PPID

Question 1

what age is most commonly affected by PPID

Answer 1

older horses

Question 2

What does PPID mean

Answer 2

pituitary pars intermedia dysfunction

Question 3

List 4 possible early clinical signs of PPID

Answer 3

1. muscle atrophy- epaxial
2. hair abnormalities- (more hair in anagen phase - hair does not shed and longer hairs/ curly coat)
3. Lethargy
4. regional adiposity

Question 4

List 3 possible clinical signs of PPID in later stages

Answer 4

laminitis- often presenting complaint
recurrent infections due to immune dysfunction
PUPD

Question 5

List 6 uncommon signs of PPID

Answer 5

pseudo-lactation
Hyperhidrosis leads to anhidrosis (excessive sweating leads to lack of sweating)
suspensory ligament breakdown
blindness
keratitis
low fertility or irregular cycling

Question 6

How to diagnose PPID

Answer 6

Baseline ACTH- best
TRH stimulation test

Question 7

Which horses do we use Baseline ACTH test when diagnosing PPID

Answer 7

good for animals which we have high suspicion of
less sensitive in early stages- can get false positives
sensitivity can depend on the season of the year

Question 8

which horses do we use TRH stim test for diagnosing PPID

Answer 8

More accurate in horses with a lower clinical suspicion than baseline ACTH

Question 9

what can affect ACTH- and therefore diagnosis of PPID

Answer 9

stress, excitement, trailering
pain- so postpone testing till pain controlled
sedation- can’t test 24-48 hours after

Question 10

what is important to consider when interpreting PPID diagnostics

Answer 10

variation in reference ranges
think about clinical signs and if they support an equivocal result
consider re-testing in a different month

Question 11

How to treat PPID

Answer 11

Pergolide- start at initial dose
recheck baseline ACTH 4-6 weeks later and change dose depending on result
once dose established - recheck baseline ACTH every 6-12 months

Question 12

what do we expect treatment of PPID to do in 1 month and in 6 months

Answer 12

1 month: improved attitude and activity, laminitis control

6 months: improved hair coat, muscle mass along with reduction in laminitis and infectious episodes

Question 13

when treating PPID what should we consider

Answer 13

concurrent diseases e.g. EMS
laminitis management
treatment of any secondary infections

Question 14

How is ACTH produced

Answer 14

produced by cleavage of POMC

Question 15

What inhibitis ACTH production

Answer 15

dopamine

Question 16

when do ACTH levels increase in a horse

Answer 16

in the autumn due to shortening days

Question 17

How does PPID occur

Answer 17

loss of inhibitory dopamine from the hypothalamus leads to loss of inhibtion on the melanotropes and therefore an over production of ACTH, alpha-MSH, CLIP and beta-endorphins

Question 18

why do we lose the inhibitory dopamine in PPID

Answer 18

who knows

Question 19

when is ACTH naturally higher

Answer 19

August- october

Question 20

If you get a negative result for PPID but you have clinical signs that fit what should you do

Answer 20

retest in 3 months

Question 21

List 5 unlicensed treatment options for PPID

Answer 21

cryroheptadine
cabergoline
trilostane
chaste tree berry
Beomicriptine

Question 22

what is cyproheptadine

Answer 22

serotonin antagonist (blocks POMC production)

Question 23

how cabergoline works

Answer 23

slow release dopamine agonist

Question 24

How does chaste tree berry work

Answer 24

acts as a dopamine agonist - not shown to work well and should not be recomended as a sole treatment

Question 25

How does bromicriptine work

Answer 25

dopamine agonist

Question 26

How does trilostane work

Answer 26

inhibitor of adrenal steroidogenesis

Question 27

List 6 side effects of pergolide

Answer 27

decreased appetite
weight loss
diarrhoea
colic
lethargy
behavioural changes