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Signalment and history: A 6-year-old female spayed Beagle mix presented for panting, lethargy, and increased respiratory rate and effort. She initially presented to another emergency facility three days prior to referral for panting and lethargy and was administered subcutaneous fluids and medications for diarrhea. She was eating and drinking normally that day, but in the evening, she started panting and became lethargic. An increased respiratory rate and effort persisted. She had a history of dietary indiscretion, including eating a large steak and possibly chicken bones that were in the trash the day before she became ill.

Physical examination and initial diagnostics: The patient was quiet, alert, and responsive. Her respiratory rate was elevated and characterized by increased abdominal effort. Bilaterally, lung and heart sounds were decreased. The remainder of the physical examination was within normal limits. A serum chemistry panel showed elevated ALP (309 U/L; 23-212). A complete blood count showed mature neutrophils were within normal limits; however, there were suspect immature neutrophils and a monocytosis, indicating inflammation.

Due to the patient’s tachypnea and decreased heart and lung sounds, thoracic radiographs were made. A moderate bilateral hydropneumothorax was confirmed. A thoracic CT was recommended after a diagnostic thoracocentesis found a septic pleural effusion.

 

Thoracic CT prior to administration of contrast in lung and soft tissue algorithms.
The patient's right is on the right side of the images.

Bone and soft tissue algorithms post-contrast.
The patient's right is on the right side of the images.

Soft tissue post-contrast in sagittal reconstruction, with dorsal plane reference.
The patient's right is on the right side of the images.

Originating in the gastric fundus, there is a sharp thin foreign body 15 cm in length and 100-150 HU that bulges the ventral gastric wall, courses dorsally to perforate the gastric cardia wall, left diaphragmatic crus, left caudal pleural space, left caudal lung lobe, and then terminates in the left epaxial muscles at the 11th intercostal space. In the left epaxial muscles, there are small foci of intramuscular gas where the foreign body terminates. There is no evidence of pneumoperitoneum. Within the left pleural space, there is a large volume of gas and a small volume of ventrally distributed, fluid attenuating material. Dorsal portions of the left caudal lung lobe are adhered to the parietal surface of the dorsal thoracic body wall. The left caudal and left cranial lung lobes are diffusely consolidated (soft tissue attenuating) and hypoinflated. There is a rightward mediastinal shift, compatible with increased pressure within the left pleural space.
In the right pleural space, a moderate volume of fluid attenuating material is present ventrally, and caudodorsally there is a small volume of gas. Throughout the right lung lobes, there are moderate amorphous to uniform soft tissue attenuating regions.

Conclusions
1. Long skewer foreign body perforating the gastric cardia wall, left diaphragmatic crus, left pleural space, left caudal lung lobe, and left epaxial muscles. Small foci of intramuscular gas at the termination site of the foreign body are compatible with epaxial abscess formation.

2. Marked left-sided tension pneumothorax with moderate pleural effusion. Immediate therapeutic thoracocentesis was recommended.

3. Bilateral pulmonary consolidation.
Consider secondary to hypoinflation and reactive pneumonitis/pleuropneumonia.

Surgery
An exploratory laparotomy and a thoracotomy were performed. A wooden skewer was pressing ventrally from within the stomach and dorsally perforated the stomach, diaphragm, left caudal lung lobe, and epaxial musculature. Purulent material was present in both the abdomen and thorax. The gastric defect was closed with 2-0 PDS in a double layer continuous pattern. A 4 mm diameter defect in the diaphragm was left to heal on its own. The left caudal lung lobe was punctured, so it was excised. Thoracic and abdominal cavities were copiously lavaged prior to closure. A thoracostomy tube exiting the left thorax and a Jackson-Pratt drain exiting the right abdomen were placed. Lung tissue and fluid from the stomach were submitted for culture. After surgery, the patient remained hospitalized for several more days for IV antibiotics, pain control, and supportive care prior to discharge. The patient recovered uneventfully and continues to do well at home.

Diagnosis
Pyoneumothorax and gastric perforation secondary to a penetrating wooden foreign body. A secondary alpha-hemolytic Streptococcus spp. infection was confirmed with culture.

Discussion
Wooden foreign bodies occur fairly commonly in small animal patients and are often caused by either penetrating trauma or ingestion.1 The foreign material can then migrate to distant sites in the abdomen or thorax. Ingested foreign bodies may migrate into the thorax with or without evidence of gastric perforation.2 Computed tomography has been shown to be both highly specific and accurate in localizing wooden foreign bodies, and it aids in surgical planning.3 Wood can have varying attenuation based on chronicity and the degree of moisture within the wood itself. In one study, the attenuation values for confirmed wooden foreign bodies ranged from -344HU to 640 HU.3 For this reason, it is helpful to evaluate CT images using a wide window, especially with suspected intrathoracic foreign bodies. Contrast enhancement may also be helpful in order to assess for abscessation. Pyothorax is common secondary to migrating foreign bodies and can either be treated medically or surgically.2 In this case, the penetrating foreign body caused a septic pleural effusion and progressive pneumothorax that necessitated a caudal lung lobectomy. Pneumothorax is another potential sequela to migrating foreign bodies.4 In this case, the foreign body penetrated the caudal aspect of the left caudal lung lobe, which led to both a pyothorax and pneumothorax. Since the penetrating trauma to the lung created a one-way valve, the intrathoracic pressure within the left hemithorax continued to increase, resulting in a tension pneumothorax that required immediate recognition and intervention.5

References:
1. Ober CP, Jones JC, Larson MM, Lanz OI, Werre SR. Comparison of ultrasound, computed tomography, and magnetic resonance imaging in detection of acute wooden foreign bodies in the canine manus. Vet Radiol Ultrasound. (2008) 49:411–8. doi: 10.1111/j.1740-8261.2008.00399.x

2. Choi YD, Han HJ. Pyothorax induced by an intrathoracic foreign body in a miniature dachshund: Migration of a popsicle stick from the stomach. J Vet Med Sci. 2017;79(8):1398-1403. doi:10.1292/jvms.17-0057

3. Lamb CR, Pope EH, Lee KC. Results Of Computed Tomography In Dogs With Suspected Wooden Foreign Bodies. Vet Radiol Ultrasound. 2017;58(2):144-150. doi:10.1111/vru.12457

4. Wisner E., Zwingenberger A. Atlas of Small Animal CT and MRI. Ames, IA: John Wiley & Sons, Inc. 2015:398-405.

5. Thrall D. Textbook of Veterinary Diagnostic Radiology. 7th ed St. Louis, MO: Elsevier; 2018:681-682.