* Brain Injury Flashcards
What are the main parts of the brain?
- Cerebrum (biggest)
- Cerebellum (mini brain at base)
- Brainstem (midbrain, pons and medulla)
What are the 2 main types of brain injury?
- Primary
- Secondary
What is primary brain injury?
- Direct impact
- Axonal injury
~ Laceration, contusion ad hemorrhage - Location types
~ Focal-coup (localised at site of impact)
~ Polar/counter-coup (brain shift within skull and meninges -> local injury at 2 opp. poles of brain)
~ Diffuse (widespread)
What is secondary brain injury?
- Progressive damage due to physiologic response
~ Eg brain swelling, infarction, and cerebral hypoxia
~ Ischemia -> ^ ICP -> altered vascular regulation - Either diffuse (widespread) or multifocal (multiple specific areas)
~ Concussion, infection and hypoxic brain injury
What are the 3 types of intracranial hematomas?
- Epidural
- Subdural
- Subarachnoid
What are the manifestations of brain injury?
- Consciousness changes (Confusion, Delirium, Obtundation, Stupor, Coma)
~ Use GCS - Changes in sensory and motor functions
- Decorticate posture (flexor, cats paw)
- Decerebrate posture (extensor, straight arms)
- Cranial nerve reflexes (Pupil, corneal, doll’s eye reflex)
What do the abnormal cranial nerve reflexes signify?
- Pupil reflex
~ Affects brainstem and CN 2+3
~ Indicator of brain herniation
~ ^ICP can impair eye movements controlled by CN 3+4+6 - Oculovestibular reflex / Doll’s eye test
~ Eyes follow where head turns
~ Brainstem dysfunction - Corneal / blink reflex
~ Absence indicates severely impaired brain function
What are the possible fracture types of the cranial vault (above basal area)?
- Linear
~ Causes rupture of meningeal vessels - Depressed
~ Eggshell: Child abuse
~ Stellate (star): Blunt objects - Open
- Impaled object
What are basal skull fractures?
- Site of serious injury
~ Brainstem, cranial nerves, and major blood vessels found
~ Can result in anosmia (smell), partial vision loss, facial palsy, vertigo, nystagmus - Difficult to detect in X-rays
~ Due to presence of irregular, dense bones
~ Other soft tissue injuries may point to BSF
What are some soft tissue injuries?
- Hemotympanum (blood in middle ear)
- CSF rhinorrhea / otorrhea
- Postauricular ecchymoses / Battle’s sign (redness behind ear)
- Periorbital ecchymoses (racoon’s eyes)
What are the 6 types of intracranial lesions?
- Concussion
- Contusion
- Extradural hematoma
- A/C Subdural hematoma
- Subarachnoid hemorrhage
- Intracerebral hemorrhage
What is a concussion?
- Type of intracranial lesion
- Short, transient LOC, daze
- No structural lesions
Clinical features:
- Amnesia
- Retrograde amnesia (events right before)
~ Severe
- Antegrade amnesia (events after, very brief)
What is a contusion?
- Type of intracranial lesion
- Hemorrhage into brain tissue
- Due to deceleration of the brain against the skull
~ Ruptures blood vessels on brain surface
~ Affects frontal and occipital pole - Results in either a coup or counter-coup injury
Clinical features:
- Hemiparesis / gaze paralysis (frontal inj)
- Visual defect (occipital inj)
- Olfactory issues
- Cerebral edema, decorticate, decerebrate rigidity
- Coma
~ If lesions are bilateral
What are extradural hematomas?
- Type of intracranial lesion
- Bleeding is between the skull and dura mater
~ Damage to the middle meningeal artery
~ Arterial bleed
~ Rapid worsening of conditn
Clinical Features:
- Brief LOC -> Short “lucid interval” -> Coma
- Decerebrate, coma, death
- Convex + lighter area on CT scans
What is an acute subdural hematoma?
- Type of intracranial lesion
- Bleeding between dura mater and arachnoid membrane
~ Due to rupture of surface cerebral veins in severe head injury
~ Venous bleed
Clinical features:
- Brief LOC -> Longer “lucid interval” -> coma
- Decerebrate rigidity, coma, death
- More common than extradural hematoma
- Requires surgical evacuation
