This is a uncommon condition in pets. The oesophagus is the tube between the mouth and the stomach. It carries food and water by alternately contracting and relaxing the muscles that line it. This is why you can swallow water even when you stand on your head without the water rushing out your nose (a good party trick!)
Sometimes in pets, the muscles lining the oesophagus get diseased and stop functioning. When this happens, food, saliva and/or water tends to pool in a relaxed part of the oesophagus- usually in the middle of the chest. The food and/or water just sits there and is not "pushed" into the stomach. A short time later, the pet makes a gagging sound and out plops the meal, undigested and sometimes in a sausage shape. The oesophagus is very enlarged, hence the word "mega- oesophagus".
In puppies with congenital defects of the blood vessels e.g. persistent right aortic arch
- Foreign body damage to the oesophagus e.g. large knuckle bones, swollen dried fruit
- Genetic In some breeds of dogs e.g. Border Collies, there is a genetic cause to the problem called Myaesthenia Gravis where the body's defense system accidentally decides to interfere with nerves where they attach to muscles. As a result, the muscles of the body don't work so well. Affected dogs have reduced exercise capacity and may present with mega-oesophagus.
- Hypothyroidism (an inactive thyroid gland)
- Myaesthenia Gravis
- Paralysis tick envenomation
- Unknown causes
- Markedly reduced exercise capacity if the dog has Myaesthenia gravis-it may have after only a short walk or run. There is a recovery period followed by more activity for only a short period until it weakens again (episodic weakness)
- Pneumonia if some of the vomit has been inhaled into the lungs
- Vomiting or regurgitating of food and/or saliva
- X-rays will confirm the presence of mega esophagus and also give an idea of the condition of the lungs.
- X-rays will help rule out foreign bodies.
- Vets will run a blood test to rule out Myaesthenia Gravis (Anti-AcH test) and hypothyroidism.
- If in a paralysis tick area, the dog needs a thorough check over to rule it out. Normally though, a paralysis tick case has other clinical symptoms which make it more likely to be the case.
The most common complication that often leads to euthanasia is accidental inhalation of some of the vomit into the lungs causing severe pneumonia. To avoid this, dogs are fed small rolled up pieces of food e.g. cooked mince with rice (see photo). Food should be fed by hand with the dog in a sitting position so it slides down the dilated oesophagus into the stomach. Water should be left in an elevated position e.g. at the top of a few stairs so the dog has to drink with the tail lower than the head.
To lessen the chance of stomach acid being inhaled into the lungs and causing damage, we give ant-acids 2-3 times a day e.g. Zantac.
Antibiotics play an important role in preventing secondary infection in damaged lungs.
If the cause is Myaesthenia Gravis, we give a human tablet twice a day which helps make the muscles and nerves work. Treatment is for 3-6 months before recovery occurs. Repeat blood tests will tell the vet if the Myaesthenia Gravis has finished. X-rays will also show if the oesophagus has returned to normal function.
The use of cortisone to "knock out" the immune system is controversial as it is felt it takes a few months to work and by that time, the disease may have run its course anyway. The other problem is if you "knock out" the immune system and the dog gets an inhalation pneumonia, it will be much worse off with cortisone in the body.
A case of Megaoesophagus in a dog