Week 4 - I - Brain tumours - Astrocytomas, Oligodendriogliomas, Meningiomas, Acoustic Neuroma, Pinealomas, Pituitary tumours Flashcards
What are brain tumours?
These are tumours described as being primary or secondary, benign or maligannt growth of cells within the brain
What do extra-axial and intra-axial brain tumours mean? What is the most common extra-axial brain tumour?
Extra-axial brain tumour is one that has arisen outside of the brain parenchyma (fucntional brain tissue and spinal cord) - the most common extra-axial brain tumour is the meningioma
Intra-axial brain tumours arise within the brain parencyhma
What do meningiomas arise form?
Meningiomas are usually benign and arise from the arachnoidal cells of the meninges
What is the commonest cause of cancer related deaths in patients under 40? What is the second most most common tumour in children?
Brain tumours are the most common cause of cancer related death in patients under 40 years of age
Primary brain tumours are the second most common tumour in children - second only to leukaemia (typically acute lymphoblastic leukaemia)
`What is the normal presentation of brain tumours? Remember it is a space occupying lesion so think of What nerve palsy is most common in space occupying lesions?
- * Progressive neurological deficit - eg papilloedema
- * Usually motor weakness
- * Headaches
- * Seizures
- * 6th nerve pasly is most common due to long course
- * Progressive neurological deficit 68%
- * Usually motor weakness 45%
- * Headache 54%
- * Seizures 26%
Remember - primary brain tumours second most common in children Number 1 cause of cancer related deaths in those below 40
Why is there an increased intracranial pressure? What can this increase cause as presentation?
Increased intracranial pressure a there is an increase in mass inside a rigid box - the brain is enclosed and not much room for any expansion
Can cause hydrocephalus, headaches, vomiting, seizures, mental changes
Headache -May occur with or without raised ICP When is it typically worse? When does the headache tend to increase?
The headache is typically worse in the mornings and can wake you up
Tends to increase in severity when coughing and bending forward
Also may have an association with vomiting
Why is it that the headaches tend to be worse in the mornings?
This is because the CSF does not drain as well when lying down so a mass in the brain will only further worsen the drainage on top of the pressure - increasing headache
Aetiology of tumour headache Why might a headache arise form a tumour? What vision defects may arise due to the tumour?
May occur due to raised ICP
May occur due to tumour invasion/compression of dura/periosteum secondary to vision defects - diplopia (CN III, IV, VI, INO)
Extreme hypertension
What is internuclear ophthalmoplegia? Hypertension can occur causing headaches when a brain tumour is present due to the effects of Cushings triad What is cushings triad?
When an attempt is made to adduct -(with the relative affected eye), the eye minimally or does not adduct , the contralateral eye however presents with nystagmus
Cushing’s triad is a physiological nervous system response to increased intracranial pressure (ICP) that results in Cushing’s triad of:
- increased blood pressure,
- irregular breathing, and
- bradycardia - ususally because the cerebral perfusion pressure has dropped dramtically
When there is a swollen brain, what herniations of the brain may occur? Describe each of the 4 herniations
- Subfalcine - herniates under the falx cerebri
- Subtentorial (central) - brain herniates under tentorial cerebelli
- Uncal (transtentroial)- lesions herniates towards tentorium and put pressure on the brainstem
- Tonsilar - herniation through foramen magnum - usually fatal here
What effect does uncal herniations have on the oculomotor nerve?
The uncal herniations can compress the parasympathetics that run alongside this nerve resulting in a fixed dilated pupil
Why can inability to abduct either eye be a sign of a space occyping lesion?
CN VI has a long course through the brain and therefore a SOL can compress the nerve throughout its course resulting in diplopia
When there is a lesion in the frontal lobe, what are the symptoms thought to occur? What about a lesion in the temporal lobe? Name at least 3 for each
Frontal lobe:
- * Changes in personality or behaviour
- * Uncoordinated walking
- * Weakness on one side of the body
- * Problems producing speech correctly (Brocas)
- * Also memory problems
Temporal lobe
- * Muddled speech (wernickes - comprehension)
- * Memory
- * Hearing&vision
- * Emotions
What problems can arise due to a parietal lobe lesion? What can arise due to cerebellar disturbance? (DANISH) WHat can arise due to occipital lobe lesion?
Parietal lobe lesion
- * Speech and understanding
- * Writing, reading and simple calculations
- * Finding your way around
- * Sensory loss on one side of the body
Cerebellar
- * D - dysdiadokinesia, A - ataxia, N - nystagmus, I - intention tremor, S - slurred speech, H - hypotonia
Occipital lobe
- * Visual problems
What are the symptoms of a brainstem lesion?
Double vision
Troubles swallowing or breathing
Facial weakness
Dizziness
If in the GP and a patient presents with headache worse in the mornings that wakes them up, as well as changes in behaviour What can you check for in the practice?
You can check for papilloedema in practice here - can be caused by raised intracranial pressure but patient should be referred for neurological examination
What can be given to a patient presenting with cerebral oedema and a raised ICP with a suspected SOL? This can treat the cerebral oedema and raised ICP
Can give dexamethasone + mannitol
After performing a neurological examination, which investigation would be carried out to identify the cause of the space occupying lesions?
CT +/- MRI for tumour detection
What are the two most common cell causes of primary malignant tumour in the brain? Usually tumours arise from different types of glial cells What one is the most common type of brain tumour?
Astrocytes - most common primary brain tumour in UK (60%)
Oligodendroglial cells
WHat is the function of astrocytes? What are the four different grades for astrocytomas?
Astrocytes are involved in maintaining the blood brain barrier and electrolyte balance - they are the stap shaped cell (Astron = star in greek)
- * Grade 1 - pilocytic astrocytoma, pleomoprhic xanthoastrocytoma, subependymal giant cell
- * Grade 2 - low grade astrocytoma
- * Grade 3 - anaplastic astrocytoma
- * Grade 4 - Glioblastoma multiforme
What age groups do grade 1and2 astrocytomas tend to occur in? What age groups do grade 3and4 astrocytomas tend to occur in?
Low-grade astrocytomas (grade I and II) tend to be present in younger patients and have a better prognosis.
High-grade astrocytomas (grade III and IV) present in older patients, and the prognosis is dismal.
There are no known predisposing factors except rare familial syndromes and prior radiotherapy.
The astrocytic tumors are graded, using a three-tier system, into astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme. Grading is based on pathologic features, such as endothelial proliferation, cellular pleomorphism, and mitoses
If there is necrosis, what type of astrocytoma is diagnosed? Where in the brain do grade 1 astrocytomas tend to occur?
If there is necrosis - this confirms the diagnosis of glioblastoma multiforme
Astrocytomas tend to occur in the cerebellum but can occur elsewhere in the brain
Describe grade 1 astrocytomas? Where do these pilocytic astrocytomas tend to occur? What is the treatment of option?
These are slow growing tumours with an unlikelihood of spread to other areas
Tend to occur in the cerebellum but can occurr in the optic nerve
Generally occur in children and young adults and unlikely to return after surgery
Where are the common locations of low grade astroctyomas? How are they likely to present?
Low grade astrocytoma - temporal lobe, posterior frontal or anterior parietal lobes
Seizures is the usual presentation of this tumour
Can have hemiparesis if affecting the motor cortex of frontal lobe also and headaches
Usually occurs in young
What is the most common cancerous primary brain tumour in adults? How does it spread?
The most common cancerous primary tumour is glioblastoma multiforme
It can spread via white matter tracking and CSF pathways resulting in the formatioon of multiple gliomas
Oligodendrogliomas must be differentiated from the more common astrocytoma. On CT scan of the tumour, what is uusally seen that differs it from astrocytomas?
CT demonstrates peripheral calcification of the tumour in the majority of cases
Often also have peritumoral haemorrhages and cysts
MRI is the definitive diagnostic test for meningiomas Why is this? Remember, occur form the meninges
- This is because on MRI can see various things but the dural tail is very important- shows it arises from the dura mater
- Also on MRI - contrast-enhancing tumour, possibly with surrounding cerebral oedema
- CT - homogenous, densely enhancing -oedema - hyperostosis/ skull ‘blistering’
What is the common symptoms of acoustic neuromas?
- * Hearing loss
- * Tinnitus
- * Facial weakness
- * Loss of sensation in face
- * Also balance disturbance
- * Can cause hydrocephalus if very large
What is the treatment used for hydrocephalus? What is the function of the pineal gland?
Treatment - ventriculoperitoneal shunt
Function of the pineal gland - produces melatonin which is important in regulating sleep patterns and circadian rythyms
Image shows pineal gland tumour
What germ cell tumour is AFP, PLAP and HCG risen in? Pineal gland is most common location of intracranial germinomas
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