Unit 3 - Equine Metabolic Syndrome Flashcards
What is equine metabolic syndrome (EMS)?
A collection of risk factors for endocrinopathic laminitis, and the term syndrome is used because multiple factors contribute to risk of laminitis developing in an individual horse, pony, or donkey
What is the current accepted term for EMS?
Hyperinsulinemia-associated laminitis
True or False: Any horse can develop EMS if exposed to sufficient inciting factors.
True
What are the risk factors for EMS?
Insulin dysregulation, increased adiposity, hypertriglyceridemia, altered adipokine production, and cardiovascular abnormalities
What is the central endocrine disorder of EMS?
insulin dysregulation
Insulin dysregulation encompasses the different glucose and insulin alterations observed in affected equids, including:
Fasting hyperinsulinemia (HI), postprandial/post sugar HI, and tissue insulin resistance (IR)
What the most common form of insulin dysregulation in equids?
compensated insulin dysregulation
What is compensated insulin dysregulation?
hyperinsulinemia with euglycemia
What is uncompensated insulin dysregulation?
hyperinsulinemia with hyperglycemia as a result of pancreatic insufficiency
What is another term for uncompensated insulin dysregulation?
Type 2 diabetes mellitus
What breeds are more commonly affected by EMS?
Arabians, Morgans, Paso Finos, Tennessee Walking Horses, Saddlebreds, Spanish Mustangs, ponies, and warmbloods
What is obesity?
An increase in body weight as a result of excessive fat accumulation within the body
What BCS correlates with obesity?
BCS greater than or equal to 7
What is regional adiposity?
The increased accumulation of adipose associated with certain body regions including the crest of the neck, overlying the shoulders and craniodorsal thorax, adjacent to the tail head, prepuce/mammary glands, and periorbital regions
When may subclinical laminitis be present?
When laminae undergo structural changes without overt lameness
What is it important to distinguish EMS from even though they can occur concurrently and influence one another?
pituitary pars intermedia dysfunction (PPID)
What plays a role in EMS development?
Genetics
Environmental factors - diet and exercise
Feeding what to an EMS susceptible animal is enough to induce obesity?
Feeding grain and the grass consumed on pature
How does EMS commonly present?
Laminitis, divergent hoof rings, generalized and/or regional adiposity, infertility, and sheath/mammary swelling
Genetically predisposed animals to EMS are reported by their owners to be what?
Easy keepers or good doers
Sorry this is a terrible question
Most horses, ponies, and donkeys, with EMS are _______, and a thicker than normal ______ crest is noted on physical exam.
Obese - neck
True or False: Hyperglycemia is common in EMS affected horses.
False - it is uncommon, however it may be more likely when animals are challenged by systemic disease and hospitilization
When persistent hyperglycemia is noted, it is appropriately termed as what?
type 2 diabetes mellitus
What is a common misconception about horses that are obese because obesity is associated with this condition in horses and dogs?
Primary hypothyroidism
What do the thyroid levels look like in some horses with EMS?
Low tT3 and tT4
Most of these animals have normal TRH
When should thyroid hormone supplementation be reserved in EMS patients?
For cases with persistently low free T4 concentrations and abnormal TRH stimulation thyroid test results
What PE testing should be done for EMS suspect patients?
Measures of adiposity should be performed, including BCS, cresty neck score, and ultrasound measurements of abdominal or subcutaneous fat depth
What main tests can be done for evaluation of insulin concentrations in EMS suspect patients?
Basal insulin concentration, oral sugar test, insulin tolerance test
Why is basal insulin concentration most often used as a screening test for EMS?
Because it has low sensitivity and high specificity - only identifies severely affected ID animals
What basal insulin concentration confirms EMS?
A high insulin concentration (>50)
Does a normal basal insulin concentration rule out EMS?
no
What is the current recommendation for basal insulin concentration in regards to feeding?
The patient should remain on hay and/or pasture, with only grain withheld for 6 hours prior to blood collection
What is the preferred diagnostic test to screen for insulin dysregulation?
Oral sugar test (OST)
What does the oral sugar test measure?
glucose and insulin levels
What should be done with patients prior to oral sugar testing?
Fast them for 3-6 hours
Why would you want to test the fasting blood glucose during OST?
To detect for diabetes mellitus
A dosage of what improves the OST?
using a high dose of corn syrup
When are blood samples collected during an OST?
at 60 minutes and/or 90 minutes after oral sugar administration
What levels should always be tested when insulin concentrations are measured?
Glucose levels
What plasma glucose level indicates uncompensated insulin resistance or diabetes mellitus?
> 125 mg/dl
When the OST is repeated to monitor the progress of an individual patient with insulin dysregulation, what results are considered to be significant?
Dichotomous results
What does the insulin tolerance test (ITT) evaluate?
hepatic and/or peripheral tissue insulin sensitivity
True or False: Insulin tolerance testing does not require fasting.
True
What measurement aside from insulin does the ITT require?
blood glucose levels
What is the procedure for ITT?
Collect blood measurement at time 0 and administure insulin IV
Recheck the blood glucose at 30 minutes and feed immediately after
What ‘other’ screening test for ID effectively measures adiposity?
Leptin testing
True or False: An increase in triglycerides is a consistent finding in EMS cases.
False
Individual horses that are genetically predisposed to EMS readily _____ ______ and have_______.
gain weight, hyperinsulinemia
Why is EMS often associated with a systemic, low-grade inflammatory state?
Because adipose tissues secrete inflammatory cytokines as obesity progresses. Obesity and ID have been loosely positively correlated with plasma concentrations of TNF-alpha and IL1
Reduced ______ insulin clearance may play a role in hyperinsulinemia.
hepatic
What are the 3 approaches to the management of ID?
Reducing the sugar and starch content of the feeds provided to the horse
Limiting or eliminating access to pasture until ID improves
Increasing exercise
What is the ultimate goal of managing ID?
reduce the risk of endocrinopathic laminitis
If obesity is present, what is the initial focus of ID management?
Reduce caloric intake and achieving weight loss
When trying to decrease surgar and starch in EMS patients, what feed is recommended? How much?
Low nonstructural carbohydrate (NSC) hay at 2% of body weight initially
If they aren’t losing weight by 4 weeks, what is the recommendation for feeding?
Reduce to 1.5% of the ideal body weight and if that doesn’t work reduce to 1 - 1.2 % of the body weight
Why don’t you want to feed less than 1% of body weight?
It would be severe calorie restriction and increase the risk of inducing dyslipidemia
When on hay only diets, what supplementation is recommended?
Supplementation of trace minerals, protein, and vitamin E is recommended when on hay only diets
Which is more influential in raising blood insulin levels?
a. Starch
b. Fructans
Starch > Fructans
What is the goal when feeding hay?
To feed hay that is less than 10% NCS (as-fed basis)
What can be done to the hay to reduce the sugar content?
Soaking hay in cold water for 30-60 minutes may reduce the sugar content of hay
Why do you want to limit or eliminate access to pasture until ID improves?
Grass is an unregulated source of sugar and starch, so these carbohydrates will continue to exacerbate ID
If you are going to allow pasture access in an ID patient, how long should they be able to be out there?
Limit to short periods in the very early morning hours except after a hard frost
When should you consider dry lot confinement?
In severe cases of hyperinsulinemia
In what cases of ID should exercise be increased?
If active laminitis is not present, daily exercise should be performed to increase energy consumption and accelerate weight loss
When is exercise contraindicated in ID cases?
Foot soreness or suspicion of active laminitis
How can most cases of EMS be managed?
Lowering the sugar and starch content of the diet, reducing body fat mass, instituting an exercise program, and limiting or eliminating access to pasture
What are the 2 indications for pharmacotherapy to manage EMS in horses?
Management of weight loss resistance and management of refractory hyperinsulinemia
How is weight loss resistance managed?
Levothyroxine
REMEMBER - it is not prescribed because the patient is hypothroid
How is refractory hyperinsulinemia managed?
Metformin and canagliflozin
What is the main action of Canagliflozin?
It increases renal excretion of glucose
When is Canagliflozin contraindicated?
With liver disease and hypertriglyceridemia
What is the indication for using pergolide?
When PPID is concurrently involved
