Abnormal protrusion of a body organ into another organ through an opening is medically termed as hernia. The abdominal and chest cavities are separated by a muscular wall known as diaphragm. It keeps abdominal organs such as stomach, intestines, liver etc separated from lungs and heart. The diaphragm has an opening, known as esophageal hiatus, for passage of the esophagus.
Hiatal hernia occurs when part of stomach protrudes through esophagus hiatus into chest cavity, forming a hernia. In other words, hiatal hernia is the protrusion of stomach through esophagus hiatus, the natural opening in the diaphragm for passage of esophagus.
It is mostly a congenital defect but can also occur secondary to a trauma to the chest or abdomen, respiratory conditions that cause labored breathing or gastroesophageal reflux, which is the backward flow of stomach contents up and into the esophagus. Reflux often accompanies hiatal hernias and results in subsequent esophagitis or inflammation of the esophagus.. Hiatal hernia can be persistent or intermittent in nature.
There are four types of canine hiatal hernias. Type I is called sliding, axial or oesophageal hiatal hernia ( the junction between the oesophagus and the stomach (known as the gastro-oesophageal sphincter), as well as a portion of the stomach itself, slides up above the diaphragm).
Type II is called rolling or paraoesophageal hiatal hernia (a portion of stomach goes through the diaphragm and lies beside the esophagus).
Type III hiatal hernia is a mixture of type I and type II while type IV is characterized by type III complicated by the stomach or other abdominal viscera being located in the paraoesophageal sac.
For accurate treatment, differentiating between types of hernias is vital because the underlying pathology and pathophysiology are different, necessitating different treatments.
Although this condition can affect any dog of any breed, Chinese Shar Pies and English Bulldogs are predisposed breeds with male dogs having a higher incidence rate than female dogs.
Common symptoms associated with hiatal hernia include
Shortness of breath