The diaphragm is a muscular sheet that separates chest (rib cage area) and abdomen and keeps abdominal organs such as liver, intestines etc separated from lungs and heart. The diaphragm functions as a barrier and aids in respiration. As the diaphragm contracts and relaxes, it enlarges and compresses the chest cavity. This forces air to move in and out of the lungs.
Diaphragmatic hernia is the protrusion of an organ such as liver, stomach or intestine, through an abnormal opening or rupture in the diaphragm. In other words, a rupture in the diaphragm that allows migration of abdominal organ into the chest cavity is called diaphragmatic hernia.
There are two types of this condition. One is an acquired diaphragmatic hernia which happens when the organs of the abdominal area are compressed against the diaphragm, almost exclusively secondary to a blunt trauma to the abdomen such as car accident.
Second form of diaphragmatic hernia is a defective development of the diaphragm in the fetus. This type of diaphragmatic hernia is called congenital (present at birth).
With a teat or opening in the diaphragm, abdominal organs are able to move into chest cavity and compress lungs, thus impending their ability to fully inflate. This causes breathing distress in the affected dogs. The protruded organ may also irritate heart muscles, causing irregular heart rhythms. Besides these symptoms, the dog may also exhibit vomiting, diarrhea and bloating due to damage to the bowel or stomach.
In the congenital form, the symptoms develop gradually and include muffled heart sounds or heart murmurs, abdominal defects, and trouble breathing.