Diagnostics and Treatment of Severe Swelling of the Pharyngeal Tissues of an African Elephant (Loxodonta africana)
A 10-year-old, 1545-kg, female African elephant (Loxodonta africana) presented with inspiratory dyspnea, stridor, and stertorous respiratory sounds. The problem had begun gradually 7 days after the elephant had started eating from a new shipment of orchard grass hay, and progressively worsened over the next 7 days. At that point, the elephant was sedated with 100 mg xylazine IV and 10 mg butorphanol IV. The sedation caused the clinical signs to worsen. While standing, a 3-m endoscope was passed through the left nostril of its trunk and advanced until the pharyngeal area could be visualized. The pharyngeal tissue was markedly swollen, creating folds that completely obscured the epiglottis and arytenoid cartilages. There was an approximately 7-cm opening in the swollen tissue that vibrated during respiration, through which food and water had to pass. Blood was drawn for a complete blood count and blood chemistry analysis. The white blood count was moderately elevated to 19,500 (normal range 12,000 to 16,000). The elephant was treated with 6,000 units/kg penicillin G procaine and 6,000 units/kg penicillin G benzathine IM, SID (Dual-Pen, TechAmerica Veterinary Products, Kansas City, MO) and 0.02 mg/kg dexamethasone IM, SID (Azium, Schering Animal Health, Union, NJ), and its clinical signs improved. The dose of steroids was decreased systematically over the next 4 weeks.
Four weeks later, a new shipment of timothy hay was introduced to the diet. After 8 days on the new diet, the elephant developed urticaria on its ventral abdomen and the medial aspects of its rear limbs. The urticaria resolved after 7 days. Ten days after receiving the new hay, it demonstrated pharyngeal dysphagia when it started to drop masticated food from its mouth and had difficulty swallowing. Treatments of 750 mg diphenhydramine IV seemed to afford some relief. The diet was changed to orchard grass hay. The pharyngeal condition became progressively worse, and 4 days later it could not swallow food or water for over 24 hours. This caused copious amounts of saliva to drip from its mouth. The condition included mild respiratory dyspnea. A complete blood count and blood chemistry analysis were performed. A white blood cell count of 16,500 was within normal range, and no other blood abnormalities were noted. The keepers noted that while being fed the new diet of orchard grass, the elephant had access to timothy grass hay, still offered to the other elephants, which it preferred over the orchard grass. This access was eliminated. The steroid dose was increased to 0.06 mg/kg dexamethasone IM, SID, 750 mg diphenhydramine IM was given SID x 10 days, and another endoscopy was performed. The appearance of the pharyngeal tissues was similar to the first examination, and the opening of the esophagus could not be found with the endoscope. The pharyngeal tissue appeared to respond to the therapy as the elephant was able to swallow food normally over the next few weeks.
Two other African elephants, one of similar age, had endoscopy performed for comparison. The epiglottis and the corniculate processes of the arytenoid cartilages of these animals were easily viewed, as was the opening to the esophagus.
Serum was sent to Spectrum Laboratories for allergy testing. There was a strong positive reaction indicating allergy to all of the grass hays, including timothy, orchard, and rye, as well as a variety of other food items. The only types of hay it was not allergic to were alfalfa and oat. Serum from another elephant was used for comparison allergy testing and did not show similar positive reactions.
Antibiotic and steroid therapy was continued for 4 months. Nutritional supplementation was directed at long-term allergy relief. After 2 months of therapy that included a strict hypoallergenic diet, antibiotics, steroids, and vitamins, endoscopy was performed. Moderate improvement was noted. Antibiotic therapy was continued; however, the steroid dose was decreased slowly. Six weeks later, another endoscopy allowed us to see marked improvement. The epiglottis and arytenoid were now clearly visible. At this point, the elephant could eat, drink, and breathe normally.
It could not be determined conclusively if the swollen pharyngeal tissue was the result of an infection, an allergy, or another etiology. Clinical response and comparative serum testing for allergies suggest a food-allergy etiology.
The use of the 3-m endoscope as a diagnostic aid was critical to the treatment of this elephant. The elephant had previously been trained to allow a stomach tube to be passed into the trunk, which later allowed easy passage of the endoscope with only light tranquilization. All of the elephants used for comparison were well-trained for medical behaviors and tolerated the endoscopic procedure extremely well with minimal sedation. However, if elephants are exhibiting clinical signs of pharyngeal dysfunction and respiratory distress, it is important to be cognizant of the potential exacerbation of the problem after sedation with alpha-2 agonists.