Coagulopathy and Progression of Intracranial Hemorrhage in Traumatic Brain Injury: Mechanisms, Impact, and Therapeutic Considerations

BACKGROUND: Traumatic brain injury (TBI) remains one of the most challenging health and socioeconomic problems of our times. Clinical courses may be complicated by hemostatic abnormalities either pre-existing or developing with TBI. OBJECTIVE: To review frequencies, patterns, mechanisms, novel approaches to diagnostics, treatment, and outcomes of hemorrhagic progression and coagulopathy after TBI. METHODS: Selective review of the literature in the databases Medline (PubMed) and Cochrane Reviews using different combinations of the relevant search terms was conducted. RESULTS: Of the patients, 20% with isolated TBI display laboratory coagulopathy upon hospital admission with profound effect on morbidity and mortality. Preinjury use of antithrombotic agents may be associated with higher rates of hemorrhagic progression and delayed traumatic intracranial hemorrhage. Further testing may display various changes affecting platelet function/numbers, pro- and/or anticoagulant factors, and fibrinolysis as well as interactions between brain tissues, vascular endothelium, mechanisms of inflammation, and blood flow dynamics. The nature of hemostatic disruptions after TBI remains elusive but current evidence suggests the presence of both a hyper- and hypocoagulable state with possible overlap and lack of distinction between phases and states. More "global" hemostatic assays, eg, viscoelastic and thrombin generation tests, may provide more detailed and timely information on the overall hemostatic potential thereby allowing early "goal-directed" therapies. CONCLUSION: Whether timely and targeted management of hemostatic abnormalities after TBI can protect against secondary brain injury and thereby improve outcomes remains elusive. Innovative technologies for diagnostics and monitoring offer windows of opportunities for precision medicine approaches to managing TBI.