Nervous System & Special Senses

Traumatic brain injury: severity grading and ICU management

Clinical Overview and When to Suspect Traumatic Brain Injury

— Bimodal age peaks: young adults (MVC, assault, sports) and elderly ≥65 (ground-level falls, often on anticoagulants).

— Falls are the #1 mechanism overall in the US; MVCs lead to death and severe TBI.

— Anticoagulated elderly with even minor head strike = high-risk cohort for delayed intracranial hemorrhage.

— Any witnessed or suspected head impact with LOC, amnesia, confusion, vomiting, seizure, or focal deficit.

— Polytrauma patient with GCS <15, unexplained hypotension/bradycardia (Cushing), or asymmetric pupils.

— Intoxicated patient with abnormal mentation — never attribute solely to alcohol until TBI excluded.

— Suspected non-accidental trauma in children (retinal hemorrhages, subdural in <2 yo).

— Mild: GCS 13–15 (concussion spectrum; ~80% of TBI).

— Moderate: GCS 9–12.

— Severe: GCS ≤8 → "GCS 8, intubate."

— Primary: irreversible mechanical damage at moment of impact.

— Secondary: preventable injury from hypoxia, hypotension, ↑ICP, hypoglycemia, hyperthermia, seizures — this is what ICU management targets.

Board pearl: A single episode of SBP <90 or SpO₂ <90% in severe TBI roughly doubles mortality — secondary insult prevention (avoid hypoxia and hypotension) drives the entire resuscitation algorithm. In Step 3 stems, the "right next step" in a severe TBI vignette is almost always airway control plus restoration of MAP/CPP before advanced imaging or neurosurgical consult.

Definition: Traumatic brain injury (TBI) = alteration in brain function or pathology caused by external mechanical force (blunt, penetrating, blast, acceleration-deceleration). Encompasses concussion → diffuse axonal injury → focal contusion/hemorrhage.

Epidemiology relevant to Step 3:

When to suspect TBI:

Severity grading by initial GCS (after resuscitation, before sedation):

Primary vs secondary injury — the central ICU concept:

Presentation Patterns and Key History

— Transient confusion, "fog," headache, dizziness, nausea, photophobia, retrograde/anterograde amnesia.

— LOC not required; if present, typically <30 min. Post-traumatic amnesia <24 h.

— Symptoms may evolve over hours — repeat assessment essential.

— Persistent confusion, lethargy, focal deficits, vomiting, possible early seizure.

— Higher rate of intracranial lesion on CT (~40%).

— Comatose or near-comatose, posturing, pupillary asymmetry, Cushing triad (HTN + bradycardia + irregular respirations) = late herniation.

— Epidural hematoma: temporal blow, brief LOC → lucid interval → rapid deterioration. Middle meningeal artery, biconvex CT.

— Subdural hematoma: elderly, anticoagulated, fall; insidious confusion/headache over days–weeks; crescent-shaped.

— Diffuse axonal injury (DAI): high-velocity rotational MVC; coma disproportionate to CT findings.

— Contusion: coup/contrecoup, frontal/temporal poles; can blossom 24–72 h.

— Penetrating/blast: GSW, IED — high mortality, infection risk.

— Time and mechanism of injury, helmet/seatbelt, airbag deployment.

— Loss of consciousness duration, seizure activity, vomiting count.

— Anticoagulants/antiplatelets — warfarin, DOACs, clopidogrel, aspirin.

— Alcohol/drug use, prior TBI, baseline cognitive status, advance directives.

— Premorbid neuro disease (dementia, stroke) for GCS baseline.

Key distinction: Epidural = arterial bleed, lucid interval, lens-shaped, doesn't cross sutures. Subdural = venous (bridging veins), crescent-shaped, crosses sutures but not midline. On Step 3, an elderly patient on apixaban who "seemed fine after the fall" and presents 2 days later confused → SDH until proven otherwise. Always document anticoagulant timing and last dose — it changes reversal decisions and disposition cadence.

Concussion (mild TBI):

Moderate TBI:

Severe TBI:

Mechanism-specific patterns:

Critical history elements (AMPLE + trauma-specific):

Physical Exam Findings and Hemodynamic Assessment

— Eye (1–4), Verbal (1–5), Motor (1–6). Motor is the strongest prognostic component.

— Document each subscore (e.g., E2V1M4 = GCS 7), not just total. Note "T" if intubated for verbal.

— Unilateral fixed, dilated pupil = uncal herniation compressing CN III → ipsilateral lesion in 90%.

— Bilateral fixed/dilated = catastrophic herniation or severe hypoxia.

— Pinpoint reactive = pontine lesion or opioid (consider naloxone trial).

— Hemiparesis (contralateral to lesion usually; Kernohan notch can flip).

— Decorticate (flexor) posturing = above red nucleus; decerebrate (extensor) = brainstem, worse prognosis.

— Aphasia, cranial nerve palsies, gaze deviation.

— Raccoon eyes (periorbital ecchymosis), Battle sign (mastoid), hemotympanum, CSF rhinorrhea/otorrhea ("halo sign" or β-2 transferrin +).

— Avoid nasogastric tube — use orogastric instead.

— CPP = MAP − ICP. Target MAP usually ≥80–90 mmHg if ICP unmeasured; CPP 60–70 mmHg when monitored.

— Hypotension in isolated TBI is rare — search for hemorrhagic source (chest, abdomen, pelvis, long bones, scalp in peds).

— Cushing reflex (HTN + bradycardia + irregular respirations) = impending herniation, NOT to be "treated" by lowering BP.

Step 3 management: In a hypotensive TBI patient, resuscitate first — give isotonic crystalloid or blood, identify bleeding source. Do NOT permit permissive hypotension in TBI even if there's hemorrhagic shock; SBP <90 is forbidden. Norepinephrine is first-line vasopressor once euvolemic to maintain CPP.

Glasgow Coma Scale (GCS) — score before sedation/paralytics:

Pupillary exam:

Focal neuro deficits:

Signs of basilar skull fracture:

Hemodynamic assessment — critical for CPP:

C-spine: Assume injury in all moderate–severe TBI; maintain rigid collar until cleared clinically (NEXUS/Canadian C-spine) or radiographically.

Diagnostic Workup — Initial Labs, Imaging, and Decision Rules

— Detects acute hemorrhage, fracture, mass effect, midline shift, herniation, hydrocephalus.

— Order in ALL moderate/severe TBI immediately after stabilization.

— Canadian CT Head Rule (adults ≥16, GCS 13–15, LOC/amnesia/confusion):

— High risk (CT mandatory): GCS <15 at 2 h, suspected open/depressed skull fx, basilar fx signs, ≥2 vomiting episodes, age ≥65.

— Medium risk: amnesia >30 min, dangerous mechanism (pedestrian struck, ejection, fall >3 ft/5 stairs).

— PECARN (pediatrics) — separate rules for <2 yo and ≥2 yo; emphasizes observation over CT in low-risk children to reduce radiation.

— New Orleans Criteria — applies to GCS 15 only; more sensitive, less specific.

— CBC, BMP, glucose (avoid hypo- and hyperglycemia), coagulation panel (PT/INR, PTT), platelets.

— Type and screen/cross for moderate–severe TBI.

— Ethanol, urine drug screen if mental status altered out of proportion.

— β-hCG in reproductive-age females before imaging/medications.

— ABG if intubated — target PaCO₂ 35–40, PaO₂ >60.

— Lactate, troponin if polytrauma; consider serum sodium baseline (anticipate SIADH/CSW/DI).

— FDA-cleared to help rule out intracranial injury in adults with mild TBI and GCS 13–15 within 12 h.

— Negative result → CT can often be avoided.

Board pearl: In an anticoagulated elderly patient with any head strike — even GCS 15, no symptoms — obtain non-contrast head CT. The pretest probability of occult ICH (and delayed bleeding) is high enough that decision rules don't apply the same way. Also check INR or DOAC level (anti-Xa for apixaban/rivaroxaban, dilute thrombin time for dabigatran).

Non-contrast head CT — gold standard initial imaging:

Mild TBI — use validated decision rules to select for CT:

Laboratory workup:

Serum biomarker — GFAP + UCH-L1 (Banyan BTI):

C-spine imaging: CT C-spine in any moderate/severe TBI or per NEXUS/Canadian rules.

Diagnostic Workup — Advanced and Confirmatory Studies

— Indicated 6 h after initial CT for any intracranial hemorrhage to assess progression.

— Earlier if clinical deterioration (drop in GCS ≥2, new focal deficit, pupil change, refractory ↑ICP).

— Anticoagulated patients with initial negative CT — many centers obtain delayed CT at 6–24 h or extended observation; warfarin/INR >1.5 has higher delayed bleed risk than DOACs.

— Indicated for blunt cerebrovascular injury (BCVI) screening: cervical seatbelt sign, basilar/petrous skull fx, C1–C3 fx, Le Fort II/III, GCS ≤8 with no CT explanation, near-hanging.

— Modified Denver/Memphis criteria guide screening — BCVI causes stroke days later if missed.

— Superior for DAI (susceptibility-weighted imaging shows microhemorrhages), brainstem injury, small contusions.

— Used when CT findings don't explain coma, or for prognostication days into ICU course.

— Avoid in unstable patients; not first-line acute.

— Indications (BTF guidelines): severe TBI (GCS ≤8) with abnormal CT, OR normal CT plus ≥2 of: age >40, posturing, SBP <90.

— External ventricular drain (EVD) — measures ICP AND therapeutic (drains CSF). Preferred when hydrocephalus or need to drain.

— Intraparenchymal monitor (bolt) — easier placement, no drainage capacity.

— Normal ICP <22 mmHg; treat sustained ICP >22.

— Brain tissue oxygen (PbtO₂) — target >20 mmHg.

— Continuous EEG — detect non-convulsive seizures (up to 20–25% of severe TBI).

— Transcranial Doppler — vasospasm/CPP estimation.

Key distinction: CT = acute hemorrhage and surgical lesions; MRI = axonal injury, prognosis, occult lesions. On Step 3, a comatose post-MVC patient with "unremarkable CT" but persistent coma → diffuse axonal injury suspected → MRI confirms. Do not delay neurosurgical consult waiting for MRI when CT shows a surgical lesion.

Repeat non-contrast head CT:

CT angiography (CTA) head/neck:

MRI brain:

Invasive ICP monitoring:

Adjunct neuromonitoring:

Risk Stratification and First-Line Management Logic

— A/B — Airway: Intubate for GCS ≤8, inability to protect airway, hypoxia, agitation requiring sedation, anticipated deterioration. Use RSI with neuroprotective agents (see chunk 7). Avoid hypoxia (SpO₂ <90) and hyperventilation.

— C — Circulation: Maintain SBP ≥110 in adults 15–49 and ≥70, ≥100 in ages 50–69 (BTF). Isotonic crystalloid (NS preferred over LR to avoid hyponatremia); avoid hypotonic fluids and glucose-containing solutions.

— D — Disability: GCS, pupils, lateralizing signs, glucose.

— E — Exposure: Full trauma exam; prevent hyperthermia (worsens secondary injury).

— Mild (GCS 13–15) without ICH: Observe 4–6 h, return precautions, no acute pharmacotherapy needed beyond analgesia (avoid NSAIDs/ASA in first 24 h if any bleed risk).

— Mild with ICH or moderate: Admit for serial neuro checks q1–2 h, repeat CT at 6 h, neurosurgery consult.

— Severe: ICU admission, ICP monitor consideration, neurosurgery, advanced airway, CPP optimization.

— Tier 1: Head of bed 30°, neck midline, sedation/analgesia (propofol, fentanyl), normothermia, normocapnia, CSF drainage if EVD.

— Tier 2: Hyperosmolar therapy (3% saline bolus or mannitol), neuromuscular blockade, mild hyperventilation (PaCO₂ 30–35) as bridge only.

— Tier 3: Pentobarbital coma, decompressive craniectomy, hypothermia (controversial — not for routine ICP).

— Warfarin + ICH: 4-factor PCC (preferred over FFP) + IV vitamin K 10 mg.

— Dabigatran: idarucizumab. Apixaban/rivaroxaban: andexanet alfa or 4F-PCC.

— Antiplatelets: platelet transfusion generally NOT recommended (PATCH trial) except possibly pre-neurosurgery.

CCS pearl: In the CCS severe TBI case, order in this sequence — secure airway → IV access × 2 → isotonic fluids/blood → non-contrast head CT + C-spine CT → neurosurgery consult → ICU admit → ICP monitor → reverse anticoagulation if present → continuous EEG if comatose. Advance the clock in small intervals; recheck pupils and GCS frequently.

ABCDE primary survey — TBI-specific modifications:

Severity-based pathway:

Tiered ICP management (when ICP >22):

Anticoagulation reversal — urgent:

Pharmacotherapy — First-Line Drug Regimen

— Pre-treat: Fentanyl 1–3 mcg/kg to blunt sympathetic surge (avoid if hypotensive).

— Induction: Etomidate 0.3 mg/kg (hemodynamically neutral) or ketamine 1–2 mg/kg (formerly avoided due to theoretical ICP rise; now considered safe and often preferred for hypotensive TBI patients).

— Paralytic: Rocuronium 1.2 mg/kg (longer-acting, preserves later neuro exam less than succinylcholine but avoids transient ICP rise/hyperkalemia risk). Succinylcholine acceptable if no contraindications.

— Avoid propofol bolus for induction in hypotensive patients (drops MAP).

— Propofol infusion (titrate to RASS −2 to −3); watch for hypotension, propofol infusion syndrome with prolonged high-dose use.

— Fentanyl infusion for analgesia.

— Avoid benzodiazepines as first-line (delirium, prolonged ventilation); dexmedetomidine an option for lighter sedation.

— 3% hypertonic saline 250 mL bolus (or 23.4% 30 mL via central line for herniation) — preferred in hypotensive patients; target Na 145–155.

— Mannitol 0.25–1 g/kg IV bolus — osmotic diuretic; avoid if hypovolemic or renal failure. Follow serum osm (<320) and osmolar gap.

— Levetiracetam 500–1000 mg IV BID × 7 days for severe TBI, depressed skull fx, penetrating injury, cortical contusion, subdural/epidural with cortical involvement.

— Phenytoin equally effective per BTF but more drug interactions. Continue only if seizure occurs.

Board pearl: Steroids are contraindicated in TBI — the CRASH trial showed increased mortality with methylprednisolone. This is a frequent distractor on Step 3. Also: avoid prophylactic hyperventilation (PaCO₂ <30) — causes vasoconstriction and ischemia; use only as short bridge for herniation.

RSI (rapid sequence intubation) for severe TBI:

Sedation/analgesia (post-intubation):

Hyperosmolar therapy:

Seizure prophylaxis:

Antibiotic prophylaxis: For open/depressed skull fx, penetrating injury, CSF leak (e.g., cefazolin ± metronidazole per institution).

Stress ulcer prophylaxis (PPI/H2 blocker) and VTE prophylaxis — mechanical immediately; chemical (enoxaparin 30 mg BID or UFH) typically 24–72 h after stable CT.

Procedures and Neurosurgical Management

— Epidural hematoma: >30 mL, or >15 mm thickness, or midline shift >5 mm, or GCS ≤8 with anisocoria → emergent craniotomy/evacuation regardless of GCS.

— Acute subdural hematoma: thickness >10 mm or midline shift >5 mm on CT regardless of GCS; or GCS drop ≥2 with ICP >20 or pupillary changes.

— Intraparenchymal contusion: >50 mL, or progressive neurologic deterioration, or refractory ↑ICP.

— Posterior fossa lesions: lower threshold — small bleeds can rapidly cause brainstem compression/obstructive hydrocephalus.

— Depressed skull fracture >1 cm or open with dural penetration → elevation and washout.

— Right frontal Kocher's point; coronal suture, mid-pupillary line.

— Therapeutic (CSF drainage) and diagnostic (ICP measurement, CSF sampling).

— Complications: hemorrhage along tract, infection (ventriculitis 5–10%), malposition.

— DECRA, RESCUEicp trials: secondary/last-tier intervention for refractory ↑ICP despite maximal medical management.

— Reduces ICP and mortality but increases proportion of severely disabled survivors → shared decision-making with family.

— EVD (gold standard) vs intraparenchymal bolt (Camino, Codman).

— Calibrate at tragus (foramen of Monro level).

— Hemicraniectomy for malignant edema.

— Burr hole evacuation for chronic SDH in elderly.

— Endovascular embolization of middle meningeal artery — emerging therapy for chronic/subacute SDH to reduce recurrence.

Step 3 management: A patient with biconvex temporal hematoma, blown right pupil, and decerebrate posturing — immediate neurosurgery consult, mannitol or hypertonic saline bolus, intubate with neuroprotective RSI, hyperventilate transiently to PaCO₂ 30–35 only as bridge to OR. Do NOT delay for MRI or CTA. This is a time-critical EDH with herniation.

Indications for urgent neurosurgical intervention:

External ventricular drain (EVD) placement:

Decompressive craniectomy:

Intracranial pressure monitors:

Adjunct procedures:

Operative timing: Epidural with herniation = minutes count. Acute SDH = within 4 h ideal. Chronic SDH = elective unless symptomatic.

Special Populations — Elderly and Renal/Hepatic Impairment

— Falls dominate mechanism; ground-level fall often suffices to cause significant injury due to brain atrophy stretching bridging veins.

— Higher rates of subdural hematoma, often subacute/chronic with insidious symptoms (gait change, confusion, falls).

— GCS underestimates severity in elderly — baseline cognitive impairment, polypharmacy mask deterioration.

— Anticoagulant/antiplatelet use is prevalent: ALWAYS check med list, INR, DOAC dosing/timing.

— Reverse coagulopathy aggressively even for "small" bleeds — these progress.

— Higher mortality at every GCS level; consider early goals-of-care discussion.

— Geriatric trauma protocols → trauma + geriatrics co-management improves outcomes.

— Pre-existing dementia complicates GCS assessment — use family for baseline.

— Polypharmacy review: discontinue offending meds (sedatives, anticholinergics, orthostasis-inducing antihypertensives) on discharge.

— Mannitol — avoid if CrCl <30 or AKI (worsens renal failure, causes pulmonary edema). Use hypertonic saline instead.

— LMWH (enoxaparin) for VTE prophylaxis — dose-reduce to 30 mg daily if CrCl <30, or switch to UFH 5000 U SC q8–12h.

— Levetiracetam — renally cleared; dose-adjust (e.g., 250–500 mg BID if CrCl <50).

— DOAC reversal: dabigatran is dialyzable; idarucizumab still preferred.

— Coagulopathy from cirrhosis confounds bleeding risk — check INR, fibrinogen, platelets; correct with cryoprecipitate if fibrinogen <150, platelets if <50–100.

— Avoid acetaminophen >2 g/day for analgesia in severe liver disease.

— Sedation: propofol metabolized hepatically but generally safe short-term; reduce fentanyl doses (accumulates).

— Lactulose for hepatic encephalopathy may confound mental status assessment.

Board pearl: An 80-year-old on warfarin (INR 3.2) with ground-level fall and GCS 15 has a small SDH on CT. Immediate management: 4-factor PCC + IV vitamin K, admit ICU, neurosurgery consult, repeat CT at 6 h, hold warfarin. Do NOT use FFP as first-line — slower, larger volume, less effective.

Elderly (≥65) — the highest-risk TBI demographic:

Frailty and disposition:

Renal impairment:

Hepatic impairment:

Special Populations — Pregnancy and Pediatrics

— Leading cause of pediatric death/disability; mechanisms: falls (<4 yo), MVC, sports/bicycle (school age), assault (NAT).

— Larger head:body ratio, thinner skull, open fontanelles → different injury patterns; infants can hide significant blood loss into subgaleal/intracranial space.

— Pediatric GCS modified for verbal/motor in preverbal children.

— PECARN rules identify children at very low risk of clinically important TBI who can be observed without CT — minimize radiation.

— Cushing reflex is late; tachycardia and altered mental status precede hypotension.

— Non-accidental trauma (NAT): suspect with retinal hemorrhages, posterior rib/metaphyseal fractures, multiple-stage injuries, inconsistent history, subdural in infant <2 yo. Mandatory reporting to CPS.

— Cerebral autoregulation more fragile; tighter CPP targets (age-dependent, generally 40–50 mmHg in young children).

— Hypertonic saline preferred over mannitol in pediatric ICP management.

— Maternal stabilization first — best fetal outcome = best maternal outcome.

— Don't withhold head CT for clinically indicated imaging; abdominal shielding minimizes fetal dose (head CT exposes fetus to <0.01 mGy).

— Left lateral tilt (15°) after 20 weeks to relieve aortocaval compression.

— Consider Kleihauer-Betke test in Rh-negative mothers with abdominal trauma; RhoGAM if indicated.

— Phenytoin teratogenic — levetiracetam preferred for seizure prophylaxis.

— Mannitol crosses placenta — can cause fetal dehydration; use hypertonic saline preferentially.

— Continuous fetal monitoring if ≥23 weeks for at least 4–6 h after trauma; longer if contractions, bleeding, or abnormal tracing.

— Perimortem C-section within 4 min of maternal arrest if ≥23 weeks.

Key distinction: In pediatric vs adult TBI, secondary injury prevention is even more critical because pediatric brains have better recovery potential if hypoxia/hypotension/hyperthermia are prevented. Hypotension in pediatric TBI is defined by age-specific SBP (e.g., <70 + 2×age for children 1–10 yr); a "normal" adult-style SBP of 90 in a 4-year-old is shock.

Pediatric TBI:

Pregnancy:

Complications and Adverse Outcomes

— Herniation syndromes: uncal (CN III palsy, contralateral hemiparesis), central (Cushing, decerebrate posturing), tonsillar (apnea, death), subfalcine (ACA stroke).

— Post-traumatic seizures: early (<7 days) — provoked, prophylaxis with LEV × 7 days; late (>7 days) — epilepsy risk 10–25%, treat as new-onset epilepsy.

— Hydrocephalus: communicating (post-SAH/blood blocking arachnoid villi) or obstructive; may need permanent VP shunt.

— Cerebral vasospasm (post-traumatic SAH) — peak days 4–14; monitor with TCD.

— Blunt cerebrovascular injury (BCVI): carotid/vertebral dissection → delayed stroke; treat with antiplatelet/anticoagulation.

— Neurogenic pulmonary edema — sudden, sympathetic surge; treat with supportive ventilation.

— Cardiac dysfunction: stress (takotsubo) cardiomyopathy, arrhythmias, troponin elevation.

— Coagulopathy of TBI — release of tissue factor; correlates with worse outcomes.

— VTE: very high risk (30–40% without prophylaxis); balance with bleed risk for chemoprophylaxis timing.

— Ventilator-associated pneumonia, central line infections, catheter-associated UTI — bundle prevention.

— Critical illness myopathy/neuropathy.

— Diabetes insipidus (central) — hypernatremia, polyuria, low urine osm → desmopressin.

— SIADH — hyponatremia, concentrated urine → fluid restriction (cautiously; CPP).

— Cerebral salt wasting — hyponatremia with volume depletion → hypertonic saline + salt.

— Hypopituitarism — chronic; screen survivors at 3–6 months.

— Post-concussive syndrome — headache, dizziness, cognitive/mood symptoms.

— Chronic traumatic encephalopathy (CTE) — repetitive subconcussive injury.

— Cognitive deficits, depression, PTSD, behavioral changes, sleep disorders.

Board pearl: Distinguishing SIADH from cerebral salt wasting in TBI hinges on volume status: SIADH = euvolemic/hypervolemic → restrict fluids. CSW = hypovolemic → give salt + volume. Restricting fluids in CSW worsens cerebral perfusion — a classic Step 3 trap.

Acute neurologic complications:

Systemic/ICU complications:

Endocrine/electrolyte:

Chronic sequelae:

When to Escalate Care — ICU, Consult, Inpatient Triage

— All severe TBI (GCS ≤8) regardless of CT findings.

— Moderate TBI (GCS 9–12) with abnormal CT or clinical instability.

— Mild TBI with any intracranial hemorrhage or skull fracture.

— Need for ICP monitoring, ventilator, hyperosmolar therapy, or close neuro checks (q1h).

— Anticoagulated patient post-reversal with ICH.

— Post-craniotomy/craniectomy.

— Any acute intracranial hemorrhage on CT.

— Skull fracture (especially depressed, basilar, open).

— GCS ≤12, focal deficit, pupillary asymmetry.

— Worsening exam regardless of initial imaging.

— Mild TBI with isolated small SDH/contusion, stable repeat CT at 6 h, GCS 15, no anticoagulation, reliable neuro exam.

— Concussion with persistent vomiting or symptoms needing observation.

— Normal CT or negative validated decision rule.

— Symptoms improving, tolerating PO, ambulating safely.

— Sober, reliable caregiver, return precautions reviewed.

— Not on anticoagulation (or appropriately observed if so).

— Any moderate/severe TBI at facility without neurosurgery 24/7.

— Pediatric TBI to pediatric trauma center when possible.

— Penetrating TBI, depressed/open skull fx.

— Do NOT delay transfer for non-essential workup; "scoop and run" with airway/CPP support.

Step 3 management: A community ED has a GCS 6 patient with large SDH and 8 mm midline shift, no neurosurgeon on call. Action: intubate with neuroprotective RSI, mannitol or 3% saline, elevate HOB 30°, call air transport to nearest level I trauma center, send CT images electronically with patient. Do NOT keep patient for further imaging.

ICU admission criteria:

Neurosurgery consultation (immediate):

Step-down/floor admission acceptable:

Discharge from ED criteria (mild TBI, GCS 15):

Transfer to trauma/neurosurgical center:

Key Differentials — Same-Category (Traumatic/Intracranial) Causes

— Arterial (middle meningeal artery typical), temporal bone fracture, biconvex/lentiform shape, doesn't cross sutures.

— Classic "lucid interval" then deterioration. Surgical emergency if >30 mL or symptomatic.

— Venous (bridging veins), crescent-shaped, crosses sutures but not midline.

— Higher mortality than EDH due to associated parenchymal injury.

— Elderly, anticoagulated, alcoholic patients overrepresented.

— Weeks–months after minor or forgotten trauma; hypodense or mixed-density on CT.

— Elderly with insidious cognitive decline, gait disturbance, headache — mimics dementia/NPH.

— Burr hole drainage or MMA embolization.

— Blood in sulci, basal cisterns; less likely to cause vasospasm than aneurysmal SAH but possible.

— Often coexists with other injuries; usually managed conservatively.

— Coup/contrecoup, frontal/temporal poles most common.

— Can "blossom" 24–72 h — repeat CT mandatory.

— High-velocity rotational/shear forces; coma disproportionate to CT.

— MRI SWI shows punctate hemorrhages at gray-white junction, corpus callosum, brainstem.

— Poor prognosis with brainstem involvement.

— Linear (most common), depressed (surgical if >1 cm), basilar (CSF leak, cranial nerve injury), open (infection risk).

— GSW, stab; high mortality, especially bihemispheric or transventricular trajectory.

Key distinction: EDH = lens-shaped, doesn't cross sutures, often arterial, classic lucid interval. SDH = crescent-shaped, crosses sutures but not midline, venous, elderly/anticoagulated. tSAH = blood in sulci, usually managed medically. Memorizing these three CT shapes is virtually guaranteed on Step 3 imaging questions.

Epidural hematoma (EDH):

Acute subdural hematoma (SDH):

Chronic subdural hematoma:

Traumatic subarachnoid hemorrhage (tSAH):

Intraparenchymal contusion:

Diffuse axonal injury (DAI):

Skull fractures:

Penetrating TBI:

Key Differentials — Other-Category (Non-Traumatic) Causes

— Aneurysmal SAH: thunderclap headache, blood in basal cisterns, "worst headache of life" — CT angiography or LP (xanthochromia).

— Hypertensive ICH: basal ganglia, thalamus, pons, cerebellum; long-standing HTN.

— AVM rupture: younger patients, lobar bleeds.

— Amyloid angiopathy: lobar bleeds in elderly, recurrent.

— Always consider whether the head strike was the cause or the result of an event.

— Get ECG, troponin, glucose, CT/CTA, consider neurologic etiology of fall.

— Tongue laceration, urinary incontinence, post-ictal confusion.

— May have head strike during seizure → both processes simultaneously.

— Confusion, altered mental status mimicking TBI; check glucose, electrolytes, ammonia, toxicology.

— Meningitis, encephalitis — fever, meningismus, headache; rare to confuse with trauma but consider in elderly fall patient with fever.

— Spontaneous bleed into glioma, melanoma metastasis, renal cell metastasis; atypical location/edema pattern on CT/MRI.

— Atypical presentations of altered mental status, headache, seizure.

— Arrhythmia, aortic stenosis, vasovagal — workup with ECG, echo, telemetry.

Step 3 management: Elderly patient "found down" with bruise on head and small SDH on CT. Don't stop at "trauma" — workup the cause of the fall: orthostatics, ECG (arrhythmia, MI), glucose, electrolytes, medication review (antihypertensives, sedatives), and consider syncope evaluation. Treating only the SDH and discharging without identifying recurrent fall risk is a Step 3 patient-safety failure.

Spontaneous (non-traumatic) intracranial hemorrhage:

Ischemic stroke causing fall → "trauma":

Seizure with post-ictal state mimicking TBI:

Hypoglycemia, hyponatremia, hepatic encephalopathy, uremia, drug intoxication:

CNS infection:

Brain tumor with hemorrhage:

Vasculitis, reversible cerebral vasoconstriction syndrome (RCVS), PRES:

Cardiogenic syncope causing fall:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Acetaminophen first-line for headache; avoid NSAIDs/ASA × 24–48 h if any bleed risk.

— Antiemetics (ondansetron) PRN for nausea.

— Resume home medications cautiously; reconcile carefully.

— Hold anticoagulation after ICH; restart timing individualized — typically 1–4 weeks for high-thrombotic-risk patients (mechanical valve, recent VTE), 4–8 weeks otherwise.

— Multidisciplinary discussion: neurology/neurosurgery, cardiology, hematology.

— DOACs generally preferred over warfarin when restarting (lower ICH recurrence).

— Antiplatelets for primary prevention often permanently discontinued; secondary prevention (post-MI, stroke) usually resumed at 1–2 weeks.

— Continue levetiracetam only if seizure occurred or high-risk (penetrating injury, depressed skull fx with cortical injury).

— Routine post-TBI prophylaxis beyond 7 days NOT indicated — doesn't prevent late epilepsy.

— Home safety eval (remove rugs, lighting, grab bars), PT/OT referral.

— Vision exam, medication review (deprescribe sedatives, anticholinergics).

— Vitamin D + calcium; bone density evaluation.

— Driving evaluation if cognitive or motor deficits.

— Concussion: stepwise return-to-play (RTP) over ~7 days; symptom-limited; no same-day RTP after concussion (sports concussion guidelines).

— Return-to-learn (school) often precedes return-to-play.

— Driving restrictions — no driving until cleared, particularly with seizure or visual deficit (state-specific reporting laws).

Board pearl: After a single concussion, return to play is graded over a minimum of 6 stages with 24 h between stages, only progressing if asymptomatic. Second-impact syndrome — catastrophic cerebral edema from a second concussion before the first resolves — is rare but devastating and the rationale for strict RTP rules in adolescent athletes.

Discharge medications after mild TBI/concussion:

Anticoagulation/antiplatelet management post-TBI:

Seizure prophylaxis after discharge:

Fall prevention (elderly):

Return to activity protocols:

Helmet/seatbelt counseling, alcohol/substance use counseling.

Follow-Up, Monitoring Parameters, and Rehabilitation

— PCP or sports medicine follow-up in 1–2 weeks; sooner if symptomatic.

— Persistent post-concussive symptoms (>4 weeks adults, >2 weeks children) → refer to concussion clinic, neurology, or neuropsychology.

— Validated tools: SCAT5 (Sport Concussion Assessment), Rivermead Post-Concussion Symptoms Questionnaire.

— Neurosurgery 2–4 weeks for imaging review and incision/EVD site check.

— Neurology for seizure management, cognitive evaluation.

— Physical medicine & rehabilitation (PM&R) early — inpatient acute rehab when medically stable.

— Speech/language pathology, OT, PT, neuropsychology.

— Glasgow Outcome Scale–Extended (GOS-E).

— Disability Rating Scale, FIM (Functional Independence Measure).

— Screen for hypopituitarism at 3 and 12 months post-severe TBI (fatigue, weight changes, sexual dysfunction → check IGF-1, cortisol, TSH/free T4, gonadotropins, prolactin).

— Depression, anxiety, PTSD common — PHQ-9, GAD-7 screening at follow-ups.

— Substance use screening.

— Suicide risk elevated post-TBI; ask directly.

— Routine repeat imaging not needed after small stable bleeds; clinical-driven.

— Chronic SDH may need follow-up imaging if symptoms recur.

— Cognitive demands assessed; gradual reintegration.

— Vocational rehabilitation referral for adult survivors with persistent deficits.

Step 3 management: For a patient discharged after moderate TBI, set up a multidisciplinary cadence: PCP at 1 week, neurosurgery at 2–4 weeks, PM&R/rehab initiated before discharge, neuropsych testing at 4–6 weeks, endocrine screen at 3 months, mental health screen at every visit. This bundled longitudinal plan is the Step 3 "right answer" for chronic TBI management.

Mild TBI/concussion follow-up:

Moderate/severe TBI follow-up:

Cognitive and functional outcome measures:

Endocrine follow-up:

Mental health monitoring:

Imaging surveillance:

Driving, work, school return:

Ethical, Legal, and Patient Safety Considerations

— Severe TBI patients lack capacity → surrogate decision-maker (advance directive > spouse > adult children > parents > siblings, per most state hierarchies).

— Emergency exception (implied consent) for life-saving interventions in unconscious patients.

— Document capacity assessments serially as patients recover.

— Avoid premature withdrawal of life-sustaining therapy ("self-fulfilling prophecy") — prognostic models (IMPACT, CRASH) inform but don't dictate; wait 72 h minimum, often longer.

— Family meetings early and repeatedly; involve palliative care.

— Brain death determination per institutional protocol if applicable (apnea test, ancillary testing).

— Decoupled from goals-of-care discussion; involve organ procurement organization (OPO) per federal law before any conversation with family about donation.

— Suspected child abuse/NAT: mandatory to CPS in all states — concrete Step 3 trigger.

— Elder abuse: mandatory in most states.

— Intimate partner violence: state-specific; some require, most encourage.

— Gunshot/stab wounds: mandatory law enforcement reporting in most states.

— Impaired driving (seizure, dementia post-TBI): state-specific DMV reporting (e.g., California mandatory; others voluntary).

— Medication reconciliation at every transition (ED → ICU → floor → rehab → home) — anticoagulants, antiepileptics, antihypertensives are the highest-risk meds.

— Clear documentation of when/whether to restart anticoagulation, with named responsible clinician and follow-up date.

— Closed-loop communication with PCP within 48 h of discharge.

— Written discharge instructions in patient's language and reading level; verify understanding (teach-back).

— Reliable caregiver to monitor for 24 h with specific red flags (worsening headache, vomiting, confusion, weakness, seizure).

Board pearl: Concrete Step 3 trigger — an infant with subdural hematoma, retinal hemorrhages, and inconsistent history → mandatory CPS report before discharge, regardless of family's wishes; admit for safety and protective workup. Failure to report is both clinically and legally indefensible.

Informed consent and decision-making capacity:

Goals of care and prognostication:

Organ donation:

Mandatory reporting:

Transition-of-care safety:

Return precautions:

High-Yield Associations and Rapid-Fire Clinical Facts

Key distinction: A "GCS 13" mild TBI patient with abnormal CT is managed like a moderate TBI — admit, serial neuro checks, neurosurgery consult, repeat CT. The number alone doesn't dictate disposition; CT findings + anticoagulation status + age do.

Epidural = middle meningeal artery + temporal bone fx + lucid interval + biconvex.

Subdural = bridging veins + elderly/anticoagulated + crescent + crosses sutures.

Diffuse axonal injury = MVC + coma + minimal CT findings + MRI SWI shows microbleeds at gray-white junction/corpus callosum/brainstem.

Cushing triad = HTN + bradycardia + irregular respirations = impending herniation.

Battle sign + raccoon eyes + hemotympanum + CSF rhinorrhea = basilar skull fracture; no NG tube.

GCS ≤8 → intubate.

CPP = MAP − ICP; target CPP 60–70, ICP <22.

Avoid: hypoxia (<90% SpO₂), hypotension (SBP <90/100/110 by age), hyperventilation (<30 PaCO₂ routinely), hypotonic fluids, glucose-containing fluids, steroids (CRASH trial).

Prefer: isotonic NS, levetiracetam > phenytoin for prophylaxis, hypertonic saline > mannitol in hypotensive or renal-impaired patients.

Anticoagulant reversal: warfarin → 4F-PCC + IV vitamin K; dabigatran → idarucizumab; apixaban/rivaroxaban → andexanet alfa or 4F-PCC.

Platelet transfusion for antiplatelet-associated ICH NOT routinely beneficial (PATCH trial).

Seizure prophylaxis LEV × 7 days for severe TBI, depressed skull fx, penetrating, cortical contusion.

Decompressive craniectomy reduces ICP and mortality but increases severe disability (RESCUEicp).

Pediatric: PECARN rules, hypertonic saline preferred, NAT screening mandatory.

Pregnancy: don't withhold CT; levetiracetam over phenytoin; left lateral tilt.

Endocrine sequelae: central DI (acute), hypopituitarism (chronic) — screen at 3–12 months.

Sodium disorders: SIADH (euvolemic, restrict fluid carefully), CSW (hypovolemic, give salt), DI (hypernatremic, give DDAVP).

Concussion RTP: 6 stepwise stages, 24 h between, symptom-limited progression.

Second-impact syndrome: catastrophic cerebral edema in adolescent with second concussion before first resolved.

BCVI screening: CTA neck for high-risk fx patterns; treat with antiplatelet/anticoagulation to prevent stroke.

VTE prophylaxis: mechanical immediately, chemical 24–72 h after stable CT.

Board Question Stem Patterns

— Answer: emergent craniotomy; CT shows biconvex temporal hematoma. Intubate first, mannitol or 3% saline bridge.

— Answer: 4-factor PCC + IV vitamin K, admit ICU, neurosurgery consult, repeat CT at 6 h.

— Answer: resuscitate with isotonic fluid/blood to SBP >110, then norepinephrine for CPP 60–70; ICP monitor, hypertonic saline; AVOID steroids; AVOID prophylactic hyperventilation.

— Answer: mandatory CPS report, admit, skeletal survey, ophthalmology, social work.

— Answer: MRI brain (SWI shows microhemorrhages) confirms DAI; supportive ICU management, prognosis guarded.

— Answer: do NOT lower BP — sign of impending herniation. Hypertonic saline/mannitol, hyperventilate as bridge, emergent neurosurgery.

— Answer: stepwise RTP protocol, must remain asymptomatic through graduated stages with ≥24 h between, full RTP only after final asymptomatic stage.

Step 3 management: Recognize the mechanism + CT pattern + anticoagulation status + GCS trajectory as the four data points that drive disposition and pharmacotherapy. The exam rewards systematic resuscitation order over esoteric details.

Stem 1 — Classic epidural: "Young male struck in the temple with a baseball; LOC for 1 min, then awake and conversant for 30 min, now obtunded with right pupil fixed and dilated."

Stem 2 — Anticoagulated elderly fall: "82-year-old on warfarin (INR 3.5) tripped on rug, hit head; GCS 15, mild headache. CT shows 4 mm SDH."

Stem 3 — Severe TBI initial management: "GCS 5 post-MVC, BP 80/40, intubated. CT shows diffuse cerebral edema."

Stem 4 — Pediatric NAT: "5-month-old with seizure; CT shows acute and chronic subdural, retinal hemorrhages; story changes."

Stem 5 — DAI: "Post high-speed MVC, GCS 6, CT normal/minimal findings."

Stem 6 — Cushing reflex: "Severe TBI patient, BP 200/110, HR 45, irregular respirations."

Stem 7 — Concussion RTP: "16-year-old football player with concussion last week, asymptomatic at rest, wants to return Friday."

Stem 8 — SIADH vs CSW vs DI: Sodium puzzle in TBI patient; check urine output, volume status, urine osm.

Stem 9 — When to restart anticoagulation: mechanical mitral valve patient with resolved SDH 2 weeks ago — risk/benefit, often resume warfarin around 2–4 weeks with shared decision.

Stem 10 — BCVI: "C2 fracture, cervical seatbelt sign" → CTA neck → start antiplatelet/anticoagulation.

One-Line Recap

Traumatic brain injury management hinges on preventing secondary injury — secure the airway when GCS ≤8, maintain SBP and CPP, image with non-contrast CT, reverse anticoagulation urgently, escalate to ICU with neurosurgery for any acute intracranial hemorrhage, and stratify long-term care by severity with structured follow-up for cognitive, endocrine, and mental health sequelae.

Board pearl: The single most tested principle in Step 3 TBI questions is secondary injury prevention — every "next best step" answer in a severe TBI vignette involves restoring oxygenation, perfusion, and CPP before pursuing definitive diagnostics or specialty interventions. Master that order, and the rest of the topic falls into place.

Severity grading: GCS 13–15 mild, 9–12 moderate, ≤8 severe — but CT findings and anticoagulation status modify disposition regardless of score.

The "do nots" of TBI: No steroids (CRASH), no prophylactic hyperventilation, no hypotonic fluids, no permissive hypotension, no NG tube with basilar skull fx, no routine platelet transfusion for antiplatelet-associated ICH.

The "always do's": Intubate GCS ≤8 with neuroprotective RSI, target SBP ≥110 and SpO₂ >90, reverse coagulopathy emergently (PCC + vitamin K for warfarin, idarucizumab for dabigatran, andexanet for factor Xa inhibitors), levetiracetam × 7 days for severe/penetrating/depressed/cortical, repeat CT at 6 h for any bleed.

Step 3 longitudinal care: Multidisciplinary follow-up — neurosurgery, PM&R/rehab, neurology, neuropsychology, endocrine screen at 3–12 months, mental health screening at every visit, fall prevention bundle for elderly, stepwise return-to-play for concussion, and individualized restart of anticoagulation balancing rebleed and thrombotic risk through shared decision-making.