EMS pathophysiology

Question 1

what is EMS

Answer 1

Not a single disease, but a collection of risk factors for endocrinopathic laminitis
1. Insulin dysregulation
2. Obesity
3. Laminitis

Question 2

why does hyperinsulinaemia matter

Answer 2

Predictive of laminitis risk
Hyperinsulinaemia is also causative of laminitis

Question 3

List 3 risk factors for EMS

Answer 3

genetically predisposed breeds
obesity/ regional adiposity
pregnancy associated Insulin dysregulation

these help us to decide which to test for EMS

Question 4

List 4 clinical signs of EMS

Answer 4

• ‘Easy keeper’/’good doer’
• Regional adiposity= Cresty neck, ‘Fat pads’ or Sheath/mammary gland swelling
• Laminitis
• Divergent hoof rings

Question 5

How do we test for EMS

Answer 5

basal tests
1. Basal insulin concentration
2. Adiponectin
Dynamic tests
1. Oral sugar test
2. Combined glucose insulin test

Question 6

What do we do in basal insulin test

Answer 6

don’t fast before hand
1-3 hours after coming off pasture- Not after big feed
Can be used to assess response to diet change
Not sensitive - lots of false negatives

Question 7

Describe adiponectin concentration test

Answer 7

Adipose derived, insulin-sensitising hormone
Low concentration associated with increased laminitis risk
Not really used

Question 8

Describe oral sugar test

Answer 8

collect baseline insulin
Administer oral Karo Light syrup
60-90 min later collect blood – insulin and glucose

Question 9

Describe the combined insulin test

Answer 9

Combined glucose insulin test
Fast overnight, collect baseline insulin and glucose
Administer IV glucose and insulin
Frequent glucose sampling, insulin at 45min

Question 10

List the 3 components of insulin dysregulation - how are these tested

Answer 10

Prolonged hyperinsulinaemic response (OST or CGIT)
Basal hyperinsulinaemia- basal insulin concentration
Tissue insulin resistance- CGIT

Question 11

List 3 reasons Why we choose oral test vs. IV dynamic tests

Answer 11

Oral administration of glucose stimulates more insulin secretion than intravenous administration
Oral administration simulates ‘real life’ more closely
Oral glucose affected by other factors

Question 12

Describe the enteroinsular axis

Answer 12

Ingestion of glucose –> incretins (GLP-1 and GLP-2) –> stimulate insulin release

Question 13

How can we assess risk of laminitis in horse

Answer 13

Identify hyperinsulinaemia
Dynamic tests
Decreased apidonectin concentration
Assess for concurrent risk factors- E.g. PPID
Evidence of previous episodes- e.g. ‘Footy’or Divergent hoof rings

Question 14

How to manage EMS

Answer 14

Diet- reduce Carb intake and manage obesity
Exercise- as increases insulin sensitivity
Medication- SGLT2 inhibitors (ertugliflozin, canagliflozin)