Place: Selwo Zoo, Spain
Data provided by: Cecilia Sierra Arqueros, DVM
Species: Asian elephant
Age, gender: 54 years, female
For several years this female Asian elephant had episodes of rhythmic contractions in the ventral area of the neck at the entrence to the thorax (video 1). These contractions were only observed during in the cold seasons of the year.
At the age of 54 years, she suddenly became unable to swallow her food and water (video 2).
Video 1. Rhythmic contractions in the ventral neck area of an Asian elephant
The elephant tried to drink water. After 10-20 seconds the water came out her mouth again (regurgitation). The regurgitated water was clear and had no abnormal smell (no stomach smell).
Appetite: in the morning she ate horse pellets and some roughage, but then she refused bread and apple slices (her favorites!). She tried to eat fresh gras, but after chewing on it, it came out; no smell of stomach contents. Refused to eat anymore.
Regular defecation, though the fecal balls became smaller during the following day. The digestion of the fibers had not changed.
No change. Oral inspection: 2 small (5 mm Ø) ulcerations on the tongue base, that were not there the day before. The animal did not cooperate as good as she did on the first day.
A standing sedation was performed using detomidine and butorphanol.
A 2.4 m plastic tube and flexible endoscope could be advanced into the esophagus, reaching the stomach. No mouth opener or gag was used. Gastric fluids were seen, but no obstruction in the esophagus was encountered.
Video 2. Regurgitation of water.
Plastic tube with endoscope advanced into the esophagus.
Antibiotic + flunixin meglumine + Vit E/selenium
Standing sedation using detomidine and butorphanol.
Treatment: antibiotics, dexamethasone, vitamin B complex, 240 L rectal fluids
In the morning, the elphant was able to drink water. Nevertheless another standing sedation was performed using detomidine and butorphanol.
3.5 meter tube inserted in esophangus with mini-camera.
Antibiotic + dexametasone +vit- sel + complex B + Buscopan
Thirty minutes after finishing the procedure, the elephant started to drink and she ate a melon.
From that moment on her appetite came back and she did not regurgitate anymore.
Esophagus constriction: unlikely because this would have been confirmed by endoscopic examination.
Botulism. Botulism had occured in the same environment 200 kilometers from this place, resulting in paralysis of the entire body and the death of the 4 affected elephants.
Esophagus spasms in elephants have not been described before. There is only anecdotal evidence of this phenomenon in horses (van der Kolk, pers. comm. 2021). Hypocalcemia is high on the list of the differential diagnoses. Hypocalcemia has also been associated with "hiccups" in Asian elephants, occuring in the cold seasons.
The total calcium concentration in this elephant was 2.7 - 2.9 mmol/l while the hematocrite was 48-50% (average normal value 35%), which is an indication that the elephant was dehydrated. The actual total serum calcium concentration in non-dehydrated condition was probably lower: 35/50 x 2.7 = 1.89 mmol/l.
Conclusion: Hypocalcemia may have played a major role in this case of esophagus spasm.