Presumed Sulfonamide-Associated Uveitis With Stevens-Johnson Syndrome in a Quarter Horse Mare.

This research study covers the first reported case of a horse developing uveitis and the Stevens-Johnson syndrome (SJS), possible reactions to sulfonamide antibiotics.

Case Summary

• The paper describes the condition of a four-year-old Quarter Horse mare that showed symptoms including fever, respiratory infection with a productive cough, confusion, and bilateral anterior uveitis which had previously been treated with Trimethoprim-sulfadiazine (TMPS), a commonly used type of sulfonamide antibiotic in veterinary medicine.
• An endoscopic tracheal wash was performed on the mare from which the bacteria Acinetobacter johnsonii was cultured, possibly indicating the cause of the respiratory infection.

Treatment

• Initial treatment involved the use of cefquinome, systemic flunixin-meglumine, local ocular atropine, and corticosteroids.
• Over the following days, the mare displayed swelling of the face, specifically around the eyelids and lips.
• There were no abnormalities in the metatarsal arteries of the horse.
• By the fifth day of treatment, the facial swelling had reduced significantly, the uveitis symptoms had considerably improved, and there was peeling of skin on the periorbital region, muzzle, and vulva, revealing nonpigmented skin beneath.

Discussion and Analysis

• The researchers explored the possibility of sulfonamides potentially causing bilateral anterior uveitis and Stevens-Johnson syndrome (SJS) in the horse. SJS or erythema multiforme major, common in human medicine, is a rare condition in horses.
• The syndrome is typically associated with sulfonamides, but it can also occur due to other drugs including anti-infectives, anti-inflammatories, anticonvulsants, analgesics, and infections.
• The paper explores a possible pathway through which sulfonamide could induce SJS.

Summary

• The research covers the first documented case of sulfonamide-associated uveitis and SJS in a horse. It provides critical insight into the potential adverse reactions of sulfonamide antibiotics in equine treatment and encourages further study in the area for improved understanding.