Cumulative Exam - Semester 2 - Block 8 Flashcards
Nissl stain (Cresyl violet) highlights what in neurons?
Nissl bodies within the ER (primarily gray matter)
Process in which microglia surround a dying neuron
Neuronophagia
Process in which neuronal cell bodies shrink, become more angular, cytoplasm becomes more eosinophilic, nucleus becomes condensed and pyknotic, loss of nuclear chromatin
Acute neuronal injury
Process of non-specific reaction to CNS injury involving glial cell hypertrophy and reactive astrocytes; CNS version of a scar
Gliosis
CNS cell type that often lines up in rows between fibers
Oligodendrocytes
Phagocytic, antigen presenting cells in the nervous system
Microglia
Specialized glial cell that lines ventricles, single layer of ciliated cells with no basement membrane
Ependyma
Specialized organ made of papillary folds of CSF-secreting ependymal cells that protrude into ventricles
Choroid plexus
UMN lesion signs
Diffuse weakness Slight, general atrophy Severe weakness with relatively little atrophy NO fasciculations Hypertonia (except in spinal shock) Hyperreflexia (except in spinal shock) Clonus can be present Babinski sign present (except in spinal shock)
UMN lesion signs
Focal weakness Focal, severe atrophy Some strength preserved despite severe atrophy Fasciculations Hypotonia Hyporeflexia NO clonus NO Babinski sign
Compare the location of the lesion in LMN vs. UMN lesions.
LMN - at or after the anterior horn cells of the SC
UMN - prior to the anterior horn cells
An ___ spinal cord lesion is usually associated with radicular pain and sensory impairment of pain and temperature up to the level of the lesion without sacral sparing.
Extramedullary
An ___ spinal cord lesion is usually associated with diffuse or no pain, with a suspended impairment of pain and temperature sensation with sacral sparing.
Intramedullary
Presentation of spinal cord transection/transverse myelopathy/myelitis + location of lesion
Sensory loss
LMN signs
UMN signs
Spinal shock if severe
Lesion - anywhere in the SC
Presentation of spinal cord hemisection (Brown-Sequard) + location of lesion
Contralateral pain and temperature deficit
Ipsilateral vibration and position sense deficit
Ipsilateral weakness
UMN signs, LMN signs
Lesion - STT, DC, CST, anterior horn cells of half of the SC
Presentation of syringomyelia + location of lesion
Suspended sensory deficit with sacral sparing (vest)
Weakness (late)
Preserved vibration and position sense
Lesion - STT
Presentation of anterior spinal artery syndrome + location of lesion
Pain and temperature deficit up to thoracic level Paraplegia and UMN signs (lower libs) Back/radicular pain Acute, stroke-like onset Preserved vibration and position sense
Lesion - STT, CST (lower thoracic and upper lumbar)
Presentation of posterolateral syndrome (subacute combined degeneration) + location of lesion
Vibration and position sense deficit in lower limbs
Spastic paraparesis, UMN signs
Preserved pain and temperature
Lesion - demyelination and degeneration of white matter, usually at thoracic levels (DC, CST)
Presentation of ALS + location of lesion
LMN signs UMN signs Preserved sensation Diffuse fasciculations No radicular pain No affected bowel/bladder M>F, presents 40-70 y/o
Degeneration of UMN/LMN (selective and progressive)
Presentation of Tabes Dorsalis + location of lesion
Severe radicular pain (lower limbs) Impaired position and vibration (+ Romberg) Eventual loss of all sensation Loss of reflexes Intact strength Charcot joinst
DC, dorsal roots
Pathway carrying vibration and position sense
Dorsal column pathway
Dorsal Column Pathway
SYNAPSE - dorsal root ganglion (SC)
SYNAPSE and DECUSSATE - internal arcuate (caudal medulla)
SYNAPSE - VPL (thalamus)
SYNAPSE - sensorimotor cortex (312)
Pathway carrying pain and temperature
Spinothalamic tract
STT
SYNAPSE and DECUSSATE - dorsal root ganglion cells (anterior white commissure of SC)
SYNAPSE - VPL (thalamus)
SYNAPSE - 312
True or false - all cerebellar pathways are ultimately ipsilateral
True
CST
Motor cortex
Pyramidal decussation in medulla (except anterior tract, which does not cross)
Nuclei of the DC pathway
Cuneate (C1-T5)
Gracile (T6-S5)
Nuclei of the STT
Nucleus proprius
Nuclei of the DCT
Dorsal - Clark’s nucleus (C8-L2, L3 and below use gracilis to get to Clark’s)
Cuneocerebellar - C1-C7, accessory cuneate nucleus
Autoimmune disease against ACh receptors
Myasthenia Gravis
Presentation - ptosis, diplopia, dysarthria, dysphagia (can have a restricted ocular form)
Autoimmune disease against pre-synaptic calcium channels
Lambert-Eaton
Presentation - proximal weakness, muscle stretch reflex appears decreased but returns after isometric exercise, autonomic symptoms
Infectious toxin that prevents ACh release by impairing SNARE proteins
Botulinum
Symptoms of polyneuropathy
Symmetrical and sensory loss or impairment early
Numbness and tingling, beginning distally
Stocking and glove
Paresthesia (pins and needles)
Dysesthesia (unpleasant sensation due to a non-noxious stimulus)
Distal weakness/atrophy
Early loss/decrease of reflexes
Presents as an ascending, areflexic paralysis (rapidly progressive polyneuropathy) after a virus
Guillain-Barre
Most common pathology for polyneuropathies
Axonal degeneration
Presentation of myopathy
Proximal weakness and fatigue Normal sensation Significant atrophy Late loss of reflexes Pain is not prominent
Test the superior and inferior rectus muscles.
Start abducted and look up (SR) and down (IR)
Test the superior and inferior oblique muscles.
Start adducted and look down (SO) and up (IO)
Test the lateral and medial rectus muscles.
Look out (LR) and in (MR)
CN III lesion presentation
Ptosis, preserved abduction, dilated pupil, unreactive to light (direct and consensual)
CN IV lesion presentation
Impairs depression contralaterally
CN VI lesion presentation
Impairs abduction
Cause of intranuclear ophthalmoplegia
Paralysis of EOMs due to a lesion of the ascending MLF (affects 3 and 6)
Normally, L brain -> R paramedian pontine reticular formation -> coordinates lateral gaze via the R CN6 and L CN3
Convergence is normal
Pupillary light reflex pathway
Light -> optic nerve -> pretectal area -> DECUSSATES -> both EWN -> CN3 -> ciliary sphincter -> constricts both sides
3 components of the near reflex
Pupillary constriction
Lens accommodation
Eye convergence
Symptoms of Horner’s syndrome
Miosis, anhydrosis, ptosis
Causes of Horner’s syndrome
- Lateral median infarction (Wallenberg syndrome) - knocks out first order neurons
- Apical lung tumor - knocks out second order neurons
- Neck trauma near the superior cervical sympathetic ganglion - knocks out third order neurons
2 major causes of trigeminal neuralgia
MS (younger)
Compression of tortuous vessels such as the superior cerebellar artery (older)
Cause of facial paralysis - lower half of contralateral face paralyzed
UMN
Cause of facial paralysis - entire ipsilateral face paralyzed
LMN
Effect of UMN lesion on tongue
No symptoms with a unilateral lesions; if a person only has contralateral innervation and this is lost, the tongue deviates away from the affected side
Effect of LMN lesion on tongue
Deviates to the affected side (lick your wounds)
CN involvement on one side and clinical sensory/motor deficit on the other side
Crossed brain stem syndrome
Presentation of Weber syndrome
Ischemic infarction of the PCA causes CN III and the nearby peduncle to be affected - ipsilateral CN III lesion, UMN signs in contralateral face and limbs
Presentation of Wallenberg syndrome
Ischemic infarction of the vertebral artery or its PICA causes pain and temperature impairment in the ipsilateral face and contralateral limbs and body; DC preserved
Treat migraines
First line - NSAIDS
Second line - triptans
Headache more common in F
Migraines
Headache more common in M
Cluster headaches
Headache associated with severe eye pain, rapid onset, occur 1-4x/day for 6-12 weeks every year or two
Cluster headaches
Bilateral headache, no N/V, band-like, most common
Tension
Headache seen in young females with increased BMI, associated with increased ICP with no localizing features
Pseudotumor cerebri
These cells myelinate peripheral axons
Schwann
These cells myelinate CNS axons
Oligodendrocytes
Common causes of bacterial meningitis in neonates (<1 month)
E. coli
GBS
L. monocytogenes
Common causes of bacterial meningitis in children (1 month-16 y/o)
H. influenza
N. meningitidis
S. pneumonia
Common causes of bacterial meningitis in adults (>15 y/o)
N. meningitidis
S. pneumonia
Common causes of bacterial meningitis in the immunocompromsied
GBS
L. monocytogenes
Most common fungal meningitis
Cryptococcus (budding yeast, mucoid capsule, India ink, Swiss cheese basal ganglia)
Most common brain parasite
Cysticercosis (SW US), pork, presents with seizures
Most common cause of viral meningitis
Enteroviruses
CSF findings of bacterial meningitis vs. viral vs. TB
Fluid quality
Bacterial - cloudy
Virus - clear
Cells present
Bacterial - PMNs
Virus and TB - lymphocytes
Protein
Bacterial - very high
Virus - slightly high
TB - moderately high
Glucose (relative to plasma)
Bacteria - low
Virus - normal
TB - mildly low
Opening pressure
Bacterial - high
Cause and presentation of Wernicke-Korsakoff syndrome
B1 deficiency
Acute - Wernicke’s encephalopathy (nystagmus, ophthalmoplegia, gait ataxia, confusion)
Chronic - Korsakoff psychosis (amnesia with confabulation)
When should a brain CT scan be performed prior to urgent LP in a patient suspected of meningitis?
High suspicion of increased ICP (LP could cause brain herniation)
Abrupt onset of focal or global neurological symptoms caused by ischemia or hemorrhage
Stroke
Describe the gross and histologic features of cerebral ischemia - acute (6-48 hours).
Gross: pale, soft, swollen, indistinct border, blurred grey-white junction
Histology:
6-12 hours - neuronal ischemia (red dead neurons), pallor (edema)
1-3 days - infiltration by neutrophils
Describe the gross and histologic features of cerebral ischemia - subacute (4 days-3 weeks)
Gross: gelatinous, friable, distinct border, tissue liquefaction
Histology: neutrophils early, sheets of foamy macrophages (4-7 days), vascular proliferation 92-3 weeks)
Describe the gross and histologic features of cerebral ischemia - chronic (>3 weeks)
Gross: cystic +/- hemosiderin staining, secondary degeneration
Histology: astrocytic gliosis, residual macrophages
Most common site of embolic infarction to the brain
MCA
Presentation of an MCA stroke
Motor/sensory cortex hemisensory loss (knocking out frontal and temporal lobes) Contralateral hemiparesis (lower face, upper extremities) Visual field defects
What happens in tonsillar herniation?
Cerebellar tonsils drop into the foramen magnum, compress the brainstem, cause cardiopulmonary arrest
What happens in subfalcine herniation?
Cingulate gyrus movies under the falx cerebri, compresses ACA, infarction infecting lower limbs
What happens in uncal herniation?
Uncus (medial temporal lobe) -> tentorium cerebelli -> compresses CN III -> eyes down and out + dilated pupil
Sudden focal neurologic deficit with completely resolves in 24 hours; risk factor for stroke
Transient ischemic attack
Infarctions of the lenticulostriate arteries, which supply the basal ganglia, thalamus, internal capsule, and corona radiate
Lacunar infarction
Type of carotid TIA to the ophthalmic artery that presents as a lowered dark shade over the eye
Amaurosis fugax
When can tPA be administered in the setting of ischemic infarction?
Within 3 hours of the event (or risk intracranial hemorrhage)
Prevent future strokes in patients with atrial fibrillation with what medication?
Warfarin (most other stroke-prone patients are treated with antiplatelet medications)
Worst headache of your life suggests what?
Cerebral hemorrhage
Cerebral hemorrhage in the striatum or thalamus are most likely from ___
HTN
Causes low tone hearing loss
Conductive hearing loss (impaired air conduction)
Causes high tone hearing loss
Nerve damage
Explain the Weber test
Top of the head
If nerve deafness - no bone or air conduction - normal ear hears better
If conduction loss - bone conduction is enhanced, affected ear hears better
Explain the Rinne test
Mastoid bone to the ear
If partial nerve problem (air>bone) - do hear at affected ear
If conductive - do not hear at affected ear
Cause of L eye blindness
L optic nerve (or ocular/retinal cause)
Cause of bitemporal heteronymous hemianopsia
Inner optic chiasm lesion
Cause of binasal heteronymous hemianopsia
Outer optic chiasm lesion
Cause of R homonymous hemianopsia
L optic tract lesion
Cause of R superior homonymous quadrantanopsia
L INFERIOR optic radiation lesion (temporal lobe, Meyer’s loop)
Cause of R inferior homonymous quadrantanopsia
L SUPERIOR optic radiation lesion (parietal lobe)
Cause of R homonymous hemianopsia with macular sparing
L occipital lobe lesion
The basal ganglia has a ___ effect on the motor cortex via the medial globus pallidus.
Inhibitory
What happens to globus pallidus activity in Parkinson’s disease vs. Huntington’s disease?
Parkinson’s - GPm further increased
Huntington’s - GPm further decreasd
4 primary clinical signs of Parkinson’s
Resting tremor (pill-rolling)
Rigidity (cog-wheeling)
Bradykinesia
Impaired postural reflexes
Histologic finding of Parkinson’s
Loss of neurons in the substantia nigra Lewy bodies (alpha synuclein)
Lesion - broad-based ataxic gait
DC, sensory nerves, cerebellum
Lesion - hemiplegia (swinging gait + ipsilateral flexion of upper limb)
Stroke (1 side)
Lesion - tabetic gait (foot slapping to feel the floor)
DC
Lesion - steppage gait (foot drop)
Unilateral - perineal nerve or L5
Bilateral - severe neuropathy, motor neuron disease, L5 root lesion
Lesion - waddling (swagger)
Myopathy
Lesion - scissors gait
UMN (not compensatory)
Clinical features of __- dysfunction: gait ataxia, dysmetria, kinetic tremor, dysdiadochokinesia, rebound phenomenon, dysarthria, nystagmus
Cerebellar
Over/undershooting of a target by the hand or foot
Dysmetria (test with heel to shin or finger to nose)
Uncoordinated nonrhythmic sloppy hand movements
Dysdiadochokinesia (uncoordinated non-rhythmic sloppy hand movements)
Location of lesion - ipsilateral limb impairment + other cerebellar symptoms
Hemisphere
Location of lesion - trunk unsteadiness, impaired balance, gait ataxia
Vermis
Purposeless random non-rhythmic movements
Chorea
Slow writhing continuous movements of limbs
Athetosis
Rapid violent flinging movements of proximal limbs on one side (+ lesion site)
Hemiballismus (contralateral STN)
Continual sustained painful muscle contractions
Dystonia
Rapid shocklike jerks of the limbs and trunk
Myoclonus
Disorder of previously acquired language ability due to a lesion in a critical language center
Aphasia
Impaired fluency, preserved comprehension + lesion site
Broca’s aphasia
Inferior frontal lobe in dominant hemisphere
Preserved fluency, impaired comprehension + lesion site
Wernicke’s aphasia
Posterior superior temporal lobe in dominant hemisphere
Intact fluency (mostly), mild comprehension impairment, paraphasia (abnormal word substitutions) + lesion site
Conduction aphasia
Arcuate fasciculus (connects B and W)
No communication, comprehension, severe hemiplegia, cannot read
Global aphasia
Perisylvian area
Semantic and emotional meaning conveyed by change in pitch, inflection, melody, and tone
Prosody
Impaired prosody is due to non-dominant cortical lesions
Presentation of MS
- Optic neuritis (decreased monocular vision, pain with eye movements, decreased red-green color, afferent pupillary defect, heat intolerance)
- Brainstem syndromes
- SC syndromes
- Romberg sign
Narrowing of gyri, widening of sulci, dilated centricles
Gross features of AD
Misfolded amyloid beta plaques, neurofibrillary tangles (tau)
Histologic feature of AD
Lewy bodies on histology + dementia and parkinsonism
Lewy body disease
Pick bodies (globose neuronal cytoplasmic inclusions made of tau)
Pick’s disease
Majority of adult brain tumors occur in what region?
Supratentorial region
Majority of childhood brain tumors occur in what region?
Infratentorial region
Most common brain tumors in adults
Meningioma
Scwhannoma
Glioblastoma
Most common brain tumors in kids
Pilocytic astrocytoma
Ependymoma
Medulloblastoma
Most common glioma
Astrocytoma
Hair-like tumor cells, biphasic architecture, rosenthal fibers (eosinophilic corkscrew globules)
Pilocytic astrocytoma
Butterfly lesion
Glioblastoma
Common location of ependymoma
4th ventricle (rosettes)
Common location of medulloblastoma
Cerebellum
Homer-Wright rosettes (small blue cells)
Medulloblastoma
Psammoma bodies, whorls, syncytial appearance, dural tail (gross)
Meningioma
Brain tumor that may cause loss of hearing and tinnitus
Schwannoma
Flexner-Wintersteiner rosettes (cells arranged around an empty lumen)
Retinoblastoma
Bone lesions, Cafe-au-lait spots, neurofibromas, bag of worms
NF 1
Bilateral vestibular schwannomas, multiple meningiomas, gliomas
NF 2
Hamartomatous lesions involving multiple organs; adenoma sebaceum, seizures, mental retardation
Tuberous sclerosis
Hemangioblastoma, pheochromocytomc, RCC
VHL
Mammillary body lesions
Wernicke Korsakoff
Features of temporal lobe syndrome
Amnesia, cortical deafness, Kluver-Bucy, Wernicke’s
Features of parietal lobe syndrome
Sensory cortex issues (right-left confusion, difficulty with writing (agraphia) and difficulty with mathematics (acalculia). It can also produce disorders of language (aphasia) and the inability to perceive objects normally (agnosia).)
Seizure with a focal onset in the brain
Partial
Simple - no altered consciousness
Complex - impaired conscious
Can combine with generalized tonic clonic (focal onset evolves)
Most common partial seizure + symptoms
Temporal lobe
Epigastric aura, staring, unresponsive
Type of partial seizure that occurs at night, head and eyes turn to the side opposite the seizure
Frontal lobe
Type of generalized seizure, 4-10 y/o, brief but frequent, starting spells, EEG with 3 Hz spiek and wave pattern, treat with ethosuximide
Absence
Type of generalized seizure, shock-like contraction of muscle groups
Myoclonic
Type of generalized seizure, sudden loss of tone
Atonic
Type of generalized seizure - out of the blue, flexion of trunk, opening of mouth and eyelids, upward deviation of eyes, ictal cry, post-ictal confusion
Tonic (contraction producing extension and arching) Clonic (alternating muscle contractoin-relaxation)