Атлас по рентгенологии травмированных собак и кошек / an-atlas-of-radiology-of-the-traumatized-dog-and-cat

22 Radiology of Thoracic Trauma

Case 2.2

2

	Thorax wall injury 23
Signalment/History: “Snoopy” was a 1-year-old, female	caused by the subcutaneous air and the bandage around the
mixed breed dog who had been attacked by two larger dogs.	thorax. The diaphragm was intact.
The thorax was wrapped with a bandage in an effort to reduce	Treatment/Management: The dog was treated with cage
the flow of air into the pleural space and to prevent the obvi-
ously fractured rib ends from further injuring the underlying	rest and radiographs made three days later showed a decrease
lungs.	in the subcutaneous emphysema. Collapse of the right middle		2
Physical examination: The severe injury to the right chest	lung lobe remained. The right caudal lobe had cleared com-
	pletely and was aerating normally.
wall was evident and crepitus was apparent on palpation of the	As an uncomplicated contusion to a lung lobe with only hem-
ribs.
	orrhage and edema should clear within 24 to 48 hours follow-
Radiographic procedure: Two views of the thorax were	ing trauma, but whereas the radiographs made on day 3
made.	showed continued right middle lobe collapse, it was assumed
	that either the trauma had been more severe than supposed,
Radiographic diagnosis: Soft tissue swelling along the right	bronchial obstruction was present, or a pneumonia was super-
thoracic wall with subcutaneous emphysema was seen over the	imposed over the injured lung. “Snoopy” was placed on an-
badly distorted fractured ribs on the right. The bandaging had	tibiotic therapy because of the possibility of a secondary pneu-
collapsed the subcutaneous space on the right side and forced	monia in that lung lobe and she improved clinically within the
most of the subcutaneous air to relocate along the left thoracic	next few days and was discharged.
wall. Underlying injury to the right middle lung lobe had	Comments: Note how difficult and incomplete the radi-
caused its collapse with additional injury to the right caudal
lobe dorsally (black arrows). The cardiac silhouette was shifted	ographic interpretation would have been if only a single later-
to the right and the left hemidiaphragm was shifted caudally to	al radiograph of the thorax had been made; having two views
permit compensatory hyperinflation of the left lung. Pneu-	makes the study more complete.
mothorax was difficult to detect because of the shadows

24 Radiology of Thoracic Trauma

Case 2.3

2

Signalment/History: “Chamois” was a 7-year-old, female Maltese Terrier that had been bitten across the thorax by a larger dog.

Physical examination: A definite defect associated with the suspected puncture wound was palpable in the right thoracic wall with associated subcutaneous emphysema. The lung fields on the right were quiet on auscultation, while more normal lungs sounds were heard on the left.

Radiographic procedure: Radiographs were made of the thorax.

Radiographic diagnosis: Subcutaneous emphysema was present on the right cranial chest wall plus a wide separation of the right 7th and 8th ribs that indicated a tearing of the intercostal muscles (arrow). The increase in fluid density in the right middle lung lobe plus the loss in volume suggested both contusion and atelectasis. The right caudal lung lobes as well as the left lung appeared to be well inflated. A portion of the right scapula created an apparent region of increased fluid density in the region of the right cranial lobe. Retraction of the caudal lung lobes from the diaphragm on the lateral view indicated a pneumothorax. Minimal pleural effusion was evident on the right. The diaphragm was intact with the left hemidiaphragm more caudal in position. Identification of the spleen confirmed the absence of adjacent peritoneal fluid.

Treatment/Management: “Chamois” was treated conservatively and recovered.

Comments: The trauma was more of a puncture wound suggesting the possibility of severe injury to the underlying lung that could require a longer time in healing. Pocketing of pleural fluid often occurs around partially collapsed lung lobes.

Thorax wall injury 25

2

26 Radiology of Thoracic Trauma

Case 2.4

2

Thorax wall injury 27

Signalment/History: “Peppy”, a 2-year-old, male Pekingese, had been found by his owner in respiratory distress several hours earlier. The owner assumed another dog had attacked him.

Physical examination: Physical examination was difficult to conduct because of pain. Subcutaneous emphysema was palpated along the left thoracic wall, along with an obvious displacement of the mid-thoracic ribs.

Radiographic procedure: It was difficult to position the dog for the DV view because of the soft tissue injury around the left shoulder.

Radiographic diagnosis: Severe thoracic wall injury was evident with multiple fractures of the left 5th, 6th, 7th, and 8th ribs resulting in a flail chest. Generalized subcutaneous emphysema was present. The left lung lobes had a loss in volume plus an increased fluid density, probably resulting from a combination of pulmonary contusion and atelectasis. The right lung lobes had only a minimal increase in fluid density from the passive atelectasis caused by the pneumothorax (white arrows). The collapse of the left lobes and severe injury to the chest wall probably resulted in the pleural air shifting into the right hemithorax. The left lung collapse had resulted in a minimal mediastinal shift to the left. The cranial mediastinum was widened at the level of the first ribs suggesting a hemomediastinum (black arrows). No pleural fluid could be identified, although it was difficult to make any judgment of possible flu-

id in the left hemithorax. The cardiac silhouette appeared separated from the sternum because of the mediastinal shift. The caudal displacement of the right hemidiaphragm was expected with the lung changes noted.

Treatment/Management: The patient was not left for	2
treatment.

Comments: A pneumothorax on the side opposite to the trauma is not very common and indicates the presence of a fenestrated mediastinum. The origin of the subcutaneous air is probably associated with the puncture wound although a lung lobe could also have been lacerated. A skin laceration, especially in the axillary region, can function as a “pump” activated by movement of the forelimb thereby filling the subcutaneous space with air.

The position of the mediastinum in this patient is affected by:

(1) atelectasis on the right, (2) pneumothorax on the right, and

(3) lung injury with lobar collapse on the left. The free pleural air contrasts with the aorta and esophagus on the lateral view making them more visible.

Note that the lateral view is oblique as shown by the location of the rib ends dorsally and ventrally. Also, the shoulder joints are not superimposed. Oblique positioning of this type can be easily corrected by the placement of small sponge wedges under the sternum and under the ventral portion of the abdomen.

28 Radiology of Thoracic Trauma

Case 2.5

2

Thorax wall injury 29

2

Signalment/History: “Rax”, a 9-year-old, male DSH cat, had been attacked by a dog 10 days previously. Following the trauma, he had run away and had been missing for the intervening 10 days. He had only returned home on the day of presentation.

Physical examination: Palpation of the thorax indicated marked abnormality in the region of the sternum with severe soft tissue swelling. The cat was dyspneic.

Radiographic procedure: Thoracic radiographs were made with the background knowledge that they were probably made 10 days after the injury.

Radiographic diagnosis (day 10): Injury to the sternum had resulted in a ventral and cranial displacement of sternebrae 6, 7, and 8 (top left). The xiphoid process remained in a nearnormal position. Injury to the thoracic wall on the left had caused a flail chest with multiple fractures of left ribs 7–10, which were characterized by fragment displacement and severe injury to the thoracic musculature (DV view). Subcutaneous emphysema was seen. The left crus of the diaphragm was shifted cranially, but appeared to be intact. The left lung lobes had an increased water density indicating contusion and atelectasis to the caudal half of the cranial and caudal lobes.

Treatment/Management: This case was unusual since the history suggested that the cat had been injured 10 days prior to presentation for treatment. It illustrates how survival can be achieved if one lung remains functional despite the open pneumothorax and severe injury to one chest wall.

Additional radiographs were made nine days later (top right) following surgical repair of the flail chest by the placement of an external splint around the chest wall, which permitted a lateral “fixation” of the larger rib fragments to the external device.

It is remarkable that “Rax” continued to improve clinically and was eventually released.

30 Radiology of Thoracic Trauma

Case 2.6

2

Thorax wall injury 31

Signalment/History: “Blimp”, an obese, 5-year-old, male DSH cat, was dyspneic and had a puncture wound in the right thorax and subcutaneous emphysema on the left.

Physical examination: The obesity of this cat made it almost impossible to auscultate the lungs or to learn of the status

of the patient by physical examination.

2

Radiographic procedure: Radiographs were made of the thorax with the hope of learning more of the origin of the puncture wound and its severity. Two right lateral views were made, one on greater inspiration.

Radiographic diagnosis: A marked infiltrative pattern within the lung lobes was located primarily in the middle and caudal lobes on the right (DV). The pattern was assumed to be interstitial since an air-bronchogram pattern could not be identified. Subcutaneous emphysema was more severe on the left and a single metallic pellet lay in the soft tissue at the level of the 9th rib on the left. Fracture of the 7th rib on the right with a small metallic fragment adjacent to the fracture site suggested the shot had passed through the thorax. The diaphragm was intact. Pleural fluid was difficult to evaluate because of the cat’s obesity.

Treatment/Management: The fracture plus identification of the single pellet indicated a gunshot wound resulting from a high-pressure airgun. “Blimp” recovered and returned to his life of leisure.

Comments: The cat’s obesity had resulted in the deposition of fat adjacent to the parietal pleura making the detection of minimal pleural fluid impossible. Lack of inspiration in this obese patient made determination of the severity of lung injury impossible.