Esophageal foreign bodies, esophagitis and strictures (Proceedings)

Esophageal foreign bodies and esophagitis have the potential, if not identified and treated, to cause esophageal strictures or megaesophagus, which can be more difficult to treat. Failure to consider the possibility of regurgitation in the patient presented for vomiting could lead to delays in diagnosis, treatment errors, and undesired complications such as aspiration events, esophageal perforations and esophageal stricture formation. The common esophageal diseases of dogs and cats that are the focus of these notes, are esophageal foreign bodies, esophagitis, and esophageal strictures; megaesophagus, another important esophageal disease, has been discussed separately elsewhere. Less common, but still important, causes of esophageal disease include esophageal neoplasia and gastroesophageal intussusception.

Esophageal foreign bodies

The diagnosis of esophageal foreign bodies is often straightforward as most animals, particularly dogs, will have a history of foreign body ingestion witnessed by owners followed by typical clinical signs. Some animals, however, have no suggestive history, and in such patients, the diagnosis of an esophageal foreign body could be delayed if the clinician does not ask the right questions of an owner to arouse suspicion that the patient is actually regurgitating, and not vomiting, which is the most common owner complaint associated with esophageal foreign bodies. The author has seen dogs with esophageal foreign bodies that have been present for approaching 3 weeks, primarily because the attending clinician did not suspect that the patient was regurgitating and not vomiting. Once the suspicion of an esophageal foreign body is raised, confirmation of the diagnosis will often be evident on plain thoracic radiographs on which the foreign body will be seen. If needed, administration of a contrast agent can facilitate detection of an obstruction, but there is a risk of aspiration of contrast agent in patients with esophageal disease.

Esophageal foreign bodies are considered emergencies. The longer a foreign body resides in the esophagus, the greater the potential for complications such as aspiration pneumonia, esophageal perforation, or development of bronchoesophageal fistulas. Treatment of esophageal foreign bodies centers on removal of the foreign body. Endoscopic retrieval is possible in many, but not all, animals with foreign bodies. The preferred approach is to remove the foreign body orally as long as the foreign object can be securely grasped and advanced toward the oral cavity without inducing more serious injury. The author has used large (as large a diameter as the patient can safely accommodate) tubes with some length that are passed through the oral cavity into the esophagus, and then passed the endoscope through this "speculum" to help maneuver foreign bodies out of the esophagus, typically by drawing them partially into the tube. This strategy has proven successful for removal of bones and other foreign bodies, such as fishhooks, with sharp points. Other helpful tools to have on hand include wire baskets and rat-tooth grasping forceps. If a foreign body can't be removed orally, the next option is to push the object into the stomach. In the stomach, the object may be repositioned and grasped for oral removal, or retrieved by gastrotomy; bones are often left in the stomach where gastric acid will quickly demineralize the bone and allow passage without surgery. When it comes to retrieval of esophageal foreign bodies, in the author's view there are no real rules save two that govern one's approach: do not cause additional esophageal injury, and protect the endoscope. Creative thinking and use of "unconventional" tools can be helpful and are not only allowed, but encouraged as the situation demands!

If the foreign body cannot be retrieved or pushed into the stomach, then positioning the object as close to the cardia as possible can facilitate removal through a gastrotomy, with the surgeon reaching through the cardia into the esophagus to remove the foreign body. The last option for removal of esophageal foreign bodies is esophagotomy, which carries a high rate of post-operative complications because of healing properties of the esophagus. Ideally, after foreign body retrieval, the esophagus should be carefully inspected endoscopically for esophagitis, or evidence of perforation. Esophagitis can be treated as noted below. Patients with perforations should be treated with broad-spectrum antibiotics.

Esophagitis

Esophageal inflammation most commonly develops in patients that have had either chemical or mechanical injury to the esophagus. For patients that develop chemical induced esophagitis, a breakdown in one or more of the esophageal protective mechanisms (anatomic configuration of the lower esophageal sphincter, mucus production in the mucosa, epithelial tight junctions), or injury that overwhelms such protective mechanisms, usually precedes esophagitis. In dogs, one of the most common causes of esophagitis is esophageal reflux during general anesthesia, which can be associated with relaxation of the lower esophageal sphincter (LES) and reflux of gastric acid or other injurious agents (bile, lecithin) into the esophagus. Available studies suggest that esophageal reflux is a very common event during general anesthesia, and the fact that esophagitis is not recognized more often than it is speaks to the ability of most dogs to overcome reflux-associated injury. Any other condition that disrupts the LES (e.g. hiatal hernias) can result in reflux esophagitis. Chronic vomiting, which can chronically bathe the esophageal mucosa with harmful gastric secretions, can also predispose to esophagitis. Chemical injury from some medications, e.g. doxycycline (best documented in cats) can cause esophagitis. Other less common causes of esophagitis include ingestion of caustic agents, infection (Pythium sp in some parts of the country) and esophageal surgery.

Clinical signs of esophagitis are similar to those for esophageal foreign body. In addition to regurgitation, the clinical presentation of animals with esophagitis can be confusing if esophagitis is secondary to chronic vomiting. Esophagitis can also be a clinically silent condition until a stricture (see below) develops.

The diagnosis of esophagitis is suspected based upon the presence of compatible clinical signs, exclusion of other causes of regurgitation (especially esophageal foreign bodies and megaesophagus), and documentation of esophageal inflammation. Diagnosis of anesthesia-associated esophagitis requires a high index of clinical suspicion, and the author takes the view that any patient that has a complaint of vomiting within 7-10 days of a general anesthetic episode, no matter the duration of general anesthesia, is a suspect for esophagitis-induced regurgitation and is aggressively treated as such. When necessary to confirm a diagnosis, esophagoscopy is the most sensitive means of detecting lesions of esophagitis, although some patients can have histologically evident esophagitis without obvious endoscopic lesions. Contrast esophagram abnormalities (mucosal irregularities, retention of contrast) can suggest the diagnosis in the absence of endoscopic capabilities, but the sensitivity is considered poor.

Treatment of esophagitis should initially focus on identification and correction, whenever possible, of any predisposing risk factors or causes. Other important treatment aspects include limiting additional injury to the mucosa, typically by reducing gastric acid secretion through the use of H2 blockers (famotidine, ranitidine) or proton pump inhibitors (omeprazole and related). The proton pump inhibitors are considered the most potent of acid suppressors, and tend to be favored in the treatment of esophagitis. A commonly used approach, though clinically unproven in small animals, is to administer sucralfate (often as a slurry in water) with the goal of providing a "band-aid" to the eroded/ulcerated mucosa to limit additional injury. Metoclopramide is often administered to increase the tone of the LES. Theoretically, feeding a higher protein diet would be of benefit because such diets stimulate the release of gastrin, which can increase tone of the LES. Treatment is typically provided well beyond resolution of clinical signs in the absence of repeated endoscopic assessment. While there are no clinically proven guidelines for dogs, the author typically treats 7-10 days beyond resolution of clinical signs.

Drugs used in the management of esophagitis

While it is likely that many animals will have resolution of esophagitis without problems, if esophageal injury is severe enough, and/or injury involves the diameter of the esophageal wall, then the potential for esophageal stricture formation, megaesophagus and subsequent aspiration pneumonitis increases. Because of difficulties in treating esophageal strictures, it is best to avoid their formation whenever possible, and maintaining a high index of suspicion of esophagitis becomes a must.

Esophageal stricture

Clinical signs of esophageal stricture are as for other diseases noted above; regurgitation can be severe in the face of marked compromise of the esophageal lumen with some animals unable to retain even water without regurgitation. The presence of a stricture is often suggested historically by the appearance, or worsening of, regurgitation, especially following a known episode of esophagitis, or following a known risk factor for esophagitis (e.g. an episode of general anesthesia). Strictures are easily confirmed during esophagoscopy, or with contrast esophograms. Advantages of the latter include the ability to establish the length of a stricture, particularly for those strictures that are too small to permit advancement of an endoscope.

Treatment of esophageal strictures requires dilation of the stricture, either by balloon dilation, or esophageal bougienage. In people, studies have not demonstrated a clear advantage of one technique over another, and the technique used is often a reflection of training and/or personal preference. Repeated dilations are commonly needed to restore a functional lumen, which is the goal of dilation. Using electrocautery to create 3-4 "fracture" sites around the circumference of the stricture has been advocated as a means to reduce the amount of post-dilation esophageal injury and reduce the number of dilations needed to achieve an acceptable outcome.

Since dilation usually causes additional injury, treatment of patients after dilation is the same as for esophagitis. The role of glucocorticoids in the management of patients with esophageal strictures is not well-established by evidence of efficacy in veterinary medicine. Administration of glucocorticoids by local injection under endoscopic guidance, or systemically administered glucocorticoids, is often used by other clinicians, and is used in some cases by the author. The author commonly puts in gastrostomy tubes to help facilitate administration of medications, in addition to providing fluid and nutritional support, while evaluating the outcome of esophageal dilations.

References

Sellon RK, Willard MD. Esophagitis and esophageal strictures. Veterinary Clinics North America Small Animal Practice 2003; 33:945-967.