Large Animal Diseases Flashcards
(88 cards)
How can you differentiate between thyroid glands and the retropharyngeal lymph nodes in a horse?
Thyroid glands are palpable, movable structures in throat latch area;
Retropharyngeal lymph nodes will not move
What is the most accurate thyroid hormone assay in the horse?
Free T4 by dialysis
Foals can have very high/low T3 and T4 at birth, and these levels will increase/decrease in the first 3-4 months.
High, decrease
What 2 drugs can falsely lower thyroid hormones in horses?
Corticosteroids and phenylbutazone
What effect does fasting, strenuous exercise, and diets high in energy, protein, copper, or zinc have on thyroid hormone levels in horses?
Falsely lowers THs
Considering the factors that can falsely lower THs, how long should animals be free of these things prior to testing?
At least 2-4 weeks
What test is less affected by nonthyroidal illnesses?
Free T4 by equilibrium dialysis
What are 3 general differentials for enlarged thyroid glands in horses?
Hypothyroidism, hyperthyroidism, and thyroid tumors
What is congenital hypothyroidism in foals caused by?
Too little or too much iodine in dam’s diet or goitrogenic plants (i.e. kelp)
A one-week-old foal that has signs of dysmaturity, an enlarged thyroid gland, poor suckling, hypothermia, flexural deformities, and mandibular prognathism (monkey mouth) is most consistent with what disease?
Congenital hypothyroidism
What is the treatment for congenital hypothyroidism in foals?
Supportive care, correct mare’s diet, and provide thyroid supplementation if foal is low
What is the prognosis for congenital hypothyroidism in foals?
Poor, most foals die within 1-2 weeks of birth but can do well if owners are willing to do aggressive and consistent supportive care
What is the most common cause of hypothyroidism in adult horses?
Most due to other disease processes
In addition to misdiagnosed hypothyroidism, name some other reasons why horses may be treated with Levothyroxine (4 answers)
Laminitis, anhidrosis, poor fertility, and equine metabolic syndrome
What is the most common cause for a unilaterally enlarged thyroid gland in horses? (Especially in older horses)
Thyroid neoplasia; specifically, a thyroid adenoma
What condition in horses is defined as a collection of risk factors (especially obesity/increased adiposity and insulin dysregulation) highly associated with an increased of hyperinsulinemia-associated laminitis and other morbidities?
Equine Metabolic Syndrome
In older horses, what condition may co-exist with PPID?
Equine Metabolic Syndrome
Horses that are considered to be “easy keepers” or have a “thrifty gene” are predisposed for Equine Metabolic Syndrome. What do these terms mean?
These horses have good metabolic efficiency and can maintain their weight with a smaller amount of feed (don’t cost a lot of money to maintain)
T/F: Horses with Equine Metabolic Syndrome can have either regional adiposity or generalized adiposity.
T
What common regions on a horse would you see increased adiposity in cases of EMS? 3 answers.
Neck, tail head, preputial/mammary swelling
Adipose tissue is an active endocrine organ that secretes _____________, which have local and systemic effects resulting in a(n) chronic/acute inflammatory state.
Secretes adipokines, chronic inflammatory state
If a horse has insulin dysregulation, what 3 things may it have?
Resting hyperinsulinemia, postprandial hyperinsulinemia, or tissue insulin resistance
What may hyperinsulinemia predispose a horse to?
Laminitis
T/F: Insulin dysregulation only occurs when Equine Metabolic Syndrome is present.
F, can occur in the absence of EMS and with other cases (such as PPID, systemic illness, stress, pregnancy, and/or starvation)
