Mild Traumatic Brain Injury

Timothy Johnson, MD, FACEP, FAAEM

Fairview Southdale Emergency Department

Objectives

• Review the epidemiology of mild TBI.

• Learn to appreciate the risks and benefits of CT imaging in the ED TBI population.

• Learn the ACEP/CDC adult mild TBI clinical policy.

• Review the 2008 Zurich Consensus Statement on Concussion in Sport.

• Learn about the Zackery Lystedt Law

The Explosion in Head injury

• More than 1 million U.S. ED visits annually for TBI

• About 1 in 300 people annually

• In North America, 650k pediatric ED head injury patients annually.

The Explosion in Explosions

• TBI has been labeled the “signature injury” of the Iraq & Afghanistan wars

• 20% of returning combat personnel have sustained TBI, mostly due to IEDs and modern body armor.

The Explosion in Sports Injuries

• 4 in 1,000 aged 8-13

• 6 in 1,000 aged 14-19

• 1% of patients ages 8-19 will be seen in the ED each year with a head injury related complaint.

Team sports injuries

• From 1997 to 2007, ED visits for organized team sports more than doubled.

• Girls hockey injuries increased almost 350% from 1990 to 2006.

• Competitive cheerleading injuries.

The Explosion in CT scanning

• Over 70 million annually

• 3-fold increase from 1993 to 2007

• Almost 1 in 4 Americans will get a CT scan every year.

• $2.17 B in 2007

• Trauma patients 3.4 times more likely to be scanned in 2007 compared to 1998.

Better outcomes for the money?

• No significant change in the proportion of hospital admissions.

• Life-threatening conditions were diagnosed in 2% of patients in 2007, 1.7% in 1998.

• In 2007, 18.7 million head CTs costing over $750 million demonstrated significant intracranial injuries in <60,000 patients.

But the highest cost is clearly not $$$

Smith-Bindman, et al. Radiation Dose Associated with Common Computed Tomagraphy

Examinations and the Associated Lifetime Risk of Cancer. Arch Intern Med. 2009, Dec14/28, vol.

169(no.22), pp 2078-86.

• Radiation doses vary significantly between different CT studies.

• 2 mSV for non-contrast head CT

• 31 mSV for a multiphase abdomen & pelvis

A Brief Primer on Radiation

Ionizing Radiation

• High-energy radiation that is capable of producing ionization in the tissues through which it passes and can be absorbed.

• One gray (Gy) is the absorption of 1 joule (J) of radiation by 1 kg of matter.

• 0ne gray (Gy) = 100 radiation absorbed doses (rad).

• One rad = one centigray or 10 milligrays.

One sievert=one gray x a quality factor

Human organs(in decreasing order of radiation sensitivity)

• Breast tissue

• Gonadal tissue

• Glandular tissue

• Lung

• Liver

• Muscle

• Skin

Here’s some radiation doses to help you benchmark

Average Background. US

• A-bomb survivors, Hiroshima & Nagasaki

• Citizens of Chernobyl (dose over 70 year period)

• Terrorist “dirty bomb”

• Radiation worker limit

• Astronaut on the space station

3 msV/year

• 100-200 msV

• 14 msV

• 3-30 msV

• 20 msV/year

• 170 msV/year

X-ray doses

Study Dose (msV) # CXRs

2 view chest x-ray 0.02 1

3 view ankle x-ray 0.0015 1/14th

Screening mammogram (breast dose)

3 msV 150

CT doses

Study Dose (msV) # of CXRs

CT head, non-contrast 2-4 100-200

CT chest, PE protocol 10 500

CT abdomen/pelvis w/contrast

16 800

CT cervical spine 4 200

Smith-Bindman, et al. Radiation Dose Associated w/CTs and the Associated Lifetime Cancer Risk

• Radiation doses vary from 2 msV (head CT) to 31 msV (multiphase abdomen/pelvis).

• Even within study types (even at the same institution), radiation dose can vary 3-22 fold.

• Younger patient age, radiation-sensitive organ exposure, and higher radiation dose all contribute to higher future cancer risk.

Estimated number of patients undergoing CT that would lead to the development of one new cancer, by type of CT.

20 Y female

20 Y male 40 Yfemale

40 Y male 60 Y female

60 Y male

head 4360 7350 8100 11,040 12,250 14,680

neck 2390 4020 4430 6058 6700 8030

strokeprotocol

660 1120 1230 1682 1860 2230

Chest for P.E.

330 880 620 1333 930 1770

abdo / pelvis non-contrast

500 660 930 1002 1400 1330

abdo / pelvis w/ contrast

470 620 870 942 1320 1250

Why haven’t we seen an explosion of cancer?

• Cancer is already a high-incidence disease

• Remember the 2-hit hypothesis of mutation.

Berrington de Gonzalez, et al. Projected Cancer Risks from Computed Tomography Scans Performed in the United States in

2007. Arch Intern Med. 2009, Dec.14/28. vol.169 (no.22), pp 2071-77.

• Estimated the number of radiation-related cancers from 2007 scans as 29,000.

• 15% of cancers in patients younger than 18 at time of the CT scan.

• 66% of the cancers will be in women.

Mean lifetime cancer risk per 10,000 CT scans

Age (Y) Head C spine Chest A & P

3, female 8 70 40 20

15, female 4 50 30 20

30, female 2 5 10 10

50, female 1 2 7 8

70, female 1 1 3 3

3, male 9 10 10 20

15, male 5 10 9 20

30, male 3 3 5 10

50, male 2 2 4 9

70, male 1 1 3 5

Clinical decision rules for neuroimaging

• Pediatrics—none yet validated nor widely accepted

• The Canadian Assessment of Tomography for Childhood Head Injury (CATCH) rule was published march, 2010.

• Mild TBI is defined as injury w/in 24 hrs associated w/witnessed LOC, amnesia, disorientation, persistent irritability, or vomiting more than once, with GCS 13-15.

Head CT if at least one item is present:

• GCS <15 at 2 hours after injury

• Suspected skull fracture

• Worsening headache

• Irritability

• Signs of basilar skull fracture

• Large, boggy scalp hematoma

• Dangerous mechanism (fall >3 feet or 5 steps)

CATCH rule

• Would catch 98.1% of brain injuries that would be visualizable on head CT.

• 100% of injuries requiring neurologic intervention would be identified.

• 52% of patients would get a head CT.

• 0.6% would require neurosurgical intervention.

The Image Gently Movement

So, what if we didn’t CT any mild TBIs?

• For adults (age 16 and older) with mild TBI and GCS 15, 6-15% will have an acute lesion on head CT.

• 0.4-0.5% will require neurosurgical intervention.

• The ED physician therefore is weighing options between two low-incidence, HIGH CONSEQUENCE events.

The ACEP/CDC 2008 Clinical Policy: Neuroimaging and Decisionmaking in Adult Mild Traumatic Brain Injury

in the Acute Setting: 4 questions

• Which patients with mild TBI should have a non-contrast head CT in the ED?

• Is there a role for head MRI over non-contrast CT in the ED evaluation of a patient with acute mild TBI?

• In patients with mild TBI, are brain-specific serum biomarkers predictive of an acute intracranial injury?

• Can a patient with an isolated mild TBI and a normal neurological examination be safely discharged from the ED if a non-contrast head CT shows no evidence of intracranial injury?

Question 1: Who should have a head CT?

• Level A recommendations: Head trauma patients with LOC or post-traumatic amnesia if one or more is present: headache, vomiting, age >60, drug or alcohol intoxication, deficits in short term memory, physical evidence of trauma above the clavicles, post-traumatic seizure, GCS <15, focal neurologic deficit, or coagulopathy.

Question 1: Who should have a head CT?

• Level B recommendations: Head trauma patients with no loss of consciousness or post traumatic amnesia if there is: focal neurodeficit, vomiting, severe headache, age >64, signs of basilar skull fx, GCS <15, coagulopathy, or dangerous mechanism (ejection from motor vehicle, pedestrian vsMV, fall from height >3 feet or 5 stairs).

What rule do I use? The EPPA 9

• Vomiting more than once

• Evidence of skull fracture

• Abnormal behavior (intoxication, confusion, irritability, lethargy)

• Focal neuro deficit

• GCS <15

• Scalp hematoma

• Coagulopathy

• Age >65

• Significant headache

Question #2: MRI over CT?

• Level A and B recommendations: Not yet.• No good studies…

• But scan times are decreasing.

• Functional MRI and diffusion tensor MRI show promise.

Question 3: Is there a blood test?

• Level A and B recommendations: no.

• Level C recommendation: In mild TBI patients without significant extracranial injuries and a serum S-100B level less than 0.1 µg/L measure within 4 hours of injury, consideration can be given to not performing a head CT.

Question #4: Can they go home from the ED if the CT and exam are normal?• Level A recommendation: none specified.

• Level B recommendation: Patients with isolated mild TBI and a negative head CT are at minimal risk for developing an intracranial lesion and may be safely discharged from the ED. There are inadequate data to include patients with a bleeding disorder; who are on anticoagulant or antiplatelet therapy; or who have had a previous neurosurgical procedure.

• Level C recommendation: discharged patients should be informed about postconcussive symptoms.

6 factors deemed important for postdischarge patient monitoring

• GCS <15

• Amnesia

• Headache

• Vomiting

• Neurologic deficit

• Seizure

Post concussive symptoms (are the same as acute concussion sx)

• Headache, sleep disturbances, dizziness, nausea, fatigue, oversensitivity to light or noise, attention/concentration problems, memory problems, irritability, anxiety, depression, and emotional lability.

• 58% of adult ED patients have symptoms 1 month post injury, 28% at 6 months.

The CDC “Heads Up” Campaign

Consensus Statement on Concussion in Sport: the 3rd International Conference on Concussion

in Sport Held in Zurich, 2008.

• Concussion is different from mild TBI, though they declined to define what that difference might be.

• “I know it when I see it”.—Supreme Court Justice Potter Stewart on the difference between art and pornography.

Concussion definition

• Force transmitted to the head

• Rapid onset of short-lived impairment that resolves spontaneously

• A functional rather than structural injury

• May not involve loss of consciousness, and in a small percentage of cases, postconcussivesymptoms may be prolonged

• No abnormality is seen on standard neuroimaging.

Recommendations for on-field or sideline evaluation of concussion

• Player evaluated onsite with standard emergency management principles and c-spine precautions.

• The player should be safely removed from practice or play and urgent physician referral arranged.

• Once first aid is addressed, assessment of concussion should be made using SCAT-2 or a similar tool.

• For several hours after the incident, the patient should be watched for deterioration and not left alone.

• No RTP on the day of injury.

Sideline assessment

• SCAT 2 (sports concussion assessment test)

• BESS test (balance error scoring system)

Computer platform neurocognitivetesting

• ImPACT®

• Headminder Concussion Resolution Index (CRI)®

• Cogsport®

• Automated Neuropsychological Assessment Metric (ANAM)®

Doctors at Fairview (FSOC, Institute of Athletic Medicine) familiar with

ImPACT®

• Sarah Lehnert, MD—Burnsville

• Alex Noll, DO—Burnsville

• Paresh Ghodge, MD—Elk River

• Scott Ahrenholz, DO—Wyoming

• Kevin Ronnenberg, MD—Wyoming

• Suzanne Hecht, MD—FSOC University

What does ImPACT ® measure?

• Demographic/concussion hx questionnaire

• Concussion symptom scale (21 item Likertscale)

• 8 neurocognitive measures: memory, working memory, attention, reaction time, mental speed, verbal memory, visual memory, and processing speed

• Gives a detailed report that is automatically computer scored.

BE AN ADVOCATE FOR A CHILD:Even if symptoms subside, young athletes

should never return to play on the same day they may have had a concussion.

• 2nd impact syndrome

• Post-concussive disorder

The Zackery Lystedt Law

• Also called the “shake it off law, passed in 2009.

• 8 states now have it, Congress is considering a federal law.

• Schools and coaches love it.

The young athlete should have a graduated return to play protocol over at least 7-10 days

• No activity—complete physical and cognitive rest.

• Light aerobic exercise (<70% MPHR, no weights).

• Sport-specific exercise

• Non-contract drills (may resume resistance training)

• Full-contact practice

• Return to play

Each step should take at least 24 hours.

Things to Google later

• Heads Up campaign

• Image Gently Campaign

• Zurich 2008 Concussion Statement

• Scat 2 concussion tool

• ImPACT testing

• Zackery Lystedt law

See me later for references if you would like them.