Lit Matters 1: Decision rules for discharging mild TBI patients

Mild traumatic brain injury is not always a mandatory admission, even in patients on anticoagulants when the initial head CT is negative and the neurologic exam is normal. Positive CT findings are different: early-discharge rules like HSC-DR are highly conservative, with excellent sensitivity but very low yield for sending patients home.

ACEP Mild TBI Decision Rules

• Mild TBI definition: ACEP defines mild traumatic brain injury as GCS 14-15, improving to 15 within 2 hours if initially 14, with or without loss of consciousness, amnesia, or disorientation and presentation within 24 hours.
• Preferred head CT rule: The Canadian CT Head Rule carries the strongest ACEP endorsement for deciding which adult minor head injury patients need imaging, while NEXUS Head CT and New Orleans Criteria are less specific.
• Anticoagulation imaging caution: Do not use standard head CT decision tools to rule out imaging in patients taking anticoagulants or antiplatelet agents other than aspirin, because these rules were not built for that risk profile.
• Single negative CT discharge: For anticoagulated or antiplatelet-treated patients with a normal baseline neurologic exam and no hemorrhage on the initial CT, routine repeat imaging and routine admission are not recommended.
• Post-concussive risk factors: Female sex, psychiatric history, intoxication, assault mechanism, loss of consciousness, and GCS below 15 all raise concern for prolonged symptoms; we get into the discharge counseling nuances in the episode.

Positive CT Discharge Tools

• HSC-DR clinical target: The Hull Salford Cambridge Decision Rule was built for the harder question: which mild TBI patients with a positive head CT can still be discharged safely rather than admitted for observation.
• Sensitivity versus usefulness: In CENTER-TBI validation, HSC-DR reached 100% sensitivity for deterioration but identified only 3.5% of patients as safe for discharge, making it reassuring yet operationally limited.
• BIG comparison signal: BIG criteria discharged more patients than HSC-DR but missed clinically important deterioration in this cohort, a reminder that external validation can look very different from the derivation study.
• Deterioration outcome meaning: The composite outcome was not trivial observation alone; it included neurosurgical intervention, ICU admission beyond monitoring, intubation, seizure, death, or a documented GCS decline.
• Current bottom line: Early-discharge rules for CT-positive mild TBI are promising but not mature enough to broadly change practice, and the conservative-versus-practical tradeoff is worth hearing in the chapter.