Cushings disease in horses
Ponies and horses are living longer due to an improved quality of life and advances in medical care and dentistry but they are susceptible to old-age conditions such as Cushings disease. Cushings is caused by the loss of a neurotransmitter - dopamine - in the brain, which has an inhibiting function on part of the pituitary gland. This leads to enlargement of the pituitary and abnormal amounts of hormones being secreted.
Symptoms
- Abnormal hair growth
- Increased drinking & urination
- Susceptibility to infection
- Depression & poor performance
- Pot-belly & bulging around the eyes
- Laminitis, chronic & recurrent
- Diabetes
Online presentation on Equine Cushings by Dr. Hal Schott, DVM | Michigan State University:
Treatment
We usually perform blood tests to see if your pony has Cushings. However this is not an easy decision as two of the tests can be unreliable and another can result in a painful attack of laminitis.
There are no drugs that will cure the condition but the symptoms can usually be controlled with drugs. Until recently we have used either Periactin which is the cheapest alternative but only effective in about 25% of cases or Celance, a dopamine agonist, which is effective in around 95% of cases but very expensive (the generic form of Pergolide is less expensive).
We can often use Trilostane, a 3-betahydroxysteroid dehydrogenase inhibitor, which acts to block adrenal steroidogenesis. Research has suggested that the drug improves the quality of life in over 80% of effected ponies by reducing excess drinking and urination, lethargy and symptoms of laminitis. The daily cost of treatment varies from £1 to £5 per day depending on bodyweight and dose required.