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{|cellpadding="10" cellspacing="0" border="1"
{|cellpadding="10" cellspacing="0" border="1"
|'''Acquired Diaphragmatic Hernia<br>
|'''Acquired Diaphragmatic Hernia<br>
'''Displacement of Stomach into Thorax'''
'''Displacement of Stomach into Thorax'''
|-
| Do not confuse with:
| Do not confuse with:
|'''[[Hiatal Hernia]]<br>
|'''[[Hiatal Hernia]]<br>
==Description==
==Description==
[[Image:stomach diaphragmatic hernia.jpg|thumb|right|150px|Post-mortem image of displacement of the stomach into the thorax through a diaphragmatic rupture (Copyright BioMed Image Archive, all rights reserved)]]
[[Image:stomach diaphragmatic hernia.jpg|thumb|right|150px|Post-mortem image of displacement of the stomach into the thorax through a diaphragmatic rupture (Copyright BioMed Image Archive, all rights reserved)]]
Rupture of the diaphrgam is an acquired condition that often has a traumatic origin in small animals. The rupture is not a true hernia as the parietal peritoneum is disrupted and displaced organs are not contained within a defined hernial sac. Most cases occur in animals which have suffered blunt abdominal trauma with an open glottis, most commonly during a road traffic accident (RTA). If the animal has a closed glottis at the moment of impact, the lung parenchyma is more likely to rupture. Any of the peritoneal abdominal organs may move into the thorax, of which the most commonly herniated are the liver and small intestine. In some cases, the stomach may be displaced into the thorax and, as its outflow is disrupted, it may become dilated and filled with gas. This situation requires urgent surgical intervention. Affected animals often have other injuries associated with the traumatic event, including:
Rupture of the diaphragm is an acquired condition that often has a traumatic origin in small animals. The rupture is not a true hernia as the parietal peritoneum is disrupted and displaced organs are not contained within a defined hernial sac. Most cases occur in animals which have suffered blunt abdominal trauma with an open glottis, most commonly during a road traffic accident (RTA). If the animal has a closed glottis at the moment of impact, the lung parenchyma is more likely to rupture. Any of the peritoneal abdominal organs may move into the thorax, of which the most commonly herniated are the liver and small intestine. In some cases, the stomach may be displaced into the thorax and, as its outflow is disrupted, it may become dilated and filled with gas. This situation requires urgent surgical intervention. Affected animals often have other injuries associated with the traumatic event, including:
*'''Thoracic injuries'''
*'''Thoracic injuries'''
**Pulmonary contusion
**Pulmonary contusion
*'''Respiratory distress''' as displaced abdominal organs in the thorax prevent the lungs from expanding fully and because the damaged diaphragm is incapable of contracting normally. Affected animals may also develop pleural effusion if abdominal organs become incarcerated or strangulated in the thorax or if they have concurrent thoracic pathology.
*'''Respiratory distress''' as displaced abdominal organs in the thorax prevent the lungs from expanding fully and because the damaged diaphragm is incapable of contracting normally. Affected animals may also develop pleural effusion if abdominal organs become incarcerated or strangulated in the thorax or if they have concurrent thoracic pathology.
*'''Heart sounds may be muffled''' on auscultation and borborygmi may be heard.
*'''Heart sounds may be muffled''' on auscultation and borborygmi may be heard.
*'''Percussion''' of the chest wall may reveal hyporeseonance (due to a displaced gas-filled stomach) or hyperresonance (due to the presence of pleural fluid or solid organs, such as the liver, in the chest).
*'''Percussion''' of the chest wall may reveal hyporesonance (due to a displaced gas-filled stomach) or hyperresonance (due to the presence of pleural fluid or solid organs, such as the liver, in the chest).
*'''The apex beat''' of the heart can usually be palpated and this may be displaced from the normal position on the left cranial ventral chest wall.
*'''The apex beat''' of the heart can usually be palpated and this may be displaced from the normal position on the left cranial ventral chest wall.
*In chronically affected animals, '''gastro-intestinal signs''' may be observed due to partial intestinal obstruction or pancreatitis.
*In chronically affected animals, '''gastro-intestinal signs''' may be observed due to partial intestinal obstruction or pancreatitis.
===Radiography===
===Radiography===
'''Plain chest radiographs''' will show that the margin of the diaphragm is no longer evident and abdominal organs, particularly gas-filled loops of small intestine, may be observed within the chest. This appearance should be distinguished from that of peritoneopericardial diaphragmatic hernia in which abdominal organs only overly the cardiac silhouette. If the diagnosis is not certain, a barium swallow series could be performed or contrast medium could be instilled directly into the peritoneal cavity but these procedures have largely been superseded by the use of ultrasound.
'''Plain chest radiographs''' will show that the margin of the diaphragm is no longer evident and abdominal organs, particularly gas-filled loops of small intestine, may be observed within the chest. This appearance should be distinguished from that of [[Hernia, Peritoneo-pericardial Diaphragmatic|peritoneopericardial diaphragmatic hernia]] in which abdominal organs only overly the cardiac silhouette. If the diagnosis is not certain, a barium swallow series could be performed or contrast medium could be instilled directly into the peritoneal cavity but these procedures have largely been superseded by the use of ultrasound.
===Ultrasonography===
===Ultrasonography===
====Post-operative Care====
====Post-operative Care====
Animals that have been treated for diaphragmatic rupture often require intensive care in a dedicated unit. The following aspects of care should be considered:
Animals that have been treated for diaphragmatic rupture often require intensive care in a dedicated unit. The following aspects of care should be considered:
*'''Thoracostomy tube''': This can be placed through the diaphragm during surgery or a conventional tube can be passed through the chest wall. Negative pressure should restored to the pleural cavity after the rupture is repaired and the diaphragm should be seen to return to its concave shape when viewed from the abdomen. The chest should be drained (of air or fluid) regularly until no more can be aspirated than is expected due to the presence of the tube (~2 ml/kg/hour). Bupivacaine or another local anaesthetic agent can be instilled through the tube to provide topical analgesia.
*'''Thoracostomy tube''': This can be placed through the diaphragm during surgery or a conventional tube can be passed through the chest wall. Negative pressure should restore to the pleural cavity after the rupture is repaired and the diaphragm should be seen to return to its concave shape when viewed from the abdomen. The chest should be drained (of air or fluid) regularly until no more can be aspirated than is expected due to the presence of the tube (~2 ml/kg/hour). Bupivacaine or another local anaesthetic agent can be instilled through the tube to provide topical analgesia.
*'''Pulmonary oedema''' may develop as the lungs re-expand due to physical forces acting on the alveoli and due to reperfusion injury to the alveolar capillaries. This condition should be suspected if the patient remains hypoxaemic even with oxygen therapy and it can be avoided by removing air from the pleural space slowly so that the lungs reinflate in a controlled manner. Animals can also be pre-treated with intra-venous corticosteroids to try to prevent the formation of reactive species in reperfusion injury.
*'''Pulmonary oedema''' may develop as the lungs re-expand due to physical forces acting on the alveoli and due to reperfusion injury to the alveolar capillaries. This condition should be suspected if the patient remains hypoxaemic even with oxygen therapy and it can be avoided by removing air from the pleural space slowly so that the lungs reinflate in a controlled manner. Animals can also be pre-treated with intra-venous corticosteroids to try to prevent the formation of reactive species in reperfusion injury.
*'''Incomplete repair''' or presence of a '''second rupture''': The whole diaphragm should be assessed before closure to ensure that a second tear is not present.
*'''Incomplete repair''' or presence of a '''second rupture''': The whole diaphragm should be assessed before closure to ensure that a second tear is not present.
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