A diaphragmatic hernia occurs when abdominal organs or fat prolapse into the chest.
Symptoms of a diaphragmatic hernia can occur suddenly or develop over a longer period of time. Some hernias might even cause no impairment at all and can be coincidental findings during examination. Depending on the size and nature of the hernia, the animal may develop mild to severe breathing difficulties. Severely affected dogs often stand spread-legged to make use of their abdominal muscles to facilitate breathing. If there is a marked decrease in oxygen intake, gums and mucous membranes appear cyanotic (blue).
The most common orifice for herniation into the thorax is where the esophagus passes through the diaphragm. Parts of the stomach, fat or the omentum (double fold of serous skin that covers the inside of the abdomen and its organs) can prolapse here into the chest. The hernia then consumes space and – if big enough - puts extra pressure on the lung this impairing inflation. Herniation may occur spontaneously after localized weakening of the diaphragmatic muscle or after accidents.
Hernias often cause marked dislocation of thoracic organs, which can be seen on x-rays of the chest. Quick intervention is usually beneficially in order to prevent damage to either the lungs or possibly the herniated material. In most cases surgery is warranted in order close the orifice inside the diaphragm and prevent future prolapses. If there is no bleeding or necrotic tissue present, the prognosis for recovery is usually good.
If your dog is showing symptoms of a diaphragmatic hernia, consult a veterinary clinic immediately.