History
A 14-week-old sexually intact male Pug was referred for evaluation because of a 1-week history of dyspnea, coughing after drinking, and exercise intolerance. The puppy was acquired 2.5 weeks prior to the onset of clinical signs and was clinically normal over that period. Physical examination revealed inspiratory dyspnea associated with an intermittent soft, fluctuant swelling in the left caudal aspect of the cervical region, which was present on inspiration and absent on expiration. Peak inspiratory thoracic radiographic views were obtained that included the cranial portion of the thorax and cervical region (Figure 1).
Lateral (A) and ventrodorsal (B) radiographic views of the cranial portion of the thorax and cervical region of a 14-week-old Pug evaluated for a 1-week history of dyspnea, coughing, and exercise intolerance.
Citation: Journal of the American Veterinary Medical Association 236, 6; 10.2460/javma.236.6.627
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Radiographic Findings and Interpretation
There is a well-circumscribed oval shaped radiolucency within the ventral aspect of the cervical region that is cranial to the thoracic inlet and evident on both orthogonal views (Figure 2). In the ventrodorsal view, there is right lateral deviation of the trachea by the radiolucent structure without lateral deviation of the heart. Radiographic findings are consistent with an intermittent cranial lung lobe herniation. The main differential diagnosis is cervical esophageal diverticulum. On a barium esophagram, no esophageal abnormality was seen and the cervical radiolucent structure was absent (Figure 3).
Same radiographic views as Figure 1. There is a radiolucent area in the cervical region (white arrows) causing lateral displacement of the trachea (black arrow).
Citation: Journal of the American Veterinary Medical Association 236, 6; 10.2460/javma.236.6.627
Lateral barium esophagram of the same dog as in Figure 1. There is normal movement of barium through the esophagus (black arrow) with no evidence of an esophageal diverticulum. The previously observed air-filled structure is no longer evident in the cervical region.
Citation: Journal of the American Veterinary Medical Association 236, 6; 10.2460/javma.236.6.627
Comments
Three dogs with herniation of the cranial lung lobe into the cervical region have been reported.1,2 All were ≥ 13 years old, had a history of chronic airway disease, and had clinical evidence of lung herniation only on expiration. Spontaneous hernias occur as a result of a sudden increase in intrathoracic pressure typically associated with clinical signs secondary to chronic obstructive airway disease, such as coughing and sneezing, and in conjunction with a localized weakness in the thoracic wall.3 To our knowledge, a congenital cranial lung lobe herniation has not been reported for dogs but is suspected in the dog of this report because of the dog's age, history, and herniation that occurred during inspiration.
A diagnosis of cranial lung lobe herniation can be made through several imaging modalities, including survey radiography, computed tomography, and fluoroscopy. Computed tomography can aid in detecting the location and extent of the thoracic wall defect; however, it can produce false-negative results as a result of the quiet breathing associated with anesthesia necessary to perform the procedure. Fluoroscopy is currently thought to be the best imaging technique, as it allows evaluation of lung movement during the respiratory cycle.1
Complications secondary to lung herniation are rare but may include incarceration and strangulation of the herniated lobe, pain, hemoptysis, recurrent infection, and interference with normal activity. In the dog of this report, surgical repair was the treatment of choice because of the clinical signs and potential curative nature of surgery. Surgery was declined by the owner, and an intermittent cranial lung lobe herniation was confirmed on necropsy. No gross evidence of bronchitis or tracheitis was found.
- 1.↑
Guglielmini C, De Simone A, Valbonetti L, et al. Intermittent cranial lung herniation in two dogs. Vet Radiol Ultrasound 2007;48:227–229.
- 2.
Coleman MG, Warman CGA, Robson MC. Dynamic cervical lung hernia in a dog with chronic airway disease. J Vet Intern Med 2005;19:103–105.
- 3.↑
Brock MV, Heitmiller RF. Spontaneous anterior thoracic lung hernias. J Thorac Cardiovasc Surg 2000;119:1046–1047.
