Which condition is characterized by hematuria and red blood cell casts?

The presence of hematuria and red blood cell casts is a hallmark sign of glomerulonephritis. This condition involves inflammation of the glomeruli, which are the tiny filtering units within the kidneys. The inflammation leads to increased permeability of the glomerular membrane, allowing red blood cells to escape into the urine, resulting in hematuria.

Red blood cell casts are formed when red blood cells aggregate in the renal tubules and take on the shape of the tubular structure. This occurrence is indicative of glomerular damage, further supporting the diagnosis of glomerulonephritis.

In contrast, other conditions listed do not typically present with both hematuria and red blood cell casts. Acute tubular necrosis, while it may cause renal impairment and some degree of hematuria, usually does not lead to the formation of red blood cell casts. Bladder infections (cystitis) primarily cause hematuria but are not associated with red blood cell casts because the issue lies in the bladder rather than the kidneys. Nephrolithiasis may cause hematuria due to stone irritation, but it lacks the specific presence of red blood cell casts, which further distinguishes it from glomerulonephritis.

Thus,