Biomarkers of Brain Injury: Magnitude and Outcome of Mild and Moderate TBI

Mild/Moderate TBI Group Inclusion Criteria: 1. 18 years or older 2. GCS 9-15 3. CT scan as part of clinical evaluation 4. experienced some level of altered mental state at time of injury 5. determination of study eligibility within 4 hours of injury Exclusion Criteria: 1. Pregnant females 2. Prisoners 3. Anemia or significant blood loss (hemoglobin \< 12 mg/dL and/or hematocrit \< 35%, and/or clinical state requiring resuscitation with more than 6L of colloid or crystalloid fluid) 4. no clear history of trauma as primary event 5. previous history of stroke, or head injury requiring hospitalization 6. dementia or psychotic illness or neurological condition which may affect outcome 7. unable to speak or understand English Orthopedic Control Group Inclusion Criteria: 1. 18 years or older 2. Isolated extracranial orthopedic injury, including fractures 3. Stable vital signs on presentation to ED (pulse \< 100bpm and systolic blood pressure \> 100 mmHg) Exclusion Criteria: 1. evidence of brain injury, including abnormal neurological examination, alteration in consciousness, memory or mental status, headache, dizziness, or vomiting following injury 2. not enrolled within 4 hours of injury 3. Pregnant females 4. Prisoners 5. Anemia or significant blood loss (hemoglobin \< 12 mg/dL and/or hematocrit \< 35%, and/or clinical state requiring resuscitation with more than 6L of colloid or crystalloid fluid) 6. previous history of stroke, or head injury requiring hospitalization