be impaired for other reasons. The condition may cause flank pain, nausea, or no symptoms at all and is generally identified through imaging such as ultrasound or CT. Hydronephrosis is distinct from a simple kidney infection: it describes pressure and dilation caused by impaired drainage, which may lead to infection or impaired kidney function. The word is especially useful to anyone studying medicine or reading radiology and urology reports, because it identifies a particular anatomical condition rather than a general symptom such as back or abdominal pain. Prompt assessment matters, particularly when the condition is severe or affects one kidney only.
nounA medical condition in which the kidney's collecting system becomes swollen because urine accumulates and cannot drain normally. It may result from an obstruction such as a kidney stone or from other causes that impair urinary flow.
- Swelling of the kidney's pelvis and calyces caused by the accumulation of urine, usually because of an obstruction or impaired drainage.
"An ultrasound revealed hydronephrosis in one of the patient's kidneys."
"The scan showed hydronephrosis caused by a blockage in the ureter."
"Severe hydronephrosis may permanently damage the affected kidney if it is not treated promptly."
The plural is used when referring to cases of the condition or abnormalities affecting multiple structures.
"The radiologist documented bilateral hydronephroses."
Its name literally describes what happens: “hydro” means water, “nephro” refers to the kidney, and “-osis” denotes a condition.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does hydronephrosis come from?
The term comes from Greek roots meaning “water,” “kidney,” and “condition.” It was formed in the 19th century from hydr-, referring to water, and nephros, meaning kidney, together with the suffix -osis. Its components parallel related medical terms such as nephrology, while hydro- also occurs in words connected with water.
Related word forms
How hydronephrosis is actually used
This is a specialized medical term used in radiology, urology, and nephrology. It is normally diagnosed with imaging and should not be used as a casual synonym for any form of kidney pain.
Easily confused with hydronephrosis
Hydronephrosis is swelling of the kidney's urine-collecting system, whereas hydrocephalus is an abnormal accumulation of cerebrospinal fluid within the brain.