Conditions or ailments that are the cause of a problem that you see - your observation.

Your vet may diagnose

Guttural Pouch Mycosis

Synonyms: Aspergillosis


The guttural pouches are paired air-filled outpocketings of the upper airway (pharynx). They are located near the throat latch region of the neck. Major vessels and nerves supplying the head course through the walls of the pouch. The pouch is accessed with an endoscope through a small slit in the pharynx.

The guttural pouches are thought to be involved in cooling blood that passes to the brain through the large carotid arteries. They may also have a role in equalizing air pressure on the tympanic membrane. The guttural pouch volume in an average horse is 300-500 ml each.

Mycosis is fungal growth in the body. Occasionally, a pathogenic fungus (usually Aspergillus spp) invades a guttural pouch, growing on the carotid artery. The main danger in this is that the fungal plaque can erode through the wall, causing a life-threatening bleeding episode.

Treatment involves a procedure in which the affected arteries are occluded on either side of the guttural pouch by means of balloon-tipped catheters. This starves the fungus and prevents bleeding.

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Other conditions or ailments that might also need to be ruled out by a vet.

Very Common
Less Common
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The prognosis is poor with older treatments including anti-fungals. Balloon occlusion of the feeding vessel is effective in a fairly high percentage of cases. In some cases, though, there can be nerve damage resulting in a variety of other severe and chronic problems including difficulty swallowing.

Related References:

Millar H. Guttural pouch mycosis in a 6-month-old filly. Can Vet J Mar 2006; 47(3):259-61.

Higgins AJ, Snyder JR eds. The Equine Manual. 2nd Ed. Edinburgh: Elsevier Saunders 2006.

Author: Doug Thal DVM Dipl. ABVP