Peripheral Nerves & Skeletal Muscles, CNS, Eyes Flashcards
A 30-year-old male patient
presents with symmetric
ascending paralysis and
areflexia following a history of
diarrhea. What is the most
likely diagnosis?
Guillain-Barre Syndrome
(GBS)
Microbial infections associated
with GBS
Campylobacter jejuni,
CMV, EBV, and
Mycoplasma
CSF finding in GBS
Albuminocytologic
dissociation - ↑ CSF
protein
without significant ↑ in
inflammatory cells
Most common chronic acquired
inflammatory
peripheral neuropathy
Chronic inflammatory
demyelinating
polyradiculoneuropathy
Most common cause of
peripheral neuropathy
Diabetes Mellitus
Characteristic pattern of
involvement in diabetic
neuropathy
Distal symmetric sensory
polyneuropathy (Glove
and stocking pattern)
Accumulating substance that
causes osmotic damage in
diabetic neuropathy
Sorbitol
Most common inherited
peripheral neuropathies
Charcot-Marie-Tooth
disease
Autoantibodies linked to
myasthenia gravis (MG)
Antibodies to
postsynaptic ACh
receptor
Thymic abnormalities
associated with myasthenia
gravis
Thymic hyperplasia,
thymoma
Electrophysiology finding in
MG
↓ response with repeated
stimulation
Autoantibodies linked to
Lambert-Eaton myasthenic
syndrome (LEMS)
Antibodies to
presynaptic Ca channel
Lung cancer associated with
LEMS
Neuroendocrine lung
carcinoma
Electrophysiology finding in
LEMS
↑ response with repeated
stimulation
Most common inflammatory
myopathy in children
Dermatomyositis
Dermatomyositis in adults
usually occur as a form
Paraneoplastic disorder
Morphologic hallmark of
dermatomyositis
Perifascicular atrophy
Lilac-colored rash on upper
eyelids
Heliotrope rash
Dusky red patches on knuckles,
elbows, and knees
Gottron papules
Autoantibodies associated with
Gottron papules and heliotrope
rash
Anti-Mi2
Autoantibodies associated with
interstitial lung disease,
Nonerosive arthritis, Skin rash
(“mechanic’s hands”)
Anti-Jo1
Similar symmetric proximal
muscle weakness involvement
with dermatomyositis but
absent cutaneous
manifestations
Polymyositis
Genetic mutation in Duchenne
muscular dystrophy (DMD)
Total absence of
dystrophin
(Deletion/Frameshift)
Genetic mutation in Becker
muscular dystrophy
Truncated version of
dystrophin (↓ activity)
Enzyme elevated in early
stages of DMD but decreased in
the late stages
Creatine kinase
Etiology of schwannoma
NF2 loss
Type of schwannoma located in
the cerebellopontine angle,
attached to vestibular branch
of CN VIII
Vestibular schwannoma
Cell-dense area of palisading
spindle cell fascicles in
schwannoma
Antoni A
Cell-poor areas with prominent
myxoid stroma
Antoni B
Most common peripheral nerve
sheath tumors
Neurofibroma
Etiology of neurofibroma
NF1 loss
Etiology of neurofibromatosis
type 1
(Neurofibromin, Ch17)
loss → ↑ RAS signaling
Etiology of neurofibromatosis
type 2
NF2 (Merlin, Ch22) loss
Malignant peripheral nerve
sheath tumors, optic nerve
gliomas, pheochromocytoma,
Lisch nodules, Cafe au lait spots
Neurofibromatosis type 1
Schwannoma, meningioma,
ependymoma
Neurofibromatosis type 2
Earliest morphologic marker of
neuronal cell death or acute
neuronal injury
Red neurons
Most important pathologic
marker of CNS injury
Gliosis - astrocytic
hyperplasia and
hypertrophy
Type of cerebral edema
observed in infection,
inflammation and tumors
occurring due to increased
vascular permeability
Vasogenic edema
Type of cerebral edema
observed in generalized
hypoxic injury where the ionic
balance of cells are disrupted
Cytotoxic edema
Type of hydrocephalus which
occurs due to ↓ CSF resorption
by arachnoid granulations i.e.,
in healed subarachnoid
hemorrhage
Communicating
hydrocephalus
Type of hydrocephalus when a
focal obstruction within the
ventricular system is present
Noncommunicating
hydrocephalus
Cerebral artery compressed in
subfalcine herniation
Anterior cerebral artery
Neurovascular structures
compressed in transtentorial
(uncal) herniation
Ipsilateral CN III and
Posterior cerebral artery
(PCA), and cerebral
peduncle
Linear/Flame-shaped
hemorrhagic lesions in
midbrain/pons
Duret hemorrhages
Compression of this structure
in tonsillar herniation causes
cardiac and respiratory
depression
Brainstem
Most common CNS
malformation
Spinal dysraphism (Spina
bifida)
Deficiency of this vitamin is a
known risk factor for NTDs
Folic acid
Extension of spinal cord and
meninges through a vertebral
column defect
Myelomeningocele
Most common site of
encephalocele
Occiput
This cranial dysraphism occurs
due to a failure in the closure of
the anterior neural tube
Anencephaly
Incomplete separation of
cerebral hemispheres across
midline
Holoprosencephaly
Absence of white matter
bundles that carry cortical
projections from one
hemisphere to another
Agenesis of corpus
callosum
Small posterior fossa causing
downward extension of
cerebellar tonsils and medulla
through the foramen magnum
Chiari II Malformation
(Arnold-Chiari)
Low-lying cerebellar tonsils
through foramen magnum
Chiari I Malformation
Hypoplasia/agenesis of the
vermis resulting in cystic
enlargement of 4th ventricle
Dandy-Walker
malformation
Fluid-filled cavity in the inner
portion of the cord
Syringomyelia
Most common route of CNS
infection
Hematogenous
Viruses with retrograde spread
in the nervous system
Rabies, VZV
Most common cause of acute
pyogenic meningitis overall
S. pneumoniae
Common etiologies of acute
pyogenic meningitis in
newborns
Group B streptococci, S.
pneumoniae, L.
monocytogenes, E. coli
Common etiologies of acute
pyogenic meningitis in teen and
young adults
N. meningitidis, S.
pneumonia
Most identifiable agent of acute
aseptic meningitis
Enteroviruses
CSF protein and mononuclear
cells are markedly elevated in
this type of meningitis
Tuberculous meningitis
Risk factors for brain abscess
formation
Acute bacterial
endocarditis, Congenital
heart disease (R→L
shunts), Chronic
pulmonary infections,
Immunosuppression
Morphologic findings in
meningovascular neurosyphilis
Obliterative endarteritis,
Perivascular plasma
cells, Gummas
Virus associated with
hemorrhagic necrotizing
encephalitis of the temporal
lobe
HSV
Virus associated with
microcephaly, periventricular
calcification
CMV
Cytoplasmic, round,
eosinophilic inclusions in
pyramidal neurons of the
hippocampus and Purkinje
cells of the cerebellum in rabies
infection
Negri bodies
Most common cryptococcal
infection in immunosuppressed
patients
C. neoformans
Location of skull fracture
associated with Raccoon sign
and CSF rhinorrhea
Anterior skull base
Location of skull fracture
associated with CN III, IV, V, VI
injuries, Carotid injury
Central skull base
Most common type of skull
fracture
Temporal fracture
Mastoid hematoma
Battle sign
Rapid neurologic deterioration
with lucid intervals
Epidural hematoma
Blood vessel lacerated in
epidural hematoma
Middle meningeal artery
CT scan finding in epidural
hematoma
Lentiform hyperdense
lesion
Blood vessel lacerated in
subdural hematoma
Bridging veins
CT scan finding in subdural
hematoma
Crescent-shaped
hyperdense lesion
Above which cervical vertebra is
respiratory compromise expected
in cases of spinal cord injury
C4
Neurons most susceptible to
ischemic injury
Pyramidal neurons of
Hippocampus (Area CA1: Sommer sector),
Cerebellar Purkinje cells,
Pyramidal neurons in cerebral cortex (Layers III and IV)
Most common location of
watershed infarcts in global
cerebral ischemia
ACA-MCA border
Most common site of deep
parenchymal hemorrhage
Putamen
Etiology of lobar hemorrhage
Cerebral amyloid angiopathy – Amyloid (Aβ) deposits in vascular wall
Most common type of
intracranial aneurysm; Most
common cause of spontaneous
subarachnoid hemorrhage
(SAH)
Saccular “Berry” Aneurysm
Most common site of berry
aneurysm
Circle of Willis – ACA-ACoA junction (40%)
Associated conditions with berry aneurysm
ADPKD, Ehler-Danlos (Type IV), NF1, Marfan, Fibromuscular dysplasia,
Coarctation of aorta
Most common clinically
significant vascular
malformation
Arteriovenous
malformation
Usual site of AV malformation
MCA territory
A patient presents with
multiple neurologic deficits
separated in time and space
and optic neuritis; Lesions are multiphasic; CSF findings
include moderate pleocytosis,
mildly ↑ protein, ↑ IgG. What is
the most likely diagnosis?
Multiple sclerosis
CSF electrophoresis finding in
multiple sclerosis
Oligoclonal IgG bands
Partial seizure that starts with
one group of muscles then
spreads “marches” to other
groups of muscles
Jacksonian march
Disease associated with rapid
correction of hyponatremia that leads to quadriplegia and “locked in syndrome”
Cerebral pontine myelinolysis
Most common prion disease
Creutzfeldt-Jakob disease (CJD)
Central core with radiating
spicules of amyloid seen in the
cerebellum of CJD patients
Kuru plaques
Most common cause of
dementia in older adults
Alzheimer disease (AD)
Associations with Alzheimer
disease
Trisomy 21,
apoE (ε4) allele (Ch19)
Focal spherical collections of
dilated, tortuous axonal or
dendritic process around a central
amyloid core; Specific for AD
Neuritic plaques (Aβ)
Basophilic fibrillary structures;
Not specific for AD but
correlates better with degree of
dementia
Neurofibrillary tangles (Ta)
A patient presents with
diminished facial expression,
slow movement, stooped
posture, festinating gait,
rigidity, pill-rolling tremor.
What is the most likely
diagnosis?
Parkinson disease
Most important risk factor for
Parkinson disease
Gaucher disease
(Glucocerebrosidase)
Cytoplasmic, eosinophilic,
round to elongated inclusions
with a dense core and
surrounding pale halo seen in
Parkinson disease
Lewy body (α-synuclein)
Parkinsonism + dementia +
visual hallucination
Dementia with Lewy
bodies
Trinucleotide repeated or
expanded in Huntington
disease
CAG expansion on Huntingtin (HTT) gene) (Ch4)
Most common immediate cause
of death
Pneumonia
Vitamin deficiency in Wernicke
encephalopathy and Korsakoff
syndrome
Thiamine
Triad of ataxia, confusion,
ophthalmoplegia
Wernicke
encephalopathy
Triad of confabulation,
hallucination, amnesia
Korsakoff syndrome
Most common group of
primary brain tumors
Glioma
Most common primary malignant
brain tumor in adults
Glioblastoma multiforme
Brain glioma with fried egg
appearance of the tumor cells
and chicken-wire appearance
of the vasculature
Oligodendroglioma
Etiology of oligodendroglioma
IDH1 or IDH2 mutation
AND 1p/19q codeletion
Most common type of glioma
Astrocytoma
Most common glioma in
children; (+) Rosenthal fibers; Well-circumscribed cystic lesion w/ mural nodule
Pilocytic astrocytoma
Perivascular pseudorosettes
are seen in which brain tumor
Ependymoma
2nd most common primary
malignant tumor in children; (+)
Homer-Wright pseudorosettes; (+)
Drop metastasis
Medulloblastoma
Most common CNS neoplasm in
adults
Metastasis
Most common CNS neoplasm in
immunocompromised
individuals
Primary CNS lymphoma
Optic nerve tumors causing
proptosis of the eye
Glioma, meningioma
Most common primary tumor
of the orbit
Vascular tumors
Granulomatous lesion of the
eyelid due to sebaceous gland
drainage obstruction
Chalazion
Most common malignancy of
the eyelid
Basal cell carcinoma
Submucosal conjunctival
elevations in sun-exposed
areas of conjunctiva
Pinguecula, pterygium
(grows onto cornea)
Common site of conjunctival
tumors
Limbus
Condition associated with blue
sclerae
Osteogenesis imperfecta
Cone-shaped cornea associated
with Down syndrome, Marfan
syndrome, atopy
Keratoconus
Drug associated with cataract
formation
Corticosteroids
Metabolic disease associated
with cataract formation
Galactosemia, DM,
Wilson disease
Type of glaucoma wherein the
iris adheres to the trabecular
meshwork, obstructing the
outflow of aqueous humor
Angle-closure glaucoma
Most common form of
glaucoma
Primary open-angle
glaucoma
Inflammation within vitreous
humor
Endophthalmitis
Inflammation of retina, choroid,
sclera
Panophthalmitis
Autoimmune disorders
associated with uveitis
Reactive arthritis, Behçet
syndrome, Juvenile
idiopathic arthritis
Most common intraocular
malignancy in adults
Choroidal metastasis
Most common primary
intraocular malignancy in
adults
Uveal melanoma
Type of retinal detachment
with full-thickness retinal
defect
Rhegmatogenous
Infarcts from choroidal vessel
damage in hypertensive
retinopathy
Elschnig spots
Copper/silver wiring in
hypertensive retinopathy
Retinal arteriosclerosis
Most common retinal vascular
disease
Diabetic retinopathy
Earliest sign of nonproliferative
diabetic retinopathy
Microaneurysms
Neovascularization is present
in these vascular disease of the
retina
Proliferative diabetic
retinopathy, ischemic
retinal vein occlusion,
retinopathy of prematurity, wet age-
related macular degeneration
A patient presents with sudden
onset unilateral blindness.
Fundoscopy showed diffuse
retinal pallor and cherry red
spot in the macula. What is the
most likely diagnosis?
Central retinal artery
occlusion
Type of age-related macular
degeneration where Drusen
spots or Bruch membrane
deposits are seen
Dry/Atrophic age-related
macular degeneration
Most common primary
intraocular malignancy in
infants and young children
Retinoblastoma
Characteristic spoke-and-wheel
shaped cell formation seen in
retinoblastoma
Flexner-Wintersteiner
Rosettes
Atrophic, internally
disorganized; often called as
end-stage eye
Phthisis bulbi
Chromosome where the RB
gene is located
Chromosome 13
Bilateral edema of the optic
nerve or papilledema is a sign of
Increased intracranial
pressure
Onion bulb formation
Chronic Inflammatory Demyelinating Polyradicular Neuropathy (CIDP)
Types of Charcot Marie Tooth Dse
CMT1A: Demyelination
CMT2A: axonal
CMT1X: X-linked
Heliotrope rash and Gottron papules
Dermatomyositis (Anti-Mi2 antibody)
Anti Jo1 dermatomyositis & associated condition
Interstitial lung dses
Skin rash (mechanic hands)
Nonerosive arthritis
Anti-P155/P140 dermatomyositis
Paraneoplastic, juvenile cases
Hallmark of dermatomyositis
Perifascicular atrophy
Random patchy atrophy, endomysial inflammation (CD8+)
Polymyositis
Antibody in inclusion body myositis
Anti-cytosolic 5’ nucleotidase (cN1A)
Polymyositis + rimmed vacuoles
Inclusion body myositis
Weakness sites in Inclusion Body Myositis
Quadriceps
Distal upper extremity
Esophageal
Pharyngeal
Gower sign
Muscular dystrophy
Etiology of Schwanomma
NF2 loss
Verocay bodies
Schwanomma
IHC of schwanomma
S100
SOX10
IHC of neurofibroma
S100 - Schwann
CD34 - Stromal
Shredded carrot appearance of Stromal collagen
Neurofibroma
Multinodular “bag of worms”
Plexiform intraneural neurofibroma
Infiltrative (+) Pseudo Meissner corpuscles
Diffuse cutaneous neurofibromas
Alternating hypo and hypercellular areas of spindle cell fascicles (Marbled tapestry appearance)
Malignant Peripheral Nerve Sheath Tumor
Divergent differentiation
Malignant Triton Tumor
Malignant Peripheral Nerve Sheath Tumor
Neurofibromatosis 1 etiology
NF1 (Neurofibromin (Ch17) loss –> ↑ RAS signaling
Neurofibromatosis 2 etiology
NF2 (Merlin, Ch 22) loss
NF1 important components
Neurofibromas
MPNSTs
Pheochromocytoma
Lisch nodules
Cafe au lait spots
NF2 important components
Bilateral 8th nerve schwanomma
Multiple meningioma
Intraspinal ependymoma
Compressed structures in Subfalcine herniation
ACA
Corpus callosum
Compressed structures in transtentorial (uncal herniation)
PCA
Cerebral peduncle
CNIII (Ipsilateral)
Compressed structures in tonsillar herniation
Brainstem
Duvet hemorrhages
Linear frame shaped hemorrhagic lesions in midbrain/pons
Holoprosencephaly is associated with Trisomy ___________; features are __________________
13; cyclopia, arrhinencephaly
Clinical feature of syringomyelia
Isolated loss of pain and temperature sensation in upper extremities (cape-like distribution)
Charcot joint
loss of pain/sensation that leads to joint/skin damage in tabes dorsalis neurosyphilis
(+) Organism in expanded Virchow-Robin spaces, (-) inflammation and gliosis
Parenchymal invasion by Cryptococcus neoformans (also cause chronic meningocele)
Retracted yellowish brown plaque seen in morphology of old parenchymal injury
Plaque jaune –> may become eliptogenic foci
AVM mutation
KRAS
AVM morphology
Enlarged abnormal vessels separated by gliotic tissue; high flow lesions
Cavernous malformation morphology
Distended loosely organized back to back vascular channels, (-) intervening brain tissue; low flow lesion
Usual vessel bleed site: Focal cerebral ischemia
Basal nuclei
Hemispheric white matter
Brainstem
Usual vessel bleed site: Global cerebral ischemia (watershed infarct)
ACA-MCA border
Usual vessel bleed site: Deep parenchymal hemorrhage
Basal nuclei
Thalamic vessels
Putamen
Usual vessel bleed site: Lobar hemorrhage
leptomeningeal
cortical
cerebellar
Usual vessel bleed site: Saccular berry aneurysm
ACA-ACoA junction
Usual vessel bleed site: AVM
MCA territory (SAH and/or brain vessels
Usual vessel bleed site: Cavernous malformation
Cerebellum
Pons
Subcortical areas
Neuromyelitis optica antibody
Aquaporin 4 ab
3 morphologic findings in neurodegenerative diseases
Neuronal loss
gliosis
inclusions
Morphology of Creutzfeldt-Jakob Disease
Spongiform transformation of cerebral cortex and deep grey matter structures, Cerebellar kuru plaques
Frontotemporal atrophy in Pick disease manifests morphologically as
Wafer-thin knife edge gyri
Etiopathogenesis of Friedrich ataxia
GAA expansion in frataxin gene (Ch9)
Affected organs in Friedrich ataxia (due to ↓ frataxin)
Brain
Cardiac
Pancreas (Beta cells)
Etiopathogenesis of Amyotrophic Lateral Sclerosis
Mutations in Cu Zn Superoxide dismutase, TDP43 and FUS –> leads to upper and lower motor neuron degeneration
Bunina bodies (PAS + autophagic vacuoles
Amyotrophic Lateral Sclerosis
Progression of muscular weakness in ALS
Extremities –> Respiratory –> EOMs
Alzheimer Type II cells in cortex, basal nuclei, subcortical grey matter
Hepatic encephalopathy
Etiology of astrocytoma, IDH-mutant
IDH1 and IDH2 missense mutation
Etiology of glioblastoma, IDH-wildtype
EGFR, TERT, +7/-10 chromosome copy number alterations
ADULT TYPE DIFFUSE GLIOMAS: necrosis and/or microvascular proliferation
Glioblastoma IDH-wildtype
ADULT TYPE DIFFUSE GLIOMAS: pseudopalisading and microvascular proliferation
Astrocytoma IDH mutant
Homozygous loss of what gene automatically classifies a diffuse glioma as CNS WHO Grade 4?
CDKN2A/2B loss
Molecular subtype of medulloblastoma that has the best prognosis
WNT-activated
Site/imaging of meningioma
Extra-axial dural based solid mass w/ dural tail
Common genetic anomaly in meningioma
NF2 loss
Important components of Tuberous Sclerosis Complex
Cortical tubers
Subependymal giant cell
Astrocytoma
Renal angiomatous lipoma
Cardiac rhabdomyosarcoma
Structures affected in external hordeolum
Eyelash follicle
Glands of Zeiss and Moll
Precursors of ocular actinic damage-related malignancies
Squamous cell carcinoma and melanoma
Uveal melanoma etiologic genes
GNAQ
GNA11
BAP1 (Ch3) loss
Cotton wool spots and cytoid bodies
Hypertensive retinopathy (Retinal arteriosclerosis)
Hollenhorst plaques
Retinal Artery Occlusion
Blood and thunder appearance
Retinal vein occlusion
Most common intraocular malignancy in adults
Choroidal metastasis
Most common primary intraocular malignancy in adults
Uveal melanoma
Retinoblastoma gene affectation
Rb loss
