29 August 2008 11:19
My horse has been diagnosed with a partially paralysed left laryngeal muscle. The vet thinks that she is a grade two and has suggested that, because of our workload (hacking, local jumping and dressage), it’s probably not worth operating.
Could you tell me more about this condition, the gradings and whether there’s anything else I can do to help my horse?
Answer
By Your Horse
Vet Malene Jørgensen replies:
This condition has many names, including recurrent laryngeal neuropathy (RLN), idiopathic left laryngeal hemiplegia, or roaring. They all indicate a neural affliction of the nerves around the larynx (voice box). It’s seen in Thoroughbreds, Warmbloods and draught horses, and is more common in male horses and those aged between two and five years old.
Damage to the nerve, which relates to the muscles of the (most commonly) left-hand vocal cord, causes an asymmetrical opening of the vocal cords during respiration. This results in a partial obstruction of the airways, especially during exercise. Signs of the condition include excessivenoise, particularly during exercise, and diagnosis is usually made with an endoscope during high-speed treadmill exercise.This nerve damage can have several possible causes, including:
● Damage due to viral infection.
● Guttural pouch fungal infection or strangles.
● Toxic damage due to heavy metals or organophosphates.
● Epiglottis entrapment.
● Cysts or polyps.
● Neoplasia.
● Damage to the facial nerves.
● Damage due to intravenous injection going perivascular (beside the vein).There are four grades of laryngeal dysfunction, ranging from one (normal) to five, the most severe. As your horse’s symptoms are mild and she’s not competing at a high level, you could consider trying a homeopathic remedy. Seek help from a qualified veterinary homeopath – look at www.trusthomeopathy.org for more information.