Traumatic brain injuries are caused by external mechanical forces such as: - Falls - Transport-related accidents - Assault

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1 PP2231 Brain injury Cerebrum consists of frontal, parietal, occipital and temporal lobes Diencephalon consists of thalamus, hypothalamus Cerbellum Brain stem consists of midbrain, pons, medulla Central nervous system protected by: - Bone skull and vertebrae column - Meninges membranous layers made of: o Dura mater top layer (beneath bone) o Arachnoid mater middle layer (between dura and pla) o Pia mater inner-most layer (surrounds brain and spinal cord) - CSF circulates through ventricles, sub-arachnoid space, brain floats in CSF, protection from mild moderate trauma. Traumatic brain injuries are caused by external mechanical forces such as: - Falls - Transport-related accidents - Assault Non-traumatic brain injuries may be: - Congenital - Due to disease (metabolic, diabetic comas, tumours) - May be caused by drug abuse. - Damage is usually spread throughout the brain

2 Traumatic Brain Injury (TBI) - Males more susceptible year olds due to MVA and/or assault related Primary TBI - Tissue damage that occurs at the onset of brain injury or at the time of injury - Directly caused by mechanical event - E.g. laceration, fractures, intracranial haemorrhages Secondary TBI - Further damage following initial mechanical event - Delayed onset - Maybe causes more damage than the primary event - E.g. hypoxia, ischemia, swelling, infection Primary brain trauma categorisation Categorised by type of injury: 1. Concussion a. Mild brain trauma b. Alteration/transient loss of consciousness c. No evidence of brain damage with diagnostic imaging d. Symptoms: nausea, vomiting, fatigue, blurred vision, headache, dizziness. 2. Contusion a. More severe trauma b. Necrosis, laceration or bruising of neuronal tissue (CT scan) 3. Intracranial haematoma a. Localised collection of blood, following damage Types of intracranial haematomas - Epidural Collection of blood in the epidural space (between skull and dura mater)

3 - Subdural haematoma in space between the dura and outer arachnoid membrane - Subarachnoid haemorrhage into subarachnoid space (normally filled with CSF) - Intracerebral collection of blood within the brain itself - Intraventricular blood within the ventricles of the brain Categorised by location of damage: 1. Focal a. Primary injury localised to the site of the impact on the skull 2. Polar a. Injury at the site of impact as well as opposite pole (coupcontrecoup) b. Common in MVA 3. Diffuse a. Rotational movement of the brain causes widespread neuronal b. Severe diffuse injury frequently results in coma recovery maybe limited Skull fractures - Skull fractures are breaks in the integrity of the skull bone - TBI may occur from open skull fractures with concurrent brain injury - Types of skull fractures: o Hairline crack o Depression dent or cave in o Compound depression where the bone fragments are driven into the brain o Diastatic fracture along the suture lines o Basal bones at the base of the skull break (ecchymosis raccoon eyes, battles sign ) Assessing someone with TBI - Monitor Vitals - Glasgow coma scale

4 - Pupil response - Motor/sensory response - Post traumatic amnesia Spinal cord injury - Most of spinal cord gives origin to sympathetic nervous system - Sacral region of spin gives origin to parasympathetic - E.g. MVA, assault, falls, birth injuries Spinal cord injury management - Priority!! Stabilise patient and prevent secondary neuronal injury - Airway management if GCS less than 8 - Blood pressure management SNS may be hyperactive treat with BB s - Manage intracranial pressure Mechanisms of Traumatic spinal injuries HYPEREXTENSION

5 COMPRESSION ROTATION HYPERFLEXION

6 Systemic effects of spinal injury - Spinal shock o Acute complication o Sensory deficit loss of pain, feeling o Loss of spinal reflexes below injury o Lasts for hours weeks o Return of reflexes = end of spinal shock - Neurogenic shock o Occurs in spinal cord injuries above T6 level o Loss of sympathetic tone cant counteract the parasympathetic NS o Bradycardia and vasodilation = hypotension MONITOR BP!! - Respiratory depression o Especially if in the C3-C5 region - Impaired thermoregulation o Cannot shiver or change blood vessel diameter - Autonomic dysreflexia o Complication in chronic phase of SCI above T6 o Sudden episode of hypertension overstimulation of sympathetic NS o Painful stimulus below injury occurs spinal reflexes cause SNS response to pain = vasoconstriction and BP - Chronic phase of spinal cord injury o Hyperreflexia and spasticity is a chronic complication of SCI o Characterised by motor and sensory deficit below injury Classification of spinal injury - Classified by: o Vertebral level T6 o Degree complete is no function below injury site & incomplete is some function below injury site o Primary vs. secondary damage caused directly from event or damage occurring after event (ischemia, inflammation)