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Had a previous history of pericarditis with pericardial effusion. Had a pericardectomy performed six months prior to presentation. Also has a previous history of DMVD B2 and is on Pimobendan. At a cardiology recheck one week prior to the emergency presentation, a scant amount of pleural effusion was noted. Physical examination revealed a mildly increased respiratory rate with respiratory effort. There were crackles auscultated on the right hemithorax and muffled lung sounds ventrally. Point of care bloodwork was unremarkable and a thoracocentesis performed removed 180 mL of hemorrhagic fluid from the right hemithorax.


Ultrasound video clip, right intercostal spaces

  • A lung lobe within the middle right hemithorax is enlarged and emphysematous.
  • This abnormal lung is further characterized by a thin hypoechoic peripheral band (“hypoechoic band sign“) encapsulating numerous reverberating hyperechoic foci, consistent with gas. The peripheral lung is devoid of vascular markings on color Doppler. No bronchi can be seen. ]
  • Mild to moderate echogenic effusion is located in the pleural space.
  • Enlarged and emphysematous right middle lung lobe, without peripheral evidence of vascularity. A lung lobe torsion is given primary consideration, however pulmonary necrosis without torsion cannot be ruled out.
  • Mild to moderate volume of echogenic pleural effusion. A suppurative and/or hemorrhagic effusion is prioritized, likely secondary to lung lobe torsion.

Thoracic Radiographs

Left lateral radiograph of the thoraxcaption
Right lateral radiograph of the thoraxcaption
Ventrodorsal radiograph of the thoraxcaption
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There is a moderate volume of pleural effusion, more on the right. The region of the right middle and right caudal lung lobes have increased soft tissue opacity with many numerous small pinpoint gas foci interspersed throughout. This stippling of lung may be in an enlarged right middle lung lobe. The bronchus of the right middle lung lobe is focally attenuated near the hilus, then becomes visible again, directed caudally and ventrally. An increased interstitial pulmonary pattern is present in the caudal segment of the left cranial lung lobe, best visualized on the VD projection. The cardiac silhouette margins are partially effaced by the increased soft tissue opacity on all projections. The pulmonary vasculature where visible is within normal limits. The remainder of the trachea and mainstem bronchi are gas filled and normal in diameter. The esophagus is mildly gas filled. The cranial mediastinum mildly widened, likely secondary to fluid accumulation. The sternal and tracheobronchial lymph nodes are not visualized. The imaged cranial abdomen has normal serosal detail. The liver is normal. The stomach is gas filled. There is multifocal spondylosis deformans that is unchanged from the previous examination. T

Radiographic Diagnosis:

  • Stippled gas accumulation in an enlarged right middle lung lobe.
  • Caudoventrally directed bronchus of the right middle lung lobe.
  • Pleural effusion.

The effusion and parenchymal lung changes hinder evaluation of the heart, but the cardiac silhouette is still likely enlarged. The primary differential for the combination of findings is right middle lung lobe torsion. The lung pattern in the right caudal lung lobe and left cranial lung lobe may be related to mild compressive atelectasis from the surrounding effusion. Vascular compromise (lung necrosis) without torsion of the right middle lung lobe cannot be ruled out.  Thoracotomy is recommended.