Renal Chemistry (chem lect 5, 6) Flashcards

1
Q

Function of Urinalysis

Specific gravity

Protein level

A

To evaluate kidney function

Specific gravity: make sure tubules are concentrating

Total protein: to evaluate glomerular function

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2
Q

Clinical Signs of Renal Dz

A
  1. Nonspecific
  2. Dehydration
  • inability to concentrate urine
  • vomiting
  1. Halitosis, oral ulcerations, excessive salivation
  • build up of nitrogenous wastes: comes from protein breakdown
  • Build up of uremic toxins
    • causes vomiting as well
  1. Palpable abnormalities
  2. Changes in water intake and / or urination
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3
Q

Acute renal failure

vs

Chronic renal failure

A

Acute renal failure

  • anuric

Chronic renal failure:

  • polyuric
  • can’t concentrate
  • dehydrated
  • CBC
    • mod anemia
    • non regenerative
    • normo chromic
    • normo cytic
    • No erythropoietin

Pyelonephritis: screamingly painful on palpation

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4
Q

Significant Clinical Findings

A

Distrubances in water intake and/or urine output

  • early, most sig indicator of urinary tract dz
  • PU/PD
  • Anuria/oliguria: no output/reduced output
  • Pollakiuria: inc frequency of urination
  • Dysuria: difficulty urinating
  • Incontinence
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5
Q

Polyuria/polydypsia

A

Production of urine and consumption of water in excess of normal

  • Early indicator of renal dz
  • Renal tubules have lost ability to concentrate urine

Extremely important clinical finding

  • Primary renal dz
  • Non renal disorders that affect abilitiy of kidney to concentrate urine

Diagnosis

  • Consistently low urine S.G.
  • Inc water intake (>100 ml/kg/day)
  • Increased urine output (> 50 ml/kg/day)
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6
Q

Causes of PU/PD

1.

2.

3.

4.

5.

A
  1. Loss of medullary gradient or medullary washout
  2. Decreased ADH
  3. ADH resistance
  4. Iatrogenic
  5. Psycogenic
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7
Q

Loss of Medullary Gradient or medullary washout

Osmotic diuresis

Medullary Washout

A

Osmotic diuresis

  • CRD
  • Diabetes mellitus: Hyperglycemia, glucosuria
  • Fanconi syndrome: Normoglycemia, glucosuria
    • Tubules lose ability to resorb amino acids and glucose
  • Post obstructive diuresis: unblocked obstructed cat
    • Hyperkalemia will kill you

Medullary washout

  • Any Chronic PU/PD
  • Liver failure (decreased urea)
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8
Q

Decreased ADH Secretion

A
  1. Rare cause PU/PD
  2. Central DIabetes Insipidus
  3. Can be caused by damage to hypothalamus or pituitary gland
  • Surgery
  • Infection
  • Inflammation
  • Tumor
  • Brain injury
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9
Q

Synthetic ADH

A

Vasopressin

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10
Q

ADH Resistance

A

Pyometra: endotoxin

Pyelonephritis: endotoxin

Cystitis: endotoxin

Hypercalcemia: interferes with ADH at distal tubules

Hypokalemia: decreased medullary gradient

Cushings

Addisons

Hyperthyroidism

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11
Q

Iatrogenic causes PU/PD

A

Diuretics

Corticosteroids

  • Causes insulin resistance => higher glucose => osmotic

Anticonvulsants

Fluid therapy

  • MAKE SURE URETHRA IS PATENT
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12
Q

Investigating PU/PD

History

Physical Exam

Diagnostic tests

A
  1. History
  • Drugs
  • Glucocorticoids
  • Anticonvulsants
  • Excessive thyroid
  • Diuretics
  • Estrus cycle
  1. Physical Exam
  • Clinical signs of cushings:
  • pyometra
  1. Diagnostic tests
    * MDB: UA, CBC, Biochem profile
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13
Q

Anuria / Oliguria

Critical clinical findings

A
  1. Requires Agressive therapy
  2. Determine Potassium level ASAP
  3. Determine cause of anuria/oliguria
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14
Q

Oliguria/anuria

History and physical exam

A
  1. Exposure to nephrotoxins
    * NSAIDs, Aminoglycosides, Ethylene Glycol
  2. History of damage to Urinary tract
  3. Hydration status
    * Interpret SG: dehydration is ‘pre-renal’
  4. Bradycardia or ECG changes
    * Hyperkalemia
  5. Abdominal palpation and imaging
    * Calculi, masses, free fluid in abdomen, bladder integrity
  6. Pass a catheter
    * Establish / motinor urine
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15
Q

Laboratory Dxs of stone

1.

2.

3.

4.

5.

A
  1. Urinalysis: (SG, Casts, crystals)
  2. Bichem profile
  • Potassium
  • TCO2 (Bicarb)
  1. Uroabdomen: male foals with full bladders, Goats
  • High BUN/Creatinine
  • Low sodium
  • High potassium
  1. Ethylene Glycol intoxication
  • BUN/Creatinine
  • low calcium (precipitates with the crystals)
  • high anion gap
  • seizures
  1. CBC findings
    * non regenerative anemia = chronic renal failure (no EPO)

University of Minnesota for stone analysis

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16
Q

Dysuria

A
  1. (Painful, difficulty in urinating)
  2. Partial or complete urethral obstruction
    * Identify quickly because uremia, hyperkalemia and death can occur w/in 48-72 of complete obstruction
  3. Neuro
  • UMN dz (inhibitory neurons): tight distended bladder, diff to express
  • LMN dz: large flaccid bladder, easy to express
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17
Q

Biochemical Abnormalities

A
  1. Renal function tests
    * BUN and Creatinine
  2. Electrolytes
  • Na and Cl (Resorbed)
    • these both follow water
  • K and Ph (excreted)
  • Ca (hypercalcemia diff. to interpret)
  1. Albumin and lipids
    * to evaluate glomerular function
  2. Acid base and anion gap
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18
Q

Renal Function Tests

A
  1. BUN and Creatinine
  • Markers for glomerular filtration rate (GFR)
  • Dehydration will increase these (pre-renal azotemia)
  1. Used to monitor therapy and disease progression
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19
Q

Azotemia

vs

Uremia

A

Azotemia

  • Increased BUN and/or Creatinine
  • Due to a decrease GFR
  • Consider muscle mass (If no muscle mass animal won’t have high creatinine)

Uremia

  • azotemia plus clinical signs of disease
  • Lethargy, depression, vomiting, weight loss, PU/PD, urine output disturbances, nose bleeds from uremic toxins coating platelets
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20
Q

BUN

(Blood Urea Nitrogen)

A
  1. Urea formed in liver from nitrogenous waste products like ammonia resulting from protein breakdown in gut
    * Liver failure = low BUN
  2. Passes through glomerular filter
  3. Inc levels in blood
  • Dec flow rate in kidney = inc reabsorption
  • Inc protein catabolism (Jens dogs tearing up rawhides to save furniture)
  • Hemorrhage in GI tract

4. Reabsorbed by tubules at (25%-40%), inversely proportional to flow rate

  1. Unreliable indicator of renal dz in ruminants: cows excrete urea into alimentary tract
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21
Q

High BUN low Creatinine

top differential:

A

Upper GI bleed

Unless you’re Jen and feed rawhides all. the. time.

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22
Q

High Alk Phos

NORMAL IN

A

Growing animals (bone resporption and remodeling)

High alk phos with high bilirubin or other indicators of liver problems

  • ​follow up on this

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23
Q

Ammonia (ammonium ion)

A
  1. Common byproduct of metabolism of nitrogenous compounds
  2. Smaller than urea and more mobile
  3. Urease bacteria make ammonium ion and inc pH of urine = struvite crystals
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24
Q

Increased BUN (Azotemia)

Pre-renal

renal

post renal

A

Pre-renal (doesn’t involve kidneys)

  • Decreased filtration rate b/c of dehydration and dec blood flow to glomeruli
  • High protein diet or GI hemorrhage (creatinine normal)

Renal (kidney disease)

  • Dec filtration rate (kidneys not absorbing/secreting like they should)

Post Renal (UT dz past kidneys => bladder and urethra)

  • Decreased filtration rate from obstruction
  • Obstructed outflow/rupture in outflow tract
  • most common in males (narrow urethra)
  • Dx made by PE and Hx, more than lab eval
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25
Q

Pre-renal Azotemia

A

Results from dec blood flow to kidneys

  • Dehydration
  • Shock: cardiovascular, hypovolemic, endotoxic

Kidneys attempt to conserve water to inc GFR

Urine SG elevated

  • Cats > 1.035
  • Dogs > 1.030
  • Horses and cows > 1.025

Elevations in PCV, RBC, Cl, Plasma protein/albumin

Analyze Urinalysis PRIOR to fluid therapy

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26
Q

Crystals common in horse urine

A

Calcium carbonate

  • Brown radiating spheres
  • dumbells
  • alkaline urine

Calcium oxalate

  • Dihydrate
    • squares with two lines
    • Seen wtih cushings
    • Ingestion oxalate containing plants
  • Monohydrate
    • Picket fence (ethylene glylcol poisoning dogs)
    • NOT 3D
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27
Q

Pre-Renal Azotemia NOTE

A

High Urine SG doesn’t rule out renal disease

Possibility of glomerular dz w/o tubular disease

=> Results in significant proteinuria with a benign sediment still maintaining ability to concentrate urine

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28
Q

Tx for endotoxic shock

A

Want to increase blood pressure and blood flow

  • Epinephrin
  • Dopamine
  • Fluids
29
Q
  1. Waxy casts and isothenuria
  2. Granular Casts
  3. Hyaline casts
A

1. Waxy casts were once cellular casts => NOT NORMAL

  1. Granular casts: normal cellular turn over NBD
  2. Hyaline casts: maybe ate a lot of protein: NBD
30
Q

Granular casts

vs

Cellular casts

A

Granular casts => can be normal cellular turnover

Cellular casts => Shedding whole renal tubule, never normal

  • can be aminoglycoside intoxication
31
Q

Pre-renal azotemia

PCV

NA, Cl

Total protein

A

Pre-renal azotemia indicates dehydration

Should have a higher PCV (relative erythrocytosis)

Na and Cl tend to be increased

Higher total protein

32
Q

Hypoalbuminemia Tx

A
  1. Hetestarch
  2. Plasma
  3. Synthetic proteins
  4. Epinephrine (vasoconstriction)
33
Q

Renal Azotemia IMP NUMBERS

A
  1. Concentrating ability lost when 2/3 nephrons lost
    * Spec Grav goes first
  2. When 75 % nephrons non-function
    * Increase BUN and Creatinine => Azotemia happens second
34
Q

High BUN and Low Creatinine

a.

b.

-look for:

A

a. Cat with chronic renal failure and no muscle mass to break down
b. young healthy-ish dog with an upper GI bleed

  • Blood is a great protein
  • Look for hypochromic, microcytic, non-regenerative anemia (1+ polychromasia is not regenerative 80K vs 300K retics)
35
Q

Things that keep renal tubules from reacting to ADH

A

1. Booze

2. Steroids

  • Prednisone
  • Cortisol (cushings)

3. Endotoxins

4. Calcium

36
Q

Urine will not be adequately concentrated if azotemia is due to:

A

Renal dz

37
Q

Hyposthenuria (<1.008) is NOT a sign of

Usually indicates

A

Renal failure

Abnormally dilute urine from

  • Central diabetes insipidus
  • blockage of ADH
38
Q

Post-renal Azotemia general features facts

A

Blocked cats

Azotemia with hyperkalemia and hyponatremia

Urine spec grav not helpful

Eval of abdominal fluid

  • low protein
  • BUN vs Creatinine
39
Q

Renal dz w/o Azotemia

A

Greater than 25% functional nephrons

Requires urinalysis to detect renal dz

  • Proteinuria
  • Glucosuria w/o hyperglycemia (Fanconi)
  • Casts
  • Reduced ability to concentrate in dehydrated animal

Monitoring of animals receiving aminoglycosides

  • monitor UA and serum BUN and creatinine
40
Q

Evaluatin of animals with Dec BUN

A

NBD large animals: they look for hypercalcemia

Could be NBD in small animal

  • Can happen in vegetarians, or inc GFR, or overhydration

Hepatic failure:

  • BUN made in liver from ammonium ions
  • Check other liver products to see if they are low
    • Glucose
    • Albumin
    • PT/PTT
41
Q

Evaluation of Creatinine

A

Product of muscle metabolism

Greyhounds tend to have higher Creatinine

Not a product of diet or GI hemorrhage

Inc in severe muscle damage

42
Q

Electrolytes in Urinary Tract Disease

A

Potassium

  • excreted in kidneys

Sodium

Chloride and Bicarb

Phophorus

  • excreted by kidneys so inc with renals dz

Calcium

  • Renal failure in horse: hypocalcemia…?
43
Q

Potassium

A

Can inc

  • Postrenal azotemia
  • Renal azotemia

Hyperkalemia often assoc w/

  • anuric renal failure
  • oliguric renal failure

Hypokalemia develops in

  • polyuric renal failure
  • mostly cats, cows, 25% dogs
  • NOT HORSES
44
Q

Hypophosphatemia will cause

A

Intravascular hemolysis

no phospohorus => no atp => no cell membrane

45
Q

High potassium=

Low potassium=

A

cardiac arrest

respiratory arrest

46
Q

Decreased Potassium/hypokalemia in large animals

A

Anorexia

47
Q

PCV in the toilet is what kind of renal failure?

A

Chronic renal failure

48
Q

PCO2

vs

TCO2

A

PCO2: how well your lungs are breathing off acid

  • Blood gas

TCO2: bicarb

  • Serum biochemistry
49
Q

Bicarb

A

Gets titrated out of body with acid

Anion gap stuff

50
Q

Chloride and Bicarb slide

A
  1. Cl- dec in horses and cattle with renal dz
  2. Cl- can be elevated in prerenal azotemia
  3. Cl- and bicarb regulated by the kidney
    * levels may vary inversely in acidosis
  4. Biochemical profile TCO2 = Bicarbonate (HCO3-)
  • often reduced in cats and dogs b/c of lack of excretion or organic acid waste
    • gets titrated out by lactic acid and uremic acid
51
Q

Two types of metabolic acidosis

A

Loss of bicarb, kidneys conserve Cl-

  • normal anion gap

Build up of acids (Lactic acid, uremic acids, ethylene glycol, DKA)

  • Bicarbonate not lost, kidneys do not conserve Cl-
  • Increased anion gap
52
Q

Inc lactic acid associated with

A

Hypovolemia

53
Q

Chloride

A

Chloride and Sodium usually in 1:1 ratio

Selective loss/gain of Chloride compared to sodium indicates acid-base prob

54
Q

Pseudo addisons

vs

addisons

A

Pseudo addisons (whipworm dz)

  • Causes extreme secretory diarrhea
    • lose electrolytes
    • looks like adrenal glands aren’t working
    • Na/K ratio effed
    • Na and Cl extremely low
  • makes it look like your body can’t absorb anything

Addisons

  • when adrenal glands don’t work and make cortisol
  • ACH stim if no cortisol put on Pred
  • must give these animal Na and Cl or they’ll DIE
  • undiagnosed addisons in sx = patient will DIE
55
Q

Loss of Chloride in Excess of Sodium

Not on test

A

Horses:

  • sweating
  • diarrhea

Cattle: can lose in saliva

Gastric reflux

56
Q

Phosphorus

Hyperphosphatemia

A

Hyperphosphatemia common in renal dz

  • due to dec exretion of P
  • exception is cattle and horses
  • Occurs rapidly in ARF, b/c dec GFR
  • Steadily progressive in CRF

Controlling hyperphosphatemia imp

  • Secondary hyperparathyroidism w/ bone resporption and renal mineralization
  • Renal damage due to elevated P
57
Q

Uremic Frosting

A

When Ca X P > 70

Crystalizes things throughout body incl. kidneys

58
Q

Calcium

Hypercalcemia

Hypocalcemia

A

Hypercalcemia

  • common in horses with seere renal dz
  • rare in other species
  • can cause renal dz in dogs and cats b/c it makes distal tubules refractory to ADH

Hypocalcemia

  • May be seen in cats and cattle with CRF due to polyuria
59
Q

Acid Base abnormalities with Renal DZ

A

Metabolic acidosis

  • common in cats and dogs
  • decreased excretion of H+ and organic acid products
  • loss of ability to conserve / make bicarb

Ruminants

  • metabolic alkalosis
  • Rumen stasis and sequestration of HCl
60
Q

Albumin and Lipids in renal dz

A

Pre-renal azotemia: albumin inc

Renal dz: Normal or dec albumin

Protein losing nephropathy

  • Glomerular dz
  • Protein : Creatinine ratio
  • Results in hypercholesterolemia
  • Nephrotic syndrome
    • Proteinuria
    • hypoalbuminemia
    • hypercholesterolemia
    • peripheral pitting edema
61
Q

ARF

vs

CRF

Why care?

A

ARF

  • Toxic or ischemic damage to kidney
  • Guarded short-term prognosis
  • Good long-term prognosis if renal function restored

CRF

  • Cause not usually identified
  • Good short term prognosis
  • Progressive dz => bad long-term prognosis
62
Q

Distinguishing ARF & CRF

A

ARF

  • Initially anuric or oliguric
  • Later polyuric
  • Typically good BCS

CRF

  • Usually present PU/PD
  • Will become oliguric or anuric in end stage
  • Usually anemic: NO EPO
63
Q

Lab finding

ARF: Anuric / Oliguric

A

Hyperkalemia

Metabolic acidosis with high anion gap

Na & Cl normal or high due to dehydration

NOT ANEMIC

Possibly inc phosphorus

64
Q

Lab findings

CRF: Polyuric

A

Na and K likely to be low b/c of renal loss

Cl may be elevated due to loss of bicarb

Metabolic acidosis with normal anion gap

Non-regenerative anemia of CRF

Possibly elevated phosphorus

65
Q
  1. Trace of +1 protein dipstick and high SSA test, be concerned for….
  2. High Protein on dipstick and SSA…..
A
  1. Multiple myeloma
  2. Not multiple myeloma
66
Q

Bilirubin crystals in cats is bad, can indicate

A

extravascular hemolysis

liver disease

67
Q

Cats with renal failure will have high

A

Phosphorus and calcium

68
Q

Ammonium biurate crystals:

  1. In Dalmations or bulldogs:
  2. In other dogs:
A
  1. NBD
  2. hepatic disease
69
Q

Rough catheterization can cause

A

Proteinuria and heme