Head Injury Flashcards
What is a TBI?
Traumatic brain injury (TBI) is a nonspecific term describing blunt, penetrating, or blast injuries to the brain. TBI can be classified as mild, moderate, or severe, typically based on the GCS and/or neurobehavioral deficits after the injury.
TBI classification by severity
Mild/Minor TBI: GCS 13-15; mortality 0.1%
Moderate TBI: GCS 9-12; mortality 10%
Severe TBI: GCS <9; mortality 40%.
What is a “concussion”?
The term “concussion” is often used interchangeably with mild TBI and minimal or minor closed head injury in the sports literature.
Due to a blunt or mechanical force that results in some type of transient confusion, disorientation or loss of consciousness lasting not more than 30 minutes
Concussion - features
- direct blow to the head or deceleration of the head from an impulsive force that results in a change in mental status.
- might present with headache, dizziness, balance problems, memory difficulty, N+V, confusion
- CT head is normal and done to rule out other pathology
- Treatment is conservative –> rest and analgesia
What is post-concussion syndrome?
Set of symptoms that may continue for weeks, months, or a year or more after a concussion. Typical features include - headache - fatigue - anxiety/depression - dizziness
Brain injury - classification by type of trauma
Blunt TBI: external mechanical force leads to rapid acceleration or deceleration with brain impact. Setting of motor vehicle-related injury, falls, crush injuries, or physical altercations.
Penetrating TBI: object pierces the skull and breaches the dura mater, seen in gunshot and stab wounds.
Blast TBI: commonly occurs after bombings and warfare, due to a combination of contact and inertial forces, overpressure, and acoustic waves
TBI - classification by brain involvement
Diffuse brain injury includes diffuse axonal injury, hypoxic brain injury, raised ICP, diffuse cerebral edema, or diffuse vascular injury.
Focal injury includes specific lesions such as contusions, intracranial hematomas, infarctions, axonal tears, cranial nerve evulsions, and skull fractures.
What are contusions?
Contusions are a type of hematoma, which refers to any collection of blood outside of a blood vessel.
(medical term for the common bruise)
Contusions occur in 20% to 30% of patients with moderate to severe TBI, and 6% of patients with minor TBI
What features warrant hospital admission for assessment of brain injury?
GCS<15 at initial assessment
post-traumatic seizure (generalised or focal)
focal neurological signs
signs of a skull fracture (including cerebrospinal fluid from nose or ears, haemotympanum, boggy haematoma, post auricular or periorbital bruising)
loss of consciousness
severe and persistent headache
repeated vomiting (two or more occasions)
post-traumatic amnesia >5 minutes
retrograde amnesia >30 minutes
high risk mechanism of injury (road traffic accident, significant fall)
coagulopathy, whether drug-induced or otherwise
On admission, what features suggest need for immediate CT head?
(NICE)
- GCS < 13 on initial assessment
- GCS < 15 at 2 hours post-injury
- suspected open or depressed skull fracture.
- any sign of basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign).
- post-traumatic seizure.
- focal neurological deficit.
- more than 1 episode of vomiting
On admission, what features suggest need for CT head within 8 hours of injury?
(NICE)
- age 65 years or older
- any history of bleeding or clotting disorders
- dangerous mechanism of injury (a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a motor vehicle or a fall from a height of greater than 1 metre or 5 stairs)
- more than 30 minutes’ retrograde amnesia of events immediately before the head injury
If a patient is on warfarin who have sustained a head injury with no other indications for a CT head scan, perform a CT head scan within 8 hours of the injury.
What about the cervical spine?
In adult patients who are GCS<15 with indications for a CT head scan, scanning should include the cervical spine. CT scanning of the cervical spine should include the base of skull to T4 images
At the start of the assessment* consider whether the cervical spine requires immobilisation via a semi-rigid collar, blocks, and tape
For a patient who was admitted due to brain injury, what observations need to be done?
The GCS should not be used in isolation and other parameters should be considered along with it, such as: pupil size and reactivity limb movements respiratory rate and oxygen saturation heart rate blood pressure temperature unusual behaviour or temperament or speech impairment.
What features suggest deterioration and require immediate reassessment by a doctor?
Any of the following examples of neurological deterioration should prompt urgent re-appraisal by a doctor:
the development of agitation or abnormal behaviour
a sustained decrease in conscious level of at least one point in the motor or verbal response or two points in the eye opening response of the GCS score
the development of severe or increasing headache or persisting vomiting
new or evolving neurological symptoms or signs, such as pupil inequality or asymmetry of limb or facial movement.
Reduction in GCS suggests progression of haemorrhage / worsening mass effect. Urgent discussion with Neurosurgical team - repeat CT or NS intervention.
What are the types of intracranial bleed?
- Intracerebral haemorrhage (intraparenchymal and intraventricular)
- Subarachnoid haemorrhage
- Subdural haemorrhage
- Extradural haemorrhage
Intracerebral haemorrhage - features
- RF: HTN, vascular lesions, brain tumour, stroke with thrombolysis
- History of HTN, sudden onset severe posterior headache, dysphasia and vomiting, right hemiparesis
- CT = areas of white lesions (haemorrhage) and sorrounding low density/dark (oedema)
- treatment usually conservative, unless there is a big clot with impaired consciousness which requires surgical evacuation
- BP control (labetalol or nicardipine) for prevention
SAH - features
- RF: hypertension, smoking, positive family history, and autosomal dominant polycystic kidney disease
- Sudden onset severe occipital headache (‘worst ever’), “thunderclap” (starts and intensifies quickly) with nausea and photophobia, loss of consciousness/coma/seizures
- CT = Blood (hyperdense - bright) is seen within the CSF spaces - in the basal cisterns, fissures and sulci
- LP used to confirm SAH if CT is -ve. LP is performed > 12h following the onset to allow the development of xanthochromia (result of RBC breakdown)
SAH - management
Referral to neurosurgery to be made as soon as SAH is confirmed
- cardiopulmonary support (ICU)
- aneurysm: open surgical clipping or endovascular coil embolisation (interventional neuroradiologists)
- prophylaxis: CBB (nimodipine) to lower BP +/- anticonvulsant (eg phenytoin) +/- stool softener (prevent straining) +smoking cessation
- Hydrocephalus (if present) is treated with an external ventricular drain (CSF diverted into a bag at the bedside) or, if required, a long-term ventriculo-peritoneal shunt
Subdural haematoma - features
- RF: trauma, coagulopathy, anticoagulant use, >65 years
- less commonly rupture of aneurysm of AVM
- typically caused by high-speed injuries or acceleration-deceleration injuries, or blow to the side of the head
- CT = dense (white) semi-lunar blood collection
- headache, N+V, diminished eye response, diminished verbal response, diminished motor response, confusion
When is surgery for subdural haematoma NOT required?
1) Glasgow Coma Scale (GCS) score 9 to 15; subdural haematoma <10 mm; and midline shift <5 mm
2) GCS <9, stable between injury and emergency department; haematoma <10 mm; midline shift <5 mm; pupils reactive and symmetrical; and intracranial pressure <20 mmHg.
(normal range of ICP is 7-15 mmHg)
Subdural haematoma - management
surgery if ≥10 mm size or midline shift >5 mm or neurological dysfunction: decompressive craniotomy or burr hole or durotomy and removal of clot
- prophylactic AED as in extradural
- correction of coagulopathy
- intracranial pressure-lowering regimen as in extradural
Extradural (epidural) haematoma - features
- ~70% occur in temporoparietal region
- ~75% associated with ipsilateral fracture
- Usually middle meningeal artery at pterion (temple)
- CT = dense (white) biconvex blood collection
- “lucid interval”: immediately following the trauma and a delay before symptoms become evident - rapid decline in consciousness
- may press on CN 3 = ipsilateral fixed and dilated pupil, eye will be positioned down and out
- contralateral weakness of the extremities and contralatetral loss of visual field
Extradural haematoma - management
- supportive: iv fluids, intubation
- surgical: hematoma is evacuated through a craniotomy or emergency burr hole
- treat high ICP = raising the head of the bed to 30°, osmotic diuresis with hyperosmotic saline solution
- prophylactic antiepileptics up to 7 days (Levetiracetam or phenytoin)
Management points in general
- Where there is life threatening rising ICP such as in extradural haematoma and whilst theatre is prepared or transfer arranged use of IV mannitol/ furosemide may be required + raise bed head to 30º, maintain BP etc.
- Diffuse cerebral oedema may require decompressive craniotomy
- Exploratory Burr Holes have little management in modern practice except where scanning may be unavailable and to thus facilitate creation of formal craniotomy flap
- Depressed skull fractures that are open require formal surgical reduction and debridement, closed injuries may be managed nonoperatively if there is minimal displacement.
Skull fractures - general
Skull fractures are caused by direct impact and may be linear (majority) or comminuted. Fractures may be located on the cranial vault or in the basilar skull, and may have a varying degree of depression. Fractures can be closed or open, communicating externally via wounds, facial sinuses, the auditory canal, or the oropharynx. Most skull fractures are due to falls, assaults, or motor vehicle-related injuries.
Classification
- open or closed
- depressed or non-depressed
- linear or comminuted
- basal or not
Skull fractures - typical examples explained
- Fractures of the temporal bone that cross the meningeal artery are associated with epidural hematomas; those that cross a dural sinus can cause significant subdural hemorrhage and hematoma.
- The bones of the base of the skull are relatively thick; therefore, any basilar skull fracture implies a serious mechanism of injury with high risk of intracerebral injury.
Because the dura is tightly adhered to the base of the skull, basilar skull fractures are frequently associated with dural tears and cerebrospinal fluid leaks.
Basal skull fracture - typical features
haemotympanum
bilateral periorbital haematoma
(‘racoon or panda eyes’)
cerebrospinal fluid otorrhoea/rhinorrhoea
Battle’s sign (mastoid ecchymosis) - indicates fractured posterior cranial fossa
hearing loss
Skull fractures - management (general)
- primarily conservative (monitoring)
+/- anticonvulsant ppx (phenytoin or levetiracetam)
For depressed or open fractures, as necessary:
dural repair and cranioplasty (repair of a defect or deformity of a skull)
For persistent CSF leak in basal skull fracture:
endoscopic intranasal surgical repair
