Megaesophagus in Cats

Megaesophagus is a condition that can occur in cats of all ages and breeds, either as an acquired disease or a condition they are born with. Siamese and Abyssian cats may be prone to an inherited form of megaesophagus. Cats with megaesophagus can’t swallow their food properly, and the most common symptom they’ll show is regurgitation. Alternatively, they'll spit up undigested food before it gets to the stomach. Megaesophagus is not a contagious condition. It may be caused by an underlying disease process, genetic abnormality, nerve damage, trauma, or toxins. In some cases, the cause is unknown. Megaesophagus generally requires lifelong treatment, including special feeding methods and medications, to ensure cats receive proper nutrition and avoid medical complications. Some types of megaesophagus may be treated surgically, but it is likely cats will still need lifelong care and monitoring.

What Is Megaesophagus in Cats?

Megaesophagus develops in cats when the esophagus—the muscular tube in the throat that connects the mouth to the stomach—is unable to move food properly down into the stomach. In this condition, the muscles in the esophagus do not contract normally, and the esophagus becomes enlarged, weak, and flaccid. The inability of the muscles to contract normally is a problem called dysmotility or hypomotility. Food may pool in the esophagus and cats will regurgitate undigested food back up shortly after trying to eat.

Symptoms of Megaesophagus in Cats

Depending on the underlying cause, symptoms of megaesophagus may be present in kittens, or may develop later in cats of any age. In cases where an animal is regurgitating food and water, megaesophagus should be highly suspected as a potential cause.

Regurgitation

Regurgitation is the most common symptom of megaesophagus. Regurgitation can look similar to vomiting, and it is important to try to distinguish between the two. Regurgitation is a passive process, where a cat may appear to spit up food or water with little effort after eating or drinking. Regurgitation may occur within minutes of eating or a few hours later. By contrast, vomiting is an active process involving abdominal muscle contractions, which may be prolonged, before food or liquid is brought up from the stomach. Vomited food may be semi-digested. Cats about to vomit may become restless, lick their lips repeatedly, and make gagging sounds, but these actions are not associated with regurgitation.

Difficulty Swallowing

Because food can’t move normally down the throat when megaesophagus is present, cats will have difficulty swallowing food and water. Cats may repeatedly attempt to swallow and food may drop out of their mouths when they are trying to eat. Some cats may also become distressed while eating.

Cough or Difficulty Breathing

Cats with megaesophagus are at high risk of aspiration pneumonia, which may present as a cough, trouble breathing, lethargy, fever and/or an unusually fast respiratory rate. Aspiration pneumonia occurs when regurgitation causes food or water to be inadvertently inhaled into the respiratory tract. This causes inflammation and infection in the lungs and can lead to a serious, life-threatening pneumonia.

Excessive Salivation/Drooling

Cats are unable to swallow their saliva and may show symptoms of excessive drooling and constant wet fur and skin around the mouth, neck, and chest.

Weight Loss

Megaesophagus prevents the normal digestion of food, since food can’t reach the stomach to be broken down and used by the cat’s body for nutrients. As a result, cats with megaesophagus become malnourished and start losing weight. They may have poor body condition, ungroomed fur, and low energy as well.

Failure to Gain Weight

Kittens with congenital megaesophagus–which means the condition is present from birth–will fail to gain weight normally compared to other kittens of the same age. They may appear smaller than other littermates, or may be weak and thin.

Nasal Discharge

Nasal discharge may be present if infection or inflammation in the sinuses occurs. This may be due to regurgitation leading to respiratory infections and pneumonia, as well as their overall poor health making them more susceptible to infectious diseases. Cats may sneeze, cough, and/or have persistent nasal discharge.

Fever

Cats with aspiration pneumonia may have a fever due to the infection. Symptoms of a fever include low energy, not wanting to move or interact, loss of appetite, and hiding.

Bulge in the Throat

Food may collect in the esophagus, causing a distended or swollen appearance in the neck. This is only rarely observed and would be most evident in the lower portion of the neck close to where it meets the shoulder, known as the thoracic inlet.

Causes of Megaesophagus

Megaesophagus is caused by either congenital or acquired conditions. Congenital conditions are present at birth, may be inherited, and are usually present in young kittens. These conditions often become most evident when kittens are weaned and start eating solid food.

Acquired conditions most often develop later in juvenile and adult cats. Megaesophagus can also be idiopathic, which means the condition arises but the cause is not known.

Causes include:

• Abnormal nerve function in part (or all) of the esophagus and/or abnormal movement of muscles in the esophagus. Siamese cats may be more prone to inherited causes for this. 
• Congenital vascular ring abnormalities–presence of abnormal blood vessels that constrict the esophagus
• Idiopathic–cause unknown 
• Obstruction in the esophagus–foreign body, tumor
• Stricture of the esophagus- anything that causes scarring and/or narrowing of the esophagus can affect motility and lead to megaesphagus
• Inflammation in the esophagus
• Neuromuscular disorders–myasthenia gravis, tetanus, botulism, glycogen storage diseases 
• Autonomic nervous system diseases 
• Infectious diseases causing muscle inflammation
• Hypoadrenocorticism
• Tumors
• Polyps 
• Immune-mediated nerve disorders
• Toxins–lead, organophosphates, snake venom, certain medications

Diagnosing Megaesophagus in Cats

If your cat is showing symptoms of megaesophagus, your veterinarian will perform a complete physical examination and conduct additional tests to determine if an underlying cause can be identified. These tests include:

• Bloodwork to look for abnormalities like endocrine disease, infections, and toxins
• Specialized tests to assess for conditions like myasthenia gravis
• Xrays of the chest and neck–possibly using a liquid visible on xrays that your cat swallows to provide more information on the structure and motility of the esophagus. 
• Fluoroscopy–a continuous xray image that can show movement of the esophagus
• Endoscopy–passing a camera down into the esophagus and upper gastrointestinal tract while your cat is under anesthesia

Treatment

If the underlying cause of the megaesophagus can be identified, it should be treated. Depending on the cause, specific treatment may involve medication or surgery to correct the condition. For example, abnormal blood vessels that constrict the esophagus, called vascular ring anomalies, can be treated with surgery. Regardless of the underlying cause, most cats will likely need lifelong support to deal with the symptoms of megaesophagus. 

Treatment of megaesophagus, whether the cause is known or unknown, requires supportive care to help cats eat and reduce the risk of complications like aspiration pneumonia. Cats must be fed multiple, small meals of a high-calorie gruel. Food bowls must be elevated so cats stand on their hind feet while eating. This position uses the assistance of gravity to help move food down into the stomach. Cats must remain in an elevated position for 30 minutes after feeding. You can accomplish this by holding your cat upright in your arms or over your shoulder, or carrying your cat in a sling. 

Your veterinarian may also prescribe medications that increase the movement of the esophagus, antibiotics to treat infections, and antacids if inflammation is present in the esophagus.

Prognosis for Cats with Megaesophagus

The prognosis for megaesophagus depends on the underlying condition and whether it is treatable. Complications like aspiration pneumonia, dehydration, and malnutrition worsen the prognosis. Some forms of congenital megaesophagus may improve with age, but idiopathic megaesophagus generally has a poor prognosis, particularly if there are associated complications. If the underlying cause can be treated and cured, symptoms of megaesophagus can resolve. In other cases, megaesophagus in cats may be progressive, leading to early deaths.

How to Prevent Megaesophagus

Most causes of megaesophagus cannot be prevented, but some actions can be taken to avoid some forms of megaesophagus in cats. 

• Do not breed animals suspected to have inherited causes of megaesophagus
• Prevent the ingestion of foreign bodies–keep toys and other objects that your cat may ingest picked up and out of reach. If an obstruction is suspected, seek treatment immediately from a veterinarian. 
• If the esophagus is inflamed, treat immediately and aggressively according to your vet's recommendations. 
• To prevent injury to the esophagus, always administer water to cats via a syringe after giving them a pill to ensure the pill is flushed into the stomach.