Occult sources of bleeding in blunt trauma: A narrative review

Worldwide, hemorrhagic shock in major trauma remains a major potentially preventable cause of death. Controlling bleeding and subsequent coagulopathy is a big challenge. Immediate assessment of unidentified bleeding sources is essential in blunt trauma patients with hemorrhagic shock. Chest/pelvic X-ray in conjunction with ultrasonography have been established classically as initial diagnostic imaging modalities to identify the major sources of internal bleeding including intra-thoracic, intra-abdominal, or retroperitoneal hemorrhage related to pelvic fracture. Massive soft tissue injury, regardless of whether isolated or associated with multiple injuries, occasionally causes extensive hemorrhage and acute traumatic coagulopathy. Specific types of injuries, including soft tissue injury or retroperitoneal hemorrhage unrelated to pelvic fracture, can potentially be overlooked or be considered "occult" causes of bleeding because classical diagnostic imaging often cannot exclude such injuries. The purpose of this narrative review article is to describe "occult" or unusual sources of bleeding associated with blunt trauma.