Atypical Myopathy in Horses

This disease is life-threatening and should be treated by a veterinarian swiftly.

Atypical myopathy (“Sycamore poisoning”) is a potentially fatal disease of horses in the UK and Northern Europe caused by eating Sycamore seeds (“helicopters”) or possibly leaves.
This condition affects grazing horses and is linked to the toxins that are present in sycamore seeds which fall in the Autumn and seedlings which grow in the Spring. It is seen typically after periods of wet and windy or cold weather.

Sycamore material has been found, in varying concentrations, to contain a substance called Hypoglycin-A (HGA). When eaten, HGA is converted into a toxin within the horse’s body. The toxin has a rapid negative effect and can slow or even stop energy production in the horse’s muscle fibres.

Symptoms of Atypical Myopathy in Horses

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Treatment of Atypical Myopathy in Horses

Affected horses are in need of intensive care. There is no antitoxin for HGA but some medications can be used to stop absorption of the toxin. Symptomatic treatment includes intravenous fluid therapy, supplementation of glucose and insulin as well as administration of carnitine, vitamin E, selenium and riboflavin. Anti-inflammatory medication is used to decrease the pain and possibly increase the chance to survive. Affected horse should be kept warm.

Most affected horses that are alive 5 days after the start of clinical signs are likely to recover. Initially recovery is slow, but most affected horses that recover go on to make a complete recovery and return to work with no long-term effects of the disease.

Prevention of Atypical Myopathy in Horses

Where you know there are European Sycamores (Acer Pseudoplanatus) close enough for seeds and leaves to drop on your grazing you should consider the following precautions:

– Checking fields carefully for Sycamore leaves and seeds
– Fencing off areas where Sycamore seeds and leaves have fallen
– Hoover-up/pick up sycamore seeds off the pasture
– Turning horses out for shorter periods
– Provide extra forage (hay or haylage) especially where pasture is poor or grazing is tight
– Reducing stocking density so there is plenty of good grazing for every horse

How Happie can help you manage your horse's health

Digital health management offers numerous benefits in modern equine healthcare.

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