What does the presence of dysmorphic red blood cells in urine typically indicate?

The presence of dysmorphic red blood cells in urine is a strong indicator of intrinsic renal disease. Dysmorphic red blood cells are those that have an abnormal shape or appearance, which suggests they have been altered as they pass through the glomeruli of the kidneys. This alteration typically occurs due to damage or disease in the renal parenchyma, such as glomerulonephritis or other forms of intrinsic kidney injury, where the blood is filtered abnormally through a compromised glomerular membrane.

In the context of urinary conditions, intrinsic renal diseases often lead to hematuria associated with glomerular pathology, making dysmorphic red blood cells a key finding. This finding differentiates it from conditions where red blood cells might enter the urine from other sites (like the bladder or prostate), which typically produce normocytic or intact red blood cells rather than dysmorphic ones. This distinction is crucial in guiding further diagnostic evaluations and management decisions.