Pyothorax in a Canine Patient
Case Study
A 4-year-old working guardian Great Pyrenees Mix named Jack presented to our hospital on February 10, 2025, for severe lethargy, reluctance to walk, and generalized limb lameness. On arrival, he was febrile (105.3°F), tachypneic, and had noticeable swelling and warmth over the right elbow and axillary region. Initial diagnostics revealed cellulitis in the right elbow region (confirmed by cytology showing degenerative neutrophils with suspected intracellular bacteria), and significant pleural effusion with cytology consistent with septic exudate. A thoracocentesis was performed under anesthesia, yielding 2600 mL of purulent fluid. Bilateral chest tubes were placed and ongoing drainage and thoracic lavage were initiated. He was hospitalized and started on IV Unasyn and Enrofloxacin, along with supportive care. A CT scan was performed which showed
Right elbow fluid accumulation and soft tissue thickening, consistent with abscess/cellulitis, with additional right proximal thoracic limb subcutaneous fluid accumulation (edema, etc.)
Bilateral pleural effusion with marked ventral pleuritis and multilobar pulmonary atelectasis. Concurrent pneumonia within the right cranial, right middle, accessory, and/or caudal subsegment of the left cranial lung lobes is considered.
Right superficial cervical, bilateral axillary, and multifocal intrathoracic lymphadenopathy.
No definitive aggressive osseous pathology or foreign material is identified.
Minimally displaced segmental fracture of the right 7th costal cartilage with suspected gas accumulation in the affected portion of the cartilage and surrounding pleuritis/cellulitis. Primary consideration is given to focal trauma that resulted in both the cartilaginous fracture and introduced bacteria that resulted in the reported pyothorax, while primary costochondritis as the root cause for the pyothorax is considered somewhat less likely.
On February 11, Jack underwent a bilateral lateral thoracotomy. In surgery a floating piece of fractured rib was found and removed. A piece or mediastinum and lung lobe were also collected for histopathology. The thorax was copiously lavaged and chest tubes were replaced. He recovered on oxygen supplementation and fentanyl CRI. Postoperatively, Jack remained on intensive monitoring, including frequent pleural fluid assessments, chest tube management, and urine output monitoring via urinary catheter.
By February 12, Jack developed hypoalbuminemia, poor appetite, and low urine output. An NG tube was placed to provide trickle feeding, and fluid therapy was adjusted based on hydration and serum chemistry.
Over the following days (Feb 13–14), Jack showed gradual improvement in respiratory parameters, appetite (particularly with high-value foods), and activity. However, he became anemic, likely secondary to surgery and chronic inflammation. He received a blood transfusion on Feb 14, which led to a marked improvement in mentation and energy.
By February 15, his chest tubes were removed due to minimal production, and his oxygen supplementation, IV fluids, and fentanyl were successfully weaned. He transitioned to oral Clavamox and Enrofloxacin, and began ambulating more willingly with scheduled walks to address residual edema and mobility concerns. Notably, pleural fluid cultures grew beta-hemolytic Streptococcus, susceptible to ampicillin-class drugs.
By February 17, Jack was bright, interactive, eating well, and breathing comfortably on room air. His feeding improved significantly, and edema in the limbs was improving. He was discharged back into his owner’s care.
Histopathology of the rib, mediastinum and lung were consistent with the diagnosis of pyothorax and no neoplasia was found. Given Jack’s history as a working dog, the fractured rib and cellulitis of his elbow we suspect he sustained some type of trauma leading to his pyothorax.
Highlights of Specialty Services Provided
Advanced imaging and diagnostics: thoracic imaging (radiographs, tFAST, attempted CT), cytology, in-house point-of-care lab work.
Specialty surgical intervention: bilateral thoracotomy with chest tube management and bronchoscopy guidance.
Comprehensive ICU-level monitoring and care: oxygen therapy, blood transfusion, continuous ECG, NG nutritional support, and urinary catheterization.
Infectious disease management: culture-driven antibiotic selection with combination IV and oral therapies.
Collaborative, multi-service case management across critical care, surgery, and anesthesia.
