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Nephrology > Lab Evaluation > Flashcards

Lab Evaluation Flashcards

1
Q

Wastes products of metabolism?

3

A
  1. urea,
  2. creatinine,
  3. uric acid
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2
Q

Regulates the excretion of water and solutes such as?

How does it do this?

A

Regulates the excretion of water and solutes (sodium, potassium, and hydrogen)

largely by changes in tubular reabsorption or secretion.

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3
Q

Secretes hormones such as?

7

A
  1. Renin,
  2. prostaglandins,
  3. bradykinin
  4. Erythropoietin,
  5. calcium,
  6. phosphorus, and
  7. (1,25-dihydroxyvitamin D3 or calcitriol)
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4
Q

The function of the kidneys?

5

A
  1. Regulation of erythrocyte production
  2. regulating mineral levels
  3. Regulation of blood pressure
  4. helping regulate the acid-base balance
  5. elimination of metabolic toxins and water through the urine
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5
Q

Some have symptoms that are directly referable to the kidney such as? 2

Or external symtpoms such as? 3

A
  1. gross hematuria
  2. flank pain
  3. edema,
  4. hypertension,
  5. signs of uremia
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6
Q

Many patients, however, are asymptomatic and are noted on routine examination to have an elevated or abnormal what? 2

A

serum creatinine concentration or an abnormal urinalysis

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7
Q

WHats azotemia? 2

Oliguria? 2

Anuria? 1

A

Azotemia

  1. Elevated BUN and/or creatinine
  2. The build up of abnormally large amounts of nitrogenous waste products in the blood

Oliguria

  1. Urine output less than 400 mL/day
  2. Urine output less than 20 cc/hr

Anuria
1. Urine output less than 100 mL/day

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8
Q

What are the different kinds of azotemia?

3

A
  1. Pre-renal failure (dehydration)
  2. Intrinsic renal failure
  3. Post-renal obstruction
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9
Q

Describe the following azotemias:

  1. Pre-renal failure?
  2. Intrinsic renal failure? 3
  3. Post-renal obstruction? 2
A
  1. Volume contraction, etc (dehydration)
    • Arteriolar damage (acute hypertension)
    • Glomerulonephritis etc
    • ATN
    • Ureteral obstruction
    • Bladder outlet obstruction
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10
Q
  1. What does GFR equal?
  2. Whats normal for men?
  3. women?
  4. How does it change with age?
  5. What influences it? 4
  6. How can it be measured? 3
    (Whats the gold standard?)
A
  1. Equal to the sum filtration rate of all the functioning nephrons
  2. Normal for men = 130 mL/min/173 m2
  3. Normal for women – 120 mL/min/173 m2
  4. Decreased NORMALY with age
  5. Influenced by
    - Age,
    - sex,
    - body size
    - Renal blood flow and hydrostatic pressures in glomerulus (BP)
  6. Can be measured by:
    - Creatinine clearance
    - Urea clearance
    - Inulin clearance- exogenous polysaccharide 100% filtered- gold standard for GFR
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11
Q
  1. What is creatinine?
  2. What is a normal creatine clearance? (men and women)
  3. What is the downside to creatinine clearance testing?
  4. Why does this happen? 2
A
  1. Endogenous substance used to assess GFR
  2. Normal values (up to age 40):
    Men: 107-139 mL/min
    Women: 87-107 mL/min
  3. Overestimates true GFR by up to 40%
    • Especially in persons with decreased renal function
    • Reason: active tubular secretion of creatinine
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12
Q

Creatinine clearance procedure

What are the three steps?

A
  1. Record patient’s height and weight
  2. Collect 24-hour urine: measure total volume (TV) and urine creatinine (UCr) how much is being cleared
  3. Collect blood specimen: measure serum creatinine (SCr) to see how much is endogenously produced
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13
Q

HOw can you calculate CrCl?

A

[UCr x TV(mL)/1440(min)]/SCr x 1.73/BSA

BSA(m2) = ([Ht (cm) x Wt (kg)]/3600)1/2

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14
Q
  1. Estimated GFR/CCr calculateuion?
  2. Whats the criticism?
  3. What is this used for?
A
  1. Estimated GFR/CCr (mL/min) =
    [(140 - age) x wgt (kg)]/[72 x SCr]

Multiply results by 0.85 for women

  1. Can overestimate the GFR
  2. Measure serum creatinine and estimate GFR to assess renal function w/o urine
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15
Q

Standardizing the eGFR
MDRD Formula (Conventional calibration)
eGFR (mL/min/1.73m2) = ?

Normal should be?

A 
eGFR (mL/min/1.73m2) =
186  x  (Scr)-1.154  x (Age)-0.203

x (0.742 if female)

x (1.210 if African American)

MDRD = Modification of Diet in Renal Disease Study
(Scr) = serum creatinine value reported in mg/dL

Greater than 60

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16
Q

Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation

Why is this superior?
6

A

Creatinine measurements using external filtration markers (eg, iothalamate)
1. Provides a more accurate estimate of GFR among individuals with normal or only mildly reduced GFR
2. less bias,
3. improved precision, and
4. greater accuracy.
5. Better identification and early Tx of CKD
6. Prevent or delay renal failure
more accurate risk prediction for adverse outcomes compared with the MDRD study equation

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17
Q

Glomerular Filtration Rate (GFR)
In patients with kidney disease reduction in GFR:
1. What are the two kinds of problems it could be?

  1. Level of GFR has prognostic indications but is NOT an exact correlate to what?
  2. Stable GFR—does not necessarily imply what?
  3. Some patients w/ renal disease may go unrecognized because why?
A
  1. Either progression in underlying kidney disease or superimposed (often) reversible problem
  2. the loss of nephron mass
  3. stable disease
  4. they have normal GFR
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18
Q

BUN (blood urea nitrogen)
comes from where?

Whats the normal range?

Usually measured with what to assess kidney function?

A

Urea nitrogen is what is formed when protein breaks down

Normal range: 6-20 mg/dL

Many drugs can effect the BUN
Usually measured with creatinine to monitor kidney function

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19
Q

What would increased theh BUN? 4

What would decrease it? 2

A 
Increased:
1. Renal Disease (failure)
2. Excessive protein breakdown (catabolism- tissue necrosis)
3. Very high protein diet
4. GI Bleeding
Decreased:
1. Liver disease
2. Starvation
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20
Q
  1. Where does BUN come from?
  2. The N takes up 3 H+ to form NH3+ which is what?
  3. The ammonia (NH3+) is then processed through the what to become what?
A
  1. When protein is used for energy the carbon is cleaved from the amino acid and leaves behind a Nitrogen.
  2. ammonia.
  3. the liver to become urea.
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21
Q

When the urea enters the blood stream it is called what?

Where is this excreted?

A

blood urea nitrogen

The blood urea nitrogen is then excreted by the kidney

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22
Q

BUN increases when protein is broken down and more ammonia forms: Examples are? 6 (most common)

A
  1. Burns
  2. Tetracycline
  3. Steroids
  4. Fever
  5. Catabolic state
  6. GI bleeding*****
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23
Q

BUN will decrease in liver failure. Why?

A

If the liver is unavailable to convert ammonia to urea then the BUN will decrease and the ammonia increases

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24
Q

BUN is filtered from the body through the kidneys. Decreased GFR (glomerular filtration rate) leads to increased BUN in 2 ways. What are they?

A
  1. Decreased flow through the glomerulus

2. Slower transport time allows more BUN to be resorbed at the level of the PCT

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25
Q

What is creatinine:
1. HOw is it formed?
2. The more of what the higher the creatine?
(and vice versa)

A
  1. Creatinine is formed from the normal breakdown of muscle
  2. The more muscle mass the higher the creatinine
  3. The lower the muscle mass the lower the creatinine (therefore normal reduction in creatinine as a person ages and loses muscle mass)
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26
Q

Lab Evaluation of Renal Function

  1. What is creatine?
  2. Whats the normal range? (mena nd women)
  3. How much loss of renal function is needed to increase serum creatinine from 1.0 to 2,0 mg/dL?
  4. Used in ratio with what to determine types if azotemia?
A
  1. Waste product of protein breakdown excreted by kidneys
  2. Normal range:
    men—0.8-1.4
    women 0.6-1.2 mg/dL
  3. 50% loss of renal function is needed to increase serum creatinine from 1.0 to 2.0 mg/dL**
  4. Used in ratio with BUN to determine types of azotemia
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27
Q

When is creatinine increased? 5

When is it decreased? 2

A
  1. Increased:
  2. Renal Failure
  3. Diet: increased ingestion of meat
  4. Meds: ACEIs, diuretics, NSAIDS, many others . . .
  5. Muscle disease: muscular dystrophy, rhabdomyolysis

Decreased:
1. Pregnancy—normal occurrence
Range in pregnancy— 0.4 – 0.6 mg/dL

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28
Q

Creatinine is filtered through the kidneys:

  1. Decreased GFR also leads to _________ creatinine
  2. HOw is creatine handled differently than BUN by the kidney?
  3. In the ____ creatinine is actively secreted from the body to be eliminated by the kidneys
  4. This active secretion at the ____ can be blocked by drugs such as cimetidine and trimethoprim therefore _________ the serum creatinine
A

increased

  1. Instead of the creatinine being reabsorbed in the tubules like BUN with a decreased GFR the creatinine is just dumped out
  2. DCT
  3. DCT
    increasing
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29
Q

Increased BUN and Creatinine

BUN? 4

Creatinine? 3

How is creatinine behave differently than BUN?

A

BUN:
1. Decreased GFR
2. Less BUN presented at the glomerulus to be removed from the blood
3. Slower transport time through 4. PCT allows more reabsorption
Increased protein breakdown

Creatineine:

  1. Increased muscle breakdown
  2. Blockage at the sites in the DCT that allow for active secretion
  3. Decreased GFR as there is less creatinine presented at the glomerulus to be filtered out

not reabsorbed in the PCT like BUN

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30
Q

BUN creatinine ratio

  1. Normal?
  2. Elevated?
  3. WHy is it elevated?
  4. How do you calculate the ratio?
A
  1. Normal is 10-20:1
  2. Elevated is > 20:1
  3. Increased ratio in a low flow (low blood pressure) state
  4. Ratio = [BUN]/[serum creatinine]
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31
Q
  1. BUN disproportionately increased when azotemia is due to what?
  2. If renal dz the creatinine should do what?
A
  1. pre-renal causes

2. also be going up proportionality

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32
Q

BUN/Creatinine Ratio

  1. Increased (>20:1) w/ normal creatinine causes? 5
  2. Increased (>20:1) w/ elevated creatinine causes? 2
A

Increased:

  1. Prerenal Disease (decreased renal perfusion)****
  2. Catabolic state w/ increased tissue breakdown
  3. GI hemorrhage
  4. High protein intake
  5. Certain drugs: e.g. tetracycline, steroids

Increased:

  1. Postrenal disease (obstructive uropathy)*****
  2. Prerenal disease superimposed on renal disease*****
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33
Q

BUN/Creatinine Ratio

Decreased Ratio (less than 10:1) w/ decreased BUN causes? 5

Decreased Ratio ( less than 10:1) w/ increased creatinine?
2
A
  1. Acute tubular necrosis (Intrarenal disease)
  2. Low protein diet, starvation, severe liver disease
  3. Repeated dialysis
  4. SIADH
  5. Pregnancy
  6. Rhabdomyolysis (releases muscle creatinine)
  7. Muscular patients who develop renal failure
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34
Q

Electrolytes
Major body electrolytes

What are the cations and what are their normal values? 2

What are the anions and what are their normal values? 2

A

Cations Normal Values

  1. Sodium (Na+) 135 - 145 mmol/L
  2. Potassium (K+) 3.8 - 5.5 mmol/L

Anions
1. Chloride (Cl-) 98 - 106 mmol/L
2. Bicarb (HCO3-) 21 - 28 mmol/L
(Total CO2) 23 - 30 mmol/L

Kidneys play a major role in electrolyte balance

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35
Q

What ions are typically reabsorbed? 8

What ions are typically secreted? 3

A
  1. Sodium (Na+)
  2. Potassium (K+)
  3. Urate
  4. Chloride
  5. Calcium
  6. Phosphate ions
  7. Glucose
  8. Amino acids
  9. Hydrogen (H+)
  10. Potassium (K+)
  11. Urate
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36
Q
  1. Where is sodium freely filtered?
  2. Where is it mostly reabsorbed?
  3. What other places is it reabsorbed? 2
  4. Normally, daily sodium excretion balances daily intake
    Body needs for sodium usually can be met by as little as how much a day?
  5. What do we need to remember about sodium when we are giving fluids?
A
  1. Freely filtered at glomerulus
  2. ~60% reabsorbed isotonically in PCT
    • Reabsorbed in loop of Henle
    • Reabsorbed in DCT, secondary to an aldosterone effect (in part)
  4. 500mg/day (We average about 6 – 15g/day here in the US!!)
  5. mostly extracellular and does not move freely across the cell memebrane
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37
Q
  1. What is the most common electrolyte disorder?
  2. What is it primarily due to?
  3. Excess Na loss relative to water loss occurs via?
  4. Therapy? 2
A
  1. Hyponatremia
    Most common electrolyte disorder
  2. Primarily due to the intake of water that cannot be excreted
  3. Excess Na+ loss relative to water loss occurs via renal or extrarenal routes
  4. Therapy:
    - Correct underlying problem,
    - Na+ and fluid replacement
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38
Q
  1. When does hypernatremia occur?

2. Therapy consists of? 2

A
  1. Occurs when there is an excessive loss of water, relative to Na+
    Causes include renal and extrarenal routes
  2. Therapy consists of
    - appropriate fluid replacement combined with
    - use of diuretics to rid the body of excess Na+
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39
Q

What is the major cation in the intracellular compartment?

Gains are from? 2

Losses are from? 2

A
  1. Major cation in the intracellular compartment (all but approx 2% of body potassium is contained within body cells!)
  2. Gains
    - Normally derived from dietary sources
    - Balance usually maintained in healthy persons by daily intake of 50 to 100 mEq
  3. Losses
    Kidneys are the main source of potassium loss
    -80-90% lost in the urine,
    -the remainder lost in stool or sweat
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40
Q
  1. Important to be efficient at regulating potassium. Why?

2. What are the normals for K+ in the serum?

A
  1. A small change (1-2% of the extracellular volume) can lead to dangerously high serum levels!
  2. Remember, norms for potassium in the serum
    is around 3.5 – 5 mEq/L. Contrast that to sodium,
    which is about 135 – 145 mEq/L!
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41
Q

Potassium homeostasis is dependent upon:
3

Whats a classic example?
(how can we treat this? 3)

A
  1. pH (acid-base disturbance causes K+ shifts between fluid compartments, in acidosis K+ level go up as bringing K+ out of cells into blood)
  2. Renal function including effects of diuretics, aldosterone and renal parenchyma
  3. GI fluid losses (excessive K+ loss with V/D)

Classic Example: DKA. K+ is very low inside the cell.
Bicarbonate, insulin, and albuterol can drive it back into the cell.

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42
Q

Hypokalemia results from?

2

A
  1. K+ shifting to ICF w/o change in total amount of K+ in the body
  2. Depletion of body stores
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43
Q

Hyperkalemia occurs in? 4

Artificial hyperkalemia occurs in? 2

A
  1. Acidosis
  2. From cellular damage (e.g. fever, hemolysis, rhabdomyolysis- K leaks out of cells destroyed)
  3. Renal and adrenal diseases
  4. Medications (ACE inhibitors)
  5. Hemolyzed blood specimens
  6. Thrombocytosis or leukocytosis
44
Q

Hypochloremia occurs when there is excessive loss of Cl-. What could cause this?
5

A
  1. GI losses
  2. DKA
  3. Mineralocorticoid excess
  4. Salt-losing renal diseases
  5. High bicarbonate levels
45
Q

Hyperchloremia occurs during

what? 3

A
  1. Metabolic acidosis
  2. Lower GI losses (diarrhea)
  3. Mineralocorticoid deficiency
46
Q

What is part of the Renal Acid-Base control mechanism and filtered in the glomerulus?

Where is this ion mostly reabsorbed?
(where else?)

A

Bicarbonate

~85% reabsorbed in proximal tubule
~15% reabsorbed in distal tubule

47
Q

Ways a urinalysis can be useful

2

A
  1. Detect systemic disturbances

2. Detect intrinsic kidney/urinary system disorders

48
Q

IN what disease processes would you find the following issues?

  1. Detect systemic disturbances? 2
  2. Detect intrinsic kidney/urinary system disorders? 2
A

Detect systemic disturbances:

  1. Endocrine abnormalities
  2. Metabolic disturbances

Detect intrinsic kidney/urinary system disorders:

  1. Kidney disease
  2. UTIs
49
Q

What are the different kinds of urine specimen collections?

4

A
  1. Fresh voided urine
    - First morning specimen
    - Random specimen
    - Post-prandial
  2. Clean-catch (midstream) urine
  3. Catheterized specimens
  4. Timed urine collections
    - 24-hour
50
Q

What is the most concentrated specimen collection?

When must it be analzyed within?

A

First morning voiding (most concentrated)

Analyzed within 2 hours of collection

51
Q

Specimen handling
test fresh urine within?

Three types of examination?

A

1 hour

  1. Physical
  2. Chemical
  3. Microscopic
52
Q

What are we looking at for appearance?

4 in a UA

A
  1. Color
  2. Turbidity
  3. Odor
  4. Volume
53
Q
  1. What does color depend on?
  2. Whats the normal and abnormal turbidity of a sample?
  3. How much should volume should be ina 24 hour urine?
  4. Oliguria is how much volume? 2
  5. Anuria? 1
A
  1. Color
    - normal varies (colorless to yellow to amber)
    - depends on concentration of solutes (urochrome and urobilin)
  2. Turbidity
    - normal = clear
    - cloudy when crystals or large amounts of cells present

Volume
3. 750-2000mL in 24 hours (average 1500 mL)

  1. Oliguria
    - Urine output less than 400 mL/day
    - Urine output less than 20 cc/hr
  2. Anuria
    Urine output less than 100 mL/day
54
Q

What would the following orders indicate in a urine sample?

  1. Ammonia-like?
  2. Foul, offensive? 3
  3. Sweet?
  4. Fruity?
  5. Maple syrup-like?
A
  1. Urea-splitting bacteria
    • Old specimen
    • pus
    • inflammation
  3. Glucose
  4. Ketones
  5. Maple Syrup Urine Disease
55
Q

What would the following colors indicate in a urine sample:

  1. Colorless?
  2. Deep Yellow?
  3. Yellow-Green?
  4. Red?
  5. Brownish-red?
  6. Brownish-black?
A
  1. Diluted urine
  2. Concentrated Urine
  3. Bilirubin
  4. Blood / Hemoglobin
  5. Acidified Blood (Acute GN)
  6. Homogentisic acid (Melanin)
56
Q
  1. If a urine speciman is cloudy what is most likely the cause?
  2. How will we differentiate between the two? 2
A
  1. Typically cells or crystals
    • Cellular elements and bacteria will clear by centrifugation
    • Crystals dissolved by a variety of methods (acid or base)

Microscopic examination will determine which is present

57
Q

What does chemical analysis involve?

10

A
  1. Specific gravity
  2. pH
  3. Protein
  4. Glucose
  5. Ketones
  6. Bilirubin
  7. Urobilinogen
  8. Blood
  9. Leukocyte esterase
  10. Nitrite
58
Q

What does specific gravity affect?

3

A
  1. Reflects the relative proportions of dissolved solid components to total volume of specimen
  2. Degree of concentration or dilution of urine
  3. Measures concentrating abilities of the kidney
59
Q

What are the expected values for specific gravity:

  1. Range?
  2. Usual?
  3. Highest value is when?
A
  1. Range: 1.003-1.030
  2. Usual results: 1.010-1.025
  3. Highest value is 1st morning specimen > 1.020
60
Q

What can cause a low specific gravity? 4

What can cause a high specific gravity? 5

A

Low specific gravity:

  1. Diabetes insipidus - abnormal
  2. ADH
  3. Tubular damage and renal anomalies
  4. Well hydrated

High SG:

  1. DM
  2. Adrenal insufficiency
  3. Hepatic disease
  4. CHF
  5. Excessive sweating or other loss of water (diarrhea, vomiting, fever)
61
Q
  1. What is urine acidity primarily due to?

2. What are the normal values?

A
  1. Urine acidity due primarily to acid phosphates
    pH 7 = alkaline urine
  2. Expected values:
    Normal kidneys produce urine with pH varying from 4.5 to about 8.0
    Freshly voided urine (normal diets) ~ 6.0
62
Q

Clinical significance of Acidic urine?
3

Clinical significance of Alkaline urine?
4

A
  1. High protein diets
  2. Medications
  3. Uncontrolled diabetes or other causes of metabolic acidosis
  4. Normal post-prandial physiology
  5. Diets high in vegetable, milk and other dairy
  6. Medications
  7. UTI
63
Q
  1. What are the majority of proteins in the urine?
  2. 1/3 of protein is?
  3. What is another protein found only in urine?
A
  1. Majority is globulins (lower MW than corresponding serum globulins)
  2. 1/3 albumin (similar to serum albumin)
  3. Tamm-Horsfall mucoprotein (blood cell casts can be attached to these)
    Normal urinary protein not found in plasma
    Up to 2.5 mg/dL
64
Q

What are our expected results for protein levels in the blood per day:

  1. Excreted?
  2. Concentration?
A
  1. Average 40-80 mg protein excreted per day

2. 100 to 150 mg/day is WNL therefore concentration in random urine is 2-8 mg/dL

65
Q

Proteinuria is the single most important indicator of?

A

kidney disease

66
Q

If you see Albumin in the urine what could be the cause? 6

When would you see globulins in the urine? 2

When would you see hemoglobin in the urine? 2

When would you see Fibrinogen in the urine?

Bence jones? 2

A
  1. Strenuous exercise
  2. Emotional stress
  3. Pregnancy
  4. Infections
  5. Glomerulonephritis
  6. Neonates (1st week)
  7. Glomerulonephritis
  8. Tubular dysfunction
  9. Hematuria
  10. Hemoglobinuria
  11. Severe renal disease
  12. Myeloma
  13. Leukemia
67
Q

Is microalbuemia detected on a normal dipstick?

A

Not detected on normal dipstick

Requires use of special dipstick for microalbinuria–

68
Q

How do we detect proteinuria?

3 steps

A
  1. Generally requires 24 hr urine collection for total protein
  2. Start in am w/ first void and collect for 24 hours keeping specimen in refrigerator
  3. Then total amount of protein excreted is measured
69
Q

Benign proteinuria can be caused by? 2

A
  1. Functional changes: high fever, CHF, strenuous exercise & cold exposure
  2. Orthostatic: Occurs when upright (common in adolescence)
70
Q

Microalbuminuria is an indicator of early kidney dz at what levels?

Proteinuria shows up on a dipstick. What levels?

A

(30-100 mg/24hrs)

>100 mg/24 hrs

71
Q

Glucosuria occurs whenever the blood glucose level exceeds the renal threshold such as?

What is the benign form and what is the pathologic form?

A

Ability of renal tubule to reabsorb
Approximately 180 mg/dL

Condition may be benign (called renal glycosuria) or pathological (diabetes mellitus)

72
Q

Renal glycosuria can be caused by?

2

A

Heavy meals

Emotional stress

73
Q

Ketonuria is the result of fatty acid metabolism which occurs when there is:
2

A
  1. Inadequate carbohydrates in the diet

2. Defect in carbohydrate metabolism

74
Q

The intermediary products of fatty acid catabolism are the three ketone bodies:

A
  1. Acetoacetic acid (diacetic acid) (20%)
  2. Acetone (2%)
  3. Betahydroxybutyric acid (78%)
75
Q

Causes of ketonuria?

8

A
  1. Diabetes mellitus (DKA)
  2. Restricted carbohydrate diet in association with
  3. Fevers
  4. Anorexia
  5. GI disturbances
  6. Fasting/starvation
  7. Neurologic disorders
  8. Anesthesia
76
Q
  1. What does our bilirubin levels reflect?
  2. What are normal levels?
  3. What are the usual levels?
A
  1. Reflects serum levels of conjugated (direct) bilirubin
  2. Negative urine test is normal
  3. Concentration in urine is normally less than 0.02 mg/dL
77
Q

Clinical significance of bilirubinuria 2

Can be an early indicator of what?

A
  1. Hepatocellular disease,
  2. biliary obstruction or any disease that increases the amount of conjugated bilirubin

Can be an early indicator of disease, even before jaundice is present

78
Q

Urobilinogen production:

  1. Billirubin is conjugated where and secreted where?
  2. Where is bilirubin converted to urobilirubin
  3. Where is it excreted?
  4. Where can it be reabsorbed?
  5. Removed by? 2
A
  1. Bilirubin is conjugated in the liver and secreted into bile
  2. Bile enters intestinal tract where bacterial action converts bilirubin to urobilinogen
  3. Excreted in the feces or
  4. reabsorbed into portal circulation
  5. Removed by liver and/or excreted in the urine
79
Q

Urobilinogen
1. Normal urinary excretion rates?

  1. Clinical significance of increased urobilinogen?
  2. Urobilinogen is decreased/absent in
A
  1. 1-4 mg/24hr
  2. Pernicious anemia
  3. Liver disease: hepatitis, cirrhosis, CHF
  4. obstruction of bile duct
80
Q
  1. Hematuria
  2. Hemoglobinuria
  3. What also produced positive test?
  4. Whats normal?
A
  1. intact red cells in the urine
  2. free hemoglobin in urine
  3. Myoglobinuria
  4. No blood
81
Q

What could the following indicate?

  1. Hematuria? 3
  2. Hemoglobinuria? 5
A
    • renal disease,
    • infections,
    • neoplasm, trauma
  2. any of the above plus
    - transfusion reactions,
    - hemolytic anemia,
    - paroxysmal nocturnal hemoglobinuria (PNH),
    - severe burns,
    - various poisonings
82
Q

Leukocyte esterase

  1. What release esterases into the urine when present?
  2. Normals? 2
  3. Clinical significance of positive test?
A
  1. Neutrophilic granulocytes
  2. Normals: No WBCs; negative esterase
    • Pyuria (presence of WBCs in urine)
    • Bacteriuria/UTI
83
Q

Nitrite

  1. What is a normal urinary consituient and what is not?
  2. What does the presence of nitartes in the urine indicate?
A
  1. Nitrates is a normal urinary constituent - nitrites are NOT
  2. Some gram negative bacteria are nitrate reducers producing nitrites, therefore, the presence of nitrites in the urine indicates bacteriuria
84
Q

Bacteriuria
Nitrate reducing organisms? 5

Organsimss that dont? 1

A
  1. E. coli- 72
  2. Klebsiella/Enterobacter -16
  3. Proteus- 5
  4. Staphylococcus- 5
  5. Pseudomonas- 1

Streptococcus faecalis- 1

85
Q

Microscopic analysis
Frequently seen elements? 4

Procedures to identify these? 3

A
  1. Crystals
  2. Cells
  3. Infectious agents
  4. Casts
  5. Centrifuge 10-15 mL urine 5-10 minutes at 1500-2000 rpm
  6. Decant/discard supernatant urine
  7. Examine under low (10x) and high (40x) magnifications
86
Q

Urinalysis:
Acidic urine crystals? 7

Neutral urine crystals? 3

Alkaline urine crystals? 3

A

Acidic urine crystals

  1. Uric acid
  2. Amorphous urates
  3. Bilirubin
  4. Cystine (rare)
  5. Cholesterol (rare)
  6. Leucine (rare)
  7. Tyrosine (rare)

Neutral urine crystals

  1. Calcium oxalate
  2. Hippuric acid
  3. Triple phosphate

Alkaline urine crystals

  1. Calcium carbonate
  2. Ammonium biurate
  3. Calcium phosphate
87
Q

Cellular elements in urinalysis

3

A

RBC
WBC
Epithelial cells

88
Q

What kind of epithelial cells are we looking for in urinalysis?
3

A
  1. Renal tubular cells (round, slightly larger than WBC)
  2. Transitional cells (flat, cuboidal, columnar)
  3. Squamous (large flat cells)
89
Q

Infectious agents

3

A
  1. Bacteria
  2. Yeasts
  3. Parasites
90
Q

What kind of yeasts? 2

(especially seen in which pts?) 1

A
  1. (urinary moniliasis)
  2. Candida albicans (and others)
  3. Especially seen in patients with diabetes
91
Q

What kind of parasites are common? 2

A
  1. Trichomonas

2. Schistosoma haematobium

92
Q

Formation of casts in the urine will cause what?

2

A
  1. Decreased urinary flow

2. Increased concentration of solutes

93
Q

What disroders go with RBC casts? 2

A
  1. Acute inflammatory or vascular disorder in glomerulus causing renal hematuria
  2. May be the only manifestation of acute glomerulonephritis

More destruction/bleeding

94
Q

What disroders go with WBC casts? 3

A
  1. Indicate kidney inflammation
  2. Acute pyelonephritis
  3. Interstitial nephritis, proliferative glomerulonephritis

More infection based

95
Q

Describe Hyaline casts?

How can they be observed? 2

A

Hyaline casts are only slightly more refractile than water and have a transparent, empty appearance .

Hyaline casts may be observed with

  1. small volumes of concentrated urine or with
  2. diuretic therapy and are generally nonspecific.
96
Q

What are Granular (coarsely and finely granular) casts?

What are they considered to be characterisic of?

A

Leakage and aggregation of proteins

Coarse, deeply-pigmented granular casts are considered characteristic of ATN

97
Q

Waxy casts are thought to indicate what?

A
  1. Waxy casts are thought to be the last stage in the degeneration of a granular cast

Waxy casts are nonspecific and may be observed in a variety of acute and chronic kidney diseases

98
Q

If you are getting casts where is this coming from and why?

A

From the kidney and is almost always pathologic

99
Q

Common Findings in:
Acute Tubular Necrosis 3

Microscopic findings? 2

A
  1. SG decreased
  2. +/- blood
  3. +/- protein

Microscopic:

  1. Renal tubular epithelial cells
  2. Pathological casts
100
Q

Common Findings in:
Acute Glomerulonephritis2

Micro? 3

A
  1. Blood increased
  2. Protein increased

Microscopic:

  1. Erythrocytes (dysmorphic)
  2. Eyrthrocyte casts
  3. Mixed cellular casts
101
Q

Common Findings in:
Chronic Glomerulonephritis 3

Micro?

A
  1. SG decreased
  2. Blood increased
  3. Proetin increased

Microscopic:
1. Pathologcal casts (broad waxy casts and RBCs)

102
Q

Common Findings in:
Acute Pyelonephritis? 3

Micro?
3

A
  1. Trace protein
  2. Positive nitrate
  3. Positive LE

Microscopic:

  1. Bacteria
  2. Leukoctytosis
  3. Leukocyte, granular, waxy casts renal tubular epithelial cell casts
103
Q

Common Findings in:
Nephrotic Syndrome 1

Micro? 3

A
  1. Really high protein

Microscopic:

  1. Oval fat bodies
  2. Fatty casts
  3. Waxy casts
104
Q

Common Findings in:
Eosinophilic Cystitis 1

Micro? 2

A
  1. Positive blood

Microscopic:

  1. Numerous eosinophils (Hansel’s stain)
  2. No significant casts
105
Q

Common Findings in:
Urothelial Carcinoma 1

Micro? 1

A
  1. Positive blood

Microscopic:
1. Malignant cells in urine cytology (urine sample should be submitted separately to cytology, void or 24 hours)

Nephrology (15 decks)

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