Neuro 2 Flashcards
What are the adult brain tumors
Glioblastoma multiforme (astrocytes) Meningioma (arachnoid cells) Schwannoma (Schwann cells) Oligodendroglioma (oligodendrocytes) Hemangioblastoma Pituitary adenoma
What are the child brain tumors
Pilocytic astrocytoma (astrocytes)
Medulloblastoma (cerebellum)
Ependymoma (surrounding ventricles)
Craniopharyngioma (Rathke’s pouch)
Location of Broca’s area
Inferior frontal gyrus
Location of Wernicke’s area
Posterior section of superior temporal gyrus
What is Gerstmann syndrome
Lesion of dominant parietal cotex
Causes: agraphia (inability to write), acalculia (inability to calculate), finger agnosia (inability to distinguish fingers), left-right disorientation
Anatomy that may cause weakness
o Motor cortex o Pyramidal tract (e.g. corticospinal tract) o Extrapyramidal tract (e.g. basal ganglia) o Cerebellum o Spinal cord o Lower motor neurons o Neuromuscular junction disease o Muscular weakness
In which aphasia is repetition affected?
Broca’s, Wernicke’s, and conduction
So it is affected in the cortical aphasias, but not in the precortical aphasias
Describe path of dorsal column/medial lemniscus
♣ Processes fine touch, pressure, vibration, and proprioception
♣ First order neurons (dorsal column) have cell bodies in dorsal root ganglion or cranial nerve ganglion and ascend ipsilaterally to the nucleus gracilis (lower body) or nucleus cuneatus (upper body) in the medulla
♣ In the medulla they synapse on second order neurons which then cross the midline
♣ Second order neurons (now called the medial lemniscus) ascend to the contralateral thalamus (VPL) where they synapse on 3rd order which ascend to the somatosensory cortex and synapse on 4th order
Describe path of spinothalamic tract
♣ Processes pain, temperature, and light touch (crude touch?)
♣ First order neurons have cell bodies in dorsal horn (of gray matter) and synapse on thermoreceptors and nociceptors in the skin
♣ First order nerves synapse on second order in the dorsal horn of the spinal cord, where the second order cross the midline at the anterior white commissure and ascend to the contralateral thalamus (VPL) when second order synapse on third order which ascend to somatosensory cortex and synapse on fourth order
Describe path of corticospinal tract
♣ UMN from motor cortex descend to pyramid in the medulla
♣ Axons cross to contralateral side in the caudal medulla and descend via lateral cortico-spinal tract
♣ Enter the spinal cord at lateral white column and travel to the anterior grey horn
♣ Synapse to LMN (alpha motor neuron) which then exits via ventral spinal root to innervate muscle
Where is lesion in conductive aphasia
Arcuate fasciculus
Describe glioblastoma multiforme
• Malignant tumor of astrocytes GFAP (+)
• Found in cerebral hemispheres and may cross corpus callosum – “butterfly lesion”
• Pseudopalisading – tumor surrounding central necrosis
o THINK:
♣ Pseudopallisading looks like a star = astrocyte
♣ Central area is necrotic/dead so this must be an old people tumor – astocyte tumor of adults = glioblastoma multiforme
Describe meningioma
- Benign tumor of arachnoid cells
- Most often occurs near surfaces of brain
- Extra-axial (external to brain parenchyma) and may have a dural attachment (“tail”)
- May present with seizures
- Histology shows whorled pattern and Psammoma bodies
Describe hemangioblastoma
- Tumor of the CNS that originates from vascular origin
- Associated with Von-Hippel Lindau syndrome (increased risk of bilateral renal cell carcinoma)
- Can produce erythropoietin secondary polycythemia
Describe Schwannoma
- Benign tumor of Schwann cells S-100 (+)
- Most frequently involved CN VIII (loss of hearing and tinnitus)
- Bilateral vestibular schwannomas seen in neurofibromatosis-2
Describe Oligodendroglioma
- Most often in frontal love
* “Fried egg” appearance (round nuclei with clear cytoplasm)
Describe pituitary adenoma
- Most often a prolactinoma (hypogonadism)
* Bitemporal hemianopia (due to compression of optic chiasm)
Describe pilocytic astrocytoma
- Benign tumor of astrocytes GFAP (+)
- Usually arises in posterior fossa
- Cystic lesion with mural nodule
- Rosenthal fibers – eosinophilic corkscrew fibers
♣ THINK: Chris Rossman (Rosenthal) putting the star (astrocytes) on the top of a child’s (tumor of children) christmas tree, so it has a swirly base (corkscrew fibers)
Describe medulloblastoma
- Malignant tumor derived from neuroectodem
- Cerebellar tumor
- Can compress 4th ventricle leading to hydrocephalus
- Homer Wright rosettes (small blue cells wrap around pink areas of neuritic processes)
o THINK: Homer Simpson is dumb like a kid (tumor of children); it seems like he lost actual brain cell, neurons (tumor of neurons)
Describe ependymoma
- Malignant tumor of ependymal cells (most often in 4th ventricle)
- Can compress 4th ventricle leading to hydrocephalus
- Perivascular pseudorosettes (tumor cells surrounding vessel)
o THINK: Ependymoma = tumor surrounding ventricles; ventricles are open spaces containing body fluids; pseudorosettes is surrounding a vessel which contains body fluids
Describe craniopharyngioma
- Derived from remnant of Rathke’s pouch (where anterior pituitary sprouted from mouth)
- Supretentorial mass that may lead to bitemporal hemianopia
- Often see calcifications (derived from “tooth-like” structures)
Describe Tuberous sclerosis presentation
♣ Triad = Angiofibromas, mental retardation, seizures
♣ Other symptoms: Ash-leaf spots, hamartomas of CNS and skin, angiomyolipoma
What is the difference between partial and generalized seizures
Partial = involves single part of brain at onset
Generalized = starts as partial and spreads to rest of brain
Difference between simple and complex partial seizures
Simple = no LOC or postictal state
Complex = LOC and postictal state
Describe Sturge Weber syndrome
♣ Port-wine stain of the face in CN V1/V2 distribution
♣ Seizures/epilepsy
♣ Intellectual disability
♣ Glaucoma
Tx of absence seizures
Ethosuximide
Tx of status epilepticus
Benzos, Phenytoin, Phenobarbital
Triad of Wernicke Korsakoff
Vitamin B1 (Thiamine) deficiency
o Triad: confusion, ophthalmoplegia, ataxia
o Confabulation, personality change, memory loss (permanent)
Work-up for dementia
♣ Mini mental status exam ♣ RPR syphilis screen ♣ HIV test ♣ TSH ♣ Vitamin B12 ♣ MRI of brain
Presentation of CJD
♣ Rapidly progressive dementia + ataxia + startle myoclonus
Presentation of Lewy Body dementia
Characterized by dementia and visual hallucinations, followed by Parkinsonian
- Early onset dementia (vs. Parkinsons late onset)
Presentation of Frontotemporal dementia
♣ Degenerative disease of frontal and temporal cortex (vs. Alzheimer’s which is diffuse)
♣ Presentation:
• Early Behavior/personality changes (frontal lobe) and/or aphasia (temporal lobe)
• Late Dementia
What is the most sensitive imaging to demonstrate early cerebral ischemia or infarction
DWI - may be positive within 30 min of sx onset
When should you restart anticoagulation after an acute stroke
Remember: 1, 3, 6, 12
Tiny stroke = 1 day
Small = 3 days
Medium = 6 days
Large = 12 days
Normal LP opening pressure
6-20
What will you see on EMG for neuropathy vs. myopathy
Neuropathy = rapid firing and decreased recruitment (there are less muscle fibers so there is no reserve to call in, so instead the existing fibers must fire more rapidly)
Myopathy = early recruitment (muscle fibers are weaker so they have to call in reserve earlier)
What is a natural age to lose ankle jerk reflex
Age 60
How can you determine brain death
CT arteriogram (ICP > arterial BP so dye will not reach head)
Nuclear medicine studies (add tagged RBCs which will not reach head because ICP > BP)
What are the components of Glasgow coma scale
o Eye opening
♣ Spontaneous, to verbal command, to pain, none
o Verbal response
♣ Oriented, disoriented/confused, inappropriate words, incomprehensible sounds, none
o Motor response
♣ Obeys, localizes, withdraws, flexion posturing (decorticate), extension posturing (decerebrate), none
Describe administration of glucose/thiamine in Wernicke-Korsakoff
Give thiamine before glucose - glucose can worsen WK
Describe difference in management of a comatose patient with present vs. absent focal signs
Focal signs present = suspect structural cause (urgent neuroimaging)
Focal signs absent = suspect metabolic/toxic/infectious cause
Clinical approach to patient with AMS
- ABCs
- Look for obvious clues to etiology
- Try reversing common causes (Naloxone, Thiamine, Glucose)
- Use neuro exam to check brainstem reflexes and look for focal signs
