Megaesophagus in Dogs: Causes, Symptoms, Treatment & Prevention

Aimee Beck
5 min readJun 9, 2021

Also known as esophageal dilation, megaesophagus is a disease that causes the esophagus (the tube that carries food and liquid between the mouth and stomach) to dilate (get larger) and lose motility (the ability to move food into the stomach).

When your dog’s esophagus is functioning properly, nerves are stimulated in his mouth when he eats, sending signals to the swallowing centre of his brainstem. Those signals trigger his swallow reflex.

When esophageal motility is decreased or absent, food and liquid have difficulty getting into the stomach, and instead collect in the esophagus.

There are two types of megaesophagus:

  1. Congenital megaesophagus: a developmental condition that causes regurgitation. It begins when puppies and kittens start weaning off mom’s milk and begin to eat solid food.
  2. Acquired megaesophagus: occurs later in a dog’s life. It can present in young adults and middle-aged pets (cats, too).

The most important ongoing complication for megaesophagus patients is the risk for aspiration pneumonia.

Regurgitation is not the same as vomiting.

Vomiting is an active process. The body gags, heaves and retches as abdominal muscles forcefully expel stomach contents.

Regurgitation is a passive process. The body spits up food from the esophagus or stomach without the forceful contractions of the abdominal muscles. Regurgitation is a key sign of megaesophagus.

What causes megaesophagus in dogs?

More common in dogs than cats, canine megaesophagus is known to be hereditary in certain breeds, including wire haired fox terriers and miniature schnauzers.

Other breeds that may be predisposed to megaesophagus are:

Siamese cats are also sometimes predisposed to megaesophagus.

Myasthenia gravis (damage between the nerves and muscles of the esophagus) is the most common cause of megaesophagus. It occurs in roughly 25% of dogs with acquired megaesophagus. It’s likely the first co-morbid condition your vet will consider.

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Aimee Beck

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