Brain Tumours and Raised Intracranial Pressure Flashcards
When do the peaks in brain tumours occur during life?
Infancy and childhood
- Most are development related tumours
7th decade
What is the WHO classification of CNS tumours?
Based on presumed cell of origin
What are the common brain tumours?
Neuroepithelial tumours (gliomas) = 52% - Astrocytoma = 44% - Ependymoma - Oligodendroglioma - Medulloblastoma Metastatic tumours = 15% Meningioma = 15% Pituitary adenoma Acoustic neuroma
How are pituitary adenomas classified based on size?
Micro <10 mm
Macro >10 mm
What is the most common type of pituitary adenoma?
Prolactinoma
What are some symptoms of an acoustic neuroma?
Features of vertigo that may have a central cause
Nystagmus
CN VI and/or CN VII palsy
Why can an acoustic neuroma cause a CN VI and/or CN VII palsy?
Growth of Schwann cells on CN VIII can compress other 2 nerves, which are very close by
What is the aetiology of brain tumours?
Few clearly defined environmental risk factors
- Ionising radiation in therapeutic radiotherapy/nuclear explosions increase risk for meningioma and glioma
- No role proven for EM radiation/other environmental factors
Family history rare
Some inherited/genetic conditions predisposing
- Neurofibromatosis 1 and 2
- Li Fraumeni syndrome
Why is a sixth cranial nerve palsy a false lateralising sign?
It can occur with raised intracranial pressure (ICP) because of its long route
What is a sensitive test for pyramidal problems?
Pronator drift
What is Foster-Kennedy syndrome?
Brain tumour on one side of the brain causes optic nerve atrophy on ipsilateral side an papillary oedema on contralateral side due to raised ICP
What are the differential diagnoses for raised intracranial pressure with focal neurological deficits suggesting intracranial mass enlarging over a few weeks?
Primary brain tumour Metastatic brain tumour Brain abscess - Possible to have no fever - More likely if fever present Chronic subdural haematoma
When do malignant astrocytomas most commonly occur?
6th-8th decade
What is the prognosis for malignant astrocytomas?
Dismal
Medial survival for glioblastoma multiforme = 7-14 months
What defines a malignant astrocytoma histopathologically?
Hypercellularity Cellular atypia/pleiomorphism Mitoses Endothelial hyperplasia Necrosis/pallisading necrosis
What is the typical presentation of an intracranial mass?
Symptoms of raised intracranial pressure Seizures in 40-80% Focal neurological deficit - Depends on location of mass Duration of symptoms depends on rate of growth of mass
What does the growth rate of a tumour depend on?
Grade of tumour
From weeks to years
What are the things you see on a CT scan with raised intracranial pressure caused by a mass?
Tumour mass
Surrounding oedema
Hydrocephalus if CSF pathways blocked
What are the symptoms of raised intracranial pressure?
Headache
Nausea and vomiting
Drowsiness
Describe the headache presentation in raised intracranial pressure
Very common symptom in patients with brain tumours
Gradually progressive
Worse on waking > improves during day
Nausea and vomiting as intracranial pressure rises
- Vomiting may relieve headache temporarily
What does drowsiness indicate in raised intracranial pressure?
Important sign of critically raised intracranial pressure
Implies impending deterioration
An alert patient with severely raised intracranial pressure may deteriorate very quickly with even a small further rise
What does the clinical syndrome of raised intracranial pressure warrant?
Urgent investigation
What is the Monro-Kellie doctrine?
Cranial cavity rigid box - increase in contents > rise in pressure
Some capacity for compensation
When critical point reached, even small increases in volume result in large increases in intracranial pressure
What are some focal neurological deficits seen when the tumour is in the frontal lobe?
Mood disturbance
Personality change
Psychiatric symptoms
Especially seen in butterfly gliomas, where tumour in both frontal lobes
Where is the tumour if there is limb weakness?
Motor cortex in posterior frontal lobe
Deep pyramidal pathways
Where is the tumour if there is a visual field deficit?
Anywhere along visual pathway
- Occipital
- Temporal
- Parietal
Where is the tumour if dysphasia is present?
Dominant frontal lobe
Temporal lobe
What sort of deficits can be caused with brainstem tumours?
Multiple Weakness Sensory loss Diplopia Cranial nerve deficits
What are the principles of treatment of malignant astrocytomas?
Steroids = dexamethasone
- Reduction of vasogenic cerebral oedema and intracranial pressure
Resection of as much of tumour as safely possible
Adjuvant therapy
- Radiotherapy and chemotherapy
What does surgery for a malignant astrocytoma involve?
Tissue diagnosis essential Resection of all visible tumour if possible - Still leave microscopic tumour - Reduces mass effect and symptoms - Tissue for banking and research
Why is tumour resection often not possible?
Tumour extent - Large - Diffuse Tumour location Patient age/fitness for surgery
What is the prognosis for anaplastic astrocytoma?
2-5 years
When is prognosis worse in the cases of malignant astrocytoma?
Older age at diagnosis, especially >65
Poor neurological condition
Higher grade
Incomplete surgical removal
What is the histopathology of a low grade glioma?
Like malignant astrocytoma, but less abnormal for - Hyper-cellularity - Cellular atypia/pleiomorphism - Nuclear atypia/pleiomorphism Very few mitoses No necrosis Invades diffusely through normal brain May have calcifications
What sorts of tumours are included in low grade gliomas?
Oligodendroglioma
Astrocytomas
Mixed forms
Who is most commonly affected by low grade gliomas?
Young = 25-40
How do low grade gliomas often present?
Neurologically intact
Often only have seizures
What is the prognosis for low grade gliomas?
Prolonged = years-decades
Eventual growth of low grade tumour/progression to higher grade will occur
What are the principles of treatment of low grade glioma?
Side effects of treatment important and should be avoided
Removal of as much tumour as safely possible
Often only biopsy taken to avoid deficit
Tissue diagnosis essential
Defer radiotherapy and chemotherapy until tumour progression
What is the proportion of solitary to multiple metastatic brain tumours?
Solitary = 1/3 Multiple = 2/3
What is the cause of symptoms with metastatic brain tumours?
Often cause intense cerebral oedema that causes more symptoms than tumour mass
What are the commonest primary tumours to cause brain metastases?
Carcinoma of lung Carcinoma of breast Metastatic melanoma Carcinoma of kidney Gastrointestinal carcinoma Unknown primary
What is the presentation of metastatic brain tumours?
Similar to any mass
- Raised intracranial pressure
- Focal deficits
- Seizures
What is the treatment of brain metastases?
Steroids = dexamethasone
Surgery to remove metastasis if
- Solitary
- Primary disease stable and patient has reasonable life expectancy
If primary cancer unknown, metastasis removed to confirm diagnosis
Occasionally 1 of multiple metastases removed for palliation
Whole brain radiotherapy
Stereotactic radiotherapy
When is whole brain radiotherapy used in brain metastases?
Multiple metastases
After removal of single metastasis
When is stereotactic radiotherapy used in brain metastases?
Single high dose focused radiation for 1-3 metastases
How can large meningiomas be asymptomatic?
Slow growing so brain has more time to adjust
Not destroying neurons
What is the most common benign brain tumour?
Meningioma
When are meningiomas most likely to occur?
Middle age
Do meningiomas affect men and women equally?
No, more common in women than men
What is the cell of origin of meningiomas?
Arachnoid cells in meninges
What are the characteristic locations of meningiomas?
Most common
- Falx
- Convexity
- Sphenoid wing
What is the histopathology of meningiomas?
Multiple subtypes - Generally have no prognostic significance - Few portend poorer prognosis Whorls common features Malignancy infrequent
What is the presentation of meningiomas?
As for any intracranial mass
- Raised intracranial pressure
- Seizures
- Focal neurological deficit
Slow growing, therefore can reach very large size
- Symptoms may be present for years
- May be symptomatic and discovered incidentally
What are the principles of treatment of meningiomas?
Total surgical excision and obliteration of dural attachment most effective
Subtotal excision and diathermy of dural attachment if complete excision not possible
Radiosurgery/radiotheray for small, residual, recurrent, or malignant tumours
Extent of resection related to risk of recurrence
