Which finding in urinary sediment is indicative of pyelonephritis and interstitial nephritis?

The presence of white blood cell casts in urinary sediment is indicative of pyelonephritis and interstitial nephritis. This finding suggests that there is an inflammatory process occurring in the kidney, which can lead to the accumulation of white blood cells in the renal tubules. When these white blood cells combine with the protein matrix of the casts, they form white blood cell casts, which are specifically associated with infection and inflammation within the kidney structures.

In pyelonephritis, an infection of the kidney usually caused by bacteria, the presence of these casts indicates that the infection has led to inflammation and pus formation within the renal collecting system. Similarly, in interstitial nephritis, which can be caused by drugs, infections, or autoimmune disorders, the infiltration of white blood cells typically results in the formation of these casts as well.

The other findings in urinary sediment, such as hyaline casts, granular casts, and red blood cell casts, indicate different underlying issues or conditions and do not specifically correlate with the inflammatory processes characteristic of pyelonephritis or interstitial nephritis.