Headshaking associated with a unique presentation of guttural pouches infection and otitis media in a Quarter Horse stallion: diagnosis, medical treatment and outcome.

The study discusses a case where a 3-year-old Quarter Horse stallion develops a headshaking syndrome likely caused by bilateral guttural pouch inflammation and bilateral otitis media. The horse was successfully treated with antimicrobials, nonsteroidal anti-inflammatory drugs (NSAIDs) and rest, and no relapses were reported a year post-treatment.

Background of the Study

• The research begins with a case of a 3-year-old Quarter Horse stallion showing signs of up-and-down headshaking for one month.
• The horse was evaluated for lameness and behavioral issues, but no abnormal findings were noted.
• The headshaking syndrome was observed to accompany nose snorting during lunging and riding. However, there was an absence of such irregularities when the horse was at rest or in motion.

Diagnosis and Findings

• An endoscopic examination revealed bilateral inflammation in the horse’s guttural pouches.
• The mucosal surface in these guttural pouches had a microbullous appearance, and in some cases, these microbullae coalesced into larger bullae.
• A bacterial culture obtained from the mucosa of the guttural pouches tested positive for Serratia marcescens.
• Computed tomographic evaluation showed moderate bilateral guttural pouch inflammation, bilateral otitis media, and nuchal ligament enthesopathy.

Treatment and Outcome

• The horse was treated with antimicrobials based on sensitivity testing, systemic NSAIDs and rest.
• After one month, the horse exhibited improved headshaking condition. The endoscopic examination showed a reduction in the number of bullous lesions.
• The bacterial culture showed the presence of Streptococcus equi zooepidemicus, suggesting a remaining guttural pouch infection which was again treated with antimicrobials, systemic NSAIDs and rest.
• Two months after the initial diagnosis, the headshaking condition was considered resolved, and the horse gradually resumed training with satisfactory results.
• Final endoscopy and bacteriology tests showed no signs of guttural pouch infection.
• The horse remained symptom-free even after one year, with no reported relapses.