Microscopic UA

Question 1

When is microscopic examination typically performed?

Answer 1

On urine specimens that….

1. Show some abnormalities on the physical and chemical analysis (UA w/ reflex to microscopic)
2. Come from patients with known renal disease (e.g. chronic kidney disease)
3. Microscopic specifically ordered by the clinician (complete UA)

Question 2

What is microscopic examination used to identify?

Answer 2

1. Cells
2. Casts
3. Crystals

Question 3

What is normal sediment?

Answer 3

1. Red Blood Cell (RBC) count: small amount is normal
2. White Blood Cell (WBC) count : small amount is normal
3. Epithelial cells: occasionally can be normal, can indicate contamination
4. Bacteria: should NOT be present
5. Casts: Should NOT be present
6. Crystals: should NOT be present

Question 4

Is CKD reversible?

Answer 4

NO. CKD is rarely reversible

Question 5

CKD pathophysiology

Answer 5

1. Rarely reversible
2. Progressive decline in renal function, even after the cause has been removed
3. Reduction in renal mass → hypertrophy of the remaining nephrons
4. Hyperfiltration of remaining nephrons
5. GFR in these nephrons is at a supranormal level…overall GFR still declines

*Once once nephron fails, the rest will fail over time due to increased stress on other nephrons which will result in a decreased GFR

Question 6

What are associated conditions with RBCs found in the urine?

Answer 6

1. Infection (pyelonephritis, cystitis)
2. ureterolithiasis
3. GU malignancy (bladder cancer)
4. Renal cyst
5. Acute kidney injury (AKI)

Question 7

What are associated conditions with WBCs found on microscopy?

Answer 7

1. Infection (pyelonephritis, cystits, urethritis)
2. Renal inflammatory processes (interstitial nephritis)

Question 8

What conditions are associated with Renal tubular epithelial cells found on microscopy?

Answer 8

***Always abnormal****

1. AKI (acute tubular necrosis, interstitial nephritis)
2. Nephrotic syndrome

Question 9

What conditions are associated with squamous epithelial cells found on microscopy?

Answer 9

Contaminated catch

Question 10

What conditions are associated with oval fat bodies found on microscopy?

Answer 10

1. Nephrotic syndrome
2. Autosomal dominant polycystic kidney disease

Question 11

Graph of major causes of hematuria by age and duration

Answer 11

Question 12

What do “dysmorphic RBCs” indicate on a urine microscopy report?

Answer 12

injury or pathology on the glomerular level

Question 13

What are Urinary casts?

Answer 13

1. Urinary proteins form fibrils that attach to the epithelial cells lining the tubule lumen as:

• Urine in tubules becomes very concentrated (ex: dehydration)
• Urine flow ceases (stasis)
• Urinary pH is very low
• Urinary salt concentration is high

2. Fibrils may intertwine to form casts

• Casts may in turn entrap chemicals or formed elements that are present in the urine
• Casts are eventually washed out of their point of origin and appear in the urine

***Urinary casts are unique to the kidneys

Question 14

How do urinary casts appear?

Answer 14

They appear as cylindrical, cigar-shaped bodies that represent molds or “casts” of the lumen of the renal tubule in which they were formed

• Distal convoluted tubule
• Collecting duct

Question 15

What is the major protein constituent of normal urine and that often forms the commen matrix of casts?

Answer 15

Tamm-Hosfall glycoprotein is the major protein constituent

• It is a major defense protein of urothelium against bacteria
• Reagent chemical strips do not detect this protein (dipstick wont turn positive), because it is so heavily glycosylated

Question 16

what is an element of the urine that is truly unique to the kidney?

Answer 16

Urinary casts!

Casts are the only formed element of urine that is truly unique to the kidney

ex: WBCs can be from many different things/organs but WBC casts are ONLY from the kidney

Question 17

What conditions are associated with hyaline casts seen on microscopy?

Answer 17

nonspecific

may be “normal”- due to dehydration, concentrated urine

*If this is due to dehydration/concentrated urine then you would also see a high specific gravity and the color of the urine would be amber or dark yellow

Question 18

What conditions are associated with white blood cell casts seen on microscopy?

Answer 18

1. infection (pyelonephritis)
2. AKI/renal inflammatory processes (interstitial nephritis)

Question 19

What conditions are associated with red blood cell casts seen on microscopy?

Answer 19

1. AKI (glomerulonephritis)
2. Nephritic syndrome

Question 20

What conditions are associated with granular casts seen on microscopy?

Answer 20

AKI (acute tubular necrosis

Question 21

What conditions are associated with renal tubular epithelial cell casts seen on microscopy?

Answer 21

1. AKI (acute tubular necrosis, interstitial nephritis)
2. Nephritic syndrome

Question 22

What conditions are associated with waxy casts seen on microscopy?

Answer 22

nonspecific

CKD

Question 23

What conditions are associated with broad casts seen on microscopy?

Answer 23

CKD

Question 25

Which urinary cast is ALWAYS an abnormal finding?

Answer 25

renal tubular epithelial cell cast

Question 26

What urine crystals are normal for acidic pH?

Answer 26

1. Uric acid crystal 2. Amorphous urates 3. Calcium oxalate

Question 27

What types of urine crystals are normal for neutral pH?

Answer 27

1. Triple phosphate 2. Ammonium biurate 3. Calcium carbonate 4. Calcium oxalate

Question 28

What types of urine crystals are normal for alkaline pH?

Answer 28

1. Triple phosphate 2. Ammonium biurate 3. Calcium carbonate 4. Calcium phosphate 5. Amophous phosphates

Question 29

Where are abnormal urinary crystals usually found?

Answer 29

in acidic urinary pH

Question 30

Abnormal urinary crystals

Answer 30

* Typically found in acidic urinary pH * Always require confirmation, meaning they need chemical testing to identify the nature of the crystal -Correlation to patients drug history because some medications can cause abnormal urianry crystals \*\*For testing purposes- any crystal that is not on the normal urinary crystal list that he gave we do not need to know. Won't be asked "which of the following is an abnormal urinary crystal"- dont need to know names

Question 31

What different things can cause abnormal urinary crystals?

Answer 31

1. Antibiotics – Ampicillin, Sulfonamides 2. Amino Acids – Cystine, Leucine, Tyrosine 3. Altered metabolism – Bilirubin, Cholesterol 4. Radiographic Contrast Media

Question 32

When would a urine culture and sensitivity be performed?

Answer 32

1. UA w/ reflex to microscopic and/or culture 2. Symptomatic complaints that raise concern for infection (dysuria, increased frequency, fever, flank pain, etc). Ways to treat: * Empiric treatment * Urinalysis with treatment * Urinalysis with culture and pretreatment

Question 33

What are urine culture indications?

Answer 33

1. Evidence based medicine- important to consider patient's expectations, individual clinical expertise and best available clinical evidence 2. Suspicion of complicated infection 3. Presentation suggestive of pyelonephritis 4. Failure to respond to initial therapy, raising the possibility of a resistant organism 5. Recurrent symptoms (less than 1 month) after treatment of a previous UTI for which no culture was performed

Question 34

When are urine culture results typically available and how long until they are considered negative?

Answer 34

* Urine collected and send for culture * This usually includes a preliminary gram stain * Sensitivity of any organisms is usually helpful as well * Typically results available 24-48 hours but test considered negative after 5 days

Question 36

Urine culture and sensitivity result patterns

Answer 36

* No Growth * 100 cfu (colony forming units) * 1000 cfu * 10,000 cfu * 50,000 cfu- intermediate result---\> This is an "on the fence" culture result * \>100,000 cfu (typically the cutoff for what is considered infection)