Tumours of the CNS I Flashcards
How do frontal lobe tumours present
- loss of short term memory
- lack of foresight
- distractibility
- Dorsolateral tumours (to the back and side of the frontal lobe): hypokinesia and apathy
- orbitofrontal tumours: hyperkinesia, increased instinctual behaviour
- Broca’s area: Expressive aphasia (can comprehend but not fluent)
- Wernickes’ area: Receptive aphasia (fluent but cannot comprehend)
frontal lobe right hemisphere responsible for
holistic and musical
frontal lobe left hemisphere responsible for
analytical, information processing
temporal lobe tumour presentation
- high level auditory
- language comprehension and verbal memory
- high level visual processing of complex stimuli
- location of tumour determines presenting signs and symptoms
occipital lobe tumour presentation
- visual processing centre
- visual hallucinations (seeing bright/flashing/floaters in front of the eye)
- visual defects (hemianopia - able to see only half of their eyes vertically or horizontally)
what does the brainstem consist of
midbrain, pons and medulla oblongata
what does the brainstem connect
the diencephalon to the hindbrain
CN I
Olfactory Nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN II
Optic Nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN III
Oculomotor nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN IV
Trochlear nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN V
Trigeminal Nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN VI
Abducens nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN VII
Facial nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN VIII
Vestibulocochlear nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN IX
Glossopharyngeal nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN X
Vagus nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN XI
Accessory nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
CN XII
Hypoglossal nerve
“Oh Oh Oh To Touch And Feel Very Good Ah Heaven”
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
“Some Say Money Matters But My Brother Says Big Books Matter More”
Sensor, sensory, motor, motor, both, motor, both, sensory, both, both, motor, motor
what cranial nerves arise from midbrain
CN III, CN IV and optic tracts in midbrain at junction with diencephalon
what cranial nerves arise in the pons
CN V, CN VI, CN VII, CN VIII
what cranial nerves arise in medulla oblongata
CN XII, CN IX, CN X, CN XIc and CN XIs
three functional parts of cerebellum
vestibulocerebellum, spinocerebellum and neocerebellum
vestibulocerbellum affected by midline tumours causes what
nystagmus (scanning motion of the eye) and truncal ataxia (falling to the side from the trunk)
*medulloblastoma arise in vestibulocerbellum
what does spinocerebeullum control & what do tumour of this area cause
spinocerebeullum controls posture and gait
ataxia of stance and gait
what does neocerebeullum control & what do lesions in this area result in
neocerebellum controls coordination
lesions result in ipsilateral incoordination, faulty phonation and articulation
anatomy of meninges from outer to inner
dura matter, arachnoid matter, subarachnoid space, pia matter
two great dural folds
falx cerebri and tentorium cerebelli
supratentorial compartment
forebrain
frontal, parietal, temporal lobes
infratentorial compartment
hindbrain
mainly cerebellum but sometimes pons
how many pairs of spinal nerves are attached to the spine
31 pairs
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
where is lumbar cistern
from L1/L2 to S2, but can vary
lumbar cistern is an area that gathers fluid. important when treating medulloblastoma
we need an MRI to decipher where lumbar cistern is
what is the order of the pathways in the spine
propriospinal pathways innermost
motor pathways intermediate
sensory pathways outermost
what are neuroglia cells & what is their function
the connective tissue of CNS
nutritive and supportive functions
what are the four types of neuroglial cells
astrocytes
oligodendrocytes
microglia
ependymal cells
what do astrocytes do
- rigid cells, support brain
- mop up K+ ions and other neurotransmitters
- phagocytose decaying synaptic boutons
- can multiply at any time
- spontaneous local proliferation may give rise to astrocytoma
what do oligodendrocytes do
- wrap myelin sheaths around axons in CNS
- known as satellite cells in PNS
- satellite cells take part in ion exchange with neurons
what do microglia do
- main phagocytes of CNS
- most line areas near blood-brain barrier
what do ependymal cells do
- line the ventricular system of the brain
- cilia are present on the free surface of ependymal cells
- cilia help to circulate CSF through the ventricles
aetiology and risk factors - environmental factors
- prior ionising radiation: associated with new meningiomas, gliomas and sarcomas
- ? food containing N-nitroso compounds (smoked foods)
- ? synthetic rubber manufacturing (making tyres etc)
- ? polycyclic hydrocarbons
- ? history of head trauma/seizures, epilepsy
aetiology and risk factors - genetic factors
(be aware but not needed to learn off)
5% of pts with malignant gliomas have a family history that may be related to rare hereditary syndromes
- neurofibromatosis (NF1) syndrome - peripheral nerve sheath neurofibromas, optic and intracranial gliomas
- NF2 syndrome -bilateral acoustic neuromas, gliomas, ependymomas and meningiomas
- Turcots’ syndrome - primary brain tumours with colorectal cancer
- Lifraumeni syndrome - breast cancer, sarcoma and brain tumour
- retinoblastoma - Rb tumour suppressor gene, chromosome 13
natural history and spread
direct infiltration
- main method of spread
- all tumour of CNS enlarge through infiltration and/or compression of neural tissue
- increased peritumoural oedema leads to intra-cranial pressure
- local infiltration leads to neurologic signs
- crossing of corpus callosum invading contralateral hemisphere
natural history and spread
tumours prone to seeding
- medulloblastoma, ependymoma, pineoblastoma, germ cell tumours, lymphoma
- meningeal deposits - foramen magnum to S4
- ventriculoperitoneal shunt may lead to peritoneal seeding
if there is raised ICP that cannot be lessened with steroids, the pt will need shunt placement. VP shunt is placed in the ventricles.
clinical presentation CNS tumours
general symptoms **favourite SQ)
- epilepsy/seizures
generalised / focal - raised intracranial pressure
headache
nausea and vomiting
somnolence (falling asleep, very drowsy mid conversation)
apathy, poor concentration
memory impairment and personality change - lumbar pain (spinal tumour)
- bladder/bowel dysfunction (spinal tumours)
- hydrocephalus
obstruction of CSF circulation leading to papilloedema (optic disc swelling)
clinical presentation brain tumours
focal neurological symptoms:
- correspond to affected part of brain
- dysfunction caused by ischemia of neural tissue
- ischemia caused by local pressure from tumour
clinical presentation spinal tumours
- pain
75% pts present with pain
often localised to involved region
radicular pain illustrates tumour in the associated root (pain beyond the spinal cord) - numbness
can replace pain, more advanced sign
spinal nerve involvement/involvement of nerve tract - spinal cord compression
lesion between foramen magnum and L1/L1
upper motor neurone loss of function below the level of the compression
(upper motor neurons are a first type of first order neuron. they are unable to leave the CNS)
associated sensory loss
sphincter disturbance - cauda equina compression
lesion lies below lower limit of spinal cord
affects only nerve roots
signs of a lower motor neurone disturbance
lower motor neurone or second order neurons are cranial and spinal nerves. the cell bodies of these neurone are located in the brainstem, but their axons can leave the CNS and synapse with the muscles of the body.
affects lower limbs: hypotonia, weakness, wasting, dermatonal sensory loss, sphincter disturbance
diagnostic workup CNS tumours
- complete history and physical exam
- complete neurological examination (LQS Bloom Scale)
- opthalmoscopy: papilloedema for raised ICP
- detailed imaging
- biopsy if possible
- CSF cytology
diagnostic imaging
MRI is the main diagnostic imaging and modality
- T1 pre and post gadolinium, T2 and FLAIR
contrast agents highlight blood vessels. gadolinium can cross the blood brain barrier. T2 dampens the noise. FLAIR dampens the signal coming from the CSF
- Post-op MRI within 48 hours to document any residual disease
-PET: Juvenile Pilocytic Astrocytoma has a high uptake on PET
- MR spectroscopy: tumour = increased choline, decreased creatine, decreased N-Acetylaspaetate (marker of viable neurons)
- Dynamic MR perfusion - checks the flood flow through the tumour (cerebral blood volume (CBV). Increasing grade of astrocytoma correlates with a similar increase in CBV
WHO classification of CNS tumours
NOS suffix
‘not otherwise specified’
added when the diagnostic information necessary to assign a specific WHO diagnosis is not available
WHO classification of CNS tumours
NEC suffix
‘not elsewhere classified’
indicates that the necessary diagnostic testing has been successfully performed but the results do not permit a WHO diagnosis
