Unilateral orbital lacrimal gland abscess in a horse.

This study reports on a case of a 20-year-old horse that had unilateral periorbital swelling due to a bacterial infection in the orbital lacrimal gland, a condition known as dacryoadenitis. The paper discusses methods for diagnosing such conditions, as well as surgical management, which in this case was successful with no recurrence reported 40 months post-operation.

Background of the Case

• The case involves a 20-year-old Thoroughbred gelding that was presented for evaluation due to a swelling near its left eye. This swelling had been intermittently seen for 3 months.
• Upon physical examination, a firm, non-painful swelling was identified in the region of the orbital lacrimal gland, under the upper eyelid.
• This swelling was noted to extend from under the dorsal orbital rim and followed the contour of the globe.

Diagnostic Methods

• Ultrasonography was used to examine the swelling, which showed a mixed echogenic mass along the dorsal orbital rim.
• A CT scan revealed a mass that was enhancing the contrast moderately, and this mass was seen as contiguous with the eyelid.
• Possible diagnoses considered included inflammatory lesions like granuloma, foreign body or abscess, and neoplasia.
• The eventual diagnosis was arrived at through surgical exploration and excision of the mass. The mass was discovered to be a lobular structure with a purulent, or pus-filled, centre.

Findings and Treatment

• Post operative histopathology identified the mass as the orbital lacrimal gland and found severe dacryoadenitis, an infection in the tear gland.
• Culture of the pus from the mass revealed that the infection was due to beta-hemolytic Staphylococcus aureus, a type of bacteria.
• The patient horse was then put on supportive care, and treated with antibiotics based on the bacteria’s sensitivity to them.
• No recurrence of the condition was reported even 40 months after the operation.

Conclusion

• This case report was aimed at identifying bacterial dacryoadenitis as a cause for the unilateral periorbital swelling in horses, and discussing the potential diagnoses for these presentations.
• Also, the successful surgical management of such a condition is discussed.
• According to the author’s knowledge, this is the first case of bacterial dacryoadenitis and ensuing abscessation in the orbital lacrimal gland in a horse.