Choke! A Medical Emergency!

Erin S. Groover, DVM, DACVIM-LA
Associate Clinical Professor of Equine Internal Medicine
College of Veterinary Medicine
Auburn University, Auburn, Alabama, USA

Esophageal obstruction, also known as ‘choke,’ is a frequent chief complaint for veterinary evaluation in horses. Though some horses may resolve on their own, or quickly resolve with basic intervention by a veterinarian, the condition should be considered a medical emergency and the horse should be evaluated promptly, as some horses require more aggressive therapy and are more likely to develop complications such as pneumonia.

Esophageal obstruction is most commonly caused by impaction of pelleted-type feed, but horses have been reported to obstruct on many other things. Other frequent causes include ingestion of un-soaked beet pulp or cubed forage, treats such as carrots and apples, and other materials (lead ropes and hay nets). In many cases, the development of the problem is a one-time event and not associated with an underlying medical condition. In these cases, the horse may have too rapidly consumed the feed or had poor water intake; however, in some cases there is an underlying cause for the obstruction that may result in repeated episodes. Reported causes include overly worn or unfloated teeth — and a subsequent inability to properly chew food — neurological/neuromuscular disease, compression of the esophagus by a mass or underlying esophageal abnormalities such as narrowing.

Mouth of horse with hay

The clinical signs of acute esophageal obstruction are fairly easily recognizable. Horses will often cough during or after eating, and feedstuff or saliva will be evident coming from the nostrils. They may also often be anxious or distressed, and may or may not show retching behavior. Some horses that have been obstructed for a longer period of time may only show mucoid nasal discharge, lethargy and/or lack of appetite.

Intervention in cases of esophageal obstruction can begin as soon as it is recognized. The horse should be placed in a confined area without access to feed or water. Do not tie the horse with the head elevated; let the horse keep the head as low as possible to help with saliva drainage away from the airway. Sedation can be valuable for relieving anxiety and easing the horse’s head toward the ground. The administration of sedation under the tongue or in the muscle may be safe alternatives to intravenous administration, which if given incorrectly can be fatal. Any administration of sedation should be by veterinarian approval and direction only.

As mentioned, esophageal obstruction should be treated as a medical emergency. When the veterinarian arrives, expect him or her to perform a complete physical examination followed by sedation and an attempt to pass a nasoesophageal tube until it meets the obstruction. While ensuring that the head carriage remains low, warm water will be pumped through the tube into the esophagus to rehydrate the impaction. Water should flow back out the nostrils and mouth during this procedure. This is a normal occurrence.

If the horse has obstructed on feedstuffs, feed material will be evident in the fluid that is washed from the esophagus. After the initial attempt to relieve the obstruction with lavage, the tube will be advanced to see if the obstruction is clear or if it has moved. If the obstruction remains, continued flushing is necessary. Frequently, minimal flushing will result in passage of the obstruction and ease in advancing the tube into the stomach. Once the tube reaches the stomach, it is appropriate to assume the obstruction has cleared the esophagus.

Following resolution of the esophageal obstruction, your veterinarian will prescribe an after-care plan that frequently includes ensuring the horse is well-hydrated, possibly treating for aspiration pneumonia with antibiotics, providing anti-inflammatory therapy and modifying the diet to prevent re-obstruction. Aspiration of feed and saliva frequently results in pneumonia of varying severity. It is reported to be the most frequent complication associated with esophageal obstruction in horses (up to 70% of horses admitted to a teaching hospital) and it is an increased risk in horses that are obstructed for longer than three hours. Dietary modifications may include initially withholding feed for approximately 12-24 hours and then gradually re-introducing feeding in the form of well-soaked feed and grass.

Prior to re-introduction of feed, the horse should have an oral examination and any dental abnormalities should be corrected to ensure proper chewing. Following correction of an uncomplicated case of esophageal obstruction, most horses will respond well to therapy and return to normal attitude and appetite without problems. Dietary management and appropriate dental care should be considered an imperative part of prevention of future episodes, and early recognition by educated owners and handlers that esophageal obstruction is a medical emergency should result in more prompt veterinary intervention and fewer complications.