South African Equine Veterinary Association Congress 2015 Protea Hotel Stellenbosch
results? Finally, the ideal dosing interval and whether or not seasonal (fall) treatment can be an
approach in some animals are unresolved questions.
For researchers investigating PPID, challenges include better understanding of pathophysiology of
the varied clinical syndromes of PPID. Specifically, might there be varying hormonal profiles in
equids that are afflicted with diabetes or laminitis as compared to hypertrichosis and muscle
wasting? Additional questions include: 1) why do some horses develop signs of PPID at a
relatively early age; and 2) what is the role of insulin dysregulation in PPID? Next, although PPID
affects many breeds, it has also been anecdotally recognized in several generations within certain
families of equids. Consequently, the genetic basis for development of PPID needs to be explored.
Finally, might environmental risk factors may also play a role in development of PPID? Answers
for many of these questions will likely require longitudinal, multi-centre studies through which
progression of PPID can be studied over a number of years.
References
General reviews
van der Kolk JH. Equine Cushing‟s disease. Equine Vet Educ 1997;9:209.
van der Kolk JH, Kalsbeek HC, van Garderen E, et al. Equine pituitary neoplasia: a clinical report of
21 cases (1990-1992). Vet Rec 1993;133:594.
Schott HC. Pituitary pars intermedia dysfunction: equine Cushing‟s disease. Vet Clin North
Amer: Equine Pract 2002;18:237.
McFarlane D. Equine pituitary pars intermedia dysfunction. Vet Clin North Am: Equine Pract
2011;27:93.
Prevalence
McGowan TW, Pinchbeck GL, Phillips C, et al. A survey of aged horses in Queensland,
Australia. Part 2: clinical signs and owner perceptions of health and welfare. Aust Vet J
2010;88:465.
Ireland JL, Clegg PD, McGowan CM, et al. A cross-sectional study of geriatric
horses in the United Kingdom. Part 2: health care and disease. Equine
Vet J 2011;43:37.
Pathophysiology
van der Kolk JH, Heinrichs M, van Amerongen JD, et al. Evaluation of pituitary gland anatomy
and histopathologic findings in clinically normal horses and horses and ponies with pituitary pars
intermedia adenoma. Am J Vet Res 2004;65:1701.
McFarlane D, Dybdal N, Donaldson MT, et al. Nitration and increased alpha-synuclein expression associated
with dopaminergic neurodegeneration in equine pituitary pars intermedia dysfunction. J Neuroendocrinol
2005;17:73.
Diagnostic testing
Dybdal NO, Hargreaves KM, Madigan JE, et al. Diagnostic testing for pituitary pars intermedia
dysfunction in horses. J Am Vet Med Assoc 1994;204:627.
Couëtil L, Paradis MR, Knoll J. Plasma adrenocorticotropin concentration in healthy horses and
in horses with clinical signs of hyperadrenocorticism. J Vet Int Med 1996;10:1.
Donaldson MT, McDonnell SM, Schanbacher BJ, et al. Variation in plasma adrenocorticotropic
hormone concentration and dexamethasone suppression test results with season, age, and sex in
healthy ponies and horses. J Vet Int Med 2005: 19:217.
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