Diaphragmatic Hernia in Dogs
The term diaphragm is from the ancient Greek diaphragma meaning “to partition or divide” -- which is in part what the diaphragm does. The diaphragm is an internal skeletal muscle membrane that separates the abdomen from the thorax or chest containing the heart and lungs. The diaphragm plays a major role in breathing in that as it contracts and enlarges the chest cavity it creates a vacuum that draws air into the lungs. In some conditions the diaphragm may be compromised when the fibers of the muscle separate or tear loose from the body wall. The most common cause of this loss of integrity of the diaphragm is blunt force trauma to the abdominal wall.
When this happens, the partition is lost. Depending on the location and severity of the resulting defect in the diaphragm, abdominal organs may be drawn or slide into the chest cavity or the pericardium. The result is a reduction in the relative vacuum that assists in breathing. This means breathing becomes more dependent on the movement of chest and muscles and results in greater effort to move the air into the lungs.
Causes of a rupture
The most common cause of rupture of the diaphragm and herniation of abdominal organs (most likely a lobe of the liver, a portion of the gastrointestinal tract or intra-abdominal fat tissue) passing through the diaphragm is blunt force trauma to the abdomen. Congenital hernias also may be present or predisposed because of tissue weakness at birth. In some cases the herniated tissue passes into the pericardium (a pericardial-diaphragmatic hernia).
Herniations can be “dynamic” meaning the tissue slides back and forth from the abdomen to the chest or pericardium.
Very small hernias may not require repair but they weaken the tissue around the hernia opening and so they can become larger in the future. Herniated tissues can become scarred making later reduction and repair more difficult. Most of the time a ruptured diaphragm should be treated and repaired as soon as the patient is stable.
Treating a rupture
The only curative treatment is surgical reduction and closure. In most cases this requires sewing the torn edges of the hernia or in some more severe hernias may require translocating a muscle or using synthetic materials to allow for the hernia to be repaired.
Depending on the trauma that caused the hernia and associated damage to internal organs the outlook for