In addition to imaging studies, what clinical sign can indicate pyelonephritis?

Costovertebral angle tenderness is a significant clinical sign that can indicate pyelonephritis. This tenderness is assessed by gently tapping on the area of the lower back near the spine, which corresponds to the location of the kidneys. When this area is tender, it suggests inflammation of the kidneys, which is characteristic of pyelonephritis.

The presence of fever and chills can also be associated with pyelonephritis, indicating a systemic response to infection, but it is not as specific for kidney involvement as costovertebral angle tenderness. Hematuria, or blood in the urine, can occur in urinary tract infections and other renal issues, but it is not a definitive sign of pyelonephritis. Abdominal distension is more related to gastrointestinal conditions and is not a typical sign of kidney inflammation. Thus, costovertebral angle tenderness stands out as the key clinical indicator of pyelonephritis.