Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

94 Small Animal Radiolo g y and Ultrasono graphy
Fig. 2-67 A 1-year-old female cat showed evidence of respiratory distress
after surgery for the repair of a diaphragmatic hernia. There is air within the
pleural space separating the lungs from the lateral thoracic wall. In the ventrodorsal
(A) and lateral (B) radiographs there is atelectasis of the right caudal
lung lobe (closed arrows). There is irregularity of the diaphragm at the site
of diaphragmatic hernia repair (open arrows). In the lateral radiograph there
is air within the peritoneal cavity due to surgery (large arrows). The radiographic
findings are indicative of pneumothorax subsequent to diaphragmatic
hernia repair. The marked increase in pulmonary density in the right
caudal lung lobe indicates that there is pathology within this lung lobe. This
is most likely residual atelectasis or pulmonary contusion. Diagnosis:
Pneumothorax and atelectasis of the right caudal lung lobe, which resolved
after chest tube placement and continued aspiration of the pleural space.
A
B
Pneumothorax is most often secondary to trauma and can occur with or without rib
fractures. Spontaneous pneumothorax refers to those that occur in the absence of
trauma, resulting from rupture of a lung tumor, abscess, or bulla, or from pleural
tears. 155-163
Tension pneumothorax occurs when a tear in the visceral pleura functions as a one-way
(or “flap”) valve and air continues to accumulate within the pleural space. Under these cir-