Treatment of esophageal obstruction in elephants
The diagnosis 'esophageal obstruction' is based on the clinical signs (anorexia, regurgitation of water and/or food) and esophagoscopy performed under standing sedation.
A firm, large bore-hole tube and endoscopic camera are advanced into the esophagus as described here. Sometimes it can be difficult to insert the tube into the esophagus due to the lack of space between the molars. Opening the mouth with a mouth gag may facilitate this manoever.
Success of the treatment largely depends on the material that has blocked the esophagus passage. Packed, poorly chewed roughage particles can occupy the entire esophagus, even obstructing completely the insertion of the diagnositic tube.
Although never reported in elephants, reduction of the spasm of the esophagus might be obtained by the administration of oxytocin (dosage in horses 0.1-0.2 IU/kg BW given in a slow intravenous bolus (Meyer 2000). The antispasmodic (spasmolytic) and anticholinergic drug Buscopan can be used at the dose of 0.3 mg/kg body weight (0.14 mg/lb), slowly IV.
Maintaining hydration is important as the elephant may not have taken water for a while. Rectal administration of luke-warm fluids is the easiest and fastest way to restore the body fluids. After manually removal of the feces from the distal part of the rectum, a firm tube should be inserted deep into the rectum and luke-warm water should be administered at a dose of 10-20 ml/kg BW. After this procedure the tail must be pushed down for 1 minute to prevent water from being squeezed out by the animal.
Once the tube and camera are advanced into the esophagus, the obstruction can be visualized. Luke-warm water can be flushed into the esophagus, preferably after inserting another small diameter tube. The original large tube can then be used for draining the excessive water. Flushing should be done with care, avoiding regurgitation of the fluid into the trachea. If water does not have the expected effect, liquid paraffin can be tried respecting the same precautions.
Esophageal obstruction in elephants
Case report 1
A fatal case occured in a 3-yrs-old female African elephant (Wood, 1992). The animal regurgitated water and was unable to swallow food. 30 seconds after attempts to drink water, the water was ejected from the mouth together with a quantity of thick, stringy white mucus. (Click here to see a video of water regurgitation in an elephant with esophageal spasm). The animal was drenched with 1 liter of mineral oil, which did not resolve the problem.
After 24 hours the elephant was anesthetized with xylazine and etorphin. It was rolled in right lateral recumbency with the trunk placed on sacking to prevent the aspiration of dirt and fluid. An attempt to manually remove the obstruction failed. Some undigested food could be removed from the pharynx. A large-bore equine stomach tube was passed and several liters of warm water were flushed in the esophagus, which drained out of the mouth again. Flushing with obstetric lubricants had the same result. The tube could not be advanced. The animal was given antibiotics and phenylbutazone (IM) and 25 liters of electrolytes (IV).
During the next 24 hours the animal's condition deteriorated and another anesthesia was performed. The previous treatment was repeated and seemed to result in free passage of fluid into the stomach. An endoscope was advanced into the esophagus, but was too short to visualize the distal part of the esophagus. (Click here for an example of an easily available endoscope, which serves well if advanced into the esophagus while protected by a (stomach) tube.
During the following day water was given in 5 liter amounts without resulting in regurgitation.
Unfortunately the animal died 48 hours after the second anesthesia. At necropsy an apple was found in the distal part of the esophagus. The esophagus tissue around the apple showed marked necrosis and 2 perforations.
Case report 2
Another case describes the blockage of the esophagus in a 15-yrs-old male Asian elephant (Oo, 2018). This animal vomited 2-3 minutes after drinking some water. Body temperature was normal. Supportive treatment was given, consisting of dextrose saline (1000 ml) every 5 h to compensate for the loss of water and electrolyte and multivitamin (80 ml). On the next day a locally made mouth-gag instrument was placed into the elephant’s mouth and the upper alimentary tract was examined by palpation. A very hard mass was felt inside the throat. This mass could be removed and was found to be a bolus consisting of a mixture of sugar cane and rice, weighing 1.6 kg. Click here to read the complete manuscript.
Case report 3
A 42-year-old female Indian elephant (Elephas maximus indicus) developed a sudden onset of excessive salivation and dysphagia (Phair 2014). Esophageal obstruction was suspected; possibly related to palm frond ingestion. Esophageal endoscopy revealed a mat of plant material in the distal esophagus. An initial attempt at relieving the obstruction was unsuccessful, but subsequent use of custom-made instruments along with insufflation and hydropulsion enabled partial removal of the material. Postimmobilization care included aggressive intravenous and rectal fluids, anti-inflammatory and antibiotic administration, and fasting. Despite treatment, the dysphagia persisted and the elephant was euthanized due to lack of improvement and grave prognosis. Postmortem examination revealed remaining plant material in the esophagus, complicated by an esophageal dissection, mural hematoma, and secondary bacterial infection. Iatrogenic trauma may have contributed to the extent of esophageal injury. Although treatment was ultimately unsuccessful, the supportive care employed could potentially aid recovery in cases of less severe esophageal trauma.
Case report 4
In the Case report section you can find another report of an esophageal impaction in a 4.5-yrs-old African elephant. Click here to read the full report.
MEYER G. A., RASHMIR-RAVEN A.,HELMS R. J., and BRASHIER M. 2000. The effect of oxytocin on contractility of the equine oesophagus: a potential treatment for oesophageal obstruction. Equine vet. J. (2000) 32 (2) 151-155.
Oo Z.M., Aung T.T., Aung M.M., Nada N and Than M. 2018. Esophageal Blockage in a Captive Asian Elephant . Gajah 48, 38-39.
Phair, K. A., Sutherland-Smith, M., Pye, G. W., Pessier, A. P., & Clippinger, T. L. 2014. ESOPHAGEAL DISSECTION AND HEMATOMA ASSOCIATED WITH OBSTRUCTION IN AN INDIAN ELEPHANT (ELEPHAS MAXIMUS INDICUS). Journal of Zoo and Wildlife Medicine, 45(2), 423–427. doi:10.1638/2013-0177r.1
Wood, D.T. 1992 Oesophageal choke in an African elephant. Veterinary Record 131, 536-537.
Esophageals obstruction or “choke” symptoms can be associated with:
Congenital abnormalities of the upper digestive system; symptoms usually show up when the animal is weaned and starts eating solid food.
Mega-esophagus, which can be congenital or acquired;
Foreign bodies that get stuck in the upper digestive system;
Impaction or blockage of the stomach/duodenum;
Abnormal function of the cardiac sphincter which is the valve allowing food to flow into the stomach.
Blockage of the upper digestive system can cause damage to the esophagus resulting in strictures and narrowing, which makes the problem worse or even necrosis and rupture of the esophagus.
Regurgitation can result in food and liquid entering the trachea and the lungs. This causes a foreign body pneumonia, which in chronic cases can result in the eventual death of the animal.
Esophagus spasm should be distinguished from esophagus obstruction, though the passage of food and water can be obstructed as well.
Warning: damaging and even perforation of the esophageal wall as a result of attempts to advance a large-bore tube into the esophangus have been reported!