Which medical term refers to a kidney infection?

The term that specifically refers to a kidney infection is pyelonephritis. This condition involves inflammation of the kidney and is often caused by a bacterial infection that spreads from the urinary tract. The prefix "pyelo-" refers to the renal pelvis, which is the part of the kidney where urine collects before it moves to the bladder. Therefore, pyelonephritis accurately describes an infection that has reached the kidney itself, leading to more severe symptoms and potential complications compared to other urinary tract infections.

Nephritis generally refers to inflammation of the kidneys but does not specifically denote an infectious process. Urinary tract infection (UTI) is a broader term that can refer to infections occurring anywhere in the urinary system, including the bladder or urethra, and not limited to the kidneys. Cystitis specifically refers to inflammation of the bladder, usually due to infection, and does not involve the kidneys. Thus, pyelonephritis is the most precise term for a kidney infection.