Introduction

• Cause: chronic bronchitis, bronchopneumonia, other lung parenchymal diseases, pleural effusions or pneumothorax, prolonged lateral recumbency (hypostatic congestion).
• Signs: respiratory distress.
• Diagnosis: radiography
• Treatment: manage underlying cause, lobectomy if irreversible collapse.
• Prognosis: can be good with early treatment - depends on underlying cause.

Pathogenesis

Etiology

• Neoplasia Lung: pulmonary neoplasia.
• Foreign body Airway foreign body.
• Lung contusion Lung: contusion.
• Pneumonia Lung: bacterial pneumonia.
• Tension pneumothorax Tension pneumothorax.
• Pneumothorax Pneumothorax.
• Pleural effusion Pleural: effusion.
• Lung lobe torsion Lung: lobe torsion.
• Prolonged lateral recumbency, particularly if the animal is anesthetized (so called hypostatic congestion).

Pathophysiology

• Chronic bronchitis, bronchopneumonia and other lung parenchymal diseases → mucus plugging can lead to lung collapse (may be irreversible).
• Pleural effusions or pneumothorax → lung collapse.
• Prolonged lateral recumbency, eg while anesthetized → hypostatic congestion → lung collapse.
• Respiratory/thoracic pathology, eg thoracic surgery, trauma, effusions may cause torsion.

• Upset of normal equilibrium between intrapulmonary pressure and pleural pressures.
• Airway obstruction → reduced collateral ventilation between lung tissue, eg neoplasia, foreign body, pneumonia, hypostatic.
• Compression of lung - due to pleural fluids or congestion.
• Loss of negative pleural pressure → collapse, ie pneumothorax.
• Surfactant depletion, eg pneumonia, thromboembolism, trauma.

Diagnosis

Treatment

Outcomes