Term
| What are the two major equine endocrine diseases? |
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Definition
-PPID: equine pituitary pars intermedia dysfunction
-EMS: equine metabolic syndrome |
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Term
| What is the older common name for PPID? |
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Definition
| -equine Cushing's disease |
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Term
| Which age group of equids is affected by PPID? |
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Definition
| -AGED: usually mid to late teens |
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Term
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Definition
| -roughly one third of horses affeced |
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Term
| Which equids are predisposed to PPID? |
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Definition
-poneis
-morgans
-horses with EMS |
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Term
| What are the clinical signs of PPID? |
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Definition
-abnormal haircuoat
-weight loss due ot muscl atrophy with pot belly appearance
-secondary infection
-lethargy, change in mentation
-hyperhidrosis, actually dyshidrosis
-repro infertility
-laminitis
-insulin duregulation
-PU/PD
-abnormal fat distribution
-exercise intolerance |
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Term
| What are the four functions of the pars intermedia? |
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Definition
-seasonal regulation: metabolism and haircoat prep for winter
-metabolic regulation
-anti-inflammatory
-analgesia |
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Term
| What do we see on post mortem exam with PPID? |
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Definition
| -hypertrophy and hyperrplasia of pars intermedia, microadenomas, and macroadenomas |
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Term
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Definition
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Term
| What causes dopaminergic neurons to degenerate? |
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Definition
| -oxidative stress and misfolded proteins |
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Term
| What are our 2 diagnostic tests for PPID? |
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Definition
-plasma ACTH concentration
-TRH stim test
-post mortem exam with histology
-overnight dexamethasone suppression test |
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Term
| How do we administer an overnight dexamethasone suppression test to a horse suspected of having PPID? What results do we expect to see? |
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Definition
-pull serum at rest, give dex IM, pull serum 19h later
-normal horses suppress cortisol < 1ug/dl |
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Term
| What are the disadvantages of a dexamethasone supppression test to diagnose PPID? |
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Definition
-flase negatives are very common
-false positives occur during the Fall but a negative test during this time is strong evidence
-requires two trips
-can only diagnose late-stage disease |
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Term
| How does an endogenous plasma ACTH conc test work? |
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Definition
| -measure ACTH conc in plasma sample via chemiluminescent assay |
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Term
| What is the test of choice to diagnose PPID? |
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Definition
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Term
| How do we perform a TRH stimulation test? What results do we expect to see? |
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Definition
-give TRH IV and measure before, at 10 mins, and at 30 mins
->110 at 10 min in non-fall months says PPID |
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Term
| What is the major drawback of TRH? |
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Definition
| -not useful during fall months |
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Term
| What side effects should we warn the owner about with TRH administration? |
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Definition
| -may shake, couch, and flehmen response for a few seconds |
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Term
| If we have suggestive clinical signs in a horse for PPID but they test negative, then what do we do? |
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Definition
| -retest in 4-6m or treat anyway |
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Term
| How do we treat PPID in the horse? |
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Definition
-Pergolide (dopamine agonist): causes appetitie suppression
-Add on Cyproheptidine (serotonin antagonist)
-treat laminitis and hyperinsulinemia |
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