Pituitary pars intermedia dysfunction (PPID, formerly equine Cushing's disease) is an endocrine disease of older horses caused by an enlarged or hyperplastic pars intermedia of the pituitary. It is reported as the most common endocrine disorder of geriatric horses, affecting roughly 20 to 25% of horses over 15 years of age (Kirkwood 2022). The NAVLE tests recognition of its signs, the seasonal interpretation of ACTH, and dosing of pergolide.
Key facts
Pituitary pars intermedia dysfunction (PPID) at a glance- Species and system: horse; endocrine (pituitary).
- Typical patient: older horse, often 18 years or more when hypertrichosis appears.
- Classic sign: a long, non-shedding, curly coat (hypertrichosis), considered pathognomonic (MSD).
- Other signs: polyuria and polydipsia, poor muscle tone, abnormal fat distribution, periorbital swelling, recurrent infections, sweating, laminitis (MSD).
- Diagnosis: resting ACTH with seasonal interpretation, or TRH stimulation.
- Treatment: pergolide (Prascend), starting dose 2 mcg/kg PO once daily.
- Zoonotic: no.
What's inside
12 sections in the full guide- Key facts
- How the NAVLE tests this
- Cause and pathophysiology
- Clinical signs
- Diagnosis
- Differential diagnoses
- Treatment and management
- Putting it together in practice
- Prognosis
- Quick review
- Test yourself
- References
The full guide also has 4 tables, 1 figure, 3 self-test questions and 6 references, available to NAVLE members.
Read the full study guide
The full guide is part of every NAVLE plan, with diagnosis and treatment tables, figures, a quick review and self-test questions. Start a free trial to try the question bank, or log in if you are already a member.