Endocrinology

Question 1

what does PPID stand for?

Answer 1

pituitary pars intermedia dysfunction

Question 2

what are the three main parts of the pituitary gland?

Answer 2

pars distalis
pars intermedia
pars nervosa

Question 3

what does the pars distalis produce?

Answer 3

prolactin, growth hormone, TSH, FSH, LH

Question 4

what does the pars nervosa produce?

Answer 4

ADH and oxytocin

Question 5

what does the pars intermedia produce?

Answer 5

ACTH and MSH

Question 6

what is the pars intermedia receive information to release hormones?

Answer 6

neurotransmitter release from axons from the hypothalamus

Question 7

what neurotransmitter inhibits release of ACTH and MSH from the pars intermedia?

Answer 7

dopamine

Question 8

what neurotransmitter is responsible for PPID?

Answer 8

dopamine

Question 9

why does the pars intermedia receive neurotransmitter from the hypothalamus unlike the pars distalis?

Answer 9

pars intermedia is poorly vascularised

Question 10

how does the pars nervosa receive information regarding release/inhibiting hormone release?

Answer 10

direct axonal connection with hypothalamus

Question 11

what hormones are released in excess from the pars intermedia in PPID cases?

Answer 11

beta-endorphin, alpha-MSH and ACTH

Question 12

what is the first change within the body of a horse with PPID due to the decreased dopamine inhibition?

Answer 12

hyperplasia of the pars intermedia (due to increased hormone release)

Question 13

what is MSH?

Answer 13

melanocyte stimulating hormone

Question 14

what is alpha-MSH produced from in the pars intermedia?

Answer 14

ACTH (ACTH is processed further than in the other parts of the pituitary)

Question 15

what is the only predisposing factor to PPID?

Answer 15

horses older than 15 (rarely less than 10 years old)

Question 16

PPID is due to lack of dopamine inhibition on the pars intermedia, what type of disease does this mean PPID is?

Answer 16

neurodegenerative

Question 17

what are the clinical signs of PPID?

Answer 17

hypertrichosis (delayed/abnormal shedding to a thick curly coat)
laminitis
weight loss/redistribution
wasted epaxial muscles and pot belly
bulging supraorbital fat
lethargy/reduced exercise tolerance
sweating
PUPD

Question 18

what is hypertrichosis?

Answer 18

increased hair growth or delayed shedding

Question 19

why is it important to confirm PPID diagnosis before treatment?

Answer 19

treatment will be lifelong
needed for monitoring horse (ACTH value)
determine if they have insulin dysregulation (laminitis risk)

Question 20

how can you determine if a horse with PPID will develop laminitis?

Answer 20

evidence of insulin dysregulation

Question 21

how is PPID diagnosed?

Answer 21

basal ACTH (don’t do when horse is stressed)

Question 22

what type of tube is used to collect blood for a basal ACTH?

Answer 22

purple top tube (EDTA)

Question 23

what time of year does basal ACTH test have the highest sensitivity?

Answer 23

autumn

Question 24

what is the dynamic endocrine test for PPID?

Answer 24

ACTH response to TRH (not used very much in this country)

Question 25

how commonly is the low dose dexamethasone test used for PPID used?

Answer 25

never in UK - invalid

Question 26

what needs to be considered along with the basal ACTH test results for PPID?

Answer 26

horses age and clinical signs

Question 27

what value should be used for the basal ACTH test if there are clear clinical signs and the horse is older than 15 years old?

Answer 27

lowest value (rule in the diagnosis) - low values have high sensitivity

Question 28

what value should be used for the basal ACTH test if there is no clear clinical signs of PPID?

Answer 28

upper value (rule out diagnosis) - high values have high specificity

Question 29

are induction of liver enzymes and stress leucograms seen in horses with PPID?

Answer 29

no (these should be investigated as a concurrent disease)

Question 30

what is basal endocrine test used for PPID, that is not diagnostic?

Answer 30

glucocorticoid and insulin levels

Question 31

what is the treatment for PPID?

Answer 31

pergolide (dopamine agonist)

Question 32

how often should horses be monitored when being treated for PPID?

Answer 32

monthly in early stages to get the correct dose then every 3 months

Question 33

what is used to monitor PPID treatment?

Answer 33

basal ACTH

Question 34

how much can the dosage of pergolide be increased in PPID treatment?

Answer 34

5 times the original dose

Question 35

should horses with PPID be put on a diet to prevent laminitis?

Answer 35

no - already have catabolism so don't want to exacerbate this

Question 36

how long are horses treated for PPID for?

Answer 36

lifelong

Question 37

how is hypothyroidism tested for?

Answer 37

TRH stimulation of T3 and T4

Question 38

what does EMS stand for?

Answer 38

equine metabolic syndrome

Question 39

what does insulin do?

Answer 39

drives glucose into cells (decreases blood glucose levels)

Question 40

if the target cells fail to respond to insulin, what is this called?

Answer 40

type 2 diabetes

Question 41

what is EMS?

Answer 41

collection of risk factors for endocrinopathic laminitis

Question 42

what is the most important factor of EMS that leads to endocrinopathic laminitis?

Answer 42

insulin dysregulation

Question 43

what are the three main factors of EMS?

Answer 43

obesity laminitis insulin resistance

Question 44

what are the typical features of a obese horse (predisposing to EMS)?

Answer 44

bulging supraorbital fat enlarged crest fat pads

Question 45

what are the risk factors for EMS?

Answer 45

obesity genetics

Question 46

what does the insulin resistance have to be driven by to develop EMS and laminitis?

Answer 46

hyperinsulinaemia (by feeding high carbohydrate diet)

Question 47

how is EMS diagnosed?

Answer 47

by diagnosing hyperinsulinaemia (using resting insulin)

Question 48

what is the cut off point for unpasted insulin levels? (relating to EMS)

Answer 48

if its greater than 20 uIU/ml it has EMS

Question 49

what is used as a dynamic test for EMS?

Answer 49

oral sugar/glucose test

Question 50

how is the oral sugar/glucose dynamic test for EMS carried out?

Answer 50

fast horse for 6-12 hours then feed and sample blood 2 hours later

Question 51

other than insulin resistance, what are the other clinical signs of EMS?

Answer 51

high blood pressure hypertriglyceridaemia mild basal cortisol elevation

Question 52

what age horses can be effected by EMS?

Answer 52

any (younger than PPID)

Question 53

how can EMS be managed?

Answer 53

reduce predisposing factor (obesity) reduce hyperinsulinaemia treat/manage laminitis monitoring

Question 54

is diet or exercise better for managing obesity and EMS?

Answer 54

exercise

Question 55

what is done to the diet to manage obesity in EMS horses?

Answer 55

reduce caloric intake (give 1.5-2% body weight hay) needs to be monitored and give protein, vitamins, minerals and salt supplements

Question 56

how can hyperinsulinaemia be managed?

Answer 56

exercise diet drug therapy (thyro L) nutraceuticals