Neurology Flashcards
What is Lhermitte’s sign and what is it associated with ?
Electrical shock signal that shoots down the spine during neck flexion. Associated with MS
What are the three cortical defects (types ) of fronto-temporal dementia
1) Frontal - (associated with Picks disease) Personality disorders
2) Primary Progressive - loose the ability to use language to speak, read, write, and understand what others are saying.
3) Semantic - loose vocabulary over time
What is parinaud syndrome and what is it associated with ?
inability to gaze upwards due to a pineocytoma - pineal gland tumour. The syndrome occurs when there is compression of the superior colliculus.
Where do JPA astrocytomas occur and what syndrome is it associated with> (Juvenille pilocytic astrocytoma )
Posterior fossa - midline cerebellum when not associated with NF1
. Associated with NF1- most common is optic nerves
Defining feature is increased diffusion ( so bright on ADC)
What grade 1 astrocytome is found at the foramen of monro and which patients develop them ?
Subependymal giant cell astrocytoma.
Tuberous sclerosis
What are the characteristic features of a pleomoprhic xanthoastrocytoma ?
Cystic lesions with part solid component which enhances post contrast. Slow growing with remodelling of the overlying skull
Enhancing dural tail
Where are astrocytomas IDH-mutant located ?
2/3 are supratentorial
Frontal lobe > temporal > parietal > occipital
Peripherally, they are cystic lesions which are
Hyperintense on T2/ Hypointense on FLAIR. = T2/FLair mismatch
They do not restrict diffusion
What doe oligodendric cells do?
Myelination of the neurones
What WHO grading are Oligodendroglial Tumours?
WHO 2/3 .
Higher grade is decided by histology - showing increased mitotic activity, endothelial proliferation and necrosis
Where are Oligodendroglial Tumours usually found?
Frontal and peripheral. 90% have calcification.
Where are choroid plexus tumours mots commonly found in children?
The lateral ventricles
Adults - 4th ventricles
Where are Dysembryoplastic neuroepithelial tumours usually found and what do they commonly present with?
Multicystic lesions usually within the temporal lobe - therefore presenting with epilepsy
What are the most common locations for a ICH in bleeds caused by hypertension
Basal ganglia, cerebellum, thalamus and pons
What are the main causes of masses within the posterior cranial fossa in adults
- Cerebella metastasis - lung/melanoma/breast/thyroid
- Haemangioblastoma
- Lymphoma
What disease is associated with haemangioblastoma?
Von Hippel lindau disease or sporadic
What is the classic location of CADISIL
Anterior temporal lobe and external capsule
What is amyloid angiopathy
Accumulation of amyloid plaques within the small and medium vessels of the brain.
What disease is the sign, ‘puff of smoke’ associated with ?
Moyamoya disease. It is caused by the neo-vascularlisation resulting in the formation of small, abnormal vessels
What is moyamoya disease ?
Progressive narrowing of the distal portion of the ICA and circle of Willis with secondary collaterasliastion .
Moyamoa - is a puff of smoke due to collaterisation
What is clocc ? Is it a problem
Cytotoxic lesions of the corpus callosum , it is a benign condition
What condition is spinal ependymomas associated with ?
NF2
Where in the spinal cord are ependymomas located ?
Centrally within the spinal cord, causing expansion of the cord
Do ependymomas enhance ?
Yes they have heterogenous enhancement
What is the most common intramedullary tumour in children ?
Astrocytoma
What are astrocytomas associated with ?
NF1
What WHO grading is a spinal epdenymoma ?
WHO grad 2
What is the WHO grading for an intramedullary astrocytoma ?
WHO Grade 1/2
Which cancers most commonly metastases to the intramedullary spine ?
Lung and then breast
What condition should you think of in a patient with multiple hemangioblastomas ?
Von Hippel-Lindau syndrome
What is diastomytemylia , what is it associated with ?
The cord is split.
Desmoid cysts
what is communicating hydrocephalus and what causes it
increase in ventricles due to more csf volume - but no obstructing lesion.
It is caused by a destruction in CSF absorption by the arachnoid granulations, such as subarachoidnoid haemorrhage,meningitis or leptomeningeal metastasis
what is the classic triad of normal pressure hydrocephalus ?
ataxia, incontinence and dementia
what is cytotoxic oedema caused by
damaged sodium - potassium ATPase ion pumps which is due to acute ischameia
on imaging what does cytotoxic oedema look like ?
affects both grey-white matter
restricted diffusion due to the cells swelling
what is affected in vasogenic oedema
the blood Brain barrier is effected .
this causes fluid to go from the intracellular space to the extracellular space
there is increased grey-white matter differentiation
high t2/flair with facilitated diffusion
what is affected in vasogenic oedema
the blood Brain barrier is effected .
this causes fluid to go from the intracellular space to the extracellular space
there is increased grey-white matter differentiation
what does ionic oedema look like
this is associated with cytotoxic oedema and it results in fluid going from the blood to the extracellular space (do to the osmotic changes that occur with the cytotoxic oedema). there I therefore more fluid within the extracellular space which causes a high T2/Flair signal
what causes vasogenic oedema
brain tumours and abscesses
what is transependymal oedema
due to high intraventricular pressure
causes CSF to move from the ventricle into the extracellular space
usually due to obstructive hydrocephalus
causes high flair signal around the lateral ventricles
which artery might be compressed in subfalcine herniation and what is the clinical manifestation of this
anterior cerebral artery = the pericallosal artery
manifesting as contralateral leg weakess
what are the two types of transtentorial herniation?
central - where the basal ganglia and thalami are pushed down
lateral (uncal) - where the medial portion of the temporal lobe Is displaced
what affect can transtentorial herniation have ?
1) compression of the oculomotor nerve - causing pupillary dilatation
2) compression of the PCA - causing medial temporal/occipital lobe infarction
3) shearing of the perforating arteries from the basilar causing small haemorrhages
on Brain MRI what is T1 hyperintense
fat
melanin
proteinaceous material
methemoglobin
minerals - gad
what is T2 hypointense
most stages of blood - deoxyhaemaglobin, haemosiderin
calcification
fibrous tissue
highly cellular tumours - lymphoma and medulloblastoma
desiccated secretions into the paranasal sinuses
where does hypertensive microangiopahty affect
basal ganglia, thalami, cerebellum and pons
where does cerebral amyloid angiopathy affect
lobar in the cortico-subcortical sites , spares the deep structures
in MR spectroscopy what happens with Choline
marker of cell turnover and increases with most abnormalities
in MR spectroscopy what happens with NAA
marker of neuronal viability and decreases with most abnormalities
which way should hunters angle be pointing in normal Brian
normally the angle should be pointed upwards. as the Choline < Creating< NAA in a normal person.
In brain disease the angle point downwards
what might high choline levels distinguish
tumour vs edema
radiation induced cnecrosis
what might the prescence of 2-HG on MR Spectroscopy reveal
IDH - mutant status in gliomas
in MR spectroscopy, what are prominent lipid/lactate peaks associated with ?
high grade gliomas and lymphoma
what is very high on MR spectroscopy in Canavan disease >
NAA
this is a autosomal recessive condition where there is a deficiency in the n-acetylasparacylase which is important in myeline synthesis. this results in Increased NAA levels.
which CNS regions do no have a BBB
choroid plexus
pituitary and pineal glands
tuber cinereum - circadium rhythm in the inferior hypothalamus
area postream - controls vomiting and in the inferior aspect of the forth ventricle
which areas are typically affected in herpes encephalitis ?
medial temporal lobes and cingulate gyrus will show gyral enhancement with restricted diffusion
what are the key imaging features of a cerebral abscess
reduced diffusivity
hypointense rim on T2 weighted images
in MR, what is dural enhancement a sign of
dural edema due to a pathology
to see enhancement there must be both water and gad present. however the dural layer doesn’t usually have water. so only pathologies with water will show dural enhancement
which pathologies demonstrate dural enhancement ?
intracranial hypotension
post operatively
post lumbar puncture
meningeal neoplasm - meningioma
what does the leptomeninges include?
the Pia and arachnoid
what is the primary cause of leptomeningeal enhancement >
meningitis
which metastatic cancers cause leptomengieal enhancement
lymphoma and breast cancer
what does infarction of the artery of perchon result in
bilateral thamali infarction - as one artery supplies both
what does the recurrent artery of heubner supply?
the head of the caudate lobe and the anterior limb of the internal capsule
what’s the most common complication of a subarachnoid haemorrhage
vasospasm
what is the gold standard for diagnosisng vasospasm
DSA
what is the treatment of vaspasms.
the 3 Hs
hypertension
hypervolaemia
hemodilution
what drug is given to prevent vasospasm
oral nimodipin
what causes superficial siderosis and how does it present
iron overload of pial membrane due to repeated SAH.
Presents with sensorineural deafness and ataxia
what is classified as a giant saccular aneurysm ?
> 2.5cm
what nerve does a PCOM aneurysm compression
the oculomotor nerve
where do aneurysms formed from hypertension commonly occur
in the basal ganglia - known as Charcot-bouchard aneurysms
which diseases increase the risk of aneurysms
marfans, ehlers-danlos, PCKD, neurofibromatosis
what is the most common source for mycotic aneurysms ?
bacterial endocarditis
what is the gold standard for mycotic aneurysms ?
DSA
what is an oncotic aneurysm and what is It caused by?
tumour - usually left atrial myxoma
what is the venous angle a landmark for on cerebral angiography
foramen of munro
what does a venous infarction of the superior saggital sinus cause
infraction of the parasagittal cortex
what does a venous infarction of the deef venous system cause
infarction of both thalami
what does venous infarction of the transverse sinus cause
infarction of the posterior temporal lobe
what does extracellular methemoglobin look like
bright on T1 and T2
where does hypertensive haemorrhage typically occur
basal ganglia, thalamus and cerebllum
what is cerebral amyloid angiopathy
amyloid accumulates into the vessel walls of small and medium arteries, this causes vessel weakness and increased risk of haemorrahge
where do cerebral amyloid angiopahy haemorrhages occur
cortically within the lobes - parietal or occipital
what is moyamoya disease
non-atherosclerotic vasculopathy caused by progessive stenosis of the intracranial internal carotid arteries and their proximal branches.
this results in the formation of fragile collateral vessels, - looking like puff of smoke on MRA/DSA
what does scirrhous carcinoma look like ?
leather bottle appearance - abnormal thickening of the stomach and smaller size due to fibrosis. it is a subtype of gastric cancer.
what does abdominal tuberculosis commonly affect ?
the ileo-caeca valve - it becomes thickened resulting in narrowing of the terminal ilium
is is associated with ascitis - unlike chrons which never has ascites
what is lateral medullary syndrome caused by?
thrombus/atheroscerloss in the vertebral artery or PICA
what are the symptoms of lateral medullary syndrome
vestibular signs - falling tot he side of the lesions
Autonomic signs - hiccups. Horners
an anerysm where will cause oculomotor nerve palsy
one at the junction of the PCOM and ICA
on MRI what would a superior saggital sinus thrombus appear like ?
static blood gives a high signal on T1
what type of haemorrhages are specific for superior saggital thrombus
parasaggital haemorrahge
what is the common location for a venous epidural haematoma
the vertex
the anterior portion of the middle crania fossa
the occipital portion of the posterior cranial fossa
what is the characteristic locations of DAI
grey-white matter junctions of the cerebral hemisphere
corpus callosum
midbrain (dorsolateral)
which are the most common brain mets to bleed ?
melanoma
rcc
thyroid
choriocarcinoma
which lesions occur at the cerebellar pontine angle
vestibular schwannoma
meningioma
epidermoid cyst
which tumours arise at the pineal region?
pineoblastoma
germinoma
which tumours involve the corpus callosum
lymphoma and glioblastom
what is the most common central skull base tumour ?
chordoma , chondrosarcoma
what’s the most common suprasella tumour in an adult and then child?
adult - pituitary adenoma
child- craniopharngimoa
what is the most common posterior fossa tumour in adults
haemangioblastoma, and mts
what the most common posterior fossa tumours in children
pilocytic astrocytoma, medulloblastoma, ependymoma
most common mass in the foramen of munro? adults and children
colloid cyst - adults
subependymal giant cell astrocytoma
what is an IDH wild type tumour ?
Glioblastoma
what does gliomatosis cerebri mean
if affects more than 3 lobes
IDH mutant gliomas include
oligodendrogliomas and astrocytomas
what is the FLAIR mismatch sign specific for
astrocytomas (IDH-mutant Ip19q non-codeleated)
where are oligodendrogliomas typically found
cortically based mass found in the frontal and temporal regions with gyriform calcification
The pneumonic P-DOG MD is for Supratentorial tumours - low grade -what does it stand for ?
Pleomorphic xanthoastrocytomas
Dysembryoplastic neuroepithelial tumour
Oligodendroglioma
Ganglioglioma
Multinodular and vacuolating neuronal tumour
Desmoplastic infantile astryocytoma and ganlioglioma
what gene mutation is seen in PXA
BRAF V600E
what do PXA’s look like
enhancing mass
cyst formation
plaial tail
which tumours are associated with focal cortical dysplasia
DNET and ganglioglioma
where do gangliogliomas arise ?
temporal lobes
what lesion is a small cluster of bubbles in the cortical/subcortical region within the temporal lobe?
Multinodular and vacuolating neuronal tumour
when is imaging follow up required for pineal cysts ?
> 10mm
what type of optic nerve disease are seen in NF1 and NF2
NF1 - optic nerve gliomas
NF2 - optic sheath meningiomas
what symptoms does colloid cysts present with ?
usually arise at the formanen of munro in the 3rd ventricles, resulting in intermittent obstructive hydrocephalus. This causes a thunderclap headache - often positional
what is cowden syndrome
multiple harmatomas in the body
classic imaging finding of a pilocytic astrocytoma ?
large cystic mass centred in the cerebellum with an enhancing nodule
if found in the optic pathway - associated with NF1
what is the classic imaging finding of a medulloblaystom
large solid mass usually in the midline of the posterior fossa
avidly enhancing
low ADC values
leptomeningeal enhancement is common - icing sugar
if a patient has medulloblastoma, what needs to be imaged ?
drop metastasis are common so the whole spine needs to be imaged
if a patient has medulloblastoma, what needs to be imaged ?
drop metastasis are common so the whole spine needs to be imaged
what syndrome is lhermitte-duclos associated with ?
cow dens syndrom
(multiple harmatomatous disease)
what is the classic features of a haemangioa
large cystic mass with surrounding oedema and an enhancing nodule
posterior fossa = cerebellum
what syndrome are haemangiomas associated with
von hippel lindau
where doe pleomorphic xanthastrocytomas occur and what do they look like ?
usually occur in the temporal lobe
cystic lesion, may have haemorrhage
what do DNETs look like ?
temporla lobe lesion, soap bubbly appearance with a bring rim with enhancement
what do gangliogliomas look like
temporla lobe lesions with cystic mass and an enhancing nodule with calcification
what do desmoplastic infantile astrocytoma and gangliogliomas look like
present as infants with rapidly enlarging head
large multipcystic and solid mass - the solid mass enhances
where else might patients with a rhabdoid tumour in the brain get a problem
the kidney
where do Intraventricular meningiomas commonly occur
in the trigones of the lateral ventricles - they homogeneously enhance
what tumour commonly arises from the septum pellucidium
central neurocytoma
what condition are subependymal giant cell astrocytomas associated with
tuberous sclerosis
what is the characteristic features of a chord plexus tumor
cauliflower like Intraventricular mass that avidly enhances
entirely Intraventricular
what is the most common cause of a ring-enhancing brain mass in a patient with HIV
lymphoma
toxoplasmosis
what are the most common cancers to metastasis to the brain
lung
breast
melanoma
what are the most common haemorrhagic metastases to the brain
melanoma
renal cell carcinoma
chroicarcinoma
thyroid cancer
what condition predisposes to meningiomas
neurofibromatosis type 2
what do meningiomas look like.
avidly enhancing
dural tail - due to vasoactive substances related from the tumour
what does a cholesterol granuloma typically look like
a blue tympanic membrane,
large mass in the petrous part of the temporal bone or middle ear
contains cholesterol and blood so high on T1
what are the 3 differentials for a cerebellar pontine angle ?
schwanoma
epidermoid
meningioma
brain - causes of high T1 signal
melanin
fat
protein
contrast
methhaemaglobin (subacute bleed)
what is vernet syndrome
a lesion at the jugular foramen resulting in :
- loss of taste at the posterior 3rd of the tongue
- vocal chord paralysis
- weakness of sternocleidomastoid and traps
- dysphasia
what are the 3 neopaslsm of the pineal region
germ cell tumour - germinoma / teratoma
pineal parcenhymal tumours - pineocytoma -> blastoma
pineal glioma
what are the 4 main locations of T2 white matter lesions in MS ?
juxtacortical
periventricular
spinal - cervical
infratentorial
what can happen to the corpus callosum in chronic MS
thins
what is ADEM
acute monophasic demylinating disorder - usually occurs in children after a vaccination
what is vasogenic oedema ?
affects the white matter mainly
the BBB is disrupted
what is PRES
neurotoxic state where the posterior circulation fails to autoregulate in response to acute changes in blood pressure
this results in hyperperfusio and resultant vasogenic oedema - which mainly affects the white matter
which lobes are more specific to CADASIl
anterior temporal lobes or paramedical frontal lobes - especially when associated with migraine
what virus causes progressive multifocal leukoencephalopathy ?
JC virus
what does wernickle encephalopathy present with
ataxia, confusion and oculomotor dysfunction
where does wernickel encephalopathy usually affect
the thalamus, periductal grey matter, hypothalamus, mammillary bodies
what does fahrs disease result in
idiopathic bilateral basal ganglia calcification
what CT findings are typical of hypoxic ischaemic encephalotpahy ?
loss of grey white matter differentiation
diffuse cerebral hypoattenuation
sulcal effacement
white cerebellum sign - sparing of the cerebellum which appears relatively hyperlattenuation when compared to the affected supratentorial brain
where dose methanol posinionig usually affect
causing hemorrhagic necrosis of the putamen - but not affected the globus pallidus
what’s the hallmark finding of Carbon monoxide poisoning
symmetrical necrosis of the globus pallidi - causing hyperintenseity with a hypointense rim on FLAIR
What is the radiological manifestation of huntintons disease?
atrophy of the caudate lobe
What is polycythemia associated with ?
haemgioblastoma
in true Parkinson’s disease where will there be loss of uptake on a dopamine scan ?
the posterior putamen
what is the classic feature of Huntingtons disease?
atrophy of the caudate head - resulting in prominence of the lateral ventrciels
on PET scan for alzhiemers - where will there be low metabolism?
precuenus and posterior aspect of the cingulate gyrus
involvement of the middle cerebral peduncle makes you think of MS or small vessel disease ?
MS
where does ADEM classically invovle/
the basal ganglia - thalamus
In the brain where does Wilsons disease commonly affect ?
basal ganglia and thalami
where does herpes encephalitis commonly affect
the mesial temporal lobe
what should be the first consideration in a patient with fever and mesial temporal lobe enhancement
herpes encephalitis
where does toxoplasmosis tend to affect
the basal ganglia
what is the hockey stick and pulvinar sign associated with?
CJD - describes Hyperintensity of the dorsomedial thalami
