Essential Neurology for Concussion Evaluations

Aftab Merchant, MBBS, FCPS

Professor Pre-Clinical Sciences

Cleveland University – Kansas City

Learning Objectives

• Recognize the clinical features of concussion

• Differentiate between concussion and

structural head injury

• Recognize the sequelae and complications of

concussive injury

• Outline the assessment procedures for

patients with concussion

Traumatic Brain Injury (TBI)

Mild TBI occurs with head injury due to contact

and/or acceleration/deceleration forces

Credit: First aid for free

Glasgow Coma Scale

Rutland-Brown et al. J Head Trauma Rehabil 2006

Liaa CC et al. J Neurol Neurosurg Psychiatry 2012

Pathophysiology of TBI

Primary Brain Injury

• Occurs at the time of trauma

• Results in focal contusions and hematomas

• Due to

– Direct impact

– Rapid acceleration / deceleration

– Penetrating injury

– Blast waves

• Surgical treatment

Pathophysiology of TBI

Secondary Brain Injury

• Cascade of molecular injury mechanisms

• Includes

– Electrolyte imbalances

– Inflammatory responses

– Secondary ischemia from vasospasm

– Focal microvascular occlusion

– Free-radical injury

– Neurotransmitter-mediated excitotoxicity

Structural Brain Injury

• Cerebral contusions

• Epidural hematoma

• Subdural hematoma

• Subarachnoid hemorrhage

Cerebral Contusion

• Most frequently encountered lesions

• Permanent damage to small blood vessels on

the surface of the brain

• Acceleration-deceleration injury

• Coup-contrecoup injuries

Epidural Hematoma

• Collection of blood between skull and dura

• Caused by fracture of the bone

• Rupture of middle meningeal artery

• Lens shaped lesion on CT

• Intracranial pressure increases � herniation

and death

• Lucid interval may precede neurologic

deterioration

Pterion

Subdural Hematoma

• Venous bleeding between the dura and

arachnoid membranes

Pathogenesis

• Bridging veins between brain and dural

sinuses are torn

• Slowly enlarging blood clot covers the

convexity of the brain

Subdural Hematoma

Causes

• Blunt trauma

• Anticoagulants, hemophilia

• Child abuse, shaken baby syndrome

• Spontaneous

Risk Factors

• Elderly persons

• Alcoholics

Subdural Hematoma

Clinical Features

• Progressive neurological signs

• Fluctuating consciousness level

Complications

• Herniation and death may occur

• Dementia (chronic subdural hematoma)

Diagnosis: CT scan (imaging test of choice)

Subarachnoid Hemorrhage

• Bleeding into subarachnoid space

• MCC is rupture of saccular (berry) aneurysm

• Berry aneurysm lacks a media layer

• Most are located in anterior circle of Willis

Subarachnoid Hemorrhage

Clinical Features

• Sudden onset of a severe headache

• Described as the “worst headache ever”

• Nuchal rigidity

• LP shows xanthochromia

Subarachnoid Hemorrhage

Diagnosis

• CT scan without contrast (best test)

• MRI is most useful for posterior fossa infarcts

Complications

• Further hemorrhage

• Hydrocephalus

• Permanent neurologic deficits

Vascular Pathologies

• Cerebral vessels associated with vascular

pathologies:

Epidural

hemorrhageMiddle meningeal artery

Subdural

hemorrhageBridging veins draining into the

sagittal sinus

Subarachnoid

hemorrhageBerry aneurysms in the circle of

Willis

Concussion

Concussion is a mTBI

In severe concussions

as the brain rebounds,

it twists.

Concussions in 14 NCAA sports

2014-15 NCAA Sports Medicine Handbook

Concussion

Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by traumatic

biomechanical forces.

McCrory P. et al. Br J Sports Med 2013;47:250

Pathophysiology

Diffuse Axonal Injury

• Mild TBI results in diffuse axonal injury

• DAI affects individual nerve fibers

• Axons are severed

• Disruption of communication

• Neuron may die or swell

Pathophysiology

Rotation of head at

the time of impact

can also damage

the axons.

Department of Neurological Surgery, Weill Cornell Medical College

Concussion causes an “Energy Crisis” in the brain

Matthew et al. Pediatric Annals 2012; 41:9

Pathophysiology

• Disruption of axonal neurofilament

organization impairs axonal transport

• Release of excitatory neurotransmitters

• Generation of free radicals

Concussive injury reflects a physiological

disturbance rather than a structural injury to the brain

Mardissi M et al. Aus Fam Phy 2014; 43:3

In concussion, the exterior remains unbroken and intact while the inside contents are completely misplaced.

Etiology

• Mild traumatic brain injury (mTBI)

• Due to sudden movement of brain in the skull

• Chemical changes makes brain more

sensitive to any increase stress or injury

The management of concussion in sports. Neurology 1997; 48:581

Clinical Presentation

AsymptomaticRegular

symptoms

Asymptomatic

becomes

symptomatic

Dramatic

symptoms

No loss of consciousness

Lopez V et al. Medicine & Science in Sports & Exercise (2016)

Diagnosis

Clinical symptoms

Physical signs

Cognitive impairment

Neurobehavioral features

Sleep disturbances

Signs and Symptoms

Somatic

Headache

Pressure in head

Neck pain

Dizziness

Blurred vision

Balance problems

Sensitivity to light

Sensitivity to

noise

Feeling like ‘in a

fog’

Fatigue

Low energy

Cognitive

Difficulty:

• Concentrating

• Remembering

Confusion

Emotional

More emotional

Irritability

Sadness

Nervous or

anxious

SleepDisturbances

Drowsiness

Trouble falling

asleep

Hallmark Symptoms

• The hallmark symptoms of concussion are

confusion and amnesia

• Alteration in mental status characteristic of

concussion can occur without loss of

consciousness

Duhaime AC et al. J Neurosurg 2012

Collins ME et al. JAMA 1999

Red Flags

Headache worsens Can’t recognize people or places

Seizures Increasing confusion

Focal neurologic signs Weakness / numbness in arms or legs

Neck pain Unusual behavioral change

Repeated vomiting Decreasing state of consciousness

Slurred speech Very drowsy or cannot be awakened

Complications

Second impact syndrome

• Acute, progressive diffuse cerebral edema

• Disordered autoregulation

Post-concussion syndrome

• Seen in <1% of cases

• Symptoms lasting >3 months

Complications

Post-traumatic headaches

• Onset of headache within 7 days after injury

Post-traumatic epilepsy

• Two fold increase in the risk of epilepsy for

the first five years

• Seizures occurring within the first week are

not considered epilepsy

Complications

Post-traumatic vertigo

• Direct injury to cochlea or vestibular structure

• Labyrinthine concussion due to blunt trauma to membranous labyrinth

Cranial nerve injuries

• Anosmia (CN I)

• Diplopia (CN III, IV, VI)

• Facial pain (CN V)

Complications

Chronic traumatic encephalopathy

• Cognitive impairment

• Neuropsychological symptoms

(behavior, personality changes, depression,

and suicide)

• Parkinsonism

• Speech and gait abnormalities

Chronic Traumatic Encephalopathy

CTE is a progressive disease of the brain

found in athletes (and others)

with a history of repetitive brain trauma

CTE Center, Boston University

CTE

Tau protein buildup and tissue degeneration

CTE Center, Boston University

International Conferences on Concussion in Sport

2001: Vienna 2004: Prague

2008: Zurich 2012: Zurich

Assessment

Three main points where assessment is

valuable:

• Pre-participation evaluation

• On-site at the time of injury

• Post-injury in office setting

Pre-participation Evaluation

Ask specific questions about:

• previous symptoms about concussion

• length of recovery

• perceived number of concussions

• previous head, face, cervical spine injuries

• details regarding protective equipment used

at the time of injury

On-site Evaluation

• Address first-aid issues first

• If there is a loss of consciousness then

document the length of time the person

remained unconscious

Glasgow coma scale (GCS)

• Record level of consciousness using

Glasgow coma scale

• A person suspected of having a concussion

should not return to activities (play) on the

same day.

On-site Assessment

• Evaluate orientation and cognitive functioning

• Conduct serial monitoring

• Standard orientation questions like time,

place, and person have been shown to be

unreliable in the sporting situation.

Modified Maddocks

• Maddock’s questions are used to determine the impact of the patient’s memory at the time of the incident

• Review SCAT3 with the following slides

Onsite Standardized Assessment of Concussion (SAC)

• Onsite SAC is used for cognitive assessment

• Includes:

– Orientation questions

– Immediate memory of a five word list

– Concentration using digits backwards

– Delayed recall

SAC: Delayed Recall

• Perform delayed recall after completion of the

Balance and Coordination Examination.

• Ask the person to recall words from the list of

words read earlier.

In-office Assessment

• Comprehensive history

• Neurological examination should include

– Mental status

– Cognitive functioning

– Gait and balance

• Determine the clinical status

• Determine the need for neuroimaging

Comprehensive History

• Determine if the impact was directly to the head or transmitted to the head.

• Find out if there was any loss of consciousness, if so, how long.

• Ask if there is any amnesia for the event.

• Determine if there is an observer to collaborate what happened.

• Find out if baseline assessments were done (SAC)

• Ask if there is history of concussions. If so, what are the details?

Neurological Examination

• Neurological examination should include

– Mental status

– Cognitive functioning

– Gait and balance

• Test of memory, orientation, and

concentration as provided in the SAC is

recommended.

Standardized Assessment of Concussion (SAC)

• SAC is used for cognitive assessment

• Includes:

– Orientation questions

– Immediate memory of a five word list

– Concentration using digits backwards

– Delayed recall

Balance and Gait

Balance and Error Scoring System (BESS)

• Double leg stance

• Single leg stance

• Tandem stance

Tandem Gait

Postural stability testing assesses the motor domain of neurological functioning

BESS: Common Errors

• Hands lifted off iliac crest

• Opening eyes

• Step, stumble, or fall

• Moving hip into > 30 degrees abduction

• Lifting forefoot or heel

• Remaining out of test position for > 5 sec

SAC: Delayed Recall

• Perform delayed recall after completion of the

Balance and Coordination Examination.

• Ask the person to recall words from the list of

words read earlier.

Coordination Examination

Upper limb coordination

• Finger-to-nose task

(5 correct repetitions in < 4 seconds = 1)

Clinical Status

• Assess for the presence and severity of the symptoms using a Likert scale (0 to 6)

• 22 common symptoms are listed on SCAT3

evaluation form

Clinical Status

• Determine if the symptoms have changes

• Do symptoms worsen with activity?

• Has patient experienced any retrograde or

anterograde amnesia?

• Is there any change in behavior?

Neuroimaging

• Conventional structural neuroimaging is

typically normal in concussion injuries

Consider neuroimaging if:

• prolonged disturbance of conscious state

• focal neurological deficit

• worsening symptoms

Neuropsychology Testing

• Conduct clinical NP assessment including cognitive function on all your patients suspected of having a concussion

• Formal NP testing is not required for all patients

• Formal NP testing, if needed, should be performed by a neuropsychologist

• Routine baseline NP testing not recommended

Sport Concussion Assessment Tool 3 (SCAT3)

• Tool developed by a group of international

experts at the 4th International Consensus

meeting on Concussion in Sport held in

Zurich, Switzerland in November 2012

• Published in The BJSM Injury Prevention and

Health Protection, 2013, Volume 47, Issue 5

SCAT3 and Child SCAT3

• SCAT3 is used primarily for patients aged 13

and older

• Child SCAT3 is used for children aged 5 to 12

years old

• SCAT3 should not be used as a stand alone

method for diagnosis and management of

concussion

Special Considerations

Children and adolescents

– Child SCAT3 to assess children (5-12 years)

– Modified Maddock’s score with age-

appropriate questions

– Symptom evaluation to include both child and

parent reporting

– SAC with age-appropriate questions and

concentration test

Special Considerations

Elite vs. Non-elite athletes

– All athletes regardless of the level of

participation should be managed using the

same treatment and return to play protocol.

Treatment and Follow-up

• Physical and cognitive rest

• Pharmacology in some cases

• Graded return to activities

Rest

• Rest both from physical and cognitive

exertion for at least first 24-48 hours

• Physical and cognitive activity increases

post-concussive symptoms severity and

prolongs recovery.

• In most cases, no other intervention is

required.

Pharmacology

Two situations where pharmacology plays a role.

• In the management of specific prolonged

symptoms, e.g., sleep disturbance and anxiety.

• To modify the underlying pathophysiology of the

condition with the aim of shortening the duration

of concussion symptoms

Return to Activities Protocol

Step 1No activity, complete rest until asymptomatic.

Proceed to step two when symptoms are gone.

Step 2 Light aerobic exercise

Step 3Sport-specific exercise and training.

No contact or risk of contact.

Half days at school or work

Step 4Non-contact training drills

Light resistance training and progress to heavy weights

Full days at school or work

Step 5 Full contact training after medical clearance

Step 6 Return to competition

Treatment and Follow-up

• Majority of the patients with concussion will

recover spontaneously in less than 10 days

• If symptoms last beyond 10 days or become

worse then the patient’s treatment plan might

need to be modified.

Prevention

• Recognition of the concussive injury is of

primary importance

• Helmets are not concussion-proof

• Mouthguards are a controversial area

• Rule changes to reduce injury

Concussion

• An injury to the brain that causes a brief disruption in mental status

• Not life-threatening

• Often no STRUCTURAL damage but FUNCTIONAL damage is present

• Potential to cause long-term damage

References

• McCrory, P., et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. British Journal of Sports Medicine 2013; 47:250-258.

• McCrory, P., et al. Sport Concussion Assessment Tool – 3rd Edition. British journal of Sports Medicine 2013; 47: 259-262.

• Makdissi M, Davis G, McCrory P. Updated guidelines for the management of sports-related concussion in general practice. Australian Family Physician 2014; 43(3):94-99.

• Rutland-Brown W, Langlois JA, Thomas KE, Xi YL. Incidence of traumatic brain injury in the United States, 2003. J Head Trauma Rehabil 2006;21:544.

• Liao CC, Chiu WT, Yeh CC, et al. Risks and outcomes for traumatic brain injury in patients with mental disorders. J Neurol Neurosurg Psychiatry 2012; 83:1186.

• Grady GF, Master CL, Gioia GA. Concussion Pathophysiology: Rationale for Physical and Cognitive Rest. Pediatric Annals 2012; 41(9):377-382.

• Crossman, A.R., Neary D. Neuroanatomy: An Illustrated Colour Text, 5th ed. New York: Churchill Livingstone Elsevier, 2015.

• Bickley, L.S., Szilagyi, P.G. Bates’ Guide to Physical Examination and History Taking, 12th ed. Philadelphia: Wolters Kluwer, 2017.

• Report of the Quality Standards Subcommittee of the American Academy of Neurology. Practice Parameter: The management of concussion in sports (summary statement). Neurology 1997;48:581-585.

• Lopez V, Ma R, Weinstein MG, Cantu RC, Myers LS, Nadkar NS, et al. Concussive Injuries in Rugby 7s. Medicine & Science in Sports & Exercise. 2016;48(7):1320–30.

• Duhaime AC, Beckwith JG, Maerlender AC, et al. Spectrum of acute clinical characteristics of diagnosed concussions in college athletes wearing instrumented helmets: clinical article. J Neurosurg 2012 Dec;117(6):1092-9.