What does pyelonephritis refer to?

Pyelonephritis is characterized as a purulent infection that affects both the kidney tissue and the renal pelvis. This condition involves inflammation due to a bacterial infection, which can originate from the lower urinary tract and ascend to the kidneys. The involvement of the renal pelvis, which is the area that collects urine from the kidney before it flows into the ureter, is a key aspect of this condition.

In pyelonephritis, one can expect to find symptoms that may include fever, flank pain, and urinary symptoms such as dysuria or increased urgency. The presence of pus in the urine and the potential for kidney scarring or damage are also significant concerns.

By understanding this definition, it's clear that the option describing a blockage in the urethra pertains to a different urinary obstruction issue, while a type of nephropathy typically refers to kidney diseases which could be of various etiologies but does not specify an infection. Cancer of the kidney involves malignant growths, which is distinctly different from the infectious process seen in pyelonephritis. Therefore, recognizing pyelonephritis specifically as an infection provides a clear distinction from these other conditions.