What term is used to describe the presence of pus in urine, often indicating a urinary tract infection?

The term that describes the presence of pus in urine, which often indicates a urinary tract infection, is pyuria. Pyuria occurs when there is an increased number of white blood cells in the urine, a typical response to infection or inflammation in the urinary tract. This condition is usually diagnosed through urinalysis where cloudy or turbid urine may be observed, often accompanied by other symptoms such as dysuria (painful urination), frequency, and urgency.

In contrast, cystitis refers specifically to inflammation of the bladder and can be associated with urinary tract infections but does not specifically denote pus in urine. Polycystic kidney disease is a genetic disorder characterized by the growth of numerous cysts in the kidneys, and nephrolithiasis refers to kidney stones. Neither of these terms directly relates to the presence of pus in urine. Thus, pyuria is the most precise and accurate term for describing pus in the urine, making it the correct answer.