What does pyelonephritis involve?

Pyelonephritis is specifically characterized by the bacterial invasion of the renal parenchyma, which is the functional tissue of the kidneys. This condition is typically a result of a urinary tract infection that ascends from the lower urinary tract into the kidneys. The infection leads to inflammation and can affect one or both kidneys. This is crucial because understanding the nature of the infection helps in identifying symptoms, targeting appropriate treatments, and preventing complications.

The other options pertain to different urinary tract disorders. Inflammation of the bladder refers to cystitis, which is a separate condition primarily affecting the bladder rather than the kidney. Kidney stones formation is related to another aspect of nephrology, often involving mineral deposits in the kidneys but not necessarily linked to infection. Lastly, infection of the urethra is known as urethritis, which, while it may contribute to a urinary infection, does not specifically describe pyelonephritis. Understanding pyelonephritis as an infection of the renal parenchyma is essential for accurate diagnosis and management in nursing practice.