The diaphragm is the muscular separation between the chest and abdominal cavities. The diaphragm keeps thoracic and abdominal organs separate as well as aiding respiration.
Ruptures in the diaphragm allow abdominal organs to migrate into the chest cavity, effectively ‘squashing’ the lungs and compromising their capacity to expand during breathing. This break in the diaphragm - called a diaphragmatic hernia – can be the result of trauma such as a car accident or, more rarely, the hernia can be congenital. Sometimes the trauma has happened days, weeks or even months before the intestine or other organs find the tear and enter the chest, causing sudden respiratory distress.
Diagnosis
CVH vets diagnose and treat diaphragmatic hernias quite commonly in dogs and cats. Pets with diaphragmatic hernias are almost always presented with laboured breathing. They often have a rapid, shallow breathing pattern and sometimes will adopt an abnormal breathing posture – what we call dog-sitting – because when they lie down, the organs may slide further into the chest making it even harder for them to breathe.
X-rays of the chest show the normally distinct line of the diaphragm has disappeared. Depending on which organs have moved into the chest, there may be an obvious mass (such as the liver) or it’s possible to see a gas-filled stomach and/or intestines. Contrast radiography with barium is sometimes used to confirm the intestines and/or stomach are sitting within the thoracic cavity.
Images below: the image on the left shows a normal (dog) chest with an unbroken diaphragmatic line, clear silhouette of the heart and air-filled lungs. The image to the right shows the dense mass of the liver and stomach sitting in the chest cavity in a dog before surgery at CVH.