Monday, January 21, 2008

Laryngeal Paralysis



We seem to have had a run on laryngeal disease over the last month so I thought i would post a quick tutorial. Horses can get a variety of Laryngeal diseases, including arytenoid paralysis, ulcers,
neoplasia, epiglottic displacement, epiglottic entrapment and sub-epiglottic cysts.
Image 1-
This is a normal view through a fiber optic endoscope. What you see is epiglottis in the foreground that looks like a pointed tongue. behind this are the arytenoids that work like curtains covering the opening to the trachea.
Image 2-
In this horse you can see the left arytenoid is hanging down into the airway. This is an example of Laryngeal paralysis. Frequently this is caused by damage to the left recurrent laryngeal nerve. It can also be related to damage to the arytenoid itself such as infection of the cartilage.
This is what typically is known as roaring, when the horse makes a respiratory noise (usually on inspiration) while working.

Image 3-
This is a picture of an arytenoid ulcer.
It is actually one that is healing after having had a draining tract for several weeks.
In this case the left arytenoid was so
thick and edematous that it caused it
to hang into the airway causing a respiratory noise. It eventually led to a left laryngeal paralysis.



The treatment for this condition is the surgical tie-back where the left arytenoid is sutured back out of the airway. This will allow for adequate inflow of air during exercise and lets the horse perform at near normal levels. the down side to having this done is that the airway is now 50% open ALL the time. This means that they are more prone to tracheal and pulmonary infections and irritations from dust and debris. Another point to be made is that this will NOT eliminate the noise , which means that certain show horses will still be knocked back for respiratory noise.
Should you have a horse that makes a noise or has a performance issue that could be respiratory in origin then you should have an endoscopy done on your horse. It is simple and relatively non-invasive and can give you a wealth of information.

6 comments:

Amanda said...

I enjoy reading your blog. I'm a vet student at Cornell, so naturally I find your content entertaining and useful. I start my first large animal rotation pretty soon, so I'm thinking doubly-hard about your entry!

Dr. Alan Weldon said...

Amanda
When you see Dr Divers and Dr Ainsworth tell them hello for me.
I can only hope your time at Cornell was as wonderful as mine.
Alan

harhar said...

hello
i was checking your blog and i saw that you have an research about laryngeal paralysis i have a horse that has this problem and honestly in my country there is no doctors that make this surgery can u help me in some medicines that can help for this problem . the signs that i am seeing in my horse is while exercising he is having a lack of oxygen.
thanks alot hope you can help
Hadi Sabra
beirut Lebanon

harhar said...

hello
i was checking your website and i sow that you have an research about laryngeal paralysis i have a horse that has this problem and honestly in my country there is no doctors that make this surgery can u help me in some medicines that can help for this problem . the signs that i am seeing in my horse is while exercising he is having a lack of oxygen.
thanks alot hope you can help and send me an email what to do i realy love my horse
Hadi Sabra
Hadisabra@hotmail.com
beirut Lebanon

bev said...

i have a horse which has been coughing for 4 weeks. on the fourth vet visit we did an endoscapy and he has a lot of ulcers on his larynx. 500mg a day of seroids has stopped his coughing but what happens when we stop the steroids? and what could have caused the ulcers?

Dr. Alan Weldon said...

Bev, ulcers in the pharynx can be from the coughing, ie traumatic, or infectious from chronic pharyngitis or sometimes even neoplastic such as lymphoma. I suggest re scoping and if ulcers are still present the biopsy. As to the cough consider using an inhaler (steroid) and some environmental modifications