Progression of mycosis of the auditory tube diverticulum (guttural pouch) after arterial occlusion in a horse with contralateral temporohyoid osteoarthropathy.

The research paper focuses on a case study of a 6-year-old mare, diagnosed with a guttural pouch disease involving mycosis and osteoarthropathy. Despite treatment, the mare developed an advancement of the fungal infection, leading to various complications and eventual euthanasia.

Case Presentation

• The study revolves around the case of a 6-year-old Appaloosa mare, which was presented to the medical center due to difficulty eating, lack of appetite, and swelling, along with a mucopurulent discharge in its right eye. No significant results were found from the CBC and serum biochemical analysis.
• Ophthalmologic examination revealed corneal scarring and ulceration. Endoscopic examination identified an abnormal thickening of the right stylohyoid bone and a plaque suggestive of fungal growth on the left internal carotid artery. Radiographic examination showed otitis media on the right-side.
• From these results, the mare was diagnosed with temporohyoid osteoarthropathy in the right guttural pouch (a bony growth) and mycosis (a fungal growth) in the left guttural pouch.

Treatment and Aftermath

• While the right stylohyoid bone was surgically removed, the left internal carotid artery where the mycotic growth was identified, was occluded by placing stainless steel spring embolization coils.
• Post operation, the mare could eat without difficulty and showed clinical improvement for about 4 weeks. However, 53 days after surgery, the mare developed left-sided Horner syndrome (disruption of nerve pathway from the brain to face and eye), atrophy of the right side of the tongue, and a significant weight loss due to difficulty in swallowing, persisting for 3 weeks.
• Endoscopic evaluation indicated a progression of the fungal growth in the left guttural pouch. Given the lack of expected improvements and growing severity of the symptoms, the mare was euthanized.

Conclusions

• The researchers concluded that the mycotic lesion in the left guttural pouch, which was an incidental finding initially, progressed to cause dysphagia (difficulty swallowing) and Horner syndrome after the occlusion of the left internal carotid artery.
• They suggested that arterial occlusion, although typically associated with resolution of guttural pouch mycosis, is not necessarily a reliable method for resolving it, as evident from the presented case.