Equine haemothorax

Summary Haemothorax is an uncommon, although clinically important, condition in horses of all ages and has a wide range of aetiologies. Clinical signs can include tachypnoea, dyspnoea, tachycardia, absence of bronchovesicular sounds, haemoptysis, colic and death. The most common aetiologies are associated with trauma, neoplasia, coagulation disorders, iatrogenic causes and vessel rupture. Diagnosis is made if there is evidence of thoracic fluid on ultrasonography and confirmation of haemorrhage by thoracocentesis. The goals of treatment are to address the primary cause and provide supportive care. Prognosis depends on aetiology, severity of active bleeding and volume of blood loss.