Classification Tbi

Classification of Tbi Baroque NEUROTRAUMA REVIEW WORKSHOP 30 May 2009

Epidemiology & Statistics Ø Major cause of unnatural death in SA Ø 50% of all traumatic death result from TBI Ø 75 – 80 % mild Ø 10 % fatal (pre hospital) Ø 300/100 000 TBI hospitalisation/year Ø Male : Female 2 : 1 Ø 0 – 4 and 15 – 19 are the 2 age groups at highest risk for a TBI Ø >75 years highest rates of TBI related hospitalisation and death

Aetiology

classification Mechanism – closed / penetrating Pathological - Primary / Secondary Severity - numerous Morphology – Focal / diffuse

mechanism Closed / penetrating or open • Not a purely mechanistic division • Management implications

§ Closed: brain not in contact to the environment § High \ low velocity

§ Penetrating/open: brain exposed – dural breached with or without FB § High / low velocity

§ Severity: mild to fatal

pathological Ø Primary / secondary Primary Injury § Irreversible § Induced by mechanical force § Occurs at moment of injury

Secondary Injury • May be preventable or treatable

Primary injury 2 main mechanism qContact – impact / static local & remote • Contusions • Fractures • Lacerations

qInertial • Angular • Rotational • Translational

vCombination

Primary injury Subdivision Ø Focal • Contusion • Laceration • Fractures

Ø Diffuse • Concussion • Diffuse axonal injury

Open / closed

Secondary injury Focal Intracranial haematoma • Extradural • Subdural • Intracerebral

Herniation

Diffuse • Ischaemia – local / systemic (50 % of patients) • Cerebral swelling – local / systemic • Cytotoxicity(Na, Ca, aspartate, glutamate, ion pump failure, free radicals, proteolysis, lipid peroxidation)

morphological Focal / Diffuse Focal Ø Fractures § Vault • Linear / stellate • Depressed / non-depressed

§ Basilar • With / without CSF leak • With / without nerve palsy

Ø Lacerations (pia torn) Ø Contusions (pia intact) • • • •

Fractures Coup Contra-coup Intermediate coup(inferomedial temporal lobe, cingulate gyrus, corpus callosum, basal ganglia, brain stem)

• Herniation • Gliding

morphological Focal (cont.) Haematomas • Extradural – o Tearing of dural vessels o o

85% arterial middle meningeal artery 15% venous

• Subdural • 2 types • Burst lobe • Torn bridging vessels

• Intracerebral •

Rupture of intrinsic cerebral vessels

• Subarachnoid

Cranial nerve injuries - I,II, III, IV, V, VI,VII, VIII Pituitary & hypothalamic injury Arterial – CCF, aneurysm, dissection.

morphological Diffuse Concussion • Physiological

Diffuse axonal injury • Mild LOC 6 – 24 hours • Moderate LOC > 24 hours + decerebrate posturing • Severe LOC > 24 hours + decorticate posturing

morphological CT Classification ( Marshall)

Severity Head Injury Severity Scale

severity Head Injury or Traumatic Brain Injury Classification Ø Based on PTA

severity Arbitrary classification

severity MAYO TBI SEVERITY CLASSIFICATION SYSTEM Ø A. Classify as Moderate-Severe (Definite) TBI if one or more of the following criteria apply: 1. Death due to this TBI 2. Loss of consciousness of 30 minutes or more 3. Post-traumatic anterograde amnesia of 24 hours or more 4. Worst Glasgow Coma Scale full score in first 24 hours 13 (unless invalidated upon review, e.g., attributable to intoxication, sedation, systemic shock) 5. One or more of the following present: • Intracerebral hematoma • Subdural hematoma • Epidural hematoma • Cerebral contusion • Hemorrhagic contusion • Penetrating TBI (dura penetrated) • Subarachnoid haemorrhage • Brain Stem Injury

severity MAYO TBI SEVERITY CLASSIFICATION SYSTEM Ø B. If none of Criteria A apply, classify as Mild (Probable) TBI if one or more of the following criteria apply: 1. Loss of consciousness of momentary to less than 30 minutes 2. Post-traumatic anterograde amnesia of momentary to less than 24 hours 3. Depressed, basilar or linear skull fracture (dura intact)

severity MAYO TBI SEVERITY CLASSIFICATION SYSTEM Ø C. If none of Criteria A or B apply, classify as Symptomatic(Possible) TBI if one or more of the following symptoms are present: • • • • • • •

Blurred vision Confusion (mental state changes) Dazed Dizziness Focal neurologic symptoms Headache Nausea

TBI