Nervous System & Special Senses

Concussion: diagnosis and return-to-activity

Clinical Overview and When to Suspect Concussion

— ~3.8 million sports/recreation concussions annually in US; underreporting common

— Highest rates: football, soccer, hockey, cheerleading, military service members

— Also high yield in older adults (falls) and MVCs in ambulatory follow-up

— Brief LOC (occurs in only ~10%; not required for diagnosis)

— Confusion, "feeling foggy," amnesia (retrograde or antegrade)

— Headache, dizziness, nausea, photophobia, phonophobia

— Balance disturbance, slowed reaction time

— Emotional lability, irritability, sleep disruption

— Rotational/angular forces > linear forces for diffuse axonal stretch

— Symptoms reflect neurometabolic cascade (K+ efflux, glutamate release, Ca²⁺ influx, mitochondrial dysfunction) — energy crisis lasts 7–10 days

— This metabolic vulnerability window is the biologic rationale for cognitive/physical rest

Board pearl: Concussion is a clinical diagnosis — CT and MRI are typically normal. Ordering imaging to "rule in" concussion is incorrect; imaging is used to rule out structural injury (hemorrhage, skull fracture) when red flags are present.

— Confirm concussion clinically

— Decide if delayed imaging is needed

— Initiate symptom-guided management

— Begin a graduated return-to-learn and return-to-play protocol

— Counsel patient/family on second-impact risk

Definition: Concussion = mild traumatic brain injury (mTBI) caused by biomechanical forces (direct blow to head, face, neck, or impulsive force transmitted to head) producing transient neurologic dysfunction without structural injury on conventional imaging.

Epidemiology in Step 3 practice:

When to suspect — any blow + any of:

Mechanism pearls:

Step 3 ambulatory framing: A patient presents 24–72h post-injury to clinic with persistent headache and "not feeling right." Your job is to:

High-stakes context: Second impact syndrome (rare, catastrophic cerebral edema in adolescents who sustain second hit before recovery) drives the conservative return-to-activity guidelines tested on Step 3.

Presentation Patterns and Key History

— Somatic: headache (most common, ~85%), nausea, dizziness, photophobia, phonophobia, neck pain

— Cognitive: "foggy," slowed thinking, poor concentration, memory difficulty

— Emotional: irritability, sadness, anxiety, emotional lability

— Sleep: insomnia, hypersomnia, drowsiness, disrupted sleep architecture

— Symptom onset usually immediate but can be delayed up to 24–48h

— Typical recovery: adults 10–14 days; adolescents up to 4 weeks

— Persistent symptoms >4 weeks (peds) or >2 weeks (adults) = persistent post-concussive symptoms (PPCS)

— Mechanism (helmet-to-helmet, MVC, fall, assault) and witnessed LOC duration

— Amnesia: retrograde (events before) vs antegrade (events after) — antegrade amnesia >30 min suggests more severe injury

— Seizure activity at impact (impact seizures usually benign; post-traumatic seizures need workup)

— Number of prior concussions and time since last — major risk factor for prolonged recovery

— Anticoagulant/antiplatelet use → lowers threshold for CT

— Pre-existing migraine, ADHD, learning disability, mood disorder, sleep disorder → all predict prolonged recovery

— Worsening headache, repeated vomiting (>2 episodes)

— Increasing confusion, seizure, focal weakness

— GCS <15 at 2 hours

— Suspected skull fracture (CSF rhinorrhea, hemotympanum, Battle sign, raccoon eyes)

— Age >65, dangerous mechanism, anticoagulation

Key distinction: Concussion ≠ "had to lose consciousness." A stem describing a soccer player who heads the ball, stumbles, and complains of "fogginess" without LOC still meets concussion criteria — diagnose and remove from play.

— Female sex, adolescent age, migraine history, prior concussions

— High initial symptom burden (especially dizziness)

— Early "cognitive activity intolerance"

Four symptom clusters (memorize — exam stems map symptoms to cluster, then to targeted therapy):

Timing clues:

Critical history elements:

Red-flag history demanding immediate ED transfer / CT:

Modifiers predicting prolonged recovery (high-yield):

Physical Exam Findings and Sideline/Office Assessment

— Vital signs (rule out Cushing response: HTN + bradycardia + irregular respirations = herniation)

— Cervical spine exam — concussion and c-spine injury frequently coexist; immobilize if any midline tenderness, neurologic deficit, or distracting injury

— Scalp/skull palpation for step-off, hematoma; check for CSF leak

— Mental status: orientation, Maddocks questions (sport-specific: "What venue? Which half? Who scored last? Did we win last game?")

— Cranial nerves, especially pupils (anisocoria → CT)

— Motor/sensory symmetry, reflexes, plantar response

— Coordination: finger-to-nose, heel-to-shin

— Tandem gait / Romberg — vestibular involvement is common

— SCAT6 (Sport Concussion Assessment Tool, 6th ed.) — for ages 13+; includes symptom checklist, cognitive screen, neurologic screen, balance (mBESS)

— Child SCAT6 — ages 5–12

— VOMS (Vestibular/Ocular Motor Screening): smooth pursuit, saccades, near-point convergence, VOR, visual motion sensitivity — provoked symptoms guide vestibular therapy

— King-Devick — rapid number naming, screens saccadic function

— Orthostatic intolerance and exercise-induced symptom provocation suggest autonomic dysregulation — basis for Buffalo Concussion Treadmill Test to determine sub-symptom-threshold aerobic exercise level

CCS pearl: On the office encounter, order: focused neuro exam, c-spine exam, SCAT6 or symptom inventory, BESS or tandem gait. Avoid ordering routine CT head if no red flags — overuse of imaging is a wrong-answer trap.

— GCS <15 at 2h post-injury, suspected open/depressed skull fracture, signs of basilar skull fracture, ≥2 vomiting episodes, age ≥65, retrograde amnesia >30 min, dangerous mechanism, anticoagulant use, focal deficit

General exam priorities:

Neurologic exam — must document:

Standardized sideline/office tools:

Hemodynamic / autonomic clues:

Findings that mandate emergent CT (per ACEP/CDC):

Normal exam is the rule — a "perfectly normal" neuro exam does not exclude concussion.

Diagnostic Workup — Initial Labs, Imaging, and Biomarkers

— Canadian CT Head Rule (adults, GCS 13–15): high risk = GCS <15 at 2h, suspected open/depressed skull fx, basilar fx signs, ≥2 vomits, age ≥65; medium risk = amnesia >30 min, dangerous mechanism

— PECARN (pediatric) for age <2 and 2–18: stratifies need based on AMS, LOC ≥5 sec, severe mechanism, vomiting, severe headache, non-frontal scalp hematoma (<2y)

— Anticoagulant/antiplatelet use lowers threshold further

— Not routine in acute setting

— Consider for persistent symptoms >7–14 days, focal deficits, suspicion of diffuse axonal injury, or atypical course

— Susceptibility-weighted imaging (SWI) detects microhemorrhages

— GFAP and UCH-L1 (FDA-approved, "Banyan Brain Trauma Indicator," now "i-STAT TBI Plasma"): within 12h of injury in adults with GCS 13–15; negative test reliably rules out intracranial injury on CT — reduces unnecessary CT

— S100B used in Europe; less common in US protocols

— Glucose (hypoglycemia mimics confusion)

— Toxicology if intoxication suspected

— CBC, coags if anticoagulated or bleeding suspected

— Pregnancy test in reproductive-age females before any imaging

— EEG (only if seizure suspected)

— Routine MRI on day 1

— Cervical spine CT unless c-spine clinically positive (use NEXUS or Canadian C-Spine Rule)

Board pearl: A 25-year-old with GCS 15, mild headache, no LOC, no vomiting, no anticoagulation, normal neuro exam after a sports collision does not need a CT. Choosing "CT head" is the distractor; "clinical observation and symptom-guided care" is correct.

Foundational principle: Concussion is clinical. Tests rule out alternative or coexisting pathology, not "confirm" concussion.

CT head without contrast — indications (apply a validated rule):

MRI brain:

Serum biomarkers:

Labs to consider (not for concussion itself, but for differential):

What NOT to order routinely:

Documentation essentials for billing/safety: mechanism, GCS, symptom inventory, exam, decision rule applied, return precautions given.

Diagnostic Workup — Advanced and Confirmatory Studies

— Symptoms persisting beyond expected window (>2 weeks adults, >4 weeks pediatric)

— New or worsening focal neurologic findings

— Atypical features (severe vertigo, intractable headache, cognitive decline, mood disturbance disproportionate to injury)

— Recurrent concussions with cumulative symptom burden

— MRI brain with SWI and DWI — detects microbleeds, contusions, diffuse axonal injury

— MR venography if persistent headache + risk factors → rule out cerebral venous sinus thrombosis

— CT angiography or MRA if mechanism suggests vascular injury (carotid/vertebral dissection — especially with neck pain, Horner syndrome, or focal deficit)

— Functional MRI, DTI, PET are research tools — not standard of care; wrong-answer choices

— ImPACT, CNS Vital Signs, Axon Sports — computerized neurocognitive batteries

— Most valuable when baseline preseason testing exists for comparison

— Without baseline, normative data still useful for tracking recovery

— Help guide return-to-learn and return-to-play decisions in protracted recovery

— VOMS in office; refer to vestibular therapy if provoked symptoms in convergence, saccades, or VOR

— Videonystagmography (VNG) for persistent vertigo

— Buffalo Concussion Treadmill Test (BCTT): sub-symptom threshold heart rate identified; basis for prescribing graded aerobic exercise — now first-line for prolonged recovery

Step 3 management: For a high school athlete with persistent symptoms at 3 weeks, order MRI brain, refer to multidisciplinary concussion clinic, initiate BCTT-guided sub-threshold aerobic exercise, screen with PHQ-9/GAD-7, and consider vestibular PT — multidomain assessment is the correct answer over any single intervention.

When advanced workup is indicated:

Neuroimaging beyond CT:

Neurocognitive testing:

Vestibular and oculomotor assessment:

Autonomic testing:

Sleep evaluation: polysomnography if persistent unrefreshing sleep, hypersomnolence, or suspected sleep apnea unmasked by injury.

Mental health screening: PHQ-9, GAD-7 at follow-up — depression and anxiety drive PPCS.

Pitfall: Do NOT obtain serial CTs for symptom monitoring — radiation exposure without yield.

Risk Stratification and Management Logic

— Red flags / abnormal CT → admit, neurosurgery consult

— No red flags, normal exam → outpatient symptom-guided care + graduated return protocols

— Demographic: female sex, adolescent age (13–18)

— Injury: high initial symptom severity, prominent dizziness, amnesia, LOC >1 min

— History: prior concussions (especially within 1 year), migraine, ADHD, learning disability, anxiety/depression, sleep disorder

— Modifying: medication use, family dynamics, sport with high re-exposure risk

— Old dogma: dark room, total rest until asymptomatic → abandoned

— Current guideline (Amsterdam 2022 Consensus, AAN): 24–48 hours of relative rest, then gradual reintroduction of activity below symptom-exacerbation threshold

— Early sub-symptom-threshold aerobic exercise (light walking, stationary bike) shortens recovery and reduces PPCS

— Stage 1: Symptom-limited activity (daily activities)

— Stage 2: Light aerobic exercise (walking, stationary bike, <70% max HR)

— Stage 3: Sport-specific exercise (running drills, no head impact)

— Stage 4: Non-contact training drills

— Stage 5: Full-contact practice (after medical clearance)

— Stage 6: Return to sport/game play

— Stage 1: cognitive activity at home (10–15 min) → Stage 2: school activity at home → Stage 3: part-time school with accommodations → Stage 4: full school with accommodations → Stage 5: full school

Board pearl: Minimum time from injury to game play is typically ≥7 days in adults if asymptomatic, often longer in youth. No same-day return to play for any athlete with suspected concussion — this is absolute and frequently tested.

Initial triage decision tree:

Modifiers predicting prolonged recovery (stratify at first visit):

The modern paradigm — symptom-guided, NOT "complete rest":

Six-stage Graduated Return-to-Sport (RTS) protocol (each stage ≥24h; advance only if symptom-free at current stage; if symptoms recur, drop back one stage):

Return-to-Learn (RTL) precedes Return-to-Play — always:

"When in doubt, sit them out" — sideline removal is mandatory.

Pharmacotherapy — Symptom-Targeted Management

— Acetaminophen first-line in first 24–48h

— NSAIDs (ibuprofen, naproxen) — avoid in first 24h if any bleeding concern, then acceptable short term

— Avoid opioids — sedation masks neuro exam, addiction risk

— Limit analgesic use to <2–3 days/week to prevent medication-overuse headache

— Persistent post-traumatic headache with migrainous features: trial amitriptyline 10–25 mg qhs or topiramate; for autonomic/tension features consider propranolol (also helps with exertional symptoms)

— Acute migraine-phenotype: triptans acceptable if no contraindication

— Sleep hygiene first (consistent schedule, limit screens, no daytime naps >30 min)

— Melatonin 3–5 mg qhs — first-line pharmacologic option, especially pediatric

— Avoid chronic benzodiazepines and zolpidem (cognitive side effects)

— Trazodone or low-dose amitriptyline if needed

— Behavioral strategies first

— Stimulants (methylphenidate) only in protracted recovery, specialist-directed

— CBT first-line for anxiety/depression after concussion

— SSRIs (sertraline, escitalopram) for persistent depression — avoid if mania history

— Vestibular rehabilitation therapy is first-line, not meclizine

— Meclizine acceptable only for severe acute vertigo, short term — chronic use delays vestibular compensation

Step 3 management: A 16-year-old with concussion 5 days ago has tension-type headache and insomnia. Best answer: acetaminophen PRN limited to ≤3 days/week, sleep hygiene counseling, melatonin 3 mg qhs, and continue graded sub-symptom-threshold aerobic exercise — not opioids, not chronic benzodiazepines, not strict rest.

Core principle: No drug is FDA-approved to treat concussion. Pharmacotherapy is symptom-targeted, time-limited, and adjunctive to graded activity, sleep hygiene, and rehab.

Headache (most common symptom):

Sleep disturbance:

Cognitive/attention symptoms:

Mood symptoms:

Vestibular symptoms:

Counsel patients: "Pills support recovery; activity and time drive it."

Non-Pharmacologic and Rehabilitative Management

— Identify threshold via Buffalo Concussion Treadmill Test (BCTT) — symptom-limited treadmill protocol; HR at symptom exacerbation = threshold

— Prescribe aerobic exercise at 80% of threshold HR, 20 min/day, 5–6 days/week

— Reassess weekly; advance as tolerated

— Strong evidence: started within 2–10 days, reduces PPCS incidence by ~50% in adolescents

— Indicated when symptoms include neck pain, headache with cervical features, dizziness, or positive VOMS

— Manual therapy, sensorimotor training, vestibular-ocular reflex retraining

— For convergence insufficiency, saccadic dysfunction, accommodative disorders

— Refer to neuro-optometry if visual symptoms persist >2 weeks

— Reduced workload, extended testing time, breaks, lighting/noise modifications

— Section 504 plan if school accommodations needed >2 weeks

— Avoid total school withdrawal — isolation worsens mood and prolongs recovery

— Effective for PPCS with anxiety, fear-avoidance, catastrophizing

— Address sleep hygiene, pacing strategies, return-to-activity anxiety

— Regular schedule, morning light exposure, limit caffeine after noon, no screens 1h before bed

— Prolonged "cocoon therapy" (dark room rest >48h) — worsens outcomes

— Alcohol and recreational substances

— Driving until symptom-free with normal reaction time

Board pearl: The single most impactful intervention in modern concussion care is early, prescribed, sub-symptom-threshold aerobic exercise — not rest. Stems describing a patient kept in dark room for 2 weeks reflect outdated, wrong-answer practice.

Active rehabilitation is the cornerstone — multimodal therapy outperforms any single intervention.

Sub-symptom threshold aerobic exercise:

Cervicovestibular physical therapy:

Vision therapy:

Cognitive rehabilitation and academic accommodations:

Cognitive Behavioral Therapy (CBT):

Sleep optimization:

Nutrition/hydration: adequate hydration, regular meals, omega-3 fatty acids reasonable (weak evidence)

Avoid:

Multidisciplinary concussion clinic referral if symptoms persist >2–4 weeks.

Special Populations — Elderly and Anticoagulated Patients

— Falls are leading mechanism; concussion frequently coexists with subdural hematoma

— Lower threshold for CT — Canadian CT Head Rule lists age ≥65 as high-risk criterion alone

— Atrophy enlarges subdural space → bridging veins more vulnerable → delayed subdural can present days to weeks later

— Always reassess: progressive headache, gait change, or cognitive decline weeks after a fall → non-contrast CT head

— Mandatory CT head even after minor head injury, regardless of symptoms

— Warfarin, DOACs, dual antiplatelet therapy all confer risk

— If initial CT negative but on anticoagulation: observe 4–6 hours; consider repeat CT at 24h or admission per institutional protocol (especially warfarin with supratherapeutic INR)

— Reverse anticoagulation if ICH present:

— Warfarin → 4-factor PCC + IV vitamin K

— Dabigatran → idarucizumab

— Apixaban/rivaroxaban → andexanet alfa (or 4-factor PCC if unavailable)

— Antiplatelets → platelet transfusion controversial; generally NOT routinely indicated for spontaneous ICH per PATCH trial, but may be considered in neurosurgical patients

— Typically delayed 1–4 weeks depending on indication, bleeding severity, thrombotic risk

— Shared decision-making; weigh CHA₂DS₂-VASc vs rebleed risk

— Adjust analgesics: avoid NSAIDs in CKD stage ≥3; acetaminophen safer but cap at 2 g/day in cirrhosis

— Gabapentin requires renal dose adjustment if used for headache

— Review meds contributing to fall risk: benzodiazepines, sedating antihistamines, antipsychotics, anticholinergics, antihypertensives (orthostasis)

— Deprescribe high-risk meds; STOPP/START criteria

— Vitamin D, exercise/balance program, home safety eval — secondary fall prevention

Step 3 management: An 80-year-old on apixaban falls and hits her head, GCS 15, normal exam. Order CT head now; if negative, observe and consider repeat imaging at 24h with delayed-bleed precautions. Discharge with strict return precautions and family supervision.

Elderly (≥65 years) — high-stakes population:

Anticoagulated/antiplatelet patients:

Resumption of anticoagulation post-ICH:

Renal/hepatic impairment:

Polypharmacy considerations:

Special Populations — Pediatrics, Pregnancy, and Military

— Longer recovery: median 4 weeks vs 2 weeks adults

— Adolescents (13–18) at highest risk for prolonged recovery and second-impact syndrome

— PECARN rule guides CT decisions:

— Age <2: CT if AMS, LOC ≥5 sec, severe mechanism, non-frontal scalp hematoma, palpable skull fx, or not acting normally per parents

— Age 2–18: CT if AMS, signs of basilar skull fx, severe mechanism, LOC, vomiting, severe headache

— Return-to-Learn precedes Return-to-Play — always

— Child SCAT6 for ages 5–12

— No same-day return to play — every state has youth concussion laws (Zackery Lystedt Law model)

— Rare, catastrophic diffuse cerebral edema in adolescents who sustain second head injury before symptom resolution

— Mortality ~50%, severe disability in survivors

— Rationale for conservative pediatric return-to-play

— Trauma is leading non-obstetric cause of maternal death

— Concussion management similar; avoid NSAIDs (especially after 20 weeks — oligohydramnios; absolute contraindication ≥30 weeks — premature ductus closure)

— Acetaminophen safe in pregnancy

— Imaging: CT head acceptable with abdominal shielding; brain MRI without gadolinium preferred for non-urgent imaging

— Fetal monitoring per gestational age and mechanism (≥20 weeks: continuous EFM ≥4h after significant trauma)

— Screen for intimate partner violence in any pregnant trauma patient

— Blast-related mTBI common in service members

— High comorbidity with PTSD; screen with PCL-5

— VA/DoD guidelines emphasize multidisciplinary care, vestibular rehab, sleep optimization

Board pearl: Pediatric concussion mandates a documented return-to-learn AND return-to-play plan with medical clearance before contact sports. Coach or parent clearance is insufficient — physician sign-off is required by state law in all 50 states.

Pediatric concussion:

Second-impact syndrome:

Pregnancy:

Military / Veterans:

Pre-participation physicals are an opportunity for baseline neurocognitive testing in high-risk athletes.

Complications and Adverse Outcomes

— Intracranial hemorrhage (epidural, subdural, subarachnoid, intraparenchymal) — initial concern; rule out with CT when red flags present

— Cerebral edema / second-impact syndrome — rare, adolescent

— Post-traumatic seizure — early (<7 days) vs late (>7 days, defines post-traumatic epilepsy)

— Cervical artery dissection — carotid or vertebral; suspect with neck pain, Horner syndrome, focal deficit

— Cranial nerve injuries — CN I (anosmia), CN VII (facial), CN VIII (vestibulocochlear)

— Symptoms >4 weeks (pediatric) or >2 weeks (adult)

— Risk factors: female, adolescent, migraine history, prior concussions, high initial symptom burden, anxiety/depression

— Management: multidisciplinary clinic, BCTT-guided aerobic exercise, vestibular/cervical PT, CBT, sleep optimization

— Migraine, tension, or mixed phenotype

— Treat per primary headache phenotype; preventive therapy if frequent

— Post-concussion depression, anxiety, PTSD (especially MVC, assault, blast)

— Increased suicide risk — screen with C-SSRS at follow-up

— Usually resolves; persistent deficits warrant formal neuropsychological evaluation

— BPPV can be triggered by head trauma — perform Dix-Hallpike; treat with Epley if positive

— Convergence insufficiency common — vision therapy

— Chronic Traumatic Encephalopathy (CTE): neuropathologic diagnosis (postmortem); associated with repetitive head impacts; clinical correlates include progressive cognitive decline, mood/behavioral changes

— Increased risk of neurodegenerative disease (controversial magnitude)

— Lost school days, work absences, return-to-driving delays

Key distinction: A concussion patient who develops focal deficits, worsening headache, or repeated vomiting hours to days later has a delayed intracranial hemorrhage (often subdural in elderly, epidural in younger) — emergent CT and neurosurgical consult, not "reassurance."

Acute / subacute complications:

Persistent Post-Concussive Symptoms (PPCS):

Post-traumatic headache:

Mood disorders:

Cognitive impairment:

Vestibular/oculomotor dysfunction:

Long-term concerns:

Functional / occupational:

When to Escalate — ED Transfer, Neurosurgery, and Inpatient Triage

— GCS <15 or declining mental status

— Focal neurologic deficit (weakness, aphasia, anisocoria)

— Repeated vomiting (≥2 episodes)

— Worsening or severe headache unresponsive to analgesics

— Seizure activity

— Suspected skull fracture (CSF leak, hemotympanum, Battle sign, raccoon eyes)

— Suspected c-spine injury

— Anticoagulated patient with any concerning symptom

— Age extremes with high-risk mechanism

— Any intracranial hemorrhage on CT

— Depressed or open skull fracture

— Penetrating injury

— Persistent GCS <13

— Abnormal CT (any hemorrhage, contusion, fracture)

— Persistent GCS <15 at 6h despite normal CT

— Anticoagulated patients with concerning features (selective admission for serial neuro checks)

— Inadequate home supervision in patients requiring observation

— Persistent vomiting, severe headache

— Co-existing injuries requiring inpatient care

— GCS ≤8 (severe TBI — outside concussion spectrum, but presentation overlap)

— Hemodynamic instability

— Need for ICP monitoring or neurosurgical intervention

— Normal CT (if obtained), GCS 15, reliable adult observer for 24h

— Strict return precautions documented and verbalized

— Follow-up scheduled within 24–72h

CCS pearl: For a concussion patient being discharged from ED, your order set should include: discharge home with responsible adult, written return precautions (worsening headache, repeated vomiting, confusion, weakness, seizure), avoid alcohol/sedatives, no driving until symptom-free, no return to sport until cleared, follow-up with PCP in 24–72 hours, and provide concussion education handout.

Immediate ED transfer from clinic/field — call EMS if:

Neurosurgery consultation:

Admission criteria:

ICU criteria:

Outpatient observation (most concussions):

Return precaution checklist must be documented verbatim in the chart — patient safety and medicolegal protection.

Coordinate with school/athletic trainer for same-day notification of injury.

Key Differentials — Other Causes of Head Trauma Symptoms

— Classic: brief LOC → "lucid interval" → rapid deterioration

— Mechanism: middle meningeal artery laceration, often with temporal skull fracture

— CT: biconvex (lentiform) hyperdensity, does not cross suture lines

— Management: emergent craniotomy if symptomatic or >30 mL

— Acute: high-energy trauma, rapid neuro decline

— Subacute/chronic: elderly, anticoagulated, alcoholic; insidious headache, cognitive decline, gait disturbance over days to weeks

— CT: crescent-shaped hyperdensity (acute), iso/hypodense (chronic); crosses suture lines

— Management: surgical evacuation if symptomatic or >10 mm

— Blood in sulci/cisterns; thunderclap headache, meningismus, photophobia

— Generally managed conservatively if no aneurysm

— Coup/contrecoup injuries, typically frontal/temporal

— Focal neuro signs, may bloom on serial imaging

— High rotational forces, immediate prolonged LOC

— Initial CT often normal; MRI shows punctate hemorrhages at gray-white junction, corpus callosum, brainstem

— Linear, depressed, basilar

— Basilar signs: Battle sign, raccoon eyes, CSF rhinorrhea/otorrhea, hemotympanum

— Carotid (anterior circulation deficits, Horner) or vertebral (posterior circulation, neck pain, vertigo, ataxia)

— CTA or MRA diagnostic; anticoagulation or antiplatelet therapy

Key distinction: Concussion has a normal CT and no structural lesion. Any stem with hyperdensity on CT, focal deficit, declining GCS, or "lucid interval" is not concussion — identify the hemorrhage type and act.

Within the head-injury spectrum, differentiate concussion from:

Epidural hematoma:

Subdural hematoma:

Traumatic subarachnoid hemorrhage:

Cerebral contusion:

Diffuse axonal injury (DAI):

Skull fracture:

Cervical artery dissection:

Post-traumatic seizure must be distinguished from impact (concussive) seizures, which occur at moment of impact, are brief, self-limited, and benign.

Key Differentials — Non-Trauma and Mimickers

— Preceding history of migraine; aura, throbbing, unilateral, photophobia, phonophobia

— Triggers identifiable; responds to triptans

— May coexist with or be unmasked by concussion

— BPPV: brief positional vertigo, positive Dix-Hallpike, treated with Epley

— Vestibular neuritis: prolonged vertigo, no hearing loss

— Ménière disease: episodic vertigo + hearing loss + tinnitus

— Originates from cervical spine pathology; reproduced by neck movement

— Often coexists with concussion; cervical PT improves both

— Dizziness with positional change, normal neuro exam

— Check orthostatic vitals; consider POTS in adolescents

— Somatic symptoms (dizziness, palpitations, derealization)

— Screen with GAD-7

— Cognitive slowing, fatigue, sleep disturbance overlap with concussion

— PHQ-9 screen

— Alcohol intoxication mimics concussion; withdrawal causes tremor, confusion

— Toxicology screen when history unclear

— Especially in elderly or diabetic patients with altered mental status — always check fingerstick glucose

— Meningitis, encephalitis present with headache, AMS, photophobia; fever, meningismus, CSF findings distinguish

— Focal deficits, sudden onset; obtain CT, consider CTA — especially with vascular risk factors

— Headache, dizziness, confusion in multiple household members; check carboxyhemoglobin

— Inconsistent exam, symptom amplification; sensitive to consider in disability or litigation contexts

Board pearl: When a stem describes "concussion-like" symptoms with no clear mechanism, expand the differential — order glucose, basic metabolic panel, ECG, and consider CT depending on context. Do not anchor on concussion.

Conditions that mimic concussion symptoms without head trauma — consider when mechanism is unclear or symptoms atypical:

Migraine:

Vestibular disorders:

Cervicogenic headache:

Orthostatic hypotension / dysautonomia:

Anxiety / panic disorder:

Depression:

Substance use / withdrawal:

Hypoglycemia, electrolyte derangements, hypoxia, sepsis:

Infection:

Stroke / TIA:

Carbon monoxide poisoning:

Functional neurologic disorder / malingering / secondary gain:

Secondary Prevention and Long-Term Plan

— Repeat concussions occur at 2–4× higher rate in first year post-injury

— Cumulative concussions associated with prolonged recovery, mood disorders, possible neurodegenerative risk

— Rule changes: limit full-contact practices, eliminate head-first tackling, enforce penalties for targeting

— Education: athletes, coaches, parents, officials trained to recognize and report

— Helmet use: mandatory in football, hockey, cycling, skiing, baseball; helmets reduce skull fracture and severe TBI but do not prevent concussion

— Mouthguards: limited evidence for concussion prevention

— Neck strengthening: emerging evidence, especially in female athletes

— Home safety evaluation (remove rugs, grab bars, lighting)

— Vitamin D supplementation if deficient

— Strength and balance training (Tai Chi, Otago program)

— Medication review — deprescribe sedatives, anticholinergics, orthostasis-inducers

— Vision and hearing optimization

— Annual fall-risk screening per USPSTF

— Seatbelt use, age-appropriate child restraints, helmet for motorcyclists/cyclists

— Counseling against distracted/impaired driving

— Engineering controls, training, blast exposure mitigation

— Avoid alcohol and recreational substances during recovery

— Adequate sleep, hydration, nutrition

— Gradual return to high-risk activities

— Recognize and report new symptoms

— No universal threshold; individualized

— Considerations: multiple concussions, prolonged recovery, persistent symptoms, lower threshold for new concussions, abnormal neurocognitive testing, structural imaging changes

— Shared decision-making with athlete, family, multidisciplinary team

Step 3 management: For a 17-year-old football player with 3 concussions in 18 months and prolonged recovery from the most recent, refer to a concussion specialist for retirement-from-contact-sport discussion, formal neuropsych testing, and shared decision-making — not simply "clear when asymptomatic."

Prevent recurrence — the single most important long-term goal:

Sport-specific prevention:

Fall prevention in elderly:

MVC prevention:

Workplace and military:

Counseling at discharge / follow-up:

Retirement-from-sport considerations:

Follow-Up, Monitoring, and Counseling Cadence

— Symptom inventory (SCAT6 symptom scale or PCSS)

— Targeted neurologic exam

— Review red flags and return precautions

— Initiate or confirm graded return-to-learn plan

— Begin sub-symptom threshold aerobic exercise (within 24–48h)

— School accommodations letter as needed

— Symptom trajectory, exam, advance through RTL and RTP stages

— VOMS reassessment if vestibular symptoms

— Adjust accommodations and exercise prescription

— Screen for mood disturbance (PHQ-9, GAD-7) at 2 weeks if symptomatic

— Confirm asymptomatic at rest AND with cognitive and physical exertion

— Normal neuro exam

— Return to baseline cognitive function (neurocognitive testing if available)

— Provide written medical clearance for return to contact activity

— Refer to multidisciplinary concussion clinic

— Consider MRI brain, formal neuropsychological evaluation

— Initiate targeted rehab: vestibular PT, vision therapy, CBT, BCTT-guided exercise

— Document concussion history in EHR — cumulative count

— Annual pre-participation physical reviews concussion history

— Counsel re: cumulative risk

— Defer until symptom-free with normal reaction time and cognition (typically minimum 24–48h after symptom resolution)

— Cognitive demands of job dictate pace

— Graduated return: part-time, reduced screen time, breaks, modified duties

— Expected recovery timeline

— Importance of NOT returning to play prematurely (second-impact syndrome)

— Sub-threshold activity is therapeutic, not harmful

— Sleep hygiene

— When to seek emergency care

Board pearl: Medical clearance for return to contact sport requires the patient to be symptom-free at rest, with cognitive exertion, and with full physical exertion — and to have completed the graduated RTP protocol with a physician's documented sign-off. Anything less is a wrong answer.

First follow-up: 24–72 hours post-injury (PCP or sports medicine):

Weekly follow-up until symptom-free:

At symptom resolution:

Persistent symptoms >2 weeks (adult) / >4 weeks (pediatric):

Long-term follow-up:

Driving:

Return-to-work for non-athletes:

Patient/family counseling priorities:

Ethical, Legal, and Patient Safety Considerations

— Same-day return to play is contraindicated and constitutes a sentinel safety event — every state has youth concussion legislation (Lystedt Law model) mandating removal from play, medical evaluation, and written clearance before return

— Transition-of-care risk: discharge from ED without documented return precautions, follow-up appointment, and school/work notification creates significant medicolegal and clinical risk. Use a structured discharge checklist

— Written return precautions must be provided in patient's preferred language at appropriate health literacy level

— Adolescent athlete eager to return: balance assent with parental consent and physician judgment; physician's clinical assessment supersedes athlete/family preference

— Athlete pressured by coach, scholarship, or NIL considerations to return early — physician advocates for patient's medical interests

— Generally requires parental involvement; some states permit adolescent autonomy for certain decisions

— Coordinate with school nurse and athletic trainer with appropriate consent (HIPAA/FERPA boundaries)

— Suspected child abuse with inconsistent mechanism (especially in young children with intracranial injury) → mandatory CPS report

— Intimate partner violence in pregnant trauma patient → offer resources, safety planning; not always mandatory but always offered

— Elder abuse with suspicious falls → APS report in most states

— Impaired driving with MVC-related concussion → reporting laws vary by state

— Section 504 plans / IEPs for prolonged academic accommodations

— FMLA for working adults with PPCS

— ADA protections for return-to-work modifications

— Team physician's primary duty is to the athlete-patient, not the team

— Document removal-from-play decisions clearly

— "When in doubt, sit them out"

— Counsel without overstating evidence; CTE is a postmortem diagnosis with uncertain clinical prevalence

Step 3 management: A high school football coach calls demanding clearance for an athlete still symptomatic at 5 days. Correct response: decline clearance, document objective findings, communicate professionally with coach and family, advocate for athlete's safety, provide expected timeline — patient safety supersedes external pressure.

Patient safety — concrete Step 3 scenarios:

Informed consent edge cases:

Confidentiality and minors:

Mandatory reporting:

Disability and accommodation:

Sports medicine ethics:

Research/CTE:

High-Yield Associations and Rapid-Fire Clinical Facts

— Concussion is a clinical diagnosis; CT and MRI are typically normal

— LOC is not required (occurs in only ~10%)

— GCS by definition is 13–15 in mild TBI/concussion

— Canadian CT Head Rule, PECARN, NOC are validated decision tools — know which population each applies to

— GFAP + UCH-L1 serum biomarkers can rule out intracranial injury within 12h

— 24–48h relative rest, then sub-symptom threshold aerobic exercise

— Graduated return-to-learn precedes graduated return-to-play

— Minimum 6 stages, ≥24h each — minimum ~7 days; often longer in youth

— No same-day return to play — absolute

— Buffalo Concussion Treadmill Test identifies exercise threshold

— Acetaminophen first; limit NSAIDs/analgesics to ≤2–3 days/week

— Avoid opioids

— Melatonin first-line for sleep

— Amitriptyline or topiramate for post-traumatic migrainous headache

— Vestibular rehab > meclizine for persistent vertigo

— Female sex, adolescents, prior concussion, migraine history → prolonged recovery

— Elderly + anticoagulation = mandatory CT; consider delayed bleed

— Second-impact syndrome: adolescent, catastrophic, preventable

— Epidural: lucid interval, biconvex, middle meningeal artery

— Subdural: crescent, bridging veins, elderly/anticoagulated

— DAI: normal CT, abnormal MRI at gray-white junction

— Carotid/vertebral dissection: neck pain + neuro deficit

— GCS <15 at 2h, focal deficit, repeated vomiting, basilar skull fx signs, age ≥65, anticoagulation, dangerous mechanism, amnesia >30 min

— Helmets reduce severe TBI, do not prevent concussion

— Rule changes and education are most effective interventions

— Pediatric concussion laws in all 50 states

Board pearl: Memorize the 6-stage Graduated Return-to-Sport protocol and the principle that return-to-learn precedes return-to-play — these are tested directly on Step 3.

Diagnostic pearls:

Management pearls:

Pharmacotherapy pearls:

Population pearls:

Differential pearls:

Red flags requiring CT:

Prevention pearls:

Long-term concerns: PPCS, post-traumatic headache, mood disorders, possible CTE risk with repetitive impacts

Board Question Stem Patterns

— High school football player takes helmet-to-helmet hit, briefly dazed, normal exam, asymptomatic at sideline 10 min later

— Answer: Remove from play, no return same day, evaluation by physician, written clearance required before RTP — NOT "return when asymptomatic"

— Teen with concussion 5 days ago, persistent mild headache and difficulty concentrating

— Answer: Initiate sub-symptom threshold aerobic exercise, partial return to school with accommodations, acetaminophen PRN, melatonin for sleep, follow up in 1 week — NOT strict rest in dark room

— 22-year-old college student with concussion, GCS 15, no LOC, no red flags, normal neuro exam

— Answer: No CT needed, clinical observation and symptom-guided care — NOT routine CT

— 78-year-old on apixaban falls, GCS 15, normal exam

— Answer: CT head non-contrast immediately; if negative, observation with consideration of repeat imaging in 24h — NOT discharge without imaging

— 16-year-old, 4 weeks post-concussion, persistent headache, dizziness, depressed mood

— Answer: Refer to multidisciplinary concussion clinic; consider MRI; initiate vestibular PT, CBT, BCTT-guided exercise, PHQ-9 — NOT continued rest alone

— Patient with concussion 6h ago now with worsening headache and one episode of vomiting

— Answer: Emergent CT head; suspect delayed intracranial hemorrhage

— 17-year-old with 3 concussions in 18 months

— Answer: Specialist referral for retirement-from-contact-sport discussion, neurocognitive testing, shared decision-making

— Coach calls demanding clearance for symptomatic athlete

— Answer: Decline clearance, advocate for patient, document; physician's duty is to patient

Key distinction: Most Step 3 concussion questions test whether you choose active rehabilitation and graduated return over outdated strict rest — and whether you apply decision rules for imaging rather than reflexive CT.

Classic Step 3 vignettes to recognize:

Pattern 1 — Sideline decision:

Pattern 2 — Outpatient follow-up:

Pattern 3 — Imaging decision:

Pattern 4 — Elderly fall:

Pattern 5 — Prolonged recovery:

Pattern 6 — Red flag escalation:

Pattern 7 — Repeat concussions:

Pattern 8 — Coach pressure:

Watch for distractor answers featuring opioids, prolonged dark-room rest, same-day RTP, or chronic benzodiazepines.

One-Line Recap

Concussion is a clinical diagnosis of biomechanically induced transient neurologic dysfunction managed with 24–48 hours of relative rest, early sub-symptom-threshold aerobic exercise, a graduated return-to-learn that precedes a graduated 6-stage return-to-play, and absolute prohibition of same-day return to sport — with imaging reserved for red-flag patients identified by validated decision rules.

— Clinical diagnosis; CT/MRI normal; LOC not required

— Apply Canadian CT Head Rule (adults) or PECARN (peds) for imaging decisions

— GFAP/UCH-L1 biomarkers can rule out intracranial injury within 12h

— Red flags: GCS <15 at 2h, focal deficit, repeated vomiting, basilar skull fx signs, age ≥65, anticoagulation, dangerous mechanism

— 24–48h relative rest, then early sub-symptom-threshold aerobic exercise (Buffalo Concussion Treadmill Test guides threshold)

— Return-to-learn precedes return-to-play; both are 4–6 stage graduated protocols

— Each stage ≥24h; advance only if symptom-free

— Absolute: no same-day return to play

— Symptom-targeted pharmacotherapy: acetaminophen first-line for headache, melatonin for sleep, amitriptyline/topiramate for post-traumatic migraine, vestibular PT for dizziness — avoid opioids and chronic benzodiazepines

— Elderly + anticoagulation → mandatory CT, consider delayed bleed

— Adolescents → highest risk for prolonged recovery and second-impact syndrome; longer recovery expected (up to 4 weeks)

— Pregnancy → avoid NSAIDs, screen for IPV

— Persistent symptoms >2 weeks (adult) or >4 weeks (peds) = PPCS → multidisciplinary clinic, CBT, targeted rehab

— Mandatory removal-from-play laws in all 50 states

— Written return precautions and structured discharge required

— Physician advocates for athlete-patient over coach/family pressure

— Document medical clearance before return to contact activity

Board pearl: When in doubt, sit them out — and rehabilitate actively, not passively.

Diagnostic recap:

Management recap:

Special population recap:

Safety and ethics recap: