Tuesday 1st of December 2020
The Gaitpost

A Personal Experience of Atypical Myopathy

As we have all been reading, this autumn there has been a worrying increase in horses being poisoned by sycamore seeds. This disease is known as Atypical Myopathy. We are very grateful to Sasha Dibben, who works for William at the Fox-Pitt Eventing Club, for writing this blog for us about her tragic experience of this horrid disease. 




sasha dibben

“Last weekend my 7 year old Thoroughbred, Yogi, was in great health.  He was schooled and hacked and I had no concerns.  He was fine Sunday evening when I checked and fed him.  However we noticed him lying down on Monday morning and, upon discovering that he was sweating and a little wobbly on his legs when he got up, I called out the vet.  

The vet arrived within 15 minutes and immediately diagnosed Atypical Myopathy.  Yogi was displaying classic symptoms – he looked exhausted, his muscles were trembling, he was sweating and was weak and stiff.  Some horses can also look like they have colic.  His urine was also very dark – a black/reddy sort of colour.  This is the myoglobin (an oxygen and iron binding protein found in the muscles) which is broken down by the toxin (Hypoglycin A) which is believed to be found in the seed of the sycamore.  


Atypical Myopathy tends to happen in the Spring and Autumn.  This autumn has seen a rise in cases and this is thought to be due to the mild and wet conditions which encourages the toxin to develop (a couple of hard frosts should kill it off).  There is no cure and the mortality rate is between 75 – 90%.  

Unfortunately Yogi did not make it.  Despite have a constant intravenous drip, pain relief and vitamin injections, all muscles throughout his body were attacked causing his heart rate to elevate to 90bpm and his diaphragm weakened so he ended up struggling to breathe.  He lasted 40 hours from being diagnosed, however some horses are found dead in the field.

The BHS have done an information leaflet which can be found here.  If you suspect a case, please contact your Vet.” 

Thank you, Sasha, for sharing this with us at such a difficult and upsetting time.

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