Equine Endocrine DisordersEquine Endocrine Disorders

Clare Ryan, DVM, PhD, DACVIMClare Ryan, DVM, PhD, DACVIMBadger Veterinary HospitalBadger Veterinary HospitalClient Education SeminarClient Education Seminar

February 7, 2013February 7, 2013

Equine Metabolic SyndromeEquine Metabolic Syndrome

Horses with:Horses with: insulin resistanceinsulin resistance obesity and/or obesity and/or regional adiposity regional adiposity prior or current laminitis. prior or current laminitis. Are often “easy keepers.”Are often “easy keepers.”

Typical age of onset is 10-20 years. Typical age of onset is 10-20 years.

Pony breeds, Morgans, Paso Finos, and Pony breeds, Morgans, Paso Finos, and Norwegian Fjords most common.Norwegian Fjords most common.

Arabians, Quarter Horses, Thoroughbreds, Arabians, Quarter Horses, Thoroughbreds, Saddlebreds, Tennessee Walking Horses and Saddlebreds, Tennessee Walking Horses and Warmbloods have also been diagnosed.Warmbloods have also been diagnosed.

Equine Metabolic SyndromeEquine Metabolic Syndrome

Clinical signs:Clinical signs:

Laminitis – often begins in the Laminitis – often begins in the spring with rapid growth of spring with rapid growth of grassgrass

Abnormal reproductive cycling Abnormal reproductive cycling in obese maresin obese mares

General obesity and/or regional General obesity and/or regional adiposity (fat deposits)adiposity (fat deposits)

Cresty neck, fat deposits Cresty neck, fat deposits around the tailhead, sheath around the tailhead, sheath and above the eyes, with and above the eyes, with occasional subcutaneous occasional subcutaneous masses on the trunkmasses on the trunk

TestingTesting

Insulin/Glucose ratioInsulin/Glucose ratio EMS horses are “insulin- resistant”, so insulin levels are EMS horses are “insulin- resistant”, so insulin levels are

elevatedelevated

LeptinLeptin

Oral Sugar Test: Oral Sugar Test: feed Karo syrup, measure insulin and glucosefeed Karo syrup, measure insulin and glucose

Combined Glucose-Insulin Test: Combined Glucose-Insulin Test: Give IV dextrose and insulin, measure glucose and insulinGive IV dextrose and insulin, measure glucose and insulin

TreatmentTreatment

Weight lossWeight loss Restrictive dietRestrictive diet Dry lot or grazing muzzleDry lot or grazing muzzle No access to rapidly growing/ spring* grassNo access to rapidly growing/ spring* grass No grain or specially formulated low calorie No grain or specially formulated low calorie

supplementsupplement Levothyroxine (Thyro-L, thyroid Levothyroxine (Thyro-L, thyroid

supplement)supplement)

*can happen any time of year!*can happen any time of year!

Treatment GoalsTreatment Goals

Improve insulin sensitivity via:Improve insulin sensitivity via: Weight lossWeight loss ExerciseExercise Reduction in carbohydrate (NSC) consumptionReduction in carbohydrate (NSC) consumption

Continue to monitor weight carefullyContinue to monitor weight carefully Repeat insulin: glucose testingRepeat insulin: glucose testing

Equine Pars Pituitary Intermedia Equine Pars Pituitary Intermedia Dysfunction (PPID )Dysfunction (PPID )

PPID or “Cushing’s syndrome”PPID or “Cushing’s syndrome”

A dysfunction of the pituitary gland A dysfunction of the pituitary gland resulting in increased levels of cortisol.resulting in increased levels of cortisol.

Different disease processDifferent disease processthan dogs or humansthan dogs or humans

Equine Cushing’s DiseaseEquine Cushing’s Disease

The age of onset is 7-42 The age of onset is 7-42 years of age. Over 85% years of age. Over 85% of the horses are > than of the horses are > than 15 years of age. 15 years of age.

Ponies and Morgans Ponies and Morgans have a high incidence of have a high incidence of the disease but the disease but allall breeds can be affected. breeds can be affected.

Equine Cushing’s DiseaseEquine Cushing’s Disease Clinical signs vary Clinical signs vary

depending on the stage of depending on the stage of disease but include:disease but include:

Hirsutism- failure to shed Hirsutism- failure to shed a long curly hair coat. a long curly hair coat.

Increased drinking and Increased drinking and urination;urination; intake of water over 25-intake of water over 25-

30L/day; consistently wet 30L/day; consistently wet stallstall

LaminitisLaminitis Lethargy or docile attitudeLethargy or docile attitude Increased sweatingIncreased sweating Ravenous appetiteRavenous appetite

Equine Cushing’s DiseaseEquine Cushing’s Disease Clinical signs Clinical signs

(continued):(continued): Muscle mass atrophy Muscle mass atrophy

(sway- backed or pot-(sway- backed or pot-bellied appearance) bellied appearance)

Regional adiposity Regional adiposity Recurrent infections:Recurrent infections:

sole abscesses, sole abscesses, tooth root infections, tooth root infections, sinusitis, and skin sinusitis, and skin diseasedisease

InfertilityInfertility BlindnessBlindness SeizuresSeizures

Testing For Cushing’s Dexamethasone supression test:Dexamethasone supression test:

Injection of dexamethasone given, measure cortisol in Injection of dexamethasone given, measure cortisol in 19 hours19 hours

Seasonal variationSeasonal variation

ACTH ACTH Single sample Single sample Seasonal variationSeasonal variation

TRH stimulation testTRH stimulation test If screening tests are normal but Cushing’s still If screening tests are normal but Cushing’s still

suspectedsuspected

Treatment for Cushing’sTreatment for Cushing’s There is no cureThere is no cure

Pergolide (PrascendPergolide (Prascend®®)) CyproheptadineCyproheptadine

Supportive CareSupportive Care Keep adequate body conditionKeep adequate body condition Monitor clinical signs closelyMonitor clinical signs closely Retest to assess drug dose, progression Retest to assess drug dose, progression

of diseaseof disease Management of feet with appropriate Management of feet with appropriate

farrier care farrier care

Does this sound like your horse?Does this sound like your horse?

Early diagnosis and treatment is the best Early diagnosis and treatment is the best way to prevent laminitis and other way to prevent laminitis and other complications.complications.

Call to get more information about testing and Call to get more information about testing and treating your horse. treating your horse. Spring is the best time to test!Spring is the best time to test!

Questions?Questions?