Sediment and Microscopic Discussion Flashcards
Pyelonephritis Macroscopic and Microscopic
Macroscopically-cloudy urine, protein, blood, nitrites, leukocyte esterase Microscopically-WBCs, renal epithelial cells, WBC casts, moderate bacteria
Discuss the presence of WBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease. Average size:
12 um in diameter. Predominant cell see is the neutrophil. Neutrophils exposed to hyptonic urine absorb water and swell. Brownian movement of the granules within these larger cells produces a sparkling appearance, and they are referred to as “glitter cells.”
Discuss the presence of WBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease. Eosinophils:
Primarily associated with drug-induced interstitial nephritis; however small number of eosinophils may be seen with UTI and renal transplant rejection. Since not commonly found in urine >1% is considered significant
Discuss the presence of WBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease Mononuclear cells
Lymphocytes may be confused with RBCs. Monocytes, Macrophages, and histiocytes may appear vacuolated or containing inclusions. An increase of WBCs in the urine is called pyuria
Describe general cast composition
Major constituent of a cast is Tamm-Horsfall protein. Tamm-Horsfall protein is a protein secreted by RTE cells of the distal convoluted tubules and upper collecting duct. The rate of excretion appears to increase under conditions of stress and exercise. Protein gels more readily under conditions of urine-flow stasis, acidity, and presence of sodium and calcium
Describe general cast formation
urinary flow within the tubule decreases due to a blocked lumen. Cast width is dependent on the tubule size in which it was formed. Formation of casts at the junction of the ascending loop of Henle and the distal convoluted tubule may produce a structures with a tapered end.
Hyaline
Little significance Dehydration, strenuous exercise, heat exposure, and emotional stress. Most common. Increased in acute glomerulonephritis, pyelonephritis, chronic renal disease, and congestive heart failure.
RBC / True blood / hemoglobin
Shows bleeding within the nephron. Associated with glomerular damage and usually associated with proteinuria and dysmorphic RBCs
WBC casts
Signifies infection or inflammation within the nephron. Most frequently associated with pyelonephritis. Primary maker for distinguishing pyelonephritis (upper UTI) from lower UTIs.
Epithelical Cells
If they contain RTE’s it represents the presence of advanced tubular destruction causing urinary stasis along with disruption of the tubular linings.
Granular (coarse & fine)
Healthy patient and renal disease
Waxy casts
Representative of extreme urine stasis, indicating chronic renal
Fatty casts
Seen in conjuction with oval fat bodies and free fat droplets in disorders causing lipiduria. Most frequently associated with the nephritic syndrome
Broad casts
Represents extreme urinary stasis. Most commonly seen are granular and waxy. May see bile stained with viral hepatitis
Sediment stains:
increases the overall visibility of sediment elements being examined using bright field microscopy. Most common stain is: Sternheimer-Malbin stain: which consists of crystal violet and safranin O. Dye is absorbed well by WBCs, epithelial cells, and casts. Toluidine blue stain (0.5 %) is a metachromatic stain that provides enhancement of nuclear detail. Can be used to differentiation between WBCs and renal tubular cells.
Discuss sediment examination using gram stains and Hansel stain
Gram Stain: Used primary for microbiological examination.
Hansel stain: Polynuclear WBCs usually in urine are neutrophils. Used to confirm presence of eosinophil’s caused by drug-induced allergic reaction producing inflammation of the renal interstitium. Stain consists of methylene blue and eosin Y.
Nephrotic syndrome
Macroscopically and Microscopically:
Macroscopically: cloudy/foamy urine, large amount of protein, small amount of blood
Microscopically: renal cells and casts, granular, waxy, fatty casts, oval fat bodies, urinary fat droplets, renal tubular epithelial cells, epithelial, fatty, and waxy casts, and microscopic hematuria.
Discuss both polarizing microscopy and the Sudan III stain and how they are used to aid in the identification of urine sediment.
Polarizing microscopy: ID of crystals and lipids. Used when sediment demonstrates birefringence which is the ability to refract light in two dimensions at 90 degrees. Used to confirm the identification of fat droplets, oval fat bodies, and fatty casts that produce a characteristic Maltese cross formation.
Lipid Stains: Oil Red O and Sudan III – can be used to confirm the presence of free fat droplets and lipid-containing cells, and casts in urinary sediment.
Describe Oval Fat Bodies
Illustrate
Origin
Significance
Illustrate: Appear highly retractile, and the nucleus may be difficult to observe.
Origin: RTE + absorbed lipids
Significance: Most commonly associated with damage to the glomerulus caused by the nephritic syndrome. Also seen with severe tubular necrosis, diabetes mellitus, and in trauma cases that cause release of bone marrow fat from long bones
Compare and contrast how cholesterol crystals, triglycerides, oval fat bodies and fatty casts look under polarized microscopy
Oval fat bodies -Maltese cross
cholesterol crystals- Rainbow squares and rectangles with notched corners.
Triglycerides- Invisible
Compare and contrast how cholesterol and triglycerides look when stained with Sudan III
Cholesterol will not stain
Triglycerides will stain red or orange
What artifacts can be mistaken for polarizing fat:
Talc crystals
Oils from creams or lubricants
Acute Glomerulonephritis
Primary UA findings include marked hematuria, proteinuria, and oliguria. Also seen are RBC casts, dysmorphic RBCs, hyaline and granular casts and WBCs.BUN may be elevated.May demonstrate a positive ASO titer.
Discuss the presence of RBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease.
Appearance
RBCs appear as smooth, non-nucleated, biconcave disks measuring approximately 7 um in diameter. In concentrated urine, the cells shrink due to loss of water and may appear crenated or irregularly shaped. In dilute urine, the cells absorb water, swell, and lyse rapidly, releasing their hemoglobin, leaving only the cell membranes which are known as “ghost’ cells
Discuss the presence of RBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease.
Other cells that may be confused with
yeast cells, oil droplets, and air bubbles can be differentiated using acetic acid.
Discuss the presence of RBCs in urine sediment including appearance, other cells that may be confused with, and clinical correlation of disease
Clinical Correlation
Dysmorphic red blood cells have been associated with glomerular bleeding.
RBC presence has been associated with damage to the glomerular membrane or vascular injury within the genitourinary tract. # of cells present is indicative of the extent of damage or injury
Macroscopic hematuria is frequently associated with advanced glomerular damage.
Microscopic hematuria has been associated with early diagnosis of glomerular disorders and urinary tract malignancies
Seen is strenous exercise
Discuss the Prussian Blue Stain
Used to confirm presence of hemosiderin granules.
Squamous
Illustrate
Origin
Significance
Illustrate - Fried egg
Origin - Lining of the vagina and the lower portion of the female and male urethra. no pathologic significance.
Significance - Poor collection technique. Largest cells found in urine sediment. Clue cell is a variation of a SEC and are indicative of Gardnerella vaginalis infection
Transitional
Illustrate
Origin
Significance
Illustrate - A Poached Egg; smaller than SECs. Have distinct, centrally located nuclei.
Origin - Originate from the lining of the renal pelvis, calyces, ureters, and bladder and upper portion of the male urethra.
Significance - Cystitis, renal carcinoma, bladder cancer, Increased numbers of TEC seen singly, pairs or clumps are seen following invasive urologic procedures and are deemed insignificant.
Renal tubular
Illustrate
Origin
Significance
Illustrate - A hard boiled egg
Origin - Renal tubules
Significance - If > 2 / hpf indicates tubular injury. Most clinical significant epithelial cell. Presence in increased amounts is indicative of necrosis of the renal tubules. Conditions producing tubular necrosis include exposure to heavy metals, drug-induced toxicity
Bright field microscopy
Objects appear dark against a light background. Urine sediments must be examined using decreased light controlled by adjust the rheostat on the light source, not by lowering the condenser. Stained sediment may increase visualization on sediment
Phase-Contrast microscopy
Two phase rings that appear as “targets” are placed in the condenser and the objective. One phase ring is placed in the condenser or below it permitting light to only pass through the center clear circular area. The second phase ring with a central circular area that retards the light by one quarter wavelength is placed in the objective.
Interference-Contrast Microscopy
Provides three dimensional image showing very fine structural details by splitting the light rays so that light beams through different areas of the specimen. Advantage of this type is that an object will appear bright against a dark background but without the diffraction halo associated with phase-contrast microscopy
Uric Acid
pH
Color
Normal/Abnormal
Appearance
pH - Acid
Color - Yellow to brown
Normal/Abnormal - Normal
Appearance - Diamond
Leucine
pH
Color
Normal/Abnormal
Appearance
pH - Acid to Neutral
Color - Yellow
Normal/Abnormal - Abnormal
Appearance - Concentric Wagon Wheel
Cystine
pH
Color
Normal/Abnormal
Appearance
pH - Acid
Color - Colorless
Normal/Abnormal - Abnormal
Appearance - Hexagon
Triple Phosphate
pH
Color
Normal/Abnormal
Appearance
pH - Alkaline
Color - Colorless
Normal/Abnormal - Normal
Appearance - Coffin Lids
Calicum Carbonate
pH
Color
Normal/Abnormal
Appearance
pH - Alkaline
Color - Colorless
Normal/Abnormal - Normal
Appearance - Small dumbells
Cholesterol
pH
Color
Normal/Abnormal
Appearance
pH - Acid
Color - Colorless
Normal/Abnormal - Abnormal
Appearance - Notched Plates
Bilirubin
pH
Color
Normal/Abnormal
Appearance
pH - Acid
Color - Yellow
Normal/Abnormal - Abnormal
Appearance - Fine needles or granules that cluster
Calicum Oxalate
pH
Color
Normal/Abnormal
Appearance
pH - Acid Neutral
Color - Colorless
Normal/Abnormal - Normal
Appearance - Small envelope
Calicum Phosphate
pH
Color
Normal/Abnormal
Appearance
pH - Alkaline, Neutral
Color - Colorless
Normal/Abnormal - Normal
Appearance - Long, thin prisms with taperated ends
Sulfonamindes
pH
Color
Normal/Abnormal
pH - Acid, neutral
Color - Green
Normal/Abnormal - Abnormal
Amorphous Phosphate
pH
Color
Normal/Abnormal
Appearance
pH - Alkaline, Neutral
Color - Colorless
Normal/Abnormal - Normal
Appearance - Small granules of white, many
Radiographic Dye
pH
Color
Normal/Abnormal
Appearance
pH - Acid
Color - Colorless
Normal/Abnormal - Abnormal
Appearance - Clear planes
Ammonium biruate
pH
Color
Normal/Abnormal
Appearance
pH - Alkaline
Color - Yellow to brown
Normal/Abnormal - Normal
Appearance - Thorny Apple
Ampicillin
pH
Color
Normal/Abnormal
Appearance
pH - Acid, neutral
Color - Colorless
Normal/Abnormal - Abnormal
Appearance - Long fine needles
Tyrosine
pH
Color
Normal/Abnormal
Appearance
pH - Acid, neutral
Color - Colorless to yellow
Normal/Abnormal - Abnormal
Appearance - Long, delicate needles in clusters
What is the appearance and clinical significance of finding bacteria, yeast, parasites, sperm, and mucous upon microscopic urinalysis.
Bacteria:
Not normally present in urine. Few may be present due to contamination during collection. Is indicative of either a lower or upper UTI. Most frequent seen bacteria are the Enterobacteriaceae family
What is the appearance and clinical significance of finding bacteria, yeast, parasites, sperm, and mucous upon microscopic urinalysis.
Yeast Cells
Appear in urine as small, retractile oval structures with or without budding. Can be seen in urine of diabetic, immunocompromised patients and with women with vaginal yeast infections. A true yeast infection should also have WBC presence.
What is the appearance and clinical significance of finding bacteria, yeast, parasites, sperm, and mucous upon microscopic urinalysis.
Parasites
Most common encountered is Trichomonas vaginalis. T. vaginalis is a pear-shaped flagellate with an undulating membrane. May be seen with rapid darting movement. Sexually transmitted pathogen
What is the appearance and clinical significance of finding bacteria, yeast, parasites, sperm, and mucous upon microscopic urinalysis
Sperm
Oval, slightly tapered heads and long, flagella-like tails. Rarely of any clinical significance unless in a legal situation
What is the appearance and clinical significance of finding bacteria, yeast, parasites, sperm, and mucous upon microscopic urinalysis
Mucous
thread-like structures with low refractive index. Most frequently present in female urine specimens but really of little clinical significance.
Describe how a urine specimen is prepared for microscopic examination.
Specimen preparation;
Specimen volume:
Centrifugation:
Sediment Preparation:
Specimens should be examined while fresh or adequately preserved. Refrigeration may cause precipitation of amorphous urates or phosphates or no pathologic crystals.
10-15 mL of urine is centrifuged in a conical tube
Optimum sedimentation is obtained by centrifuging specimen for 5 minutes at 400 RC
A uniform amount of sediment should remain in the tube after decantation.
Describe how sediment is microscopically examined.
Minimum observation of 10 fields of both 10x (low power) and 40X (high power). Slide first examined under low power to detect casts and to ascertain the general composition of the sediment. Cast identification should be at the 10X power. Examine under reduced light using bright-field microscopy.
