Answers and Discussion

Answers and Discussions to the Questions:

• What clinical signs are seen with diaphragmatic hernias?
  
  For hernias induced by trauma, the patient is usually in shock, showing tachypnea, tachycardia and pale mucous membranes.  Cardiac arrhythmias are common.  Other signs depend on which organs have herniated.  For instance, you may hear GI sounds in the chest on auscultation.  Decreased lung sounds are also common, often unilaterally.

• What diagnostic technique is most commonly used to identify diaphragmatic hernias?
  
  A radiograph often provides a definitive diagnosis.  Look for loss of the diaphragmatic line or cardiac silhouette, dorsal or lateral displacement of the lung fields, or gas-filled structures in the chest.

• What do you see on the radiograph?
  
  There is loss of the diaphragmatic line and cardiac silhouette.  There is a lot of pleural fluid present.  The lungs appear to be partially atelectic (rounded, decreased size of aerated lung lobes, etc.).  Gas densities of the GI tract appear to be in the chest cavity.
  
• When should you perform surgery, and in what instance is a diaphragmatic hernia a surgical emergency?
  
  There is evidence that surgery performed less than 24 hours after the incident leads to a higher mortality rate than if surgery is postponed until the patient is more stable.  However, finding the stomach in the chest cavity on your radiograph is cause for emergency surgery.

• What post-op complication should you be watching for?
  
  Rapid lung re-expansion following surgery may lead to pulmonary edema.   However, this is usually not a complication in dogs; it is more common in cats.   The etiology of this is unknown.  There are possibly two things to do that may help in preventing this.  One is to use positive end-expiratory pressure (PEEP) ventilation in surgery.  The other is to use drugs that stabilize the pulmonary capillary membranes, like methylprednisolone.

• Follow-Up: This dog experienced ventricular tachycardia, unresponsive to lidocaine, and dyspnea 24 hours after the trauma.  He became more depressed instead of stabilizing.  No owner came forward and due to lack of funds from the humane society, he was euthanized.  Necropsy revealed the left lateral and quadrate lobes of the liver as well as some of the small intestine were in the chest.  He had a hemothorax and hemoabdomen and pulmonary atelectasis.

Traumatic Diaphragmatic Hernia Pearls

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Copyright 2000, Wayne E. Wingfield, Colorado State University   
This page was last edited:  08/24/00