Session 9 - Head Trauma And Acute Intracranial Events Flashcards
What are the two types of primary head injuries?
Focal
Diffuse
What are the different types of focal head injuries?
Haematoma
Contusion
What are the different types of diffuse head injuries?
Concussion
Diffuse axonal injury
What are the different types of haematoma?
Extra dural
Subdural
Intracerebral
What are the different types of contusion?
Site of impact (Coup)
Site opposite impact (Contre-coup)
What is meant by a secondary head injury?
Injury is indirect, a complication of a worsening primary injury that has a delayed onset after the original primary injury.
What is a cerebral contusion?
‘Bruising’ of the brain whereby blood mixes with the cortical tissue due to microhaemorrhages and small blood vessel leaks.
Explain the pathophysiology of cerebral contusions.
Trauma causes microhaemorrhages.
Cerebral contusion forms.
Cerebral oedema/intracerebral bleed leads to raised ICP. This could lead to coma.
What is a concussion?
Head injury with temporary loss of brain function.
Explain the pathophysiology involved in concussion.
Trauma causes stretching and injury to axons.
This impairs neurotransmission, causes a loss of ion regulation and a reduction in cerebral blood flow.
Results in temporary brain dysfunction.
Give some examples of symptoms involved in post concussion syndrome?
Difficulty thinking clearly Difficulty concentrating Difficulty remembering new information Headache Nausea or vomiting Dizziness Sensitivity to light or noise Irritability More emotional Anxiety Sleeping more than usual Sleeping less than usual Trouble falling asleep
What is diffuse axonal injury?
Shearing of interface between grey and white matter following traumatic acceleration/deceleration or rotational injuries to the brain damaging the intracerebral axons and dendritic connections.
Explain the pathophysiology associated with diffuse axonal injury.
Trauma leads to shearing of grey and white matter interface.
This causes axonal death leading to cerebral oedema and therefore raised intracranial pressure.
This can lead to coma.
What is a basilar skull fracture?
Bony fracture within the base of the skull (temporal, occipital, sphenoid or ethmoid bone)
Explain the pathophysiology associated with a basilar skull fracture.
Trauma causes bone fracture which can cause tears in the meninges. This would lead to CSF leakage.
What are the clinical signs of a basilar skull fracture?
Raccoon eyes CSF rhinorrhea CSF otorrhea Battle sign Haemotypanum
What are the layers of the meninges?
Pia mater Subarachnoid space Arachnoid Dura mater (meningeal layer) Dura mater (periosteal layer)
Where does bleeding occur in a extradural haemorrhage?
Between the inner surface of the skull and the periosteal dura mater.
What is the most common cause of extradural haemorrhage?
Trauma and/or skull fracture.
90% of cases involve a severed artery - most commonly the middle meningeal artery.
Venous involvement rare but is usually the result of a torn venous sinus.
How will patients with a extradural haemorrhage present?
Patient will present with loss of consciousness due to impact of initial injury.
Followed by transient recovery with ongoing headache know as a ‘lucid interval’ in 40% of patients.
As haematoma enlarges, ICP will increase causing compression of the brain and rapidly deteriorating levels of consciousness.
Cranial nerve palsies may be found on examination as brain structures herniate.
What will an extradural haemorrhage look like of CT?
Lemon shaped
Midline shift
Prognosis of extradural haemorrhage is generally good with early intervention, however what complications might occur if it is left untreated?
Permanent brain damage Coma Seizures Weakness Psuedoaneurysm Arteriovenous fistula
Where does bleeding occur in a subdural haemorrhage?
Between the meningeal dura mater and arachnoid mater.
What causes a subdural haemorrhage?
Bleeding occurs due to shearing forces on cortical bridging veins. Most often associated with trauma but can be spontaneous. Cerebral atrophy increase the risk of rupture.
Could be acute, subacute or chronic.
Chronic subdural haemorrhage can present with symptoms similar to what other disease?
Dementia. Chronic SDH may present with insidious onset of confusion and general cognitive decline.
How do subdural haemorrhages present on CT?
Banana shaped
Doesn’t cross the midline due to the falx cerebri
Midline shift
How do acute and chronic subdural haemorrhages look different on CT?
Acute - hyper dense i.e. brighter than brain tissue
Chronic - progressively hypodense over time i.e darker than brain tissue
What two neurosurgical methods can be used to relieve raised intracranial pressure?
Burr hole
Craniotomy
Where does bleeding occur in a subarachnoid haemorrhage?
Between the arachnoid mater and the pia mater.
What are the usual causes of subarachnoid haemorrhage?
Vast majority of subarachnoid haemorrhages occur spontaneously secondary to ruptured berry aneurysm but may also be traumatic.
How will patients with subarachnoid haemorrhage present?
Sudden onset ‘thunderclap’ headache Meningism (nuchal rigidity (neck stiffness), photophobia, headache) Nausea and vomiting Fever Focal neurological deficits Loss of consciousness
What are the risk factors for berry aneurysms?
Family history
Hypertension
Heavy alcohol consumption
Abnormal connective tissue; autosomal dominant polycystic kidney disease, Ehlers-Danlos, neurofibromatosis, Marfan’s
Do berry aneurysms present with symptoms?
Largely asymptomatic it symptoms may arise if compressing on nearby structures or during early stages of rupture.
What surgical procedures can be performed if there is a high risk of berry aneurysm rupture?
Surgical clipping
Endovascular coiling
Where are the most common sites of aneurysm formation?
Generally occur at bifurcations:
- bifurcation of anterior cerebral artery
- bifurcation of internal carotid
- bifurcation of posterior cerebral artery
What procedure can be used to help diagnose a subarachnoid haemorrhage?
Lumbar puncture - presence of red blood cells or xanthochromia (red blood cell breakdown)
Outline how a subarachnoid haemorrhage managed.
Stabilise patient Prevent rebleeding Treat cerebral vasospasm Correct hyponatraemia Neurosurgical intervention if a large bleed
What are some possible complications of a subarachnoid haemorrhage?
Hydrocephalus Focal neurological deficits Coma Seizures Cognitive decline Frequent headaches Hypopituitarism
