In my (Perry Jameson's) opinion, the esophagus is one of the most underappreciated structures in the body. It transports whatever is swallowed to the stomach. We take for granted that every time we eat or drink this will happen. Most of us never think about what happens if the esophagus stops working as it should.
Esophageal function is even more amazing in pets than humans when you consider differences in our anatomy. When we eat, we usually are seated with our esophagus in a vertical position. This allows gravity to aid the esophagus in transporting whatever was eaten to the stomach. Our pets eat in a horizontal position. This means the esophageal muscles are completely responsible for transporting the food or liquids to their stomachs.
The major symptom of esophageal dysfunction is regurgitation. Regurgitation is where food never reaches the stomach but comes back out after only being in the esophagus. There is a big difference between regurgitation and vomiting, although at first glance they appear the same.
When I have a patient present for “vomiting,” I always have to make sure it is truly vomiting and not regurgitating. It is important for me to know this to form a diagnostic plan as well as to discuss a prognosis with Mom and Dad.
Vomiting is a natural event, like sneezing. When your cat or dog vomits, their bodies close off the airway to prevent aspiration. Regurgitation is not a natural event, so the airway remains open. This greatly increases the risk for aspiration that can often result in pneumonia.
With vomiting, there commonly are abdominal contractions. Often, there are sounds (yowling in cats, and heaving in dogs) and behaviors (crouched with neck extended) that clue you in that your pet is about to vomit. The food is often partially digested as it has been in the stomach and has reached the stomach acids.
With regurgitation, the material usually comes up quickly and unexpectedly. Your pet may be lying down when it happens or standing may trigger it. The food is usually not digested. It will however be moistened and softened by saliva.
During this time of year, we see an increase in the number of dogs with esophageal obstructions. The most common culprits are chicken bones with the back bone, or vertebrae, being the worst. For some reason, dogs will attempt to swallow these partially eaten or basically whole. The shape and multiple spiny projections cause them to lodge in the esophagus. This usually occurs where the esophagus narrows as it passes over the heart.
The longer the foreign material remains trapped in the esophagus, the harder it is to remove. The esophagus is like a python and continues to tighten its grip around the bone in a failed attempt to push it into the stomach. The resulting inflammation also makes it worse.
Initially, the problem is that the dog cannot pass food and/or water into the stomach. In the long term, the esophagus may perforate. Esophageal fluid will then leak into the chest resulting in a life-threatening infection. Air also may leak into the chest cavity making it hard to breathe.
The best therapy is to get the obstruction out of the esophagus as soon as possible. In my experience, I have found it nearly impossible to pull these bones back out of the mouth as the esophagus is working so hard to force things in the other direction. By placing the pet under anesthesia, which relaxes the esophageal muscle, and distending the esophagus with air, I can usually push them into the stomach. If the problem is a bone, it will be digested by the stomach acids.
In rare cases, the bone may be so lodged in place that surgical removal is required. Surgery is a last resort as occasionally where the incision is made, scar tissue (or stricture) can form that narrows the esophagus. They also may occur following foreign body removal with the endoscope, especially if the esophagus is severely damaged.
Esophageal strictures can occasionally form from causes other than an esophageal foreign body. Rarely, animals undergoing surgical procedures may reflux stomach acid while under anesthesia. This acid can burn the esophageal wall and as it heals, scar tissue may form. In cats, the antibiotic doxycycline may cause esophageal injury and stricture formation. This usually can be prevented by administering water or food immediately after giving the antibiotic so it does not remain in the esophagus.
Esophageal strictures can be frustrating to treat. The best therapy is to view the stricture in the esophagus with an endoscope and use a dilating balloon to tear the stricture. Unfortunately, the stricture often recurs as the esophagus heals. Usually, several attempts are required to redilate the narrowing. In some patients, periodic dilation is required for the rest of their lives.
During the holiday season, we all are tempted to give our furry family members something special to include them in the celebration. While the temptation is great and bones seem like a logical thing to feed a pet, I recommend avoiding these as treats as complications can be severe and life-threatening.
Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to firstname.lastname@example.org.