Esophageal disorders in horses include choking and esophageal narrowing (strictures).
Obstruction of the Esophagus (Choke)
Esophageal obstruction (choke) is a condition in which the esophagus is obstructed by food masses or foreign objects. It is by far the most common esophageal disease in horses. Obstruction is most common when a horse quickly eats dried grain, beet pulp, or hay. Diseased teeth can also limit the ability of a horse to chew forage.
The classic sign associated with choke is regurgitation of food through the nostrils. When saliva and food is discharged through the nasal openings, the materials often spill into the airway. This brings on coughing. The horse may also drool excessively or grind its teeth. The horse is anxious and may stretch and arch its neck but may still attempt to continue to either eat or drink. The horse should be moved away from any food or water, or food and water removed from its stall. Objects lodged in the upper esophagus may be felt by the veterinarian during examination. An endoscope or failure to pass a feeding tube may be used to confirm the diagnosis.
Many cases of obstruction caused by greedily eaten grain or hay improve on their own. The horse should be kept off feed and water as directed by a veterinarian. Mild sedatives, muscle relaxants, or other medications may be prescribed. The longer the obstruction is present, the greater the danger of damage from pressure on the tissues of the esophagus and complications, such as aspiration pneumonia (inflammation caused by inhalation of food particles into the lungs).
If the obstruction does not dislodge within a few hours, your veterinarian will attempt to flush it out with a feeding tube placed through the nose. Repeated pumping and siphoning of warm water by the veterinarian usually loosens the impacted food. If this is not effective, additional flushing under general anesthesia may be necessary.
After the mass has been removed, the esophagus should be examined with an endoscope to confirm that the obstruction is gone and to look for complications (such as damage to the lining of the esophagus) or underlying causes (such as a pocket within the wall of the esophagus, called a diverticulum). Food should be soaked with water and introduced gradually, as directed. The horse may receive injected antibiotics and pain medications, and the esophagus may need to be examined again to monitor healing.
The main complication of choke is aspiration pneumonia caused by inhalation of food. Longterm obstruction can cause tissue death in the esophagus due to prolonged contact with the mass of food. Constrictions of the esophagus from scar tissue (called strictures) can also result (see below). The esophagus can also rupture, which is often fatal, especially if it occurs within the chest. If the rupture is located within the neck, it may respond to draining, flushing, and placement of a feeding tube.
Some cases of obstruction are not due to food blockage of the esophagus itself. In these other cases, the cause may be injury to the neck or surrounding tissues, leading to constriction of the esophagus. Such cases may be diagnosed from a history of recurrent choke or obstruction. The veterinarian may use endoscopy or x-rays (possibly including contrast material) to locate the site of the obstruction within the esophagus. If the problem is outside of the esophagus, surgery may be necessary to determine and correct it.
Esophageal Strictures (Narrowing)
Esophageal strictures of unknown cause are sometimes seen in foals. Diagnosis can be difficult because the signs are similar to those seen in foals with cleft palates, cysts in the throat, or a displaced soft palate. Esophageal strictures in older horses typically result from damage caused by an esophageal obstruction (see above). The diagnosis is confirmed by inserting an endoscope (a flexible tube with a tiny camera at the end) to examine the esophagus. Depending on the cause, the condition is treated with dietary changes (such as soaking the food), dilation (stretching of the narrowed region), or with surgery.
Tumors of the Esophagus in Horses
The most common tumor of the esophagus in horses is squamous cell carcinoma. The outlook is uncertain. Some forms of the tumor may be treated with surgery, but most are too extensive to remove. If surgery is not possible and the horse is suffering, euthanasia should be considered.