The esophagus is the part of the digestive tract that lies between the oral cavity and the stomach. It is the place of transit of food which advances towards the stomach thanks to the contractions of its muscles.
In the event of a decrease in muscle tone, the esophagus no longer contracts effectively and dilates; this is called esophageal achalasia. The esophagus loses its ability to actively transport food, water and saliva to the stomach. These will stagnate in the esophagus or even be regurgitated.
The esophageal achalasia should not be confused with the esophageal crop caused by various obstructive causes that lead to a narrowing of the lumen of the organ. The part of the esophagus that is upstream of this narrowing expands, forming a crop. These obstructive causes are the persistence of the 4th aortic arch, or tumors for example.
Dogs are more commonly affected by esophageal achalasia than cats.
Esophageal achalasia can be congenital, present since birth, or acquired when it develops in adulthood. Several breeds such as the Labrador Retriever, German Shepherd, Irish Setter and Great Dane are predisposed to the congenital form. In the case of the congenital form the hypothesis is made that it is secondary to an incomplete development of the nervous system of the organ. The causes of acquired esophageal achalasia are numerous: muscular, neuromuscular, neurological disease, inflammation of the esophagus, hormonal disease and toxic causes. However, in the majority of cases, no cause is identified; one then speaks of idiopathic esophageal achalasia.
Regurgitation and weight loss are the main symptoms of esophageal achalasia. It is important to differentiate regurgitation from vomiting. Vomiting is an active process preceded by retching, nausea and abdominal contractions before the stomach contents are expelled. Regurgitation is a passive process in which food, water and saliva are effortlessly expelled.
The most frequent complication associated with esophageal achalasia is bronchopneumonia by erroneous passage, that is to say that there is passage of food and water in the lungs. The symptoms observed are cough, fever and sometimes acute breathing difficulties.
The chest x-ray allows in the vast majority of cases to visualize the esophageal achalasia. In case of doubt, a barium meal is administered to the patient. It consists of having the dog swallow a meal with contrast product, which allows the lumen of the esophagus to be clearly observed on the x-ray. The chest x-ray also helps to check if there is pneumonia by wrong passage.
Other complementary examinations, such as a blood test, can be carried out in order to look for a cause of acquired esophageal achalasia. However, in the majority of cases, no underlying cause is detected.
In congenital esophageal achalasia, nerve development in the esophagus may improve with age. It therefore takes a little patience before deciding on the prognosis.
In acquired esophageal achalasia, if an underlying cause is detected, it should be treated. In some cases the esophageal achalasia is reversible, which is associated with a good prognosis.
In the case of idiopathic esophageal achalasia, the treatment is conservative:
The prognosis for idiopathic esophageal achalasia depends on the response to conservative treatment. The development of recurrent bronchopneumonia darkens the prognosis.
Dr Emilie Vangrinsven
Diplomate from European college of veterinary internal medicine | PhD U-Liège
Assistant at the Liege University in the university clinic for PETs | Author and co-author of numerous scientific publications