Equine Thyroid Disease Flashcards
T/F: in horses, single point measurements are reliable indicators of thyroid function
F
what is the most reliable thyroid test in horses?
Free T4 by dialysis is most accurate -> other tests may underestimate thyroid hormone in sick horses
explain the TSH or TRH stimulation test
- inject TSH IV and compare pre- and post- TH concentrations
- Decreased response indicates hypothyroidism
foals have __ T3 and T4
very high
what may lower TH’s and should be restricted 2-4 weeks prior?
- drugs
- fasting
- strenuous exercise
- diets in high energy, protein, copper or zinc
congenital hypothyroidism is caused by what?
too little or too much iodine in the dams diet or iotrogenic plants
clinical signs of congenital hypothyroidism
- prolonged gestation with signs of dysmaturity
- born weak
- poor suckling
- hypothermia
- ms abnormalities: mandibular prognathism or incomplete ossification of cuboidal bones
tx and prognosis of congenital hypothyroidism
- supportive care
- correct mares diet
- thyroid supplementation
many foals will die within 1-2 wks but some may be able to make it!
hypothyroidism in adult horses
RARE
clinical signs of limb edema, coarse haircoat, lethargy, etc…
what are some alternative reasons a horse may be treated with levothyroxine?
- laminitis
- anhidrosis
- poor fertility
- equine metabolic syndrome
equine hyperthyroidism
RARE
Is Equine thyroid neoplasia common?
30% of aged horses had thyroid tumors
what is the most common type of thyroid tumors in horses?
adenoma
most thyroid adenomas are __ and will require excision if it __
benign, compresses the airway
T/F: true thyroid dysfunction is rare in horses
T
