A male Sumatran orangutan (Pongo pygmaeus abelii) with a history of a marsupialized air sac and chronic recurrent nasal discharge was immobilized with 6.45 mg/kg ketamine (Narketan®10, Vétoquinol AG, 3123 Belp, Switzerland) and 8.07 mg/kg, xylazine (Rompun®, Provet AG, Lyssach, Switzerland) delivered by blow dart for an admission health exam. The animal was intubated (internal diameter of 14 mm; Aire-Cuf®, Bivona Inc., Gary, IN, USA) and anesthesia was maintained by administration of isoflurane (Attane™, Provet AG, Lyssach, Switzerland) in oxygen. Hematology and blood chemistry results were within reference ranges.5 Intrapalpebral tuberculin testing was negative. Thoracic radiographs revealed a moderate, age-related bronchial pattern and a slight increased focal radiopacity in the caudal left air sac region. Multi-resistant Pasteurella multocida and E. coli were cultured in bacteriologic examination of purulent nasal discharge and air sac content. Computer tomography demonstrated a chronic destructive rhinitis, a moderate bilateral empyema in the sinusitis maxillaris and sinusitis sphenoidalis with empyema. The animal recovered well after diagnostic workup.
It was decided to perform a minimally invasive functional endoscopic sinus surgery with the purpose to re-establish ventilation and mucociliary clearance of the sinuses. Preoperative medical management included 10 days of antibiotics (10.75mg/kg cefuroxime-axetil, Zinnat®, GlaxoSmithKline, Münchenbuchsee, Switzerland) according to drug resistance testing with a 3-day course of oral steroids (1.07 mg/kg prednisone, Prednison, G. Streuli & Co. AG, Uznach, Switzerland). The animal was immobilized and maintained under isoflurane anesthesia as previously described. After local application of gauze swabs soaked with 1 ml epinephrine 1:1000 for 5 minutes to the nasal mucosa to enhance vasoconstriction, the ethmoidal infundibulum, the maxillary sinus, and the frontal recess were opened by bimanual endoscopic surgery using a 4-mm optic (0° and 45°, Karl Storz, Anklin Ltd., Binningen, Switzerland) and a paranasal sinus shaver (Karl Storz, Anklin Ltd., Binningen Switzerland).1 Although surgery was performed without significant blood loss or other complications, the orangutan went into ventricular fibrillation at the end of the procedure. Cardiopulmonary resuscitation was immediately initiated but was stopped unsuccessfully 60 minutes later.
Pathologic examination confirmed a severe, diffuse, chronic-active air sacculitis and moderate nonsuppurative sinusitis on the right side. Bacteriologic culture revealed a Corynebacterium spp. and Clostridium spp. infection. Acute cardiovascular collapse was identified as cause of death.
Chronic air sacculitis has been documented as a prevalent problem in captive orangutan.2-4,6 Etiology is still hypothetic, and most reports focus on therapeutic approaches. The frequency of involvement of chronic sinus infection in the occurrence of chronic air sacculitis, as in the present case, is unknown. Nevertheless, recommended treatments such as long-term antibiotics, according to microbiologic analysis, did not improve the condition in this case. Future clinical investigations of air sacculitis and chronic nasal discharge in orangutans should include a thorough evaluation of skull sinuses.
The authors thank especially Mr. T. Hoffmann, Anklin Ltd, Medical Supplies, Binningen, Switzerland for providing all the endoscopic equipment and technical support during the procedures. The work and organization of Ms. G. Hürlimann is gratefully appreciated.
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