Obesity & related disorders in the horse

Question 1

What is cresty neck score

Answer 1

Independent indicator of insulin resistance
Cresty neck score was more predictive of insulin dysregulation than BCS, and this may be relevant to the diagnosis of EMS.
Scale on 1-5

Question 2

Outline Obesity feeding management of horses

Answer 2

Remove concentrates
Lower calorie roughage
Roughage soaked to remove soluble sugars
Limit roughage intake (BUT not excessively)
Exercise where possible
Supplement with protein & water-soluble vitamins to meet RDA
eg Feed Balancer

Question 3

Equine Metabolic Syndrome

Answer 3

Similarities to Type II DM
Hyperinsulinaemia and peripheral insulin resistance:
Recurrent laminitis frequent presenting sign

Question 4

What is the single most common reason for obese ponies being presented for further veterinary investigation

Answer 4

Chronic lameness due to laminitis

Question 5

Outline EMS diagnosis

Answer 5

12 hour fast
Take baseline blood glucose
Give 0.3 ml/kg 50% glucose iv &
0.1 iu/kg soluble insulin iv
Take further blood samples for glucose
@ 1m, 5m, 10m,
then q 10 mins up to 1 h,
then q 30 mins up to 2½ h

Question 6

Oral Corn Syrup (Karo Light) test

Answer 6

Overnight fast
Measure basal glucose & insulin
0.45 mL/kg BW corn syrup (Karo Light Corn Syrup)
Remeasure glucose & insulin at 60 minutes
>110 μIU/mL measured by RIA

Question 7

Advantages of oral corn syrup

Answer 7

higher sensitivity for ID
Mimics response to feed
Simple to perform

Question 8

List test for EMS

Answer 8

Resting insulin concentration
Dynamic CGIT
Oral sugar/corn syrup test
Frequent sampling of blood glucose and insulin after glucose challenge
HMW Adiponectin

Question 9

Sensitivity & specificity of Resting insulin concentration test

Answer 9

Specific for EMS if elevated but low SENS

Question 10

Sensitivity & specificity of Dynamic CGIT test

Answer 10

Greater SENS for diagnosis than single insulin measurement, but still lower than ideal SENS. Glucose dyamics more variable than insulin

Question 11

Sensitivity & specificity of Oral sugar/corn syrup test

Answer 11

Mimics intestinal response to feeding

Question 12

Sensitivity & specificity of Frequent sampling of blood glucose and insulin after glucose challenge

Answer 12

Greatest sens & spec for diagnosis. Dynamic insulin response to glucose or feed challenge very informative.

Question 13

Sensitivity & specificity of HMW Adiponectin test

Answer 13

May be useful in non obese EMS cases

Question 14

Treatment for EMS

Answer 14

Progressive weight loss
Anti hyperglycaemic agents e.g Metformin (Improved hepatic sensitivity to insulin)
SGLT2 inhibitors e.g Canagliflozin (Decrease availability of glucose)
Treat underlying cause
Address laminitis when present:
Thyroxine supplementation

Question 15

PPID

Answer 15

Equine Cushing’s Disease

Question 16

Clinical sign of PPID

Answer 16

thin with poor muscling and altered fat deposition

Question 17

Hypothyroidism is common in equine (T/F)

Answer 17

False! It is very rare

Question 18

Hyperlipaemia

Answer 18

defined by elevated plasma triglycerides (TG)

Question 19

Pathogenesis of hyperlipaemia

Answer 19

Particularly seen in obese animals which develop negative energy balance
Glycogen stores depleted
Fatty acids to provide energy
Excessive mobilization of fatty acids
Hepatic lipidosis
Insulin resistance

Question 20

Hyperlipaemia is a more severe clinical syndrome than hyperlipidaemia (T/F)

Answer 20

True

Question 21

Predisposions in hyperlipaemia

Answer 21

Suspect in any poorly obese pony/donkey
Very high index of suspicion if periparturient!
Abortion

Question 22

Clinical signs of initial hyperlipaemia

Answer 22

Signs of depression and lethargy
Inappetence
Adipsia
Weakness
Reduced GIT motility and faecal output
Mucus-coated inspissated faeces

Question 23

Clinical signs of mid hyperlipaemia

Answer 23

Reluctance to move
Muscle fasciculations
Intermittent abdominal pain
Diarrhoea
CNS dysfunction; ataxia, sham drinking, dysphagia, head-pressing, circling

Question 24

Clinical signs of Late/terminal hyperlipaemia

Answer 24

Recumbency
Convulsions, champing, nystagmus, mania
Abortion

Question 25

Diagnosis of hyperlipaemia

Answer 25

Plasma – opaque
Triglycerides >5mmol/l
Cholesterol
Liver enzymes
Liver function tests –check bile acid concentration
Hypoglycaemia, azotaemia, metabolic acidosis, electrolyte disturbances

Question 26

Treatment of hyperlipaemia

Answer 26

Nutritional support
ID & treat underlying disease
Correct fluid & electrolyte deficits
Diurese to reduce metabolic acidosis
↓lipolysis & ↑clearance of lipids?
Exogenous insulin
Exogenous heparin
Monitoring (Clinical and Laboratory )