What is Megaesophagus in Dogs?
Megaesophagus in dogs is a condition in which the esophagus enlarges and loses the ability to transport food from the mouth to the stomach.
Normally, the muscular layer of the esophagus contracts (esophageal motility) and pushes food into the stomach. When the esophagus is enlarged, its motility is compromised, and food stays in the esophagus.
Weak muscles slow down and make it difficult to complete the transfer from the mouth to the stomach. The food gets effectively “stopped” in the esophagus, and the reaction of the esophagus is to “eject” the food (called regurgitation).
Canine megaesophagus can be a serious condition that requires life-long care and management. It is more common in certain dog breeds and young and middle-aged dogs.
Are There Different Types of Megaesophagus?
Yes, there are two types of canine megaesophagus – congenital and acquired. Let’s review them.
- Congenital Megaesophagus: This type is present at birth and becomes easily visible after weaning. If the condition is mild, the puppy may show no symptoms until one year old. In severe cases, puppies with megaesophagus fail to thrive as they cannot feed properly.
- Acquired Megaesophagus: This type is acquired later in life, and it can be either primary or secondary. The underlying cause of the primary acquired enlarged esophagus is unknown and called the idiopathic megaesophagus. Secondary or acquired megaesophagus is the result of another condition that causes neuromuscular dysfunction.
Is Megaesophagus Fatal in Dogs?
Yes, an enlarged esophagus in dogs may be fatal. The inability to eat results in weight loss and malnutrition. Also, there is a risk of aspiration pneumonia – a life-threatening inflammation of the lungs caused by inhaled food.
According to Dr. Teri Byrd, “When an animal is diagnosed with aspiration pneumonia, veterinarians and owners need to remember that Megaesophagus is a rule out and ensure that proper diagnostics are performed to confirm or rule out this disease.”
What Causes Dog Megaesophagus?
Congenital megaesophagus is usually caused by vascular ring anomaly. A vascular ring anomaly is a congenital defect of the heart’s blood vessels. As a result, the vessel may compress the esophagus during fetal development.
The acquired megaesophagus is more complex and can be the result of many conditions and systemic diseases. Here are some of the most common underlying conditions resulting in megaesophagus.
- Chronic Esophagitis: Esophagitis or inflammation of the esophagus is often caused by acid reflux (when stomach content gets back into the esophagus). This gastrointestinal problem is likely to trigger enlargement of the esophagus.
- Esophageal Blockage: Any condition that blocks the esophagus can result in localized enlargement. Such examples would be scar tissue strictures, esophageal tumors, and foreign bodies in the esophagus.
- Myasthenia Gravis: Myasthenia gravis is a complex neuromuscular disease. Enlargement of the esophagus is a common accompanying problem in dogs with myasthenia gravis.
- Endocrine Conditions: Certain endocrine diseases can also increase the risk of esophageal enlargement. Such conditions are hypothyroidism, hyperadrenocorticism (Addison’s disease), and hypoadrenocorticism (Cushing’s disease).
- Toxicity: Exposure to some toxins is another possible culprit. Such toxins would be thallium, lead, and organophosphate insecticides.
- Botulism & Tetanus: Botulism is food poisoning, and tetanus is a bacterial infection. Both systemic diseases can result in megaesophagus in dogs.
- Dermatomyositis: This is a specific disease affecting the skin, muscles, and blood vessels. This disease has a high incidence in Shetland Sheepdogs and Collies.
What Dog Breeds are Prone to Megaesophagus?
Here is a list of the dog breeds prone to megaesophagus:
- French Bulldog
- German Shepherds
- Labrador Retrievers
- Wire-Haired Fox Terriers
- Shar Pei
- German shepherds
- Great Danes
- Miniature Schnauzers
- Irish Wolfhounds
- English Bulldogs
- Irish Setters
What are the Signs and Symptoms of Megaesophagus in Dogs?
The most common clinical sign of megaesophagus in dogs is regurgitation – expelling swallowed food just after eating or at mealtime.
Regurgitation is different from dog vomiting. Namely, the regurgitated material never reached the stomach, while vomited material has spent some time in the stomach. Simply put, a regurgitation is a passive act – the swallowed food/water just rolls out.
Other signs and symptoms of canine megaesophagus include:
- Weight Loss: A dog that cannot eat properly will start to lose weight. In young puppies with congenital megaesophagus, this can manifest as poor growth and inability to gain weight.
- Drooling: Drooling or hypersalivation is another sign of megaesophagus. Even if the dog is not fed, it can regurgitate saliva.
- Bad Breath: Since the food often finds its way back into the mouth, food particles can start to decay and eventually cause bad breath or halitosis.
- Difficulty Swallowing: Another sign of megaesophagus is impaired swallowing.
- Lethargy: Dogs that do not eat are low in energy and likely to be weak and lethargic. They will be uninterested in everyday activities and spend most of their time sleeping.
How Do I Know My Dog Has Megaesophagus?
If your dog regurgitates within minutes to hours regularly after meals, salivates, or has trouble swallowing or other signs, a veterinary visit is needed. The vet will feel the area for any abnormalities or masses and then take an x-ray (radiograph) to see if the esophagus is enlarged in any area. They might also do a contrast study or endoscopy, or other diagnostic procedures to see if the esophagus is normal or not.
How is Megaesophagus in Dogs Diagnosed?
In most cases, the signs and symptoms are indicative of a canine megaesophagus. However, to confirm the diagnosis, the vet will perform a full physical examination.
Then, they will order thoracic radiographs. On the x-ray image, the dilatation of the esophagus is visible – the esophagus will be filled with a mixture of gas, food, and fluid, and the trachea will be misplaced.
If the regular x-ray image is not clear, the vet will give the dog barium (a contrast medium). As an alternative, the veterinarian may perform a videofluoroscopic swallow study (VFSS) or fluoroscopy. This is a real-time x-ray, as it allows the vet to see the food flow in the esophagus instead of analyzing an image.
To determine the underlying cause of the megaesophagus, the vet may suggest more diagnostic tests, such as blood screening, endoscopy, urinalysis, etc.
What is the Treatment for Dog Megaesophagus?
Sadly, there is no treatment for megaesophagus in dogs. If there is an underlying condition, it needs to be addressed properly, but the enlarged esophagus cannot be treated.
Instead, the focus is on management. Sometimes dogs can be managed with special diets and feeding positions. However, they do not always work. In such cases, the vet may recommend other approaches.
- Medication: The vet may prescribe sildenafil (the generic name of the Viagra drug). Sildenafil helps relax the smooth muscles in the esophagus and opens the lower esophageal sphincter. This is a relatively new approach, but so far, the results are promising.
- Botox Injections: Botox injections are another option for some canine megaesophagus patients. The vet will inject botox to paralyze the muscles and enable food flow. However, this only works for dogs with enlarged lower portions of the esophagus. The procedure is done under general anesthesia.
- Feeding Tube: For dogs with severe regurgitation following meals, gastric feeding tubes might be the only option. That way, the food is delivered directly into the stomach, and the dysfunction of the esophagus is bypassed. The gastric feeding tube makes mealtime more manageable but does not prevent regurgitation (the dog may occasionally regurgitate saliva).
What Do I Feed a Dog With Megaesophagus?
When it comes to feeding a dog with a megaesophagus, there are two important considerations – food type and feeding method. Let’s take a closer look at each of them.
- Food Type: Dogs with megaesophagus need a high-calorie diet. As for food consistency, some dogs do better with solid food (soaked kibble) and others with liquid food (slurry of dog food and water or blenderized gruel). Liquid food reduces the risk of regurgitation, but it is more likely to be inhaled and cause aspiration pneumonia. For most dogs, food “meatballs“ work best.
- Feeding Method: The correct way of feeding is in an upright position (between 45 – 90° to the floor). Also, the dog should remain in the same position for about 10 to 15 minutes after the meal. To do this, it is best to use the so-called Bailey chair. You can get a commercial chair or build one yourself. There are many DIY videos online.
Does Megaesophagus in Dogs Go Away?
No, megaesophagus in dogs does not go away.
Depending on the underlying cause, the condition may improve, but it does not go away. However, note that there are different types of megaesophagus. Some cases are milder than others, but all require specialized management.
What is the Prognosis for Dog Megaesophagus?
Generally speaking, the prognosis for dogs with megaesophagus is poor. While the condition itself can be managed, there is a high risk of life-threatening complications – malnutrition and aspiration pneumonia (food entering the trachea and lungs).
Also, if the cause of the megaesophagus stems from the nervous system, the dog is likely to develop additional neurological problems.
Can I Prevent Megaesophagus in Dogs?
No, you cannot prevent megaesophagus in dogs.
However, you can decrease the risk of complications. For example, feeding the right type of high-calorie dog food prevents malnutrition. And serving the food in “meatballs“ form and feeding the dog in Bailey’s chair helps prevent aspiration pneumonia.