Sediment Constituents Pt.3 - Definitions

• RED BLOOD CELLS (HEMATURIA)

  • Smooth, non-nucleated, biconcave disks
• WHITE BLOOD CELLS (PYURIA/ LEUKOCYTURIA)

  • Increased number indicates presence of infection or inflammation
• 3 types of Epithelial cells found in urine.

  • Squamous epithelial
  • Transitional epithelial
  • Renal tubular epithelial
• SQUAMOUS EPITHELIAL CELLS

  • Largest cell with abundant, irregular cytoplasm and prominent nucleus.

  • The nucleus is about the size of an RBC.

  • Point of reference of cells in urinalysis
• TRANSITIONAL EPITHELIAL CELLS (UROTHELIAL)

  • Spherical, polyhedral or caudate with centrally-located nucleus
• RENAL TUBULAR EPITHELIAL CELLS (RTE CELLS)

  • Most clinically significant epithelial cells

  • Rectangular, polyhedral, cuboidal or columnar with eccentric nucleus
• OVAL FAT BODIES

  • RTE cells absorb lipids that are present in the glomerular filtrate. They then appear highly refractile, and the nucleus may be more difficult to observe.

  • Lipid-containing RTE cells
• BACTERIA

  • Small spherical and rod-shaped structures

  • Observing this for motility is useful in differentiating them from similarly appearing amorphous phosphates and urates.
• YEAST

  • Small, refractile oval structures that may or may not contain a bud.

  • In severe infections, they may appear as branched, mycelial forms

  • Differentiation between this and RBCs can sometimes be difficult.
• 3 parasites present in urine.

  • Trichomonas vaginalis
  • Enterobius vaginalis
  • Schistosoma haematobium
• Trichomonas vaginalis

  • Most frequently encountered parasite in urine

  • Pear-shaped flagellate with jerky motility

  • Agent of ping-pong disease

  • When not moving, it may resemble WBC, TEC, or RTE cell
• Enterobius vermicularis

  • Most common fecal contaminant
• Schistosoma haematobium

  • Blood fluke with terminal spine

  • Causes hematuria

  • Associated with bladder cancer
• SPERMATOZOA

  • Oval, slightly tapered heads and long, flagella-like tails

  • Urine is toxic to this; therefore, they rarely exhibit the motility observed when examining a semen specimen.

  • Found in the urine of both men and women following sexual intercourse, masturbation, or nocturnal emission.
• MUCUS THREADS

  • Thread-like structures with a low refractive index.

  • Subdued light is required when using bright-field microscopy.

  • Care must be taken not to confuse clumps with hyaline casts.

  • Immunologic analysis has shown that uromodulin is a major constituent of this.
• HYALINE CAST

  • Prototype cast (beginning of all types of cast)

  • Appear colorless in unstained sediments and have a refractive index similar to that of urine; thus, they can easily be overlooked if specimens are not examined under subdued light
• RBC CAST

  • Primarily associated with damage to the glomerulus (glomerulonephritis) that allows passage of the cells through the glomerular membrane
• WBC CAST

  • The appearance of this cast in the urine signifies infection or inflammation within the nephron. They are most frequently associated with pyelonephritis and are a primary marker for distinguishing pyelonephritis (upper UTI) from cystitis (lower UTI).
• RTE CAST

  • Casts containing RTE cells represent the presence of advanced tubular destruction, producing urinary stasis along with disruption of the tubular linings.
• GRANULAR CAST

  • frequently seen in the urinary sediment and may be of pathologic or nonpathologic significance. It is not considered necessary to distinguish between coarsely and finely granular casts
• BROAD CAST

  • Often referred to as renal failure casts, like waxy casts represent extreme urine stasis.

  • As a mold of the distal convoluted tubules, the presence of this cast indicates destruction (widening) of the tubular walls.

  • Any type of cast can be like this (most common are granular and waxy)
• WAXY CAST

  • Final degenerative form of all types of casts

  • Waxy casts are representative of extreme urine stasis, indicating chronic renal failure.
• Amorphous urates

  • Crystal characterized as brick dust or yellow brown granules
• Uric acid

  • Most pleomorphic crystal: rhombic, four-sided flat plates (whetstones), wedges, and rosettes.
• Calcium oxalate

  • Dihydrate (Weddellite): octahedral envelope or “two pyramids joined at their bases” (bipyramidal)
  • Monohydrate (Whewellite): oval/ dumbbell
• Calcium sulfate

  • “Cigarette buff” appearance crystal
• Hippuric acid

  • crystal that is Yellow-brown/ colorless elongated prism
• Amorphous phosphates

  • crystal that is fine, or ‘lacy’ white precipitate
• Triple phosphate (ammonium magnesium phosphate; struvite)

  • Crystal that is Prism-shaped, coffin lid, fern leaf
• Ammonium biurate

  • crystal that is Yellow-brown “thorny apples”
• Magnesium phosphate

  • crystal that is colorless, elongated rectangular or rhomboid plates; end or corner may be notched
• Calcium phosphate

  • crystal that is colorless, flat rectangular plates or thin prisms often in rosette formations
• Calcium carbonate

  • crystal that is small and colorless, with dumbbell or spherical shapes
• Cystine

  • crystal that is colorless, refractile hexagonal plates, often laminated
• Cholesterol

  • crystal that is a Rectangular plate with notch in one or more corners (staircase pattern)
• Radiographic dye

  • crystal that is Flat, four-sided plates with a notched corner
• Tyrosine

  • crystal that is Fine colorless to yellow needles
• Leucine

  • crystal that is Yellow-brown oily-looking spheres with concentric circles and radial striations
• Bilirubin

  • crystal that is clumped granules or needles with bright yellow color
• Sulfonamide

  • crystal that is Fan-shaped needles, sheaves of wheat, rosettes, arrowheads, petals, round-shaped, whetstones