Head injury

Types of head injuries: skull fractures

- 1) linear or depressed; 2) simple, comminuted or compound; and 3) closed or open

Types of head injuries: major head trauma

- Contusion: bruising of the brain tissue within a focal area that maintains the integrity of the pia mater and arachnoid layers. a contusion develops areas of necrosis, infarction, haemorrhage and oedema. - Coup-contrecoup injury: coup injury occurs at the site of the direct impact of the brain on the skull and contrecoup injuries occur at a secondary area of damage on opposite side away from injury, as the brain is thrown from side-to-side, leading to multiple contused areas. - Lacerations: actual tearing of the brain tissue. - major head trauma can result in haemorrhage, haematoma formation, seizures, cerebral oedema, intracerebral haemorrhage, subarachnoid haemorrhage and intraventricular haemorrhage.

Complications of head injury

- Epidural haematoma - Subdural haematoma - Intracerebral haematoma

Clinical manifestations of different types of skull fractures

- Frontal fracture: exposure of the brain to contaminants through frontal air sinus, possible association with air in forehead tissue, CSF rhinorrhoea or pneumocranium - Orbital fracture: periorbital ecchymosis - Temporal fracture: boggy temporal muscle because of extravasation of blood, oval-shaped bruise behing ear in mastoid region (Battle's sign), CSF otorrhoea - Parietal fracture: deafness, CSF otorrhoea, bulging of tympanic membrane caused by blood or CSF, facial paralysis, loss of taste, Battle's sign - Posterior fossa fracture: occipital bruising resulting in cortical blindness, visual field defects, rare appearance of ataxia or other cerebellar signs - Basilar skull fracture: CSF otorrhoea, bulging of tympanic membrane caused by blood or CSF, Battle's sign, tinnitus or hearing difficulty, facial paralysis, conjugate deviation of gaze, vertigo

Types of skull fractures

- Linear: break in continuity of bone without alteration of relationship of parts. - Depressed: inward indentation of skull. - Simple: linear or depressed skull fracture without fragmentation or communicating lacerations. - Comminuted: multiple linear fractures with fragmentation of bone into many pieces. - Compound: depressed skull fracture and scalp laceration with communicating pathway to intracranial cavity.

Two components of consciousness

- arousal and wakefulness (cerebral hemispheres and a reticular activating system in the brain stem) - content and cognition (cerebral cortex)

Types of head injuries: minor head trauma

- concussion - signs of concussion: a brief disruption in level of consciousness, amnesia about the event and headache

Deaths from head injury

- immediately after the injury: from direct head trauma or from massive haemorrhage. - within 2 hours after the injury: progressive worsening of the head injury or by internal bleeding. - approx. 3 weeks after the injury: result from multi-system failure.

Diffuse axonal injury (DAI)

- is a widespread damage occurs primarily around axons in subcortical white matter of the cerebral hemispheres, basal ganglia, thalamus and brainstem. - major cause of unconsciousness and persistent vegetative state after severe head trauma.

Subdural haematoma

- occurs from bleeding between the dura mater and the arachnoid layer of the meningeal covering of the brain. - symptoms: immediate deterioration (acute); unconsciousness, gradual improvement, deterioration over hours, dilation of pupils, ptosis (sub acute); progressive alteration in LOC (chronic) - treatment: craniotomy, evacuation and decompression

Intracerebral haematoma

- occurs from bleeding within the parenchyma and usually occurs within the frontal and temporal lobes possibly from the rupture of intracerebral vessels at the time of injury.

Types of head injuries: scalp lacerations

- profuse bleeding due to scalp containing many blood vessels with poor constrictive abilities.

Other manifestations of deteriorating brain function

- pupils may become unreactive to light and dilated as brain function deteriorated. - as coma progresses, noxious stimuli can initiate rigidity and abnormal postures if the motor tracts are interrupted at specific levels. - decorticate: flexion of upper extremities and extension of lower extremities. results from lesions of the cerebral hemisphere or internal capsule. - decerebrate: extension of both upper and lower extremities. results from rostral-to-caudal deterioration, when lesions of the diencephalon extend to involve the midbrain and upper brain stem. - Cheyne-Strokes breathing,

Epidural haematoma

- results from bleeding between the dura and the inner surface of the skull. - symptoms: unconsciousness with a brief lucid interval followed by a decrease in LOC, headache, nausea, vomiting. - treatment: surgery to remove blood and reduce the pressure in the brain.

Methods of test determining whether the fluid leakage is CSF

- test the leaking fluid with a dextrostix or tes-tape strip to determine whether glucose is present. CSF gives a positive reading for glucose. - nurse allows the leaking fluid to drip onto a white pad or towel and observe the drainage. within a few minutes the blood coalesces into the centre and a yellowish ring encircles the blood if CSF is present.

Factors that predict a poor outcome

- the presence of an intracranial haematoma - the increasing age of the patient - abnormal motor responses - impaired or absent eye movements or pupil light reflexes - early sustained hypotension, hypoxaemia or hypercapnia - ICP levels higher than 20mmHg

Emergency management of head injury

Initial - ensure patent airway, stabilise cervical spine, administer O2, establish IV access, control external bleeding, assess for rhinorrhoea, otorrhoea, scalp wounds, remove patient's clothing. Ongoing monitoring - maintain patient warmth using blankets, warm IV fluids, overhead warming lights, warm humidified O2 - monitor vital signs, LOC, O2 saturation, cardiac rhythm, GCS score, pupil size and reactivity - anticipate need for intubation if gag reflex is absent - administer fluids cautiously

Causes of head injury

MVAs, falls, assaults, sport-related injuries, firearm injury & recreational accidents.

Head injury

any trauma to the scalp, skull or brain

Level of consciousness

awareness and response to the nevironment

Consciousness

the state of awareness of self and the environment and of being able to become oriented to new stimuli.