Which lab finding would be most concerning in a patient with acute pyelonephritis?

In the context of acute pyelonephritis, an elevated white blood cell count is a significant lab finding that indicates the body's immune response to a urinary tract infection (UTI) that has ascended to the kidneys. The presence of white blood cells reflects inflammation and infection, which are hallmarks of pyelonephritis. This condition often results from bacterial infection, and the body's attempt to fight the infection manifests in an increase in white blood cells, particularly neutrophils.

Monitoring the white blood cell count can provide valuable information about the severity of the infection and the patient's inflammatory response. A significantly elevated count may suggest a more serious infection or a complication, such as an abscess or sepsis, which require prompt intervention. Therefore, recognizing an elevated white blood cell count as concerning in a patient with acute pyelonephritis is crucial for managing their care effectively.

While the presence of ketones or dark urine with a foul smell can be observed in various urinary conditions, including dehydration or metabolic disorders, they do not directly indicate the severity or presence of an acute kidney infection. Low urine output may also be a concern, but it is not as direct an indicator of acute pyelonephritis as the elevation of white blood cells