Equine Endocrinopathies Flashcards Preview

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Flashcards in Equine Endocrinopathies Deck (94)
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1
Q

what water intake would indicate equine polydipsia?

A

100 ml/kg/day

2
Q

what does PPID stand for?

A

pituitary pars intermedia dysfunction

3
Q

in what horses is PPID common?

A

aged

60% of over 20s had PM diagnosis of PPID

4
Q

what should all horses with laminitis be tested for unless very young?

A

PPID

5
Q

What is the proposed pathogenesis of PPID?

A

decrease in production of dopamine from the hypothalamus
this reduces inhibition of the pituitary
leading to enlargement of the pituitary gland and overproduction of pituitary hormones

6
Q

why is there such a range of clinical signs with PPID?

A

there are differing levels of pituitary hormones at different times

7
Q

what is the enlargement of the pituitary in PPID known as?

A

pituitary adenoma

8
Q

what are the 2 types of pituitary adenoma?

A

micro

macro

9
Q

what are the clinical signs of PPID?

A
variable!
long curly coat
laminitis
PU/PD
weight loss
more docile
neurological impairment
hyperhidrosis
change in fat distribution
infertility
skin disease
periodontal disease
no signs at all!
10
Q

what is hyperhidrosis?

A

sweating excessively

11
Q

what is the cause of the long curly coat in PPID?

A

unknown

12
Q

what causes laminitis in PPID?

A

insulin resistance leading to high insulin levels which cause laminitis

13
Q

what causes PUPD in PPID horses?

A

deceased secretion of vasopressin

14
Q

what causes weight loss in PPID patients?

A

cortisol production
other associated disease
parasites

15
Q

why are PPID patients often docile?

A

increased CSF B-endorphin

16
Q

what causes neurological impairment of PPID cases?

A

compression from adenoma

17
Q

how is PPID diagnosed?

A

gold standard test is postmortem only

based on clinical signs and signalment

18
Q

why is PPID diagnosis difficult?

A

individual variation in hormone production

19
Q

when is pars intermedia more active?

A

Autumn (august to december)

20
Q

what is the first line diagnostic test used for PPID?

A

resting plasma ACTH concentration

21
Q

what state should the horse be in when PPID sample is taken?

A

not stressed

22
Q

how should resting ACTH blood samples be sent for analysis?

A

cold not frozen

send plasma

23
Q

what ACTH reference range should be used when diagnosing PPID?

A

autumn

24
Q

what test can be used to diagnose PPID if ACTH is borderline?

A

TRH stimulation test

25
Q

how is a TRH stimulation test performed?

A

take baseline sample
inject TRH
second blood sample in 10 mins and then 30 mins after injection

26
Q

what effect can administration of TRH have on the horse?

A

colic signs

sweaty

27
Q

when are false PPID test positives likely?

A

autumn

28
Q

what should happen if a horse has positive PPID test results?

A

start treatment

repeat tests in 4-6 weeks to check dose

29
Q

when should tests be repeated in PPID patients?

A

annually

30
Q

what should happen if a horse has a negative PPID test result but you have a strong clinical suspicion?

A

can start treatment anyway and assess clinical response however you will be unable to tell if you have the wrong dose or diagnosis if treatment won’t work

31
Q

why is routine checking for PPID in aged horses useful?

A

can find those with no clinical signs

identify if at risk of laminitis

32
Q

how is PPID treated?

A

management and medication

33
Q

what is involved in management of PPID?

A
farriery
clipping
parasite control
dental care
feeding
34
Q

when may management only of PPID be used?

A

if no laminitis

35
Q

what medical treatment is used for PPID?

A

dopamine agonist - Pergolide tablets

36
Q

what dose of Pergolide is given to PPID patients?

A

0.2-5 mg/horse per day (SID or split into BID)

37
Q

what dose of Pergolide should you start with?

A

1 mg/horse

38
Q

what is a side effect of Pergolide?

A

may go off food

39
Q

what should happen if PPID is refractory to high doses?

A

split to BID (off label)

40
Q

how should effect of Pergolide on PPID de monitored?

A

blood test and signs
adjust dose
reassess anually

41
Q

what are the 3 areas of EMS?

A

obesity or regional adiposity
insulin dysregulation / resistance
subclinical or clinical laminitis

42
Q

what is the effect of insulin dysregulation?

A

require abnormally high insulin to maintain glucose levels in the body

43
Q

what are the conditions that lead to compensated insulin dysregulation?

A

EMS

PPID

44
Q

what are the effects of compensated insulin dysregulation as seen in EMS?

A

high insulin levels to ensure normal glucose

many be seen at rest or only as response to feeding

45
Q

what is a direct cause of laminitis?

A

hyperinsulinaemia

46
Q

what is the role of genetics in EMS?

A

there is genetic predisposition for EMS in hardy breeds

47
Q

what is the role of insulin?

A

facilitates breakdown of glucose and fat stores and stimulates hepatic gluconeogenesis

48
Q

what is the survival benefit of insulin dysregulation in hardy breeds?

A

keeps glucose supply for vital tissues

are able to mobilise energy stores and prioritise vital tissues which aids survival

49
Q

what is associated with insulin resistance / dysregulation?

A

obesity

50
Q

why was insulin resistance protective?

A

would store fat over summer and become insulin resistant which would cause slower weight loss over the winter
the weight loss that did occur over the winter would then restore insulin sensitivity so they could deal with spring grass

51
Q

why is EMS and insulin dysregulation an issue in modern horses?

A

no longer subject to seasonal weight loss
lack of exercise
chronic obesity and chronic laminitis are caused as remain insulin resistant all year round

52
Q

what are the clinical signs of EMS?

A

obesity (BCS 7/9-9/9)
regional adiposity
subclinical or clinical laminitis
possible related disease (hyperlipaemia / lipoma)

53
Q

where is regional adiposity seen in EMS?

A

cresty neck
tail head
preputial swelling
mammary glands

54
Q

what conditions can cause insulin dysregulation?

A

EMS
PPID
both!

55
Q

how can you test whether a horse has EMS or PPID?

A

history and signalment

test for both

56
Q

is it possible to be lean and insulin resistant?

A

rare but possible

57
Q

what is the issue with resting insulin and glucose tests for EMS?

A

many false negatives

58
Q

what is the best first line test for EMS?

A

starved glucose tolerance

59
Q

how is EMS glucose test performed?

A

starve
blood sample to test insulin and glucose levels
bolus of glucose / corn syrup
insulin and glucose measured at 30 mins or 2-3 hours

60
Q

what is usually seen on a glucose test with a horse with EMS?

A

hyperinsulinaemia

normoglycaemia

61
Q

how is EMS managed?

A

diet
medication can be used
exercise
weight loss

62
Q

what can be changed about the diet to manage EMS?

A

low carbohydrate (so low sugar)
non concentrate
feed balancer to add vits and mins
no grass / restricted grass

63
Q

what should lean horses with EMS be fed?

A

oils to ensure calories but no sugars

64
Q

what feed could EMS patients have?

A

Happy Hoof or simular - designed for good doers

65
Q

how can exercise help to manage EMS?

A

even a small amount can have a major effect on insulin sensitivity

66
Q

how can weight loss be achieved?

A

feed 1/3 less than noraml
soak hay for >1 hr
use haynet with small holes to make food last longer

67
Q

what is the minimum amount of forage that should be fed to any horse?

A

1.5 kg per 100kg

68
Q

what drug can be used to aid EMS management in horses?

A

Metformin

69
Q

what does metformin do in EMS patients?

A

no bioavailability but blocks SI carbohydrate absorption which decreases insulin resistance by weight loss

70
Q

why is Metformin useful if it has no bioavailability?

A

if owners are struggling to get rid of the weight

helps with their mindset if horse is medicated

71
Q

what is hyperlipaemia?

A

sudden release of fat into the blood

72
Q

what is hyperlipaemia triggered by?

A

negative energy balance

stress leading to catecholamine and glucocorticoid release

73
Q

what equines are at risk of hyperlipaemia?

A

obesity
native ponies
pregnancy
donkeys

74
Q

what increases risk of hyperlipaemia?

A

excess stores of fatty acid

increased risk of insulin resistance

75
Q

what is the pathogenesis of hyperlipaemia?

A

change in metabolism associated with sudden demand

the body needs energy so pumps out fat into the circulation

76
Q

what is hyperlipaemia a disease of?

A

acute starvation

77
Q

what can be caused by hyperlipaemia?

A

too much fat which the liver is unable to convert and there is not enough hormone to reduce levels
leads to hepatic lipidosis which worsens condition
lactescent blood
fat embolism
kidney failure
pancreatitis

78
Q

what can be caused by hyperlipaemia which will worsen the condition?

A

liver failure

79
Q

what impedes the development of hyperlipaemia?

A

insulin (normal function)

80
Q

what can cause insulin resistance and so increase the risk of hyperlipaemia?

A

EMS
glucocorticoids
catecholamines
progesterone

81
Q

when should you try and diagnose hyperlipaemia?

A

when patient only has hyperlipidaemia

82
Q

what is hyperlipidaemia?

A

no gross fat present in the blood, precursor to hyperlipaemia

83
Q

how can hyperlipaemia be prevented?

A

identify those at risk and try to prevent

84
Q

what are the signs of hyperlipaemia?

A

depression
anorexia
ataxia
icterus

85
Q

what are the 5 key area of hyperlipaemia treatment?

A

improve energy intake and balance
treat hepatic disease
eliminate stress and treat concurrent disease
inhibit fat metabolism from adipose tissue
increase triglyceride uptake by peripheral tissues

86
Q

what can be done if a mare has a foal at foot and has hyperlipaemia?

A

wean foal to stop milk production as long as it isn’t too stressful

87
Q

what sort of nutrition should be given to hyperlipaemia patients?

A

enteral (via stomach tube)

tempt to eat

88
Q

what medical treatment can be used to treat hyperlipaemia?

A

glucose infusion

5% at 2ml/kg/hr

89
Q

what is the purpose of glucose infusion in a hyperlipaemia patient?

A

stop fat being mobilised into blood

90
Q

what should hyperlipaemia patients have monitored if receiving glucose infusion?

A

blood glucose hourly

91
Q

what may need to be given to hyperlipaemia patients on glucose infusion?

A

insulin SC or infusion if glucose level too high

92
Q

what is the prognosis of hyperlipaemia?

A

60-100% mortality

93
Q

what is crucial in the prevention of hyperlipaemia?

A

education of clients

94
Q

what can be done to avoid hyperlipaemia if the patient is at risk?

A

glucose infusion and insulin

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