Neuro Flashcards
Cause of CN3 (occulor motor) palsy
Think posterior communicating artery aneurysm
Cranial nerve 6 (abducens) palsy
Think raised ICP (downward displacement of the brainstem = stretching of the 6th CN.
Brain myelination progression order
Inferior to superior
Posterior to anterior
Central to peripheral
What is the last part of the brain to myelinate?
Subcortical white matter
What parts of the brain are myelinated at birth?
Brainstem
Posterior limb internal capsule
How does the corpus callosum form?
Front to back
i.e. Rostrum to Splenium
Wide spaced vertical ventricles, dilation of the occipital horns, intracranial lipoma. Diagnosis?
Agenesis of the corpus callosum
Vermis (cerebellar) hypoplasia, cystic dilatation of the 4th ventricle, lambdoid inversion of the torcular. Diagnosis?
Dandy Walker malformation
Spectrum of disease.
Mega cisterna magna (normal cerebellum and posterior fossa)
to Classic DWM (tiny cerebellum, expanded posterior fossa).
MCM - Blake Pouch - Variant DWM - Classic DWM
Large lateral ventricle on one side, with ipsilateral hamartomatous overgrowth of that cerebral hemisphere. Diagnosis?
Hemimegalencephaly
(Ramussen’s encephalitis = BIG ventricle, SMALL cerebral hemispehere)
Types of holoprocencephaly?
Lobar - <50% focal fusion of the anterior brain.
SemiLobar - >50% fusion of the anterior brain.
ALobar - Zero midline cleavage. Single ventricle.
What are the different types of Lissenchephaly?
Lissencephaly (Type 1) - failure of grey matter migration. Agyria (no gyri), thick cortex, “figure of 8” shaped brain.
Lissencephaly (Type 2) - overmigration of grey matter. Cobblestoned thickened cortex. Associated with congenital muscular dystrophy.
What is Double cortex band heterotopia?
Disorganised under migration of grey matter. Double cortex appearance, normal/mildly simplified gyri. Second layer of grey matter seen around the ventricles.
What is periventricular nodular heterotopia?
Under migration of grey matter. Nodular grey matter deposited around the periventricular region.
Cleft in the brain extending from ventricle to the surface filled with CSF. The cleft is lined with grey matter. Diagnosis?
Schizenchephaly (OPEN LIP) - Congenital split brain, lined with grey matter.
If cleft is not filled with CSF, but still lined with grey matter, then its closed lip schizencephaly.
Cleft in the brain extending from ventricle to the surface filled with CSF. The cleft is NOT lined with grey matter. Diagnosis?
Porencephaly - aquired split brain, usually secondary to vascular insult resulting in encephalomalacia. NOT lined with grey matter.
If cleft is lined with grey matter then it’s shizencephaly.
Define Chiari 1 malformation
Cerebellar tonsils >5mm below the level of basion-opistion
Features of chiari 2 malformation
Myelomeningocele
Low lying cerebellar tonsils and torcular
Thinned corpus callosum
Tectal beaking
If also has occipital encephalocele = Chiari Type 3
Patient with urinary incontinene, confusion, and ataxia. CT head shows ventricles out of proportion to atrophy, and upward bowing of the corpus callosum. Diagnosis?
Normal pressure hydrocephalus.
“Wet, Wacky, Wobbly”
Urinary incontinence, confusion, ataxia.
Type of oedema that comes secondary to infarction?
Cytotoxic oedema - INTRAcellular fluid secondary to malfunction of the Na/K+ pump. Tends to favour grey matter, causing loss of grey-white matter differentiation.
Type of oedema that comes secondary to tumour/infection?
Vasogenic oedema - EXTRAcellular fluid. Oedema tracking through the white matter. Spares the grey matter.
Alcoholic, low Na which is rapidly corrected. Now encephalopathic, low GCS, quadraparesis.
MRI shows T2 bright in central pons. Restricted diffusion in central pons.
Diagnosis?
Osmotic demyelination syndrome
Alcoholic. Confusion, ataxia, seizures, and spasticity.
CT head shows hypoattenuating regions of the corpus callosum.
MR shows T2 hyperintensities in the corpus callosum.
Diagnosis?
Marchiafava-bignami disease - demyelination of the corpus callosum.
Acute symptoms of headache, dizzyness, memory loss.
CT shows low density in the globus pallidus.
MR shows T2/FLAIR high signal in globus pallidus.
Diagnosis?
Carbon monoxide poisoning
Carbon monoxide causes “Globus warming”
Headache, dizziness, optic neuritis, vomiting.
CT shows low density in putamen bilaterally.
MRI shows high T2/FLAIR signal in the putamen.
Diagnosis?
Methanol poisoning
Previous chemoetherapy. Bilateral asymettric subcortical white matter oedema within the occipital lobe. Does not restrict on DWI.
Diagnosis?
PRES (Posterior Reversible Encephalopy Syndrome)
Post chemotherapy. New confusion.
MRI shows bilateral diffuse, confluent high T2/FLAIR signal in the subcortical white matter centrum semiovale.
Diagnosis?
Methotrexate induced leukoencephalopathy
IVDU. New cerebellar ataxia, and pseudo bulbar symptoms.
MRI shows symmetrical “butterfly” high T2 signal in centrum semiovale, posterior limb internal capsule, and deep cerebellar white matter.
Diagnosis?
Heroin induced leukoencephalopathy (Chasing the dragon)
Common locations for MS white matter lesions?
Juxtacortical
Corpus callosum
Periventricular
Infratentorial
Basal ganglia rare.
McDonald Diagnostic criteria for MS?
> 1 lesion disseminated in space (juxtacortical, Corpus callosal, periventricular, infratentorial).
> 1 lesion disseminated in time - >1 month
Active lesions enhance on MR
Old lesions do not enhance (both are T2 bright)
Female patient, 37 y/o, presents with seizure.
MR brain shows large ring enhancing lesion with incomplete ring sign. Minimal mass effect for the size of the lesion.
Diagnosis?
Tumefactive Demyelination.
15 y/o presents with seizure after having a vaccine.
MR shows multiple “incomplete ring” enhancing lesions, sparing the calloso-septal interface.
Diagnosis?
ADEM - Acute Disseminated Encephalomyelitis.
60y/o presents with dementia like symptoms.
MRI shows multiple, small, confluent high T2 signal in centrum semiovale sparing the subcotical U fibres.
Diagnosis?
Subcortical Arteriosclerotic Encephalopathy (small vessel dementia)
CADASIL - cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy - presents at a younger age due to hereditary nature.
5 year old present with progressive impariment of motor/cognitive function.
MRI shows high FLAIR signal in parieto-occipital white matter sparing subcortial U fibres, and extends across the corpus callosum.
Diagnosis?
Adrenoleukodytrophy.
(ALD)
18 month old, convulsions, loss of vision, muscle rigidity.
MRI shows high FLAIR signal in the periventricular white matter in a “tiger stripe” pattern.
Diagnosis?
Metachromatic Leukodystrophy.
Infant with large head, has progressive quadrapaerisis and seizure.
MRI shows high FLAIR signal in the frontal white matter bilaterally.
Diagnosis?
Alexander disease
Ashkenazi Jewish infant with big head. Bloods show elevated NAA.
MR shows diffuse high FLAIR signal throughout the white matter involving the subcortical U fibres.
Diagnosis?
Canavan disease
Infant with a small head.
MRI shows high FLAIR signal in the centrum semiovale and periventricular white matter, with parieto occipital predominance.
Diagnosis?
Krabbe leukodystrophy
MEN 1
Pituitary
Parathyroid
Pancreatic
MEN 2a
PMP
Pheochromocytoma
Medullary thyroid tumour
Parathyroid hyperplasia
MEN 2b
Pheochromocytoma
Medullary thyroid cancer
Mucosal neuroma
Marfanoid features
Patient with cerebellar ataxia, autonomic dysfunction, and parkinsonism.
MRI T2 shows cruciate high signal within the pons, high signal in middle cerebellar peduncles, and cerebellum.
Diagnosis?
Multi system atrophy
(Hot cross bun sign + autonomic dysfunction)
What runs through the cavernous sinus?
CN 3, 4, 5 (V1+2), 6, and the carotid artery
What travels through superior orbital fissure + inferior orbital fissure?
Superior orbital fissure - CN 3, 4, V1, 6
Inferior orbital fissure - V2
What are the Parkinson plus syndromes?
Dementia with Lewy bodies
Multisystem atrophy
Progressive supra nuclear palsy
Cortico-basal degeneration
Patient with abnormal eye movements, instability and falls.
MRI head shows midbrain atrophy with sparing of the pedicles, and flattening of the superior aspect of the midbrain.
Diagnosis?
Mickey mouse sign
Hummingbird sign
Progressive supranuclear palsy.
Patient with alien limb syndrome, asymmetric movement disorders has an MR brain showing asymmetric cortical atrophy, basal ganglia atrophy, and atrophy of the corpus callosum.
Corticobasal degeneration
Patient presents with glioblastomas and intestinal polyps. What is the diagnosis?
Turcot syndrome
16 year old boy with progressive dementia symptoms. MRI shows eye of tiger sign with high signal around the globus pallidus. Diagnosis?
PKAN - Hallervoden Spatz
What is dolichoectasia and it’s associated diseases?
Dilated and ectatic intracranial vessels.
Most commonly vertebro-basilar or internal carotid.
Can cause compression of cranial nerves.
Associated with Marfans, Ehlers-Dahnlos