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MEGAESOPHAGUS


About the Diagnosis

Cause: In animals, like in people, the esophagus is the tube that carries swallowed food from the mouth down into the stomach. There are several groups of muscles and nerves within the esophagus that coordinate movements to propel food toward the stomach opening.

Megaesophagus is a disorder characterized by decreased movement (hypomotility) and dilation or distension of the esophagus. As a result, food does not pass from the throat to the stomach appropriately and can sit in the esophagus or be brought back up to the throat (regurgitation). Pets with megaesophagus are at greater risk for developing pneumonia (lung infection), since food and liquids sitting in the esophagus or being regurgitated can be accidentally inhaled into the lungs (aspiration pneumonia).

Megaesophagus can occur in both dogs and cats, but it is much more common in dogs. Megaesophagus can be present at birth and become apparent when soft and dry foods are introduced at weaning, or it can occur later in life, usually in young to middle-aged adults. It is hereditary (genetically transmitted) in some wire-haired fox terriers and miniature schnauzers, and also commonly affects the German shepherd, Newfoundland, Great Dane, Irish setter, shar-pei, pug, greyhound, and Siamese cat.

Megaesophagus can be the primary disease, or it can occur as a result of another disease process, such as diseases that make the esophagus's muscle tissue weak or that block the esophagus and cause stretching upstream from the blockage. Although the cause of megaesophagus is often unknown (idiopathic), there are several different potential disease processes in cats and dogs which can lead to a dilated esophagus: esophageal obstructions caused by foreign material (i.e., sticks, rocks, bones), abnormal narrowing (stricture), cancers and other masses, congenital (developmental) abnormalities, neurologic and neuromuscular diseases, infectious diseases, inflammation of the esophagus (esophagitis), immune system abnormalities, hormonal disorders, and toxins.

Diagnosis: Symptoms of megaesophagus can vary from patient to patient and can be similar to several other diseases. One of the most distinguishing symptoms of megaesophagus is the regurgitation of food or water. Regurgitation involves the bringing up of foods and liquids that have not yet reached the stomach, but rather are sitting within the esophagus. It does not involve any obvious effort to bring food up, which is different from vomiting because vomiting involves belly contractions and retching and can be preceded by signs of nausea and drooling. The contents expelled after regurgitation are often undigested (whole chunks of food), and no yellow bile (stomach and intestinal fluid) is noted with regurgitation. As a result of frequent regurgitation, symptoms of excessive salivation, foul breath, and weight loss are also often noticed. If pets have developed aspiration pneumonia as a result of megaesophagus, nasal discharge, breathing difficulties, fever, coughing, and other general signs of illness may be observed.

Your veterinarian will begin by asking you several questions to try to determine if megaesophagus, or another type of problem altogether, could be responsible for the symptoms. You should provide whatever information you have when you answer these questions, which often include: the type of symptoms observed, the length of time they have been occurring, effects on vital functions such as appetite, any previous medical problems or recent procedures, the possibility of exposure to potentially poisonous substances in the past, and any current medications or supplements you are giving your pet.

When examining your pet, your veterinarian will look for some of the changes that can occur with megaesophagus, which include poor body condition, dehydration, bad breath, excessive drooling, and bulging of the esophagus or pain noted when feeling the region of the neck associated with the esophagus. In some cases, evidence of behavioral changes, neurologic disorders, and pneumonia can be detected. The symptoms listed here are not specific to megaesophagus, however, and other disorders could in fact be the cause of the problems. Therefore, if megaesophagus is suspected by your veterinarian, further testing will be recommended.

Megaesophagus can often be diagnosed with plain x-rays of the neck and chest. Some cases may require more specialized imaging techniques such as barium swallows (contrast material ["dye"] is fed and an x-ray is taken in order to outline the dilated esophagus), fluoroscopy (a continuous x-ray that allows for visualization of the esophagus in motion while swallowing), or endoscopy (a small camera which is inserted directly into the esophagus). These techniques can also be useful in detecting foreign materials lodged in the esophagus, masses, and cases that are complicated by pneumonia.

Lab work consisting of blood and urine tests is also typically recommended in order to rule out any possible underlying medical problems that produce similar symptoms.

Other tests that may be performed depending on the case can include: acetylcholine receptor titer, edrophonium test, EMG, NCV, and/or muscle and nerve biopsies (used to rule out neuromuscular abnormalities), ANA tests (used to detect immune system abnormalities), hormonal testing (used to rule out diseases such as hypothyroidism and hypoadrenocorticism), infectious disease titers, and toxicology assays (lead, thallium, etc.). These tests are considered on a case-by-case basis in order to detect possible triggers or causes of megaesophagus.

Living with the Diagnosis

Megaesophagus is a potentially serious and sometimes even life-threatening illness. The prognosis (outlook for improvement and return to normal) varies dramatically with the underlying cause of the disease, the presence of secondary complications (i.e., pneumonia), the administration of appropriate medications and treatments, and the level of nursing care and treatment compliance provided at home. Some cases will completely resolve if the underlying disease is treated, while many cases will do poorly despite all of the appropriate measures. During the course of the disease, it is very important to keep all recommended follow-up appointments and tests with your veterinarian in order to monitor the progression of disease and make any needed medication or treatment adjustments. At home by monitoring your pet's weight, as well as changes in appetite, behavior, frequency of regurgitation, and breathing, you will learn helpful information to bring to your next appointment.
Give all prescribed medications as directed by your veterinarian. These medications generally are essential in controlling the effects of megaesophagus as well as improving the quality of your pet's life.

Food and water should be maintained in an elevated position so that gravity can help move food through the esophagus, toward the stomach. This can be accomplished by placing food and water bowls on a table or stepstool or by encouraging animals to eat with their front legs placed up on a chair, table, or stepstool. Ideally animals are held in a sitting, upright position for 10 to 15 minutes after eating or drinking, to help food and water flow down into the stomach.

You should discuss an ideal diet for your pet with your veterinarian and feed only the recommended foods. If your pet is no longer willing to eat the special diet, contact your veterinarian prior to changing foods. An adequate level of nutrition is extremely important in megaesophagus. In many cases of megaesophagus, a high calorie food fed in frequent small meals through the day is ideal. The consistency of the food must be tailored to the individual pet since some animals do well with a gruel, where others do better with meatballs of canned food or more solid foods.

If your animal requires the placement of a feeding tube in order to maintain adequate nutrition, be sure to ask your veterinarian or veterinary technician to show you how to appropriately administer food, water, and medications through the tube, flush the tube if it gets clogged, and how to keep the tube entry point through the skin clean and bandaged.

Treatment

The goals of treating an animal with megaesophagus are to minimize the frequency of regurgitation, prevent overdistention of the esophagus, maintain a good level of nutrition and body condition, prevent or rapidly identify and treat complications such as aspiration pneumonia, and improve the overall quality of the pet's life.

Treatment of megaesophagus must be based on the individual patient, severity of the symptoms, underlying cause, and secondary diseases that may be involved. In every patient, however, all toxins (mainly thallium or lead- both fairly rare as causes of megaesophagus) that can cause megaesophagus should be identified and removed from the environment, and all concurrent or underlying diseases should be diagnosed and treated.

Patients with severe symptoms of megaesophagus and aspiration pneumonia will likely need to be hospitalized initially while intravenous (IV) fluids are given to correct dehydration and electrolyte abnormalities and medications including antibiotics are initiated. If hospitalization is not required, your veterinarian will start your pet on medications and treatments that can be given at home.

Appropriate diet (caloric content and consistency) and administration (elevated) is essential in managing a patient with megaesophagus (see above). Some patients will require the placement of a temporary or permanent feeding tube in order to maintain an adequate level of nutrition. This tube allows for food and water to be administered directly into the stomach or intestines.

There are several different medications available that can help improve the movement of the gastrointestinal tract, as well as help tighten the sphincter muscle between the esophagus and the stomach. Drugs that help reduce the acidity of the stomach contents and those that coat and protect the esophagus and stomach lining can also be beneficial in some cases. These drugs have varying levels of success from patient to patient.

Animals with aspiration pneumonia will need to be treated with broad-spectrum antibiotics for an appropriate time frame depending on the severity of the symptoms.

DOs

• Realize that the proper management of a pet with megaesophagus requires significant owner commitment and that in many cases the symptoms improve somewhat but that the risk of complications such as aspiration pneumonia remains present.

• Realize that serious and life-threatening complications (i.e., aspiration pneumonia) can arise if megaesophagus is severe, left untreated, or treated inappropriately.

• Keep all recommended follow-up appointments with your veterinarian since they are essential in monitoring your pet's response to medications and treatments.

• Have your veterinarian or veterinary technician show you how to give all medications and demonstrate the correct method for feeding tube handling, administration, and cleaning.

• Handle and give all medications exactly as directed by your veterinarian. If your animal is having side effects from any medications or you are finding it very difficult to medicate your animal, contact your veterinarian for advice before discontinuing the treatment.

• Ask your veterinarian questions about information you do not understand.

• If you do not trust or are not comfortable with your veterinarian, get a second opinion from another veterinarian or a veterinary internal medicine specialist.

• Consider humane euthanasia if your pet is not responding to all possible treatments and you feel he or she is suffering or has a poor quality of life.

DON'Ts

• Do not postpone a visit to your veterinarian if you observe any symptoms of illness or of megaesophagus since early diagnosis and treatment can aid in preventing serious and life-threatening complications of the disease and improve the quality of your pet's life. The initial screening tests can often be performed on an outpatient basis.

• Do not give any medications that are not prescribed by your veterinarian for the specific animal in question.

• Do not stop elevating food and water or any medications if your animal is feeling better without consulting with your veterinarian first.

• Do not assume that all sources of information are accurate or complete (i.e., Internet sites, outdated pamphlets or books, pet store workers, friends, etc.). Ask your veterinarian for recommended sources of information.

When to Call Your Veterinarian

• If you are unable to give medications as prescribed or if you require a prescription refill.
• When you have any questions or concerns related to your pet's continual treatment plan or current status.

Signs to Watch For

• Watch for general signs of illness, which can include changes in appetite, weight loss, decrease in activity, depression, dull or poorly kept coat, and changes in behavior such as hiding and aggressiveness.

• Watch for signs of megaesophagus, which can include frequent regurgitation, excessive salivation, foul breath, and weight loss.

• Watch for signs of aspiration pneumonia, which can include nasal discharge, breathing difficulties, fever, and coughing.

Routine Follow-Up

• As megaesophagus is a serious disease that can deteriorate over time, it is very important to keep all recommended follow-up appointments and tests with your veterinarian in order to monitor the progression of disease, document and treat any new problems that may arise, and make any needed medication adjustments.