Polycystic kidney disease is characterized by what?

Polycystic kidney disease (PKD) is primarily characterized by the development of numerous fluid-filled cysts within the kidney tissue. These cysts can vary in size and number and lead to the progressive enlargement of the kidneys. As the cysts grow, they can interfere with kidney function, potentially leading to complications such as hypertension, kidney stones, and eventually kidney failure. The presence of these cysts is the hallmark of the disease, distinguishing it from other renal pathologies.

The other options address different medical conditions. For instance, a high number of protein molecules in the urine could indicate a proteinuria condition but is not specific to PKD. Rapidly developing symptoms might suggest acute renal issues or other acute conditions rather than the more chronic progression seen in PKD. A history of a systemic infection does not directly relate to PKD, as this disease is a genetic disorder rather than an infectious one.