Equine Endocrinopathies Flashcards
(94 cards)
what water intake would indicate equine polydipsia?
100 ml/kg/day
what does PPID stand for?
pituitary pars intermedia dysfunction
in what horses is PPID common?
aged
60% of over 20s had PM diagnosis of PPID
what should all horses with laminitis be tested for unless very young?
PPID
What is the proposed pathogenesis of PPID?
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
why is there such a range of clinical signs with PPID?
there are differing levels of pituitary hormones at different times
what is the enlargement of the pituitary in PPID known as?
pituitary adenoma
what are the 2 types of pituitary adenoma?
micro
macro
what are the clinical signs of PPID?
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!
what is hyperhidrosis?
sweating excessively
what is the cause of the long curly coat in PPID?
unknown
what causes laminitis in PPID?
insulin resistance leading to high insulin levels which cause laminitis
what causes PUPD in PPID horses?
deceased secretion of vasopressin
what causes weight loss in PPID patients?
cortisol production
other associated disease
parasites
why are PPID patients often docile?
increased CSF B-endorphin
what causes neurological impairment of PPID cases?
compression from adenoma
how is PPID diagnosed?
gold standard test is postmortem only
based on clinical signs and signalment
why is PPID diagnosis difficult?
individual variation in hormone production
when is pars intermedia more active?
Autumn (august to december)
what is the first line diagnostic test used for PPID?
resting plasma ACTH concentration
what state should the horse be in when PPID sample is taken?
not stressed
how should resting ACTH blood samples be sent for analysis?
cold not frozen
send plasma
what ACTH reference range should be used when diagnosing PPID?
autumn
what test can be used to diagnose PPID if ACTH is borderline?
TRH stimulation test