Renal Dr. DePedro 4/4/17

Question 1

What is this & what are normal characteristics

Answer 1

normal horse urine

can range from cloudy/turbid -> pale yellow-tan

foals more likely to have clear urine normally d/t incr amt of H2O in diet (think mare’s milk)

it’s also normal for voided urine to start out sl. discolored and clear at the end of void.

Question 2

what is normal urine output for horses

Answer 2

15-30 mL/kg/day

= 6.8-13.5 L/day

• remember urine = 3-4 x more concentrated than plasma*
• 280 vs 900-1200 mOsm/L*

Question 3

what is this horse doing?

Answer 3

normal stance for urinating

the urethral sphincter is so strong horses have to use abd mm to urinate!

Question 4

what is one of the things you ck for on external evaluation of genitalia

what is that a sign of

Answer 4

urine scald

exudate

blood

crystal debris

in a postpartum mare it might be a clue that she has some urethral damage as a result of the parturition process.

Question 5

in regards to oral ulceration how does it relate to renal dz in horses

Answer 5

as opposed to SA where it could be a CS of uremia

usually in horses you are already thinking renal dysfunction before you see oral ulcers (due to dehydration)

Question 6

what might you see on rectal exam in renal dz

Answer 6

decr anal & tail tone

can palpate kidneys to assess size & pain (will react w/ pylonephritis)

ureters (must be inflammed to palpate)

bladder (may palpate uroliths)

trigone (uroliths like to be here, may palpate)

Question 7

what are some other diagnostics available

Answer 7

u/s (maybe useful?)

abdominocentesis = for ruptured bladders (mares & foals)

endoscopy = very useful

renal bx = for px purposes

water deprivation test (once rehydrated/electrolytes restored, helps ck renal function)

scintigraphy, measure GFR, urethral pressure = limited use in practice

Question 8

what are methods of urine sampling

Answer 8

free catch = not ideal for c/s purposes

manual expression

catheterization

can have horse thats trained to pee on command!

Question 9

what are these images of

Answer 9

urine scald in mares

Question 10

what is norm USG in adults horses & foals

Answer 10

Adults: = 1.020 - 1.050

Foals: = 1.008

Question 11

what = isosthenuria

hyposthenuria

concentrated urine

Answer 11

1.008-1.012 = isosthenuria

< 1.010 = hyposthenuria

> 1.020 = concentrated urine

Question 12

what pH is normal horse urine

what does this mean for proteins on the dipstick

Answer 12

alkaline

norm. protein = negative - +1
* the alkalinity can mess with coloration of protein pad leading to False +!*
* If > +1 check suggests inflammation, hematuria or glomerulonephritis*

Question 13

what are some causes of glucosuria

Answer 13

exercise

Alpha-2 agonists

equine Cushing’s

corticosteriods

septicemia

proximal tubular damage

Question 14

what is “normal” sediment in horse urine

Answer 14

few RBCs which means < 5/hpf

few WBCs which means < 5/hpf

crystals (Ca carbonate normal)

few bacteria

squamous epi cells

urine casts are rare in urine d/t alkalinity - if suspect must ck for them ASAP after collection!

Question 15

What is represented by arrowheads

arrows

Answer 15

arrowheads = WBCs

arrows = RBCs

Question 16

what is represented by arrowheads

arrows

Answer 16

arrowhead = WBC

arrow = epithelial cell (likely transitional)

Question 17

What cell types are in these pics

Answer 17

squamous cells

Question 18

what crystals are abundant in normal horse urine

Why

Answer 18

Ca carbonate

alkaline pH decr solubility of Ca & Phosphate which promotes crystal formation

Question 19

what are these crystals

Answer 19

CaOx

Question 20

what are these crystals

Answer 20

Ca carbonate

Question 21

Which enzyme if present in urine indicates renal tubular damage

where is it normally found/made

why is it helpful to note an incr in GGT in urine

Answer 21

GGT

liver/renal tubules & other organs with tubular structure (e.g. mammary tissue), & pancreas

if renal origin then the GGT of serum will not be elevated

GGT will elevate prior to azotemia occurring! (when using nephrotoxic drugs good thing to monitor)

Question 22

when do you suspect infection when you get urine culture results

Answer 22

when = >10,000 CFU/mL reported

Question 23

how will general hematology be helpful in a renal case

Answer 23

CBC = protein levels, hematocrit - indicate hemorrhage

Electrolytes = derangements due to renal dysfunction

BUN & Creatinine = azotemia

or liver function/musc. mass in pt.

Question 24

how much renal function must be lost before an incr in creatinine is seen

Answer 24

nearly 2/3 of the nephrons must be nonfunctional before creatinine exceeds normal (66%)

Question 25

define azotemia

Answer 25

laboratory abnormality = incr in urea nitrogen & creatinine

can be pre-renal, renal or post-renal

Question 26

what are the criteria for considering azotemia pre-renal

Answer 26

USG > 1.025

dehydrated

U_crS_cr > 50:1

urine volume decr.

Question 27

what are the criteria for azotemia to be renal

Answer 27

USG = 1.008-1.012

dehydrated (with polyuria)

U_cr:S_cr = < 37:1

urine volume incr w/ CRF, may be decr w/ ARF

Question 28

what are the criteria for azotemia to be post-renal

Answer 28

USG = variable

norm to dehydrated

U_cr:S_cr = variable

urine volume decr

Question 29

causes of pigmenturia

Answer 29

Myoglobin: dark red-brown–Not clear when centrifuge

Hemoglobin: red-orange–Nephrotoxic–Blood–Plasma discolored: hemolysis

Associated with exercise: rhabdomyolysis and cystic calculi

remember snow & some types of bedding can change urine color!