Minimal head injury in asymptomatic patients on antithrombotic therapy: is in-hospital observation justified after an initial normal computed tomography scan?

Patients receiving antithrombotic therapy are frequently admitted for in-hospital observation after head trauma despite a normal initial cranial computed tomography (CT) scan. The clinical value of routine observation in asymptomatic patients with minimal head injury remains uncertain. This study evaluated the incidence of delayed intracranial hemorrhage (DIH) and the relevance of routine hospital observation. We conducted a retrospective cohort study of adult patients (≥ 18 years) receiving antithrombotic therapy who presented with minimal head injury, defined as the absence of loss of consciousness, amnesia, disorientation, or neurological symptoms and a Glasgow Coma Scale score of 15. All patients had a normal initial cranial CT. Cases were identified from an institutional trauma database between January 2019 and December 2023. Patients with traumatic brain injury, prior intracranial hemorrhage, or abnormal initial imaging were excluded. According to institutional protocol, patients receiving acetylsalicylic acid monotherapy underwent home observation, whereas other antithrombotic regimens, including anticoagulants and/or antiplatelet agents, required admission. A total of 5800 patients met inclusion criteria (median age 83 years, interquartile range 77-88). Of these, 3697 were admitted and 2103 were managed as outpatients. During follow-up, 179 unique patients (3.1%) developed delayed neurological symptoms and underwent repeat CT imaging. DIH was detected in 9 patients (0.2%). Two cases occurred within 24 h; the remainder were diagnosed between three and nine days after injury. No patient required neurosurgical intervention. DIH after minimal head injury in asymptomatic patients receiving antithrombotic therapy is rare, suggesting limited clinical benefit of routine in-hospital observation after a normal CT scan. Trial registration: 'retrospectively registered' (1057/2023). Level of evidence: III.