ESOPHAGEAL FOREIGN BODY
The most commonly encountered esophageal foreign bodies in the dog are bones, whereas, in cats, are toys. They usually lodge at the upper part of the thoracic cavity, at the base of the heart, or at the hiatus of the diaphragm.
Radiography is usually diagnostic. Evaluate thoracic radiographs for mediastinitis.
The extent of esophageal damage depends on the duration of time in contact.
Esophageal foreign bodies must be removed by endoscopy or surgery. Endoscopic removal is commonly used and successfully. If the object cannot be extracted orally or there are sharp edges, advance it into the stomach and remove it by gastrotomy.
Secondary complications include perforation, fistulas, diverticula, stricture and hypomotility.
A stricture is a circular narrowing of the esophagus at any point and can be multiple. It is formed when esophageal lesions affecting both tunica muscularis and lamina propria heal by fibrosis.
Symptoms include regurgitation, dense saliva, dysphagia, increased tolerance to liquid compared to solid food, and even respiratory signs secondary to aspiration.
Contrast studies and endoscopy are usually diagnostic. Differential should include vascular ring abnormalities, periesophageal mass or adherence.
Esophageal strictures can be managed surgically or endoscopically (bougienage or balloon catheter dilation). Balloon catheter dilation exerts radial pressure over the whole stricture circumference. It is the preferred and more used method of treatment and is less likelihood of complications. Bougienage exerts longitudinal pressure, which is less effective than radial pressure. Complications are common and, therefore, this method should only be used when repeated bougienage or balloon dilation have not managed the stricture.
Treat esophagitis after performing dilation.
Esophagitis occurs when esophageal defense mechanisms are broken by chemical, thermal or mechanical injuries (ingestion of chemical irritants or caustic substances, of overheated food, foreign bodies, gastroesophageal reflux, infections, chronic or acute vomiting) and cause inflammation, erosion and/or ulceration.
Symptoms of esophagitis include regurgitation, excess salivation, and dysphagia.
Diagnosis must start with a complete history, looking for potential exposure to foreign bodies or caustic material or recent general anesthesia. Survey radiographs usually are unremarkable. Contrast studies may elicit irregular mucosal surfaces, esophageal dilation or hypomotility. Endoscopy plus biopsy is the preferred method of diagnosis
Sucralfate is beneficial in the treatment because it binds to injured mucosa and acts as an effective barrier. Sucralfate suspension is more effective than tablets. H2 antagonists are important for control of acid secretion. Cimetidine, ranitidine and famotidine can be used for this purpose. Omeprazole completely inhibits acid secretion. Consider omeprazole use in dogs unresponsive to H2 blockers. Metoclopramide and cisapride can be used to promote gastric emptying and increase gastroesophageal sphincter pressure. Cisapride appears to be more effective in both actions.
Megaesophagus refers to a large, flaccid esophagus with a severe motility disorder. It can be congenital idiopathic or acquired, or secondary.
Idiopathic congenital megaesophagus is often noted at weaning. Great Danes, German shepherds, Irish setters, Fox terriers, Miniature schnauzers, Labrador retrievers and Shar peis are predisposed. The underlying mechanism is unknown, but incomplete innervation could cause it.
Survey radiographs usually shows distension with food. A barium esophogram can be useful to evaluate dilation magnitude. Differentials should include foreign bodies, stricture, and vascular ring abnormalities.
Treatment us primarily based in nutritional support. Meals must be given with the animal in a upright position no less than 45°. Drugs are usually useless.
Acquired idiopathic and secondary megaesophagus may occur at an adult stage of life. Survey and contrast radiographs are used to confirm diagnosis. Other tests must be used to determine the underlying cause, which can include hypoadrenocorticism, polymyositis, hypothyroidism, and myasthenia gravis.
Prokinetics, specially cisapride, can be used if a reversible underlying cause can not be identified. Meals must be given with the animal in a upright position no less than 45°.
VASCULAR RING ANOMALIES
They are congenital malformations of the great vessels that entrap the intrathoracic esophagus and cause clinical signs of obstruction. These anomalies include Persistent right aortic arch, aberrant left or right subclavian arteries, double aortic arch, right ductus arteriosus with left aortic arch, and aberrant intercostal arteries.
Thoracic radiographs show a dilated esophagus cranial to the heart, which tapers to normal at the base of the heart. Differentials should include congenital megaesophagus, stricture, and foreign bodies.
Therapy is surgical, but clinical improvement is usually incomplete.
Primary esophageal tumors are rare in dogs. Tumors are usually metastatic or periesophageal.
Malignant neoplasms include squamous cell carcinoma, osteosarcoma, fibrosarcoma, and undifferentiated carcinoma. The most common benign neoplasm is leiomyoma.
Contrast studies are a good tool for the diagnosis. Definitive diagnosis is usually achieved with endoscopy plus biopsy.