Head Trauma

Definitions

• Minor head injury GCS 14-15
• Moderate head injury GCS 9-13
• Severe head injury GCS <8

Epidemiology

• Most common in:
• Children <5
• Adults >85 years

• Minor 80%
• Moderate 10%
• Severe 10%

• Causes
• Child abuse is common in 0-4 age
• MVA
• Fall
• Assault

Biology

• Cranium has fixed volume 1900ml
• Brain occupies ~80% of cranium
• CSF under normal pressure of 6.5-19.5cmH20

• Brain must maintain constant cerebral blood flow (CBF)
• Flow requires adequate Cerebral perfusion pressure (CPP)
• CPP = MAP –ICP
• CBF can be maintained well with a CPP of 50-160mmHg
• If CPP <40mmHg then CBF drops off

• MAP is maintained by autoregulation mechanisms
• A 1mmHg decrease in pCO2 causes 2-3% decrease in vessel flow
• Hence hyperventilation can be helpful to decrease blood volume in brain and hence dec. ICP

Cushings Reflex

• Progressive hypertension associated with bradycardia and diminished respiratory effort
• Specific response to raised ICP

Concussion

• An immediate and transient loss of consciousness accompanied by a brief period of amnesia after a blow to the head
• Probably caused by stretching of the reticular neurons of the upper midbrain due to rotational forces.
• Has been shown to result in subtle changes in concentration and co-ordination which can last minutes to weeks.
• No good evidence regarding best management.

Paediatric Head Injuries

• Be very suspicious of non-accidental injury – estimated 25% or more
• More often have diffuse swelling rather than haemorrhage or mass lesions
• Higher level of suspicion needed given inability to elicit symptoms – particularly < 2years
• Mortality for children <1 is higher for a given injury
• Symptoms more common in children:
• Brief impact seizure
• Postconcussive blindness

• History
• Examination
• Interaction
• Fontanels (<2yrs)
• Scalp - ?haematoma
• Pupils
• Ears and nose – for blood/csf
• Using all 4 limbs

CT Rules

See references 2 and 3

New Orleans Criteria

Patients with GCS 15 and any of the following:

1. Headache
2. Vomiting
3. >60years old
4. Drug or EtOH intoxication
5. Persistent anterograde amnesia (short-term memory)
6. Visible trauma above the clavicle
7. Seizure

Canadian CT head rule

Inclusion criteria:

• GCS 13-15
• Minor head injury
• Older than 16

· Not on Warfarin or bleeding diathesis

· Traumatic injury

High risk for microsurgical intervention:

1. GCS less than 15 at 2 hours after injury
2. Suspected open or depressed skull fracture
3. Any sign of basal skull fracture
1. Haemotympanum, racoon eyes, CSF otorrhoea or rhino rhea, Battle’s sign (mastoid eccymosis)
4. 2 or more episodes of vomiting
5. 65 years or older
6. Amnesia before impact of 30 or more minutes
7. Dangerous mechanism
1. Pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from greater than 3 metres or 5 stairs.

	Neurosurgical Intervention		Clinically important brain injury
	NOC	Canadian	NOC	Canadian
Sensitivity	100	100	100	100
Specificity	12.1	76.3	12.7	50.6

Factors found in a higher percentage of patients brain injury than normal scans:

Significant findings	Marginal significance	Non-significant findings
Vomiting Age >60-65 All 7 Canadian CT head rules Initial GCS 13 Decrease in GCS Object recall test <3/3	Persistent anterograde amnesia Seizure	Headache Drug and alcohol Trauma above the clavicle Witnessed LOC Chronic alcohol abuse

Paediatric Decision Rule

University of California-Davis Rule

See reference 1

Any of:

1. Abnormal mental status,

2. Clinical signs of skull fracture

3. History of vomiting

4. Scalp hematoma (in children < or =2 years of age)

5. Headache

99% specificity

References

1. Ann Emerg Med. 2003 Oct;42(4):492-506
2. JAMA, September 28, 2005—Vol 294, No. 12
3. JAMA, September 28, 2005—Vol 294, No. 12