8 Urinalysis - Microscopy Clinical Significance

Question 1

What is the clinical significance of seeing small or large numbers of squamous epithelial cells in a urine sample?

Answer 1

Small numbers present due to normal sloughing from urethra.

Larger quantities could be related to poor sample collection.

No clinical significance.

Question 2

What cell could be seen in larger numbers due to catheterization? And what other causes?

Answer 2

Transitional epithelial Cells.
(These are smaller than squamous epithelial & can be spherical, polyhedral and caudate).

Moderate to large quantities could be due to catheterization, malignancy, infection, and inflammation.

Question 3

What cell can be see in relation to drug-induced toxicity? What other reason could there be for the presence of this cell? Is it clinically significant?

Answer 3

Renal Tubular Epithelial Cells (RTE)

Increased numbers in tubular necrosis due to heavy metals, drug induced toxicity, viral infection, pyelonephritis, malignancy, etc.)

Question 4

What causes increased numbers of red blood cells? Are a few RBC’s normal to see?

Answer 4

A few RBCs are normal; increased numbers present with trauma, infection, inflammation, malignancy.

Question 5

What is pyelonephritis?

Answer 5

Pyelonephritis means infection of the renal tubules.

Acute or chronic infection of upper urinary tract.

Expect to see WBCs, bacteria, WBC casts, bacterial casts, protein, leukocyte esterase and nitrite.

Question 6

What does caudate mean?

Answer 6

Caudate - Tailed, possessing a tail.

Question 7

What is an increase in WBCs called and what could cause that?

Answer 7

Increase in WBCs = pyuria.

Can be present with infection or inflammation. Expect to see bacteria.

Question 8

What typically forms the matrix of casts?

Answer 8

Uromodulin, a glycoprotein formed by the loop of Henle.

Question 9

What conditions may you see hyaline casts (and it is not an issue) and what conditions are increased numbers of these casts a concern?

Answer 9

Occasional normal # in stress and exercise).

Increased in acute glomerulonephritis, pyelonephritis, chronic renal disease, and CHF.

Question 10

What conditions are RBC casts seen in?

Answer 10

RBC Casts seen in:

1. Bleeding within the nephron (glomerulonephritis) and exercise.
2. May also be associated with proteinuria and dysmorphic erythrocytes.

Question 11

When condition is WBC casts seen in?

Answer 11

WBC Casts seen in:

Inflammation or infection of the nephron (pyelonephritis).

Question 12

What condition do you see granular casts in?

Answer 12

Glomerulonephritis and pyelonephritis

Question 13

What is glomerulonephritis? What would expected to see in an urine analysis?

Answer 13

Glomerulonephritis:

Sterile inflammation of glomerulus.
Majority are of immune origin.

Expect to see Blood, proteins, and RBC casts in the urine.

Question 14

What conditions are associated with waxy cats

Answer 14

Waxy casts seen in:

Extreme urinary stasis indicating chronic renal failure.

Broad waxy casts (wide!) formed from dilated tubules also called renal failure casts.

Question 15

What is nephrotic syndrome and what objects are expected to be seen in this condition?

Answer 15

Nephrotic Syndrome:
Increased glomerular permeability.
Many causes:
Allergies, drugs, shock, loss of renal circulation and
progression of glomerulonephritis.
Massive proteinuria, oval fat bodies, RTE cells, epithelial fatty and
waxy casts.

Question 16

What condition do you see fatty cats in?

Answer 16

Nephrotic syndrome, toxic tubular necrosis (associated with fats in urine), diabetes, and crush injuries.

Question 17

What are free fat droplets in urine called?

Answer 17

Lipiduria

Question 18

What are calcium oxalate (dihydrate) crystals associated with?

Answer 18

Foods high in oxalic acid (tomatoes, asparagus, spinach, beets, etc.)

Can lead to formation of renal calculi.

Question 19

What crystal in acidic urine is associated with cases of ethylene glycol (antifreeze|) poisoning? Associated with anything else?

Answer 19

Calcium Oxalate (Monohydrate) - oval or dumbell shaped.

Besides antifreeze poisonings they are also associated with foods high in oxalic acids.

Question 20

What are cystine crystals associated with? What is high concentrations of cystine referred to as?

Answer 20

Inherited Cystinuria
Can lead to formation of renal calculi

High concentrations = cystinuria.

Question 21

What condition are bilirubin crystals seen in? What chemical test should correlate?

Answer 21

Liver disease.

Bilirubin strip test should be positive.

Question 22

What crystals may be seen in patients with leukemia receiving chemotherapy or that have gout?

Answer 22

Uric Acid Crystals.

Seen with increased levels of purines.

Question 23

What contaminant crystal occurs in refrigerated samples and interferes with microscopic examination? Can you get rid of it?

Answer 23

Amorphous Urates in acidic urine (yellow-brown granules, macroscopically appears as pink precipitate).

Will disappear when sample is warmed.

Question 24

What two abnormal crystals are seen typically with each other in association with Liver Disease? Acidic or Alkaline urine?

Answer 24

Leucine and Tyrosine in Acidic urine.

Leucine (dark yellow to brown spheres with concentric or radial striations).
Tyrosine (fine delicate needles)

Question 25

What conditions can cholesterol crystals be seen in?

Answer 25

Nephrotic syndrome in acidic urine.

Question 26

Are triple phosphate, calcium phosphate and amorphous phosphate crystals clinically significant? What condition are they seen in?

Answer 26

Not clinically significant.

Seen in alkaline urine.

Question 27

What do amorphous phosphates look similar to? What are their differences?

Answer 27

Amorphous phosphate crystals (alkaline urine, white granular) look kind of similar to amorphous urates (seen in acidic urine and are yellow brown granules).

Amorphous phosphate crystals cannot be dissolved with warming.

Question 28

What condition is bacteria seen in the urine? Could their presence be non-pathological?

Answer 28

Increased numbers of bacteria in UTIs; will also see WBCs.

Note: Could see low numbers in a poorly collected sample from genital flora or container (dirty) contamination.

Question 29

Why may someone have pinworms in their urine?

Answer 29

Pinworm ova may appear as fecal contaminant from Enterobius vermicularis infection.

Question 30

How does someone get a Trichomonas Vaginalis infection?

Answer 30

Sexually transmitted infection.

These are pear-shaped flagellate with an undulating membrane.

Rapid darting movement (unless they are dead in an old urine sample so it is important to look at the sample right away!).

Question 31

What patients get yeast infections?

Answer 31

Female patients, diabetics, and immunocompromised patients may get yeast infections.

Question 32

What is the problem with air bubbles in the urine sample? Why do they occur?

Answer 32

May resemble RBCs. Not clinically significant but interferes with interpretations.

Can happen if bubbles are introduced into the sample or when coverslip is placed on sample.

Question 33

Where does mucous come from that is seen in urine and is it clinically significant?

Answer 33

Mucous is a protein material secreted by glands and epithelium of the genitourinary tract & RTE cells. Uromodulin is a major constituent of mucous which is a glycoprotein.

No clinical significance but could be confused with hyaline casts sometimes if the mucous threads clump together.

Question 34

How can you get rid of amorphous phosphates (in alkaline urine)?

Answer 34

Amorphous phosphates are soluble in glacial acetic acid.

Question 35

How can you best see oval fat bodies in microscopic analysis?

Answer 35

Examine oval at bodies under polarizing microscope for Maltese cross formation in droplets containing cholesterol.

If negative, stain with Sudan III or Oil Red O. Orange-red colour is confirmatory for oval fat bodies made of triglycerides and neutral fats.

Question 36

Are ammonium biurate crystals clinically significant? Are they found in acidic or alkaline urine?

Answer 36

No, round in improperly stored samples found in alkaline urine.

Yellow-brown “thorny apples”.

Question 37

How can you get rid of ammonium biurate crystals?

Answer 37

Dissolve ammonium biurate crystals in glacial acetic acid.

Question 38

How can a polarizing microscope provide an advantage in identification of crystals in urine analysis?

Answer 38

Polarizing microscope can be used to I.D. and differentiate several different types of crystals based on their polarizing capabilities.

Question 39

What is renal failure? What clinical symptoms and lab results are present with this condition?

Answer 39

Renal Failure: Acute or chronic/end stage; may be a gradual loss of renal function, i.e. in diabetes. Calculi can cause temporary loss of function.

Clinical Symptoms: Swelling or edema; major symptom.
Lab results: Low SG, protein, RBCs, all casts.

Question 40

What are the implication of tubular disorders? What can you expect to see in a urinary analysis?

Answer 40

Tubular Disorders = tubular destruction and necrosis. Destruction of RTE cells.

Urinary analysis: RTE clumps or casts, granular casts, and waxy casts.

Question 41

What is Falconi syndrome?

Answer 41

Falconi syndrome –> a hereditary tubular dysfunction where there is decreased reabsorption of electrolytes and nutrients.