Extrapleural hematoma that was not detectable on initial CT in a patient with pneumonia

Extrapleural hematoma (EH) is an uncommon and occasionally life-threatening condition. Huge EH can cause potentially fatal respiratory and circulatory disturbances. The usual causes of EH are chest trauma, iatrogenic injury, and rupture of a thoracic aortic aneurysm. There have been few reports of EH as a complication of pneumonia. Here we describe a case of EH that was not detectable on initial computed tomography (CT) in a patient with pneumonia despite symptoms suggestive of hemorrhage. A 70-year-old man who had been diagnosed with pneumonia the previous day visited our hospital after developing right upper abdominal pain of sudden onset. Initial noncontrast-enhanced computed tomography (CT) showed consolidation of the right lower lobe of the lung but no hematoma. He was discharged from hospital. When the pain recurred the following day, he was transported by ambulance back to our hospital and admitted. Contrast-enhanced CT showed an EH that had not been apparent on the initial CT scan taken 33 h earlier. Coagulation tests were within normal limits. He was treated conservatively and monitored closely. His symptoms improved, and he was discharged 4 days after admission. The EH did not enlarge and had almost disappeared by 56 days after admission. The pathophysiology of the relationship between pneumonia and EH is unclear. This case suggests that EH cannot be ruled out by initial CT findings soon after an episode suggestive of hemorrhage and can occur as a complication of pneumonia. Therefore, patients in whom EH is suspected should be followed up closely.