What term refers to an infection in the kidney?

The term that refers to an infection in the kidney is pyelonephritis. Pyelonephritis is specifically an inflammation of the kidney caused by a bacterial infection, which typically arises from an infection that begins in the urinary tract or bladder and ascends to the kidneys. This condition can cause significant symptoms such as fever, back pain, and malaise, and can lead to serious complications if not treated promptly.

Nephritis, while related, is a broader term that encompasses inflammation of the kidneys but does not exclusively denote an infection. Nephritis can result from various causes, including autoimmune diseases and other non-infectious factors.

Ureteritis refers specifically to the inflammation or infection of the ureter, which is the duct that carries urine from the kidney to the bladder, not involving the kidney itself.

Cystitis is the inflammation and infection of the bladder, which is also separate from the kidneys.

Therefore, pyelonephritis is the most accurate term for indicating an infection within the kidney.