urinary assessment

Question 1

What specifc urinary questions do you need to ask with a horse a urinary issue?

Answer 1

• Past history of medications - NSAIDs, gentamicin (nephrotoxic)
• urine output
• water intake

Question 2

What are the key aspects you will examine on haem and biochem with a horse in biochem?

Answer 2

• CBC: Leucocytosis, anaemia
• Inflammatory markers - fibrinogen, serum amyloid A
• Biochemistry
  
  • Azotemia
  • BUN:Creatinine ratio
  • Electrolytes
  • Protein & albumin
  • Muscle enzymes (CK & AST) - can cause renal tubules damage
  • Glucose

Question 3

How much water should a horse drink per day?

Answer 3

20-25L
50ml/kg/day

Question 4

What are you looking for on rectal exam of a horse with urinary disease?

Answer 4

• Shrunken kidneys
• uroliths - bladder, uteters

Question 5

what is present in the mouth of horses with chronic renal disease?

Answer 5

tartar on teeth

Question 6

What is Azotemia?

Answer 6

Build up of nitrogen and creatinine in the blood

Question 7

Serum BUN is more sensitive than Serum Creatinine for the detection of a decrease in GFR?
T
F

Answer 7

F - creatinine increases proportionally more than BUN

Question 8

In prerenal azotaemia USG will likely be increased (hypersthenuria)?
T
F

Answer 8

T - unless there is also kideny disease as then the kidney will also not be able to concnetrate

Question 9

Horses with intrinsic renal azotaemia develop hyposthenuria (< 1008)?
T
F

Answer 9

F - the kidney is not functional so not able to dilute the urine this much

Question 10

In horses the BUN/Creatinine ratio is more reliably used to differentiate:
* Prerenal from renal azotaemia
* Chronic Renal Failure from Acute Kidney Injury (AKI or ARF)

Answer 10

• Chronic Renal Failure from Acute Kidney Injury (AKI or ARF)
  In the horse, a BUN/creatinine ratio of less than 10:1 is expected with acute renal failure (ARF), and when the ratio exceeds 15:1, CRF is more likely.

but is more helpful in dogs

Question 11

Hypercalcemia & hypophosphatemia are most seen in horses with:
* Acute kidney injury AKI (or ARF)
* Chronic renal failure (CRF)
* Renal Tubular Acidosis (RTA)

Answer 11

• Chronic renal failure (CRF)

Question 12

What happens to calcium and phosphate in horses with ARF?

Answer 12

hypocalcemia and hyperphosphatemia are more common with ARF

Question 13

What are the values for hyposthenuria, isosthenuria and hypersthenuria in horses?
What is the normal USG of horses?
what is the normal USG of neonatal foals?

Answer 13

• Hyposthenuria < 1008
• Isosthenuria 1008-1014
• Hypersthenuria > 1014
• Normal adult horse 1025-1045
• Neonatal foal - below 1012

Question 14

What are the key things to remember with dipstick urinalysis of horses?

Answer 14

• false + Protein
• Don’t use for USG
• Blood + may be myoglobin, haemoglobin, RBCs

Question 15

• 7 y.o. 550kg crossbred mare show-jumping
• History: Recently changed stalls (↓ turnout) Swelling in the legs & bedding very wet
• PE: BAR, mild oedema 4 limbs
• Clin Path - USG 1013, Serum creatinine 110 umol/L (RR: 88-160 umol/L), BUN 5 mmol/L (RR: 4-8.5 mmol/L), Reagent strip ++ Protein. Normal microscopy. Klebsiella spp. Growth from urine.

Is azotemia present?
If yes, what is more likely to be, renal or pre/post renal in origin?
If not, provide plausible explanations for the alterations seen?

Answer 15

• isosthenuric
• Azotemia is not present
• no intrinstic kidney disease
• horse is stressed so drinking more

Question 16

• 14 y.o. 600kg crossbred gelding pleasure riding
• History: Intermittent colic pain of 12h duration
• PE: BAR, mild/moderate intermittent colic pain, HR 38-50bpm
• Clin Path: USG 1045, Serum creatinine 120 umol/L (RR: 88-160 umol/L), BUN 24 mmol/L (RR: 4-8.5 mmol/L), Reagent strip ++ Protein.

**Is azotemia present?
If yes, what is more likely to be, renal or pre/post renal in origin?
If not, provide plausible explanations for the alterations seen?
**

Answer 16

horse has had colic so is dehydrated so this has increased the urea - kidney is concentrating the urine (Hypersthenuria within normal range)

Question 17

• 3 d.o. 50kg thoroughbred foal
• History: Flexural deformity, Treated with 4gr oxytetracycline at 24 & 48h of age
• PE: Depressed, weak, ↓ suckle reflex, HR 120bpm, RR 40bpm, T38.4, CRT 3s
• Clin Path: Serum creatinine 776 umol/L (RR: 88-160 umol/L), BUN 36 mmol/L (RR: 4-8.5 mmol/L). Small urine prod 1012 after 6hs appropriate fluids

**Is azotemia present?
If yes, what is more likely to be, renal or pre/post renal in origin?
If not, provide plausible explanations for the alterations seen?
**

Answer 17

• marked azotaemia - renal failure
• oxyteracycline is nephrotoxic