Microscope Examination Pt. 2 Flashcards
When there are casts present in the urine, where in the body is the problem?
Nephron
Where in the nephron does casts form?
DCT and collecting ducts
What is he only sediment unique to the kidney?
Casts
Casts dissolves quickly in ____, _____ urine.
dilute, alkaline
Major constituent in cast formation
Uromodulin
What secretes uromodulin
Renal tubular epithelium
What do you call casts that are well-formed at one end but tapered at the other? What does this say about the cast?
Cylindroids
Incomplete formation
Describe the formation of casts
- Precipitation of Tamm–Horsfall protein which is secreted by the epithelial tubule cells.
- Pre-existing condition (e.g., urine stasis) →
- Urine flow is slow → Aggregation of Tamm–Horsfall protein into a protein matrix can then attract the adhesion of other tubular particles
What is the initial product of cast formation?
Hyaline cast
What forms the granules in cellular casts?
Degradation of cells causing to the release of lysosomes
How do waxy casts form?
When granular casts aren’t corrected, those granules will degrade, forming the waxy cast
What’s the significance of waxy casts?
It indicates end-stage renal disease / chronic kidney failure
Are hyaline casts normal in the urine? If so, what’s the normal value?
Yes
0-2/LPF
Hyaline casts are increased in:
Strenous exercise
Dehydration
Heat exposure
Emotional stress
The presence of _____ means there’s a bleeding in the nephron
RBC casts
Under LPO, what color do RBC casts manifest?
Orange-red color
What cast is used to distinguish between upper UTI and lower UTI
WBC casts
