Developments in the Diagnosis of Pituitary Pars Intermedia Dysfunction

Introduction
Recent evidence suggests that pituitary pars intermedia dysfunction (PPID) affects over 20% of horses aged 15 years and older. As PPID is a degenerative condition that is gradual in onset many younger horses are also likely to be affected. Data collected at The Liphook Equine Hospital would support the assertion that the condition is common in animals under 15 years of age. In some cases the diagnosis may be apparent from clinical signs; however, clinical signs are frequently nonspecific and laboratory assessment has become central to diagnosis and the monitoring of treatment for the condition.

Being a slowly progressive condition that encompasses a range of histological changes it will always be challenging to definitively and dichotomously classify horses as positive or negative for PPID. Furthermore, PPID may represent a syndrome that encompasses different diseases of the pituitary. Currently, we battle the limits of our understanding in an attempt to determine which horses have pituitary dysfunction that may render them susceptible to clinical disease, particularly laminitis. [...]