Esophageal dysfunction in a weanling thoroughbred.

The study describes the diagnosis and treatment approach to a 6-month-old thoroughbred colt presenting with persistent dysphagia, or difficulty swallowing, since birth. Even after treatment and dietary management, the esophageal dysfunction lingered leading to euthanasia at 17 months of age, suggesting motor disorders of the esophagus should be considered in cases of persistent dysphagia or recurrent choke in horses.

Presenting Symptoms and Examination

• The Thoroughbred colt was experiencing persistent issues with swallowing, a condition known as dysphagia, from the time of its birth. This manifested as moderately severe regurgitation whenever the colt attempted to consume semi-solid food or drink.
• When the colt tried to eat solid food, it resulted in a complete blockage of the esophagus, a condition known as esophageal impaction.

Diagnostic Procedures

• An endoscopic examination was conducted which revealed several abnormalities in the area of the esophagus that had previously experienced impaction. These included ulcers, dilation, and a lack of peristaltic movement or contractions required for swallowing.
• A Barium esophagram, a radiographic imaging technique, confirmed the dilation in the affected area.
• Esophageal manometry, a test that measures the rhythmic muscle contractions in the esophagus, detected prolonged simultaneous contractions throughout the organ. These results raised a suspicion of a motor abnormality in the esophagus.

Treatment and Outcome

• As part of the treatment plan, the colt was given a slurry of completely pelleted feed. However, the problems with the esophagus persisted.
• Due to the unresolved issue and perhaps declining condition, it was decided to euthanize the colt at the age of 17 months.
• Upon a subsequent autopsy, no abnormalities were found in the muscular lining of the esophagus (muscularis mucosa), the web of nerves regulating gastrointestinal function (myenteric plexus), the vagus nerve involved in controlling the heart, lungs, and stomach, or the brain stem.

Conclusion and Implications

• The history, symptoms and findings from the manometric test suggest that the colt had a functional disorder of the esophagus.
• This case study suggests that motor disorders of the esophagus should be considered in horses showing symptoms of persistent trouble swallowing or recurrent episodes of choke.
• The use of esophageal manometry can help to characterize such disorders in these animals.