Obstructive shock due to a spontaneous haemothorax caused by primary lung cancer

We describe the case of a 67‐year‐old man with shock and hypoxemia. Chest X‐ray showed bilateral lung mass shadows and left pleural effusion with a mediastinal shift, suggesting malignancy. Physical examination and point‐of‐care ultrasound findings did not suggest obstructive or cardiac shock, but the patient had prolonged shock refractory to fluid and blood transfusion therapy. We inserted a drain into the left thoracic cavity, which enabled the patient to recover from shock. We diagnosed the patient with obstructive and hypovolemic shock due to spontaneous haemothorax caused by primary lung cancer. Tension haemothorax due to malignancy is rare, and when obstructive shock is combined with haemorrhagic shock, it can be very difficult to determine the cause of shock.