L58 - CT or not in traumatic brain injury

Question 1

2 main groups most at risk of TBI?

Answer 1

1. Young children
   – leading cause of death and disability
   – Associated with high societal cost from death and disability
2. Elderly
   – Increasing incidence of fall-related TBI due to population aging
   – Highest rates of TBI-associated death and hospitalization

Question 2

Gender distribution of TBI?

Answer 2

Male vs female: 2x risk of TBI and 4x risk of fatal TBI

– Males - bimodal distribution

– Females - positively skewed distribution

Question 3

Main causes of TBI in children?

Answer 3

Falls at home

Motor vehicle accidents

Question 4

2 types of Mechanisms of brain trauma?

Answer 4

• Primary damage
– direct focal impact
– sudden acceleration/deceleration within the cranium

• Secondary injury (follow primary injury)
– alterations in cerebral blood flow
– alteration in intra-cranial pressure

Question 5

Sequelae of TBI?

Answer 5

Vast majority mild in severity

2% with persisting or lifelong disability

Question 6

Importance of proper initial management of TBI?

Answer 6

• prevent secondary injury from the complications of brain injury
• significantly improve mortality and morbidity
• reducing hospital stay
• Reducing health care costs

Question 7

Why is neuroimaging needed in acute TBI setting?

Answer 7

Determine:

• Presence and extent of injury
• Severity and operability
• Inform surgical planning

Question 8

Why is neuroimaging needed in chronic TBI setting?

Answer 8

Identify:

• Prognostic indicators
• Chronic sequalae
• Rehab
• Management strategy

Question 9

Is plain skull XR used in TBI assessment?

Answer 9

No

• Very low Dx value
• Poor treatment indicator
• Only show small % of intracranial haematomas

Question 10

What is the imaging modality of choice in acute TBI setting? Why?

Answer 10

First 24h after TBI: use CT scan

• Available
• Short imaging time
• Easy to perform on intubated, agitated patient
• Good for bony detail, subarachnoid and acute parenchymal hemorrhage

Question 11

List 2 problems with routine neuroimaging in TBI?

Answer 11

Cost: both monetary and opportunity cost in taking up scanner time

Low rate of findings: <10% have positive CT scan results

Question 12

Define Defensive Medical Practice?

Answer 12

Tests and procedures primarily driven by fear of malpractice liability rather than medical indications

Deliberately choosing an aggressive patient management style

Question 13

What drives defensive medical practice?

Answer 13

Getting sued = significant predictor in defensive medical practice

Question 14

List 3 issues with defensive medical practice?

Answer 14

– Costly (and opportunity cost) to health care system

– Unnecessary additional health risks – radiation/ contrast/ invasive procedure

– Emotional/ and stress issues

Question 15

List 7 clinical criteria to reduce CT head scans? New Orleans Criteria

Answer 15

New Orleans Criteria

– headache 
– nausea and vomiting 
– age over 60 years 
– drug or alcohol intoxication 
– Persistent anterograde amnesia 
– physical evidence of trauma above the clavicles 
– seizure

Question 16

List 2 established criteria for TBI imaging?

Answer 16

• New Orleans Criteria

* Canadian Head CT rules

Question 17

Define the Canadian CT Head Rule for minor head injury.

Answer 17

CT indicated when any 1 one of the following findings is described:

• GCS:13/15
• Witnessed loss of consciousness
• Amnesia
• Confusion

Question 18

Define the Canadian CT Head Rule for high risk head injury.

Answer 18

1. GCS<15 two hours after head injury
2. Suspected open or depressed skull fracture
3. Signs of basal skull fracture (hemotympanum, racoon eyes, cerebrospinal fluid otorrhea or rhinorrhea, Battle’s sign)
4. Two or more episodes of vomiting
5. Patients ≥ 65 years old

Question 19

A Low Glasgow coma scale score and a long duration of post-traumatic amnesia = Mild or severe head injury?

Answer 19

Severe

Question 20

List some clinical presentation features that indicates major head injury?

Answer 20

– worsening level of consciousness (GCS 3-8)

– loss of consciousness for more than 5 min

– failure of the mental status to improve over time

– seizure

– penetrating skull injuries

– focal neurological findings

– signs of a basal or depressed skull fracture

– confusion or aggression on examination

Question 21

What pathology is associated with increasing duration of amnesia?

Answer 21

Transient = Mild head injury

Longer = Hemorrhage

> 30min = Bilateral cerebral hypoperfusion

Question 22

Presence of headache and vomiting indicate intracranial hemorrhage in paediatrics. T or F?

Answer 22

False

Question 23

Explain why alcohol intoxication is a predictor of TBI?

Answer 23

impaired sensoria and judgment

brain atrophy in chronic abuser

Question 24

Why should head imaging be pursued more aggressively in younger children after TBI?

Answer 24

High incidence of intracranial injuries among infants who had no signs or symptom

Question 25

4 signs to identify Basal skull fracture?

Answer 25

– Hemotympanum (blood in tympanic cavity of middle ear)
– Racoon eyes
– CSF otorrhea or rhinorrhea
– Battle’s sign (brusies over mastoid process)

Question 26

List 2 limitations of conventional CT after TBI

Answer 26

CT findings may lag behind actual intracranial damage = Underestimate injury

CT missed approximately 10–20% of abnormalities seen on MRI

Question 27

List 3 advantages of MRI over CT after TBI?

Answer 27

Greater sensitivity of in the subacute and chronic settings

– Better in finding Hematomas over time

– Superior in detecting axonal injury, small areas of contusion, and subtle neuronal damage

– Better at imaging the brainstem, basal ganglia, and thalamis

Question 28

When is MRI indicated over CT after TBI?

Answer 28

MRI = 48-72hrs after injury