EQUINE GUTTERAL POUCH: RARE BUT WORTH UNDERSTANDING


Monday, November 19th, 2012 | Filed under Medical




We still don’t know what is wrong with Slick…

His Xrays came back showing nothing. My vet is sending the Xrays to a specialist…

You readers have been very kind.  A few of you – enough to make me take note – mentioned “Gutteral Pouch”.

Hmmmm.

So I read about it.

Image of the Gutteral pouch

 

GUTTERAL POUCHES – WHAT ARE THEY?

CLICK image to read the article…

A guttural pouch is an air-filled out-pouching of the auditory or Eustachian tube. While all mammals have auditory tubes, not all have these pouches. Horses, mules, and donkeys have the largest, with one pouch lying on each side of the back of the throat.

Because the horse spent much of its evolutionary development on flat grassland, pressure regulation does not appear to be a factor in explaining the extreme size of the equine guttural pouch. More recent research points to its ability to significantly cool the horse’s brain by moving air in and out of the guttural pouch as probably its key function.

There seem to be three different types of Gutteral Pouch syndromes.  And, a gutteral pouch infection can often be a side effect of Strangles.

It can also occur from a fungal infection.

Most of the forums that had conversations about gutteral pouch infections (there were enough forums to make me think this occurs more often than indicated…) said that the largest indicator is a single nostril/sinus infection that won’t go away.  It comes and goes.  Stinky.  And, the horse has difficulty breathing.

Hmmmm.

Slick has difficulty breathing – but he always has difficulty breathing.  The infection is getting better.  But it isn’t gone.  And it is in one nostril.  I just ran outside and checked his gutteral pouch area and they were not swollen.

Slick is on antibiotics, which is one of the cures for gutteral pouch (the other is surgery – ugh), so that’s good.

Anyway, I did just leave an email with my Vet to see what he thinks…

I will keep you posted.

In the meantime, here are a few of the articles I read about gutteral pouch.

The first one is more user-friendly to read.

The second article is more technical.

 

ON GUARD: Guttural Pouch Infections

By Kenton H. Arnold, DVM

 Learn how to recognize Guttural Pouch Infections

Your horse has a thick nasal discharge that won’t go away. He gets better for a few days only to have the heavy nasal discharge return again. Or maybe your horse has difficulty swallowing his food, yet his teeth have been checked and no problems were found. Or your horse has a nose bleed for no apparent reason.

In each of these cases, the horse could have a guttural pouch infection.

Although guttural pouch infections are not common, they do occur often enough that you as a horse owner should know what the guttural pouch is and what kind of problems might occur from an infection in this area.

The guttural pouch is a blind pouch or diverticulum of the auditive tube. In both, humans and horses this tube comes from the inner ear and opens into the pharynx. A small flap covers the opening of the auditive tube. The flap opens during swallowing allowing the pressure to equalize on both sides of the eardrum. In the horse, the guttural pouch just inside the flap of the audutive tube. Its function is not totally understood, but it is believed that it evolved due to the elongated mouth and pharynx of the horse to aid in swallowing.

Because it is a dark, warm, moist environment, the guttural pouch creates an ideal place for both bacteria and fungi to thrive. Even so, guttural pouch inflections usually occur in conjunction with an upper respiratory problem, such as Strangles. The guttural pouch infection can continue long after the upper respirator infection has resolved. Symptoms may vary from case to case, but can include chronic nasal discharge from one or both nostrils, a swelling of the throat latch area, coughing, difficulty. Many times the symptoms are very mind and go completely unnoticed for a while. Diagnosis can be confirmed with radiographs or an endoscopic exam of the nasopharynx.

Treatment requires drainage and flushing of the pouches. Usually this can be accomplished with a catheter passed though the nose and directly into the pouch. Occasionally the pus in the pouch may dry and harden, forming small hard stones called chondroids. These irrating foreign bodies should be removed surgically.

Fungal infections are the most common of all the guttural pouch infections. The symptoms are the same. But usually milder. They may also cause spontaneous bleeding from the nose for no apparent reason. The internal carotid artery as well as the cranial nerves runs along the guttural pouch wall. Irritation of any of the cranial nerves can cause damage to the nerve creating problems such as difficulty swallowing to eye problems. Any horse that has a spontaneous nose bleeds or any facial paralysis for an unknown reason should be examined for a possible guttural pouch fungal infection. Treatment will include flushing the pouch and allowing fresh air ventilation through the catheter.

If nerve damage has occurred, the nerve function may never return to normal. Fortunately, these infections are not common. An early diagnosis is critical to protest your horse from life-threatening symptoms involving the structures of the head, such as the nose and mouth, eyes and ears, an endoscopic exam to the guttural pouches is warranted.

 

AND ANOTHER..

Click image to go to article and website.

Guttural Pouch Surgery

Contact us to schedule an appointment.

Guttural Pouch Horse Diseases

Endoscopic view of normal guttural pouch and stylohyoid bone (arrows)

Endoscopic view of normal guttural pouch and stylohyoid bone (arrows)

Diseases of the guttural pouches are not common, but can be life-threatening and very difficult to treat. The guttural pouches are unique to a small number of animal species, including the horse. They are sacs of air that expand from the Eustachian tube, with one on each side of the horse’s head. They are positioned beneath the ear and each guttural pouch cavity in an adult horse can hold as much as a coffee mug. The guttural pouches are lined with a very thin membrane and beneath that membrane are some critical structures, such as major arteries to the head and some of the most important nerves in the body. Most of these nerves are cranial nerves, so when they are damaged, the resulting clinical signs relate to functions of the head. Examples would be problems with swallowing food and water, breathing, facial expression and head posture.

Equine Disease: Guttural Pouch Empyema

The most common disease of the guttural pouches is called guttural pouch empyema. This is caused by a bacterial infection, usually secondary to strangles. In this disease, the thin lining of the guttural pouch becomes inflamed and the guttural pouch becomes filled with thick pus. This material can drain through the Eustachian tube opening into the pharynx, and from there to the nasal passages and out the nostril. These horses in general do not feel very well, and so they are depressed and have a fever, but damage to nerves is uncommon and to arteries is even rarer. Treatment of choice includes antibiotics, flushing the guttural pouch with a physiologic solution to remove the pus, and analgesic (pain-killing) drugs. In severe cases, the pus might have to be removed by surgical drainage. In rare cases, the pus hardens into round balls called chondroids. These usually have to be removed by surgery.

Endoscopic view of guttural pouch mycosis

Equine Disease: Guttural Pouch Mycosis

Guttural pouch mycosis is a rare but very serious disease in horses. It is caused by a fungus that infects the lining of the guttural pouch, usually on the roof of the guttural pouch. The infection can cause some deep damage to the arteries and nerves. Unlike empyema, pus does not build up in the guttural pouches and many of these horses can appear quite normal until, quite suddenly, either hemorrhage or cranial nerve damage becomes apparent. In the case of hemorrhage, huge amounts of blood can pour from the nostrils. Bleeding from the nostrils (called epistaxis) can be evident in some cases as extensive painting of the horse’s stall walls and floors with bright red blood. Hemorrhage can be fatal, and so all attempts are made to prevent this. Dr. Freeman at the University of Florida has pioneered methods for occluding affected arteries in the guttural pouch and has continued this work with our small animal cardiologists so that we currently use minimally invasive, state of the art techniques for this purpose. The success rate of these procedures is very high, provided they are applied before the horse has lost too much blood. The University of Florida has all the necessary equipment to diagnose and treat this serious disease.

The nerve damage caused by guttural pouch mycosis is another story. If mild, and affecting certain nerves, the horse might eventually recover. If severe, and especially if affecting the nerves involved with swallowing or with respiration, the chances of recovery are slim. Most affected horses will require intensive nursing and methods of feeding for months before the signs resolve. Again, the veterinarians at the University of Florida are very familiar with these methods and have had success with them.

Equine Disease: Guttural Pouch Tympany

Guttural pouch tympany is a congenital disease of horses, so the signs are usually seen in foals shortly after birth. For reasons that we do not understand, one or both guttural pouches fill with air that cannot escape and becomes trapped. These foals then develop a “chipmunk” appearance caused by air distension of the guttural pouch in the throatlatch. These foals are otherwise in good health, although some might experience difficulty swallowing and this might lead to aspiration of food and milk. Treatment is surgical and involves creating a new opening from the affected guttural pouch so the air can escape from the affected side into the normal side or into the pharynx. A variety of different methods are available and the surgeons at the University of Florida have experience using them.

Endoscopic view of callus on stylohyoid bone on roof of the guttural pouch in a horse with temperohyoid oseoarthropathy (THO)

Equine Disease: Temporohyoid Osteoarthropathy

Temporohyoid osteoarthropathy is another rare disease of guttural pouches. This is also caused by an infection, but the infection affects the middle ear of the horse. The middle ear is very close to where the stylohyoid bone forms a joint with the skull on the roof of the guttural pouch. This joint is called the temporohyoid joint. The stylohyoid bone is a long slender bone that runs from the roof of the guttural pouch, down to the base of the tongue, where it joins with the same bone from the other side through a series of connections with smaller bones. The purpose of the boney apparatus thus formed, called the hyoid apparatus, is to support the base of the horse’s tongue and part of the larynx. When the infection in the middle ear invades the nearby temporohyoid joint on the roof of the guttural pouch, the infection causes the joint and the stylohyoid bone to become thick and brittle. Then, through repeated movements of the tongue and larynx, the brittle portions of bone can fracture. As the fracture heals, it will form a callus and this callus can reach sufficient size to put pressure on some nerves that go through the guttural pouch. The nerves most typically affected are the facial nerve, which is involved in the horse’s facial expression, and the vestibulotrochlear nerve, which is responsible for balance.

When these nerves are affected, the horse will have a droop in its ear, eyelid, and muzzle on the affected side and will even have some signs of incoordination and a head tilt. If the condition is mild, it can be treated with antibiotics. In more chronic and less responsive cases, a piece of bone from the hyoid apparatus is removed on the affected side and this essentially detaches the stylohyoid bone from its connections with the tongue and larynx. Then, movement of tongue and larynx do not affect the diseased stylohyoid bone so that it can heal without any risk of further fracture and additional callus formation. The nerve signs can completely resolve or partly resolve, although in severe cases, they can persist. The University of Florida has the expertise, experience, and the equipment to diagnose and treat this disease.

Other diseases of the guttural pouch are very rare but can occur and these include cysts and tumors.

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3 comments have been posted...

  1. MamaQ

    Have him checked for an eyetooth which does not always appear near the ear but can also be in the sinus
    http://www.thehorse.com/articles/14124/ear-teeth: Dentigerous cysts, also known as temporal odontoma, temporal teratoma, heterotrophic polydontia, or ear teeth, are relatively rare but well-documented occurrences in young horses. They are composed of sacs containing a tooth or dental tissue that develop where there should not be a tooth.

    Most commonly, they occur near the base of the ear and present as a firm swelling sometimes with a draining tract discharging a thick, white fluid. They can, however, appear inside the skull or nasal cavities, where they are much more likely to cause trouble, either by pressure or obstruction.

  2. KERRY

    I have a horse that has a gutteral pouch problem of the bacterial kind. We have treated her with antibiotics and flushing of the pouch with saline three times and and the infection still keeps coming back. The antibiotic and needle are very thick and almost cruel to administer as it takes around 30 seconds of pain to administer it so I really am looking for a way to get rid of it once and for all. I’m also concerned about the recurring infection developing resistance to the antibiotics since it’s been three times.

    I’m telling you this so you don’t become complacent when a vet simply does the treatment and doesn’t put enough priority on getting it completely cured. Of course, make sure whether it’s fungal or bacterial. But given that my horse has a bacterial form and it’s becoming more of a serious problem, take heed.

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