Urinary Casts
February 15th, 2021
Overview
Urinary casts are tubular structures formed by the precipitation of Tamm-Horsfall mucoprotein. These may contain red cells, white cells or other substances, and their presence may suggest specific disease processes.
Interpretation
Acellular Casts
- Hyaline casts (solidified mucoprotein) - dehydration, exercise, diuretics
- Granular casts (degenerated cells) - glomerulonephritis, acute tubular necrosis, pyelonephritis
- Muddy brown casts (likely denatured haemoglobin) - acute tubular necrosis
- Waxy casts (severely degenerated cells) - severe acute or chronic renal failure
- Fatty casts (lipids) - nephrotic syndrome, diabetic nephropathy
- Pigment casts (haemoglobin, myoglobin, bilirubin) - haemolysis, rhabdomyolysis, liver disease
Cellular Casts
- Red cell casts (bleeding through the glomerulus or into the tubules) - glomerulonephritis, acute interstitial nephritis
- White cell casts (interstitial or glomerular inflammation) - pyelonephritis, glomerulonephritis, acute interstitial nephritis
- Renal tubular epithelial cell casts (sloughed cells) - acute tubular necrosis, acute interstitial nephritis
- Bacterial casts - pyelonephritis
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