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 Y female 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 stroke protocol Chest for P.E. abdo / pelvis noncontrast abdo / pelvis w/ contrast 660 1120 1230 1682 1860 2230 330 880 620 1333 930 1770 500 660 930 1002 1400 1330 470 620 870 942 1320 1250
Why haven t we seen an explosion of Cancer is already a highincidence disease Remember the 2-hit hypothesis of mutation. cancer?
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 noncontrast 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 neuro deficit, vomiting, severe headache, age >64, signs of basilar skull fx, GCS <15, coagulopathy, or dangerous mechanism (ejection from motor vehicle, pedestrian vs MV, 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 3 rd 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, postconcussive symptoms 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 neurocognitive testing 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 Likert scale) 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.