Renal

Question 1

What is the normal water intake and urination for a horse?

Answer 1

Water intake = 25-30L/day
Urination 5-15L/day, urination frequency 4-6 times per day

Question 2

Above what value is a horse considered polyuric?

Answer 2

> 25 L/day urination

Question 3

Above what value is a horse considered polydipsic?

Answer 3

> 50 L/day water intake

Question 4

Describe the physical exam findings consistent with a renal or urinary tract disease in horses.

Answer 4

Weight loss
Pyrexia
Lethargy and inappetence, dental calculus, oral ulceration = uraemic syndrome
Oedema - peripheral or ventral
Urine staining
Abnormal urination in terms of posture, frequency, stream/volume/concentration, colour - dysuria, stranguria, pollakiuria, haematuria, pigmenturia
PU/PD
History of colic - can be from renal pain

Question 5

What is the significance of azotaemia in a horse?

Answer 5

If it’s missed it can quickly progress to irreversible kidney disease and death

Question 6

Name 2 causes of pre-renal azotaemia in a horse.

Answer 6

Reduced perfusion - colic, dehydration
Colitis
SIRS

Question 7

Describe the characteristics of normal horse urine.

Answer 7

pH8
Contains calcium carbonate crystals commonly which give it a creamy yellow appearance

Question 8

List your DDx for dysuria and stranguria in horses.

Answer 8

Urolithiasis - cystic calculi
Idiopathic haematuria
Urethral defects in geldings
Neoplasia
Cystitis

Question 9

List 3 causes of polyuria in horses.

Answer 9

PPID
Psychogenic polydipsia
Renal failure
Iatrogenic - sedation, furosemide administration
Central or nephrogenic diabetes insipidus
Endotoxaemia/sepsis

Question 10

An owner calls you wanting to discuss their 20 year old TB mare that has been drinking more water than usual for the last 2-3 weeks. What would you like to do?

Answer 10

1. Confirm polyuria by measuring how much water the horse is drinking per day
2. Take a blood sample to run biochemistry to check for azotaemia or other changes that might point toward an underlying condition, collect urine and run urinalysis at the same time
3. If no signs of other underlying dx and the horse is not azotaemic run a water deprivation test

Question 11

List 3 DDx for haematuria in a horse.

Answer 11

Urolithiasis
Exercise-associated
Urethral rents
Urinary tract infections
Idiopathic
Neoplasia - TCC

Question 12

Name the causes of acute renal failure.

Answer 12

Pre-renal - D+, endotoxaemia/sepsis
Renal - ischaemic or toxic injury, tubular obstructon
Post-renal - obstruction or disruption to urine outflow

Question 13

You have diagnosed a horse with acute renal failure, what is your management plan?

Answer 13

Treat the primary condition
IVFT with physiologic saline or balanced electrolyte solution (avoid fluids containing K+) - correct deficit over 6-12h then 2x maintenance until creatinine decreases
If oliguria/anuria persists after 12h of IVFT consider dopamine or furosemide to increase renal perfusion or urine production but MAKE SURE they are on fluids still
Correct electrolyte disturbances - if K >6.5mEq/L give sodium bicarb, glucose and insulin, if hyperCa then don’t give lucerne hay

Question 14

A client of yours is managing a stud farm and gives you a call about a 2 day old colt who was born normal but isn’t wanting to nurse, is straining to urinate and when successful only passes small amounts and seems to have abdominal distension. What do you want to tell them?

Answer 14

A major DDx for this is uroabdomen or ruptured bladder which is a medical emergency. The foal needs to be brought in for medical attention ASAP.

The condition is more common in colts than fillies and occurs usually as a result of trauma to the bladder during birth.

Question 15

How do we diagnose uroabdomen?

Answer 15

Abdominal US - increased fluid in abdomen, tear in bladder (looks like a heart), small bladder
Abdominocentesis - peritoneal creatinine > 2x serum creatinine

Question 16

Discuss the treatment for bladder rupture.

Answer 16

Correct electrolyte derangements ASAP - calcium gluconate, sodium bicarbonate, glucose and insulin
Check IgG status
Broad spectrum antimicrobials
Surgical repair after stabilisation