New Endocrinology group Flashcards
TRH Test and OST, food?
Horses can be tested after hay is fed, but not within 12 hours after a grain meal.
Testing ok before OST but NOT within 12 hours after OST.
TRH stim any time of the year?
JULY to DECEMBER difficult!!!
MANY false positives
SO only ok to confirm negative
Starting dose for Pergolide
What to do if no response?
1mg for 500kg
re-test after 3m (then every 6-12)
if not good-> increase dose by 0,5 or 1mg/500kg
MAX 3mg/500kg + cyproheptadine
OR
go up to 5mg/500kg (off-label)
OTHER POTENTIALLY SUPPORTIVE TESTS
of PPID besides basal ACTH or TRH Stim
Overnight dexamethasone suppression test
Magnetic resonance imaging (MRI) specific for pars intermedia enlargement
What if good clinical response to Pergolide but ACTH remains high?
May increase dose or maintain dose
PRACTICE TIP: Improvement in
clinical signs and insulin status is
the most important indicator of
response to treatment.
ACTH
concentrations may remain in the
PPID likely or equivocal zone
despite clinical improvement,
and do not always warrant a
dosage increase.
horse inappetent with Pergolide
stop treatment until appetite returns and or decrease by half for 3 to 5 days and then titratenback up in 0.5 -1 mcg/kg steps every 2 weeks until the desired dose is achieved.
What happens to ACTH values if you stop pergolide?
ACTH concentrations may begin to increase within 48 hours, but the risk of
clinical signs worsening during this period is low.
takes 10d to return to previous level
Can you test horses with laminitis for PPID?
Low to moderate pain of at least 24 hours duration does not appear to impact diagnostic testing with baseline ACTH or TRH stimulation testing. Testing may be performed in laminitic horses, but it is
ideal to postpone until severe pain is controlled.
Sedation and PPID testing
ideal to avoid diagnostic testing for
PPID and insulin status within 24-48 hours of sedation.
ACTH baseline may be possible within 5-10mins after xyl/deto with or without butorphanol
PPID testing during stress
Stress, excitement, and trailering can result in a transient increase in ACTH concentrations. Samples for PPID
diagnosis via baseline ACTH should not be collected within 30 minutes of trailering, or in an animal that is
visibly excited.
HAL and PPID
HAL is detected in approximately 30% of horses with PPID and horses greater than 10 years of age should be tested
EMS at risk breeds
Pony breeds
Spanish Breeds (e.g., Andalusians)
Gaited breeds (e.g., Saddlebreds, Paso Finos)
Morgans
Miniature horses
Warmbloods
Uncertain genetic risk: Donkey
Typical EMS signs apart from obesity and laminitis
Divergent hoof rings (subclinical laminitis)
Preputial or mammary gland enlargement (adipose tissue +/- edema)
Clinical problems may be historical or current
impact of EMS on fertility?
YES
How long is insulin stable in blood tubes?
- Insulin is stable in plasma or serum for at least three days when separated from red blood cells and refrigerated (4°C).