History
A 10-year-old castrated male Labrador Retriever was referred to the University of Tennessee College of Veterinary Medicine with a 1-month history of weight loss, anorexia, labored breathing, a dry nonproductive cough, and pleural effusion. The whereabouts of the dog were unknown for 3 days prior to the onset of clinical signs. Treatment by the referring veterinarian had consisted of furosemide administration and repeated thoracocentesis.
At the time of admission, the dog was quiet and thin (body condition score, 3/9). Clinical examination revealed increased respiratory rate (44 breaths/min), muffled heart sounds, and dull sounds on percussion of the ventral aspect of the thorax. No clinically relevant abnormalities were found on a hemogram and serum biochemical profile. Initial thoracic radiography revealed a large-volume bilateral pleural effusion. Findings on echocardiography, abdominal radiography, and abdominal ultrasonography had a normal appearance. Thoracic radiography was repeated after thoracocentesis and removal of 600 mL of hemorrhagic pleural effusion (Figure 1).
Lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 10-year-old castrated male Labrador Retriever with a 1-month history of weight loss, anorexia, labored breathing, cough, and pleural effusion. Radiographs were obtained following thoracocentesis.
Citation: Journal of the American Veterinary Medical Association 235, 9; 10.2460/javma.235.9.1041
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Radiographic Findings and Interpretation
Right lateral and ventrodorsal radiographic views of the thorax (Figure 2) reveal an area of homogenous soft tissue–fluid opacity associated with the caudal area of the right hemithorax. On the ventrodorsal view, the contour of the right diaphragmatic crus is not clearly delineated; the cardiac silhouette is separate from the sternum on the lateral view, and the left lung is retracted from the thoracic wall and surrounded by a radiolucent area of gas. There are transverse fractures of the right 11th to 13th ribs, with widening of the fracture ends and periosteal new bone formation. A small radiolucent area of gas is seen in the plane of the cranial aspect of the abdomen ventral to the liver on the lateral view. Most likely differential diagnoses for the soft tissue opacity in the right hemithorax were diaphragmatic hernia with herniation of liver or fat and residual focal pleural effusion silhouetting with the diaphragm. Additional imaging diagnoses were iatrogenic pneumothorax, chronic rib fractures, and possible pneumoperitoneum.
Same radiographic views as in Figure 1. Notice the area of homogenous soft tissue–fluid opacity associated with the caudal area of the right hemithorax (white arrows). On the ventrodorsal view, the contour of the right diaphragmatic crus is not clearly delineated, and the left lung is retracted from the thoracic wall and surrounded by a radiolucent area of gas (white arrowheads). There are transverse fractures of the right 11th to 13th rib (small black arrows). A small radiolucent area of gas is seen in the plane of the cranial aspect of the abdomen ventral to the liver on the lateral view (black arrowhead).
Citation: Journal of the American Veterinary Medical Association 235, 9; 10.2460/javma.235.9.1041
A lateral horizontal beam radiographic view of the thorax with the dog positioned in dorsal recumbency (Figure 3) reveals persistent soft tissue opacity in the caudal portion of the thorax between the heart and diaphragm, consistent with diaphragmatic hernia and entrapment of liver or fat. A moderate amount of free peritoneal gas is now clearly identified between the pylorus and ventral abdominal wall, consistent with pneumoperitoneum and likely secondary to extension of air within the pleural space through a diaphragmatic rent.
A lateral horizontal beam radiographic view of the thorax of the same dog as in Figure 1. The dog was positioned in dorsal recumbency. Notice the persistent soft tissue opacity in the caudal portion of the thorax between the heart and diaphragm, consistent with diaphragmatic hernia and entrapment of the liver or fat. A moderate amount of free peritoneal gas is clearly seen between the pylorus and the ventral aspect of the abdominal wall.
Citation: Journal of the American Veterinary Medical Association 235, 9; 10.2460/javma.235.9.1041
Comments
Laparotomy was performed via midline incision. A 4-cm L-shaped tear was identified in the ventral right portion of the diaphragm, with omentum and liver trapped within the thoracic cavity. Adhesions between diaphragm, liver, and omentum were cauterized; herniated structures were retracted into the abdomen; and the diaphragmatic rent was closed. The dog was discharged from the hospital 2 days following surgery.
Approximately 50% of dogs and cats with diaphragmatic hernia are evaluated without a known history of trauma.1 However, trauma appears to be the most likely reason for diaphragmatic hernia in this dog on the basis of a history of missing from home and the concurrent radiographic finding of rib fractures. Diagnosis of diaphragmatic hernia in small animals is usually possible on the basis of 1 or more of the following findings on routine thoracic radiography: loss of diaphragmatic line, cardiac outline obscured, increased opacity of ventral aspect of the lung field, intestinal gas shadows in the thorax, intrapleural fluid, and lung collapse.1 However, diagnosis can be difficult when there is concurrent pleural effusion because free pleural fluid tends to obscure the cupula of the diaphragm and mask herniated organs.2 In these cases, interventional procedures or advanced imaging equipment are required. A nonconventional radiographic projection such as an erect ventrodorsal view or lateral horizontal beam view of the thorax may enhance the radiographic recognition of gravitational shifting of herniated viscera or redistribution of pleural effusion, compared with survey radiographs, and may simplify the diagnosis, as in this dog.3,4
- 1.↑
Garson HL, Dodman NH, Baker GJ. Diaphragmatic hernia. Analysis of fifty-six cases in dogs and cats. J Small Anim Pract 1980;21:469–481.
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Sullivan M, Lee R. Radiological features of 80 cases of diaphragmatic rupture. J Small Anim Pract 1989;30:561–566.
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Williams J, Leveille R, Myer CW. Imaging modalities used to confirm diaphragmatic hernia in small animals. Compend Contin Educ Small Anim Pract 1998;20:1199–1209.
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Suter PF, Lord PF. Thoracic radiography. A text atlas of thoracic diseases in the dog and cat. Wettswil, Switzerland: Selbstverlag Peter F. Suter, 1984.
