Vetcare Webinars by Andy Durham in 2013
There seems to be a relationship between ACTH concentration and number of clinical signs of PPID seen.
PPID is diagnosed in horses under 10 years old.
In 48% of 2045 PPID cases with laminitis, laminitis was the only clinical sign of PPID.
In 4623 PPID (TAL) cases with laminitis, most were in the autumn, then winter, then summer, then spring.
In 1154 PPID cases, Liphook found the highest ACTH in autumn, then winter, summer, spring, and the highest insulin in autumn, then winter, summer, spring.
Horses over 15 years old with PPID have a 4.65 x greater risk of laminitis than horses of the same age without PPID (McGowan et al. 2013).
67% of PPID cases demonstrate an excessive insulin response to glucose challenge (Durham, unpublished).
Pergolide may protect against neuronal oxidative damage (Uberti et al. 2002, Gille et al. 2002).
"A "grey zone" for results is inevitable with a slowly progressive disease.
Any horse of any age with laminitis deserves testing for PPID regardless of whether other clinical signs are present."
"Routine screening for PPID as part of "annual health checks" is justifiable beyond 5-7 years of age."
Important to realise that "we don't have all the answers" yet. A 3 year old obese, previously laminitic pony had results of:
fasted insulin 12 uIU/ml (<20)
Post glucose insulin 793 uIU/ml (<85)
ACTH 358 pg/ml (<29).
The question is asked, should this pony be treated for PPID (pain, stress would have to be taken into account, as well as other symptoms of PPID. TLS might suggest trying pergolide initially whilst trying to control other factors, but reducing and if possible stopping dose if follow up blood tests show ACTH return to normal, and continuing to monitor ACTH regularly).