Update on Head Injury

Outline

• Epidemiology• Mechanisms of injury• Investigation and Management• Therapeutic strategies• Controversies• Outcome after head injury

Epidemiology

• > 10 million people / year worldwide• Incidence increasing

– Increasing car use in low and middle income countries– Trauma – gun shot / blast injury

• In UK average age increasing– Traffic safety– Elderly population

• Leading cause of morbidity and death in young• Almost half experience long term disability

• Less than 0.5% need surgical intervention

Classification of Severity

• By Glasgow Coma Score– 14-15 mild– 9-13 moderate– 3-8 severe

• By CT findings

• By marker of injury– S100b

Mechanisms of injury

• Primary injury– Contusion– Haematoma– Diffuse axonal injury

• Secondary injury– Hypoxia / ischaemia– Neurotransmitter release– Free radical generation– Calcium mediated damage– Inflammatory responses – Delayed and progressive

• Patient who “talks and dies”

Investigation

• NICE head injury guidelines– No skull x rays – 2 – 4 times more CT scans

than previously

• CT scans provide snapshot view

• Approximately 25% develop new lesions or those seen will increase

• Repeat CT vs. radiation exposure

• Single scan in a child increases risk of fatal cancer by 0.07%

Management

• Non-neurosurgical centres vs. neurosurgical centres– 2.15 increase in odds of death in severe head injury – In UK < 5% of head injured patients treated by neurosurgeons

• Many recommendations based on poor evidence– NICE only 3 level 1 recommendations

• Prehospital– Hypoxia and hypotension prevention / treatment

• ED– ATLS Guidelines

• Intensive care– Optimise oxygen delivery, perfusion, nutrition, glycaemic control and

temperature homeostasis– Monitoring – localised measures of cerebral oxygenation / continuous

EEG– Prevent seizures– Reduce brain swelling

Osmotherapy

• Mannitol• Mannitol vs. hypertonic saline• RCT showed better outcomes

with hypertonic saline• But problems if prolonged use

– Hypernatraemia– Cardiac failure – Phlebitis– Bleeding diathesis

• Cochrane – “small benefit on ICP vs. control”

Hyperventilation

• Lowers ICP but may increase ischaemia

• Cochrane– Although evidence that lowers

ICP no evidence of benefit on outcome

• Avoid high pCO2 – Aim for 4.5 – 5 kPa

Therapeutic hypothermia

• Lot of poor quality trials with different protocols

• Meta-analysis showed small benefit from use

• But – counteracted by almost

threefold increase in pneumonia

• Cochrane– Not been shown to reduce

death or disability– Is associated with an

increased risk of complications – e.g. pneumonia, arrhythmia

Craniectomy

• Decompression procedure• Surge of interest• Two large trials currently underway

Other Treatments

• Steroids– CRASH trial showed worse outcomes

• Magnesium– No evidence of benefit in routine use – Only if hypomagnesaemic

• Calcium channel blockers– Useful in subarachnoid haemorrhage– No evidence of benefit in head injury

• Routine anticonvulsants– Reduce chance of seizures– No effect on death or disability

Outcome

• Most important predictors correlating with outcome are;– Age– GCS

• motor score• GCS < 5 in children

– Pupil response– CT findings– Extra cranial injuries

• Mortality >95% in patients with a GCS of 3-5

• New models can help predict outcome at early stages

• http://www.crash2.lshtm.ac.uk/Risk%20calculator/index.html

Any Questions ?