Megaesophagus in Dogs
Megaesophagus is a generalized enlargement of the esophagus -- a muscular tube connecting the throat to the stomach -- with a decreased to absent motility. Esophageal motility is required for moving food and liquid down to the stomach.
Megaesophagus is seen more often in dogs as compared to cats. Some breeds are born (congenital) with this problem; for example, wire haired fox terriers and miniature schnauzers. Other breeds reported to be predisposed to this condition include: German shepherds, dachshunds, great Danes, Irish setter, Labrador retriever, pug, and Chinese shar-pei.
Symptoms and Types
Regurgitation is considered the hallmark sign of megaesophagus. Also, aspiration pneumonia may develop due to the entrance of food or liquid into the lungs. Other common symptoms include:
- Nasal discharge
- Increased respiratory noises
- Weight loss (cachexia)
- Extreme hunger or lack of appetite (anorexia)
- Excessive drooling (ptyalism)
- Bad breath (halitosis)
- Poor growth
Megaesophagus can either be congenital in nature (born with) or acquired later in life. The congenital form is typically idiopathic or due an unknown cause; although it is rarely due to myasthenia gravis. The acquired form is also commonly idiopathic, but may also be due to:
- Neuromuscular disease (e.g., myasthenia gravis, distemper, myositis)
- Esophageal tumor
- Foreign body in esophagus
- Inflammation of esophagus
- Toxicity (e.g., lead, thallium)
- Parasitic infections
Your veterinarian will first ask you for a thorough history of your dogâ€™s health. He or she will then perform a complete physical examination on your dog and attempt to differentiate, with your description, whether it is regurgitating or vomiting, which is important in ruling out underlying diseases that cause vomiting. The shape of expelled material, presence of undigested food, and length of time from ingestion to vomiting (or regurgitation) will also help differentiate between these two issues.
Routine laboratory tests, including complete blood count (CBC), biochemistry profile, and urinalysis results, are usually normal in dogs with megaesophagus. However, abnormalities related to underlying diseases or complications, like aspiration pneumonia, may be seen. Radiographic studies will show the enlarged esophagus filled with fluid, air, or food, and will help identify abnormalities related to aspiration pneumonia.
More advanced techniques, like esophagoscopy, will be sometimes be employed, too. Esophagoscopy allows for the examination of the interior of the esophagus using an esophagoscope, a thin, tube-like instrument with and light and lens for viewing the inner areas of esophagus. It also allows for the removal of foreign bodies, evaluation of obstruction, and neoplasia.
The major goal of therapy is to treat the underlying cause. However, it is also important that dogs with compromised feed intake are meeting their daily nutritional requirements. Common food items recommended by the veterinarian will include liquid gruel, small meatballs, blenderized slurries, and other palatable, high energy foods.
Depending on the underlying cause of the problem, surgery may be employed. For instance, in cases of a foreign body, it will be removed immediately to provide relief and prevent further complications. Aspiration pneumonia is another life-threatening problem that requires immediate hospitalization, where oxygen therapy, antibiotics, and other medications are used to treat the condition.
Living and Management
Follow the guidelines related to care and nutritional requirements for your dog. Recumbent animals may require extra care; soft bedding and turning the animal every four hours are essential. If your dog is not able to take feed, your veterinarian may pass a feeding tube directly into the stomach for feeding purposes. He or she will teach you how to properly use such equipment, though it is important to clean it after each use. Regular weighing of your dog is also required to ensure it is at an adequate range (not losing too much, but not too heavy either).
For patients able to take feed, special arrangements are required for correct feeding to prevent aspiration pneumonia. These animals are kept in an upright position for 10 to 15 minutes after eating or drinking, and both food and water bowls need to be elevated (45 to 90 degrees Fahrenheit) from the floor.
You will need to visit your veterinarian for regular follow-ups to evaluate your dog and treatment progress. Thoracic radiographs are repeated if aspiration pneumonia is suspected. Laboratory testing will be repeated in cases with confirmed aspiration pneumonia diagnosis.
Most dogs with megaesophagus require life-long therapy and commitment and patience from you. Unfortunately, dogs suffering from congenital forms of the diseases, or in whom the underlying cause could not be identified, carry a very poor prognosis. Some animals may die due to complications, like aspiration pneumonia.