Minor Head Injury in Infant and Children An Evidence Based Guide to Neuroimaging of the Young Brain Sujit Iyer, M.D. Dell Children’s Medical Center of Central Texas

Goals Understand the incidence and definition of minor head injury Understand options and limitations of different modalities of neuroimaging Be familiar with the latest evidence on clinical decision rules when evaluating these patients

How common? Head trauma in children to EDs annually: – 7400 deaths – 60,000 Hospital Admissions – 600,000 ED visits – : Head CT use more than doubled – True incidence of intracranial injury from minor head injury unknown. Why? Most studies have a selected population (i.e., only those who got CT, or those with greater mechanism) – what is the true denominator? Langlois, JA; J Head Trauma Rehab, 2006 Dunning; Arch Dis Child, 2006 Kupperman; Lancet, 2009

Minor Head Injury Often considered those with GCS – GCS<14 – 20% risk of traumatic brain injury (TBI) – that’s not minor <10% of CT scans in this population (GCS 14-15) will have a traumatic brain injury Between 0.5-6% will need surgery – depends on the population you are testing Skull radiographs have no clinical utility in ruling in our out intracranial injury. Only useful in skeletal surveys. CT scans – what’s the big deal? – Estimate rate of lethal malignancies from head CT in kids is between 1:1000 to 1:5000 CTs. (risk increases as age decreases) – CT use: 0.4% of all malignancies in US are from radiation from CT studies – If current rates of CT use don’t change: 1.5-2% of malignancies may be from CT use Palchak, Ann Emerg Med, 2003 Dunning, Arch Dis Child, 2004 Brenner, NEJM, Nov 2007

CT Use and Radiation Estimated radiation to organs and cancer riskNumber of CTs done in US Adapted from Brenner, NEJM, 2007

Radiation exposure Effective dose takes into account radiation type and sensitivity of organs Unadjusted refers to same setting as adult, adjusted is settings set by body weight Taken from : Calculate the relative difference! Know this number when talking to parents The BEST web reference for you AND parents:

What are the things we should consider? History: – Age: <2 years - harder to assess, may have asymptomatic intracranial injury, higher risk for skull fracture – High risk mechanism (fall from significant height, MVC, penetrating injury, unknown mechanism – abuse?) – Seizure, confusion, LOC – Pre-existing conditions: VP shunt, AV malformation, coagulopathy (hemophilia, aspirin, etc.)

What are the things we should consider? Physical Exam: – Scalp abnormalities (hematoma, fracture, etc.) – Basilar skull fracture or ANY skull fracture signs (15-30% incidence of intracranial injury!) – Bulging fontanelle – Abnormal mental status – Focal neuro findings

How can we put this all together Things to consider: – No one symptom is going to be predictive enough for who should get a CT in minor head injury – Goal of a decision rule on who should get a CT is to NOT MISS ANYONE with an injury. That means the rule will need a high sensitivity. Do you understand why? – A decision rule will assist you on what the risk of intracranial injury is. You must still make a clinical decision based on your level of risk adversiveness.

Decision rules Goal is to NOT MISS any cases A “negative” result in a decision rule, means that you should not do the test (CT scan). And thus you assume they do not have the disease. If the rule was “wrong” and told you not to test when in fact they had the disease. That is a FALSE NEGATIVE. This is not acceptable when talking about missing head injuries Decreasing the false negative rate will effect sensitivity or specificity of a test?

What do you want: High Sensitivity or Specificity? Sensitivity = Specificity = True positive True positive + False Negative True negative True negative + False Positive

Prediction Rule 42,412 children prospectively enrolled Rule was derived AND validated on mixed population GCS 14 or 15 only Excluded: ground level fall, running into a stationary object, isolated scalp laceration, penetrating trauma, neurosurg problems Definition of clinically important TBI: death, neurosurgical intervention, intubation >24 hours, hospital admission > 2 nights

Mechanism of Injury Defined a priori as: Moderate Anything not mild or severe Mild Ground level falls Running into stationary object Severe MVC with patient ejection Death of any passenger Rollover Pedestrian or bike struck by car without helmet Falls > 5 feet (if >2 years), or >3 feet (if <2 years) Head struck by high impact object

Results Two rules developed. 2 years < 2 years Altered mental status Non-frontal scalp hematoma LOC for 5 sec or more Severe injury mechanism Palpable skull fracture Not acting normal per parents in ED > 2 years Altered mental status LOC (any length of time) History of vomiting (any) Severe injury mechanism Signs of basilar skull fracture Severe headache If you had NONE of the six, you had a.02% chance of clinically important TBI 25% of kids with none of the six variables had a head CT Negative predictive value of 100% in validation group If you had NONE of the six, you had a <.05% chance of clinically important TBI 20% of kids with none of the six variables had a head CT Negative predictive value of 99.9% in validation group

Comments Rule may seem like common sense, but would have decreased up to 25% of CTs in children’s hospitals (can hypothesize the decrease would be equivalent if not more in general hospitals) Children with altered mental status or signs of skull fracture had >4% risk of TBI (high risk, scan them) If you had ANY one of the other 4 variables, you only had a 0.9% risk of TBI (what do we do with that info?!)

Putting it together This rule is meant to decrease CT use, not predict injury There is high negative predictive value (99-100%), but low positive predictive value (2.5%) For those that have one or more variables, that are not high risk (skull fracture on exam or altered mental status), look at algorithm at how to consider these patients. Discuss this intelligently with your families

Disposition Parents do not need to wake up kids who meet low risk, but should return if symptoms change (new headache, vomiting, altered mental status, etc.) If you suspect abuse, they are not low risk. Be able to articulate why YOU think your patient should or should not get a CT to your attending – this discussion will shape your future practice

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References 1.Dunning J, Daly JP, Malhotra R, Stratford-Smith P, Lomas JP, Lecky F, et al. The implications of NICE guidelines on the management of children presenting with head injury. Arch Dis Child. 2004;89(8): Kuppermann N, Holmes JF, Dayan PS, Hoyle JD, Jr., Atabaki SM, Holubkov R, et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet. 2009;374(9696): Langlois JA, Rutland-Brown W, Thomas KE. The incidence of traumatic brain injury among children in the United States: differences by race. J Head Trauma Rehabil. 2005;20(3): Brenner DJ. Estimating cancer risks from pediatric CT: going from the qualitative to the quantitative. Pediatr Radiol. 2002;32(4): ; discussion Brenner DJ, Hall EJ. Computed tomography--an increasing source of radiation exposure. N Engl J Med. 2007;357(22): Palchak MJ, Holmes JF, Vance CW, Gelber RE, Schauer BA, Harrison MJ, et al. A decision rule for identifying children at low risk for brain injuries after blunt head trauma. Ann Emerg Med. 2003;42(4): Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K. Derivation of the children's head injury algorithm for the prediction of important clinical events decision rule for head injury in children. Arch Dis Child. 2006;91(11): Da Dalt L, Andreola B, Facchin P, Gregolin M, Vianello A, Battistella PA. Characteristics of children with vomiting after minor head trauma: a case-control study. J Pediatr. 2007;150(3): Holmes JF, Palchak MJ, Conklin MJ, Kuppermann N. Do children require hospitalization after immediate posttraumatic seizures? Ann Emerg Med. 2004;43(6):