Assessment, Diagnosis, and Ongoing Medical Management of Brain Injury
Severity, diagnosis, and the longitudinal exam
Acute assessment starts with mechanism and physiology: prevent secondary injury from hypoxia (SpO2 <90%), hypotension (SBP <90 mmHg), hyperthermia, hypo- or hyperglycemia, and seizures. Noncontrast head CT is the acute test of choice for hemorrhage, mass effect, and herniation; MRI (SWI/GRE for axonal shear and microhemorrhage, FLAIR for contusion) answers later prognostic questions.
Severity rests on three variables: GCS, loss of consciousness, and post-traumatic amnesia. Mild = GCS 13–15, LOC ≤30 minutes, PTA <24 hours; moderate = GCS 9–12, LOC 30 minutes to 24 hours, PTA 1–7 days; severe = GCS 3–8, LOC >24 hours, PTA >7 days. Use the worst documented post-resuscitation values, and never grade an intubated, sedated, or paralyzed patient - the motor score in particular is uninterpretable.
Ongoing management is a surveillance exercise: serial neurologic exams, medication review for sedating and anticholinergic burden, seizure threshold, swallowing, nutrition, VTE prophylaxis, bowel and bladder function, sleep–wake integrity, spasticity, pain, mood, and pituitary function. Post-traumatic hypopituitarism is common and underdiagnosed; screen with morning cortisol, free T4, IGF-1, and gonadal axis when fatigue, hypotension, or poor recovery is unexplained.
Trap: questions often present a patient whose GCS improved but who has prolonged PTA; PTA duration is the stronger predictor of functional outcome and of late cognitive complaints. Another trap is calling a scan 'normal' reassuring in an anticoagulated patient - delayed hemorrhage occurs.
Rule of thumb: GCS tells you how the brain is now; PTA tells you how the brain will be.
Worked example: a 34-year-old restrained driver with ED GCS 6, paralyzed and intubated for transport, has a post-resuscitation GCS off sedation of 8 and 9 days of PTA. Classify as severe and counsel the family using PTA and imaging, not the paralyzed exam.