Historical, clinical and nasal endoscopic findings in 1600 cases of equine sinonasal disease and associations with case outcome

BACKGROUND: No large study has described the signalment, pre-referral management or clinical and nasal endoscopic findings in equine sinonasal disease. OBJECTIVES: To explore associations between case outcome and signalment, pre-referral treatments, clinical and nasal endoscopic variables in sinonasal disease. STUDY DESIGN: Retrospective case series. METHODS: Data were collected from medical records of 19 equine hospitals on sinonasal disease cases they had examined and which had undergone computed tomographic (CT) imaging. Case outcome was obtained from clinical records and/or by contacting clients and referring veterinarians. Multivariable logistic regression analysis was used to examine variables at presentation associated with case outcome. RESULTS: One thousand six hundred cases met inclusion requirements, including 1457 cases of unilateral and 143 cases of bilateral sinonasal disease. Most were chronic disorders (median duration 17.9 weeks). The most common antimicrobials administered pre-referral were potentiated sulphonamides, doxycycline and procaine penicillin. Pre-referral surgical treatments included maxillary cheek tooth extraction (n = 234 teeth) in 201 horses (12.6%), sinoscopy (11.8%), nasofrontal sinus osteotomy (5.2%) and maxillary sinus osteotomy (3.6%). Nasal airflow was obstructed in 14.9%, and facial swelling was present in 26.9% of cases. Nasal endoscopy showed exudate at the sinonasal ostium in 65.8% of cases, and middle meatus abnormalities, including inspissated exudate, sequestra and sinonasal fistulae, were present in 44.6%. A multivariable model was built with data from 650 cases. Age at presentation greater than 12 years (odds ratio [OR] 0.53, 95% confidence interval [CI] 0.36-0.79), sinonasal disease of over 8 weeks duration (OR 0.63, 95% CI 0.42-0.94), nasofrontal sinusotomy prior to referral (OR 0.36, 95% CI 0.16-0.81) and presence of facial swelling or bilateral nasal discharge at presentation to a referral centre (OR 0.33, 95% CI 0.18-0.62) were significantly associated with a decreased chance of complete cure. MAIN LIMITATIONS: This was a retrospective study with incomplete data for some cases. CONCLUSIONS: Equine sinonasal disease cases aged over 12 years old, with disease of over 8 weeks duration or having had nasofrontal sinusotomy prior to referral had a decreased chance of complete cure following referral.