Where is CSF produced?
Choroid plexuses of lateral, third and fourth ventricles
What is the other name for the cerebral aqueduct?
Aqueduct of Sylvius
Where is CSF reabsorbed?
Arachnoid granulations -> Sagittal sinus
What are three problems with CSF which can cause hydrocephalus?
Overproduction
Lack of absorption
Obstruction
What is
a) non-communicating
b) communicating
hydrocephalus?
a) Non-communicating - blockage within ventricles prevents CSF flow
b) Communicating - blockage elsewhere e.g subarachnoid space or granulations causes CSF blockage and hydrocephalus
What happens if hydrocephalus occurs before the skull bones have fused?
Head enlargement
An increase in CSF volume leads to an increase in ___ ___.
intracranial pressure
What happens to the brain in response to raised intracranial pressure?
Compression
then Herniation
Why is brain herniation so dangerous?
Compression of cranial nerves and centres
How is cerebral perfusion pressure calculated?
MAP - ICP
What are the symptoms of a raised ICP?
Headaches
N&V
Papilloedema
Neck stiffness
What are some examples of space occupying lesions?
Tumour
Abscess
Haematoma
Cerebral oedema
Why are the focal headaches associated with SOLs worse in the morning?
During sleep you become slightly hypercapnic
Which increases pressure
On which side of the tentorium cerebelli do brain tumours tend to arise in
a) adults
b) children?
a) above
b) below
Brain tumours most commonly found in the population are (primary / secondary).
Secondary
metastatic cancers from liver, breast, lungs…
Why are all brain tumours considered dangerous?
Compression effect
Even benign tumours grow slowly
What is the most common type of primary brain tumour in adults?
Astrocytoma (tumour of astrocytes, supporting cells)
Which grade of astrocytoma does not progress?
Who tends to get them?
Grade I
Children
Which grades of astrocytoma have the potential to become very malignant?
II, III and IV
What is a Grade IV astrocytoma called?
Glioblastoma
What is the 2nd most common primary brain tumour in children?
Where in the brain is it found?
Medulloblastoma
Cerebellum
Medulloblastomas are (well / poorly) differentiated and have a (good / poor) prognosis.
poorly differentiated
poor prognosis
What therapy is medulloblastoma susceptible to?
Radiotherapy
What is an abscess?
Empty space filled with pus
What are the symptoms of a brain abscess?
Fever
And raised ICP symptoms (headache, N&V, visual problems, neck stiffness)
How are brain abscesses investigated and treated?
Brain imaging (CT / MRI)
Aspiration > Antibiotics
What is meant by missile and non-missile trauma?
Missile - penetrating
Non-missile - blunt
Penetrating head trauma tends to affect a ___ area.
focal area
The greater the ___ of a projectile, the greater the size of the injury it causes.
velocity
What happens to the head in a blunt force injury?
Sudden change in momentum
The greater the ___ time of a blunt force injury, the smaller the force exerted on the brain.
contact time
What happens to the brain within the skull in a blunt force injury?
Thrown around against cranial bones and protrusions
What is the primary injury of head trauma?
Is it reversible or irreversible?
Initial damage to brain
irreversible
What are some examples of secondary injury to brain trauma?
Haemorrhage
Oedema
Infection
Hypoxia
Raised ICP
What are
a) linear
b) compound
c) depressed skull fractures?
a) Straight break
b) Involving scalp, open injury
c) Dents
Skull fractures are very ___ ___ injuries.
high energy
What is a coup-contracoup injury?
In terms of head injury:
coup - injury to brain on the side of its impact within the skull
contracoup - rebound injury on the opposite side of the skull
Which impact tends to be worse in a coup-contracoup injury?
Contracoup
What is diffuse axonal injury?
Shearing damage to neurons due to impact injury
Diffuse axonal injury tends to affect ___ brain structures.
What are the symptoms?
midline
LOC, coma, vegetative state
Which
a) neurotransmitter
b) ion
is released in response to acute brain injury?
a) Glutamate
b) Ca2+
also known as excitotoxicity
What is a haematoma?
Collection of blood within the brain
Most haematomas are found within the dura.
What does the swelling of a haematoma cause?
Raised ICP
Brain herniation
Which artery may be disrupted by trauma to the area around the pterion?
Middle meningeal artery
What type of injury occurs if the middle meningeal artery is damaged?
Extradural haemorrhage
Subdural haematomas are more common in which group of patients?
Elderly
Chronic Subdural haematomas are associated with ___ of the brain in elderly people.
atrophy