Neuro - Stuff Missed Flashcards Preview

USMLE Step 1 > Neuro - Stuff Missed > Flashcards

Flashcards in Neuro - Stuff Missed Deck (159):

Tabes dorsalis

degeneration of dorsal spinal columns and nerve roots in patients with tertiary syphillis


JC virus

can cause chronic CNS demyelonation through infection of oligodendrocytes (e.g. progressive multifocal leukoencephalopathy)


Histo changes in brain 12-48 hours after infarct

"Red neurons" (Eosinophilic cytoplasm, pyknotic nuclei, loss of Nissl substance)


Histo changes in brain 24-72 hours after infarct

Necrosis and neutrophilic infiltration


Histo changes in brain 3-5 days after infarct

Macrophage infiltration and phagocytosis


Histo changes in brain 1-2 weeks after infarct

Microscopic: reactive gliosis and vascular proliferation around necrotic area

Macroscopic: Liquefactive necrosis: well-demarcated soft area (1 week - 1 month)


Histo changes in brain > 2 weeks after infarct

Microscropic changes: Glial scar

Macroscopic changes: Cystic area surrounded by gliosis (> 1 month)


Pupillary light reflex

assessed by shining light in eye and observing the response in that eye (direct) and opposite eye (consensual)



Nerves responsible for pupillary light reflect

Afferent limb: CN II (optic nerve)

Efferent limb: CN III (occulomotor nerve)



Somatic: innvervates and inferior, superior, medial rectus, inferior oblique, and levator palpebrae

Parasympathetic fibers: contract iris sphincter and ciliary muscle


Signs of CN III palsy

- Ptosis (due to paralysis of levator palpebrae)
- "Down and out" gaze - due to unopposed actions of LR and SO
- Fixed dilated pupil and loss of accomodation - loss of PS fibers


Absence of corneal reflex can result from lesions involving which CN?

CN V1 (afferent limb)
CV VII (efferent limb)


Inward deviation of left eye is caused by a lesion to what?

CN VI - result of unopposed action of CN III



located to cerebral surface
- parasaggital meningomas can cause contralateral spastic paresis of leg due to compression of leg-foot motor area


Tinnitus and unilateral hearing loss are associated with which tumors?

Cerebellopontine angle tumor (e.g. acoustic neuroma)


Headache and anosmia associated with which tumors

Meningioma located in olfactory groove


Bitemporal heminopia associated with which tumors?

Pituitary adenomas and craniopharyngiomas
due to compression of central part of optic chiasm


Meningiococcal pilli

responsible for epithelial attachment to nasopharynx
- responsible for preventing invasion and disease


Common causes of Down's Syndrome

1. Trisomy 21 (95% of cases)
2. Unbalanced Robertsonian translocations (usually 14 and 21)
3. Mociaism: patients have two cell lines: one normal and one with trisomy 21


Uniparental disomy

when patient inherits two copies of a chromosome from one parent and no copies of a chromosome from the other.


Symptoms associated with pineal tumors

1. Precocious puberty - caused by B-hcG production

2. Parinaud syndrome

3. Obstructive hydrocephalus


Precocious puberty

in males: enlarged genitalia with pubic and facial hair younger than 9
in females: appearance of breasts, pubic hair before age 7
-- if associate with paralysis of upward gaze then that suggests hormone secreting tumor


Parinaud syndrome

paralysis of upward gaze and of convergence - these symptoms due to compression of tectal area of midbrain


Lateral medullary syndrome (Wallenberg(

- due to lesions of lateral side of medulla
leads to contralateral loss of pain and temperature sensation along ipsilateral paralysis of CN V, IX, X, XI


Medially medullarysyndrome

- due to lesions on medial side of medulla
causes contralateral spastic paralysis and ipsilateral paralysis of tongue (CN XII)


Wrist drop (inability to extend wrist) is associated with injury to which nerve?

Radial nerve
- innervates the extensor compartment of the arm
- innervates the dorsal portions of 1st half of 1st to 3rd fingers


Phenotyping mixing

refers to co-infection of a host cell by two viral strains resulting in progeny virions that contain nucleocapsid proteins from one strain and genome of another

- since there is no change in the underlying genomes, the next generations of virions goes back to unmixed phenotypes



refers to changes in genomic composition that occur when host cells are co-infected with two SEGMENTED viruses that exchange whole genome segments
- can cause alterations in surface proteins (e.g. influenza)



exchange of genes between two chromosomes by crossing over within homologous regions
- changes remain present in subsequent generations


Conversion disorder

unconscious manifestation of conversion symptoms (e.g. blindness, weakness, loss of sensation, paralysis) that don't coincide with physical exam
- usually brought about by stress and resolve when stressor resolves



consciously faking or claiming symptoms for secondary gain outside of medical attention (e.g financial gain)


Body dysmorphic disorder

patient believes body part is pathologically flawed
- develops mostly in adolescence and affects men and women
- high rate of depressive disorder and suicide attemps


Patient has history of atherosclerosis and upon autopsy presents wth cystic lesion on left side. The walls of lesions composed of what cells?

Astrocytes -
- after initial lesion is eaten by macrophages and necrotic area is resorbed, cystic cavity forms.
Around cyst, astrocytes undergo gliosis (proliferate and enlarge) to form a wall around cyst.


Which Vitamin deficiency resembles Friedrich's ataxia?

Vitamin E
Like Friedrich's Ataxia, Vitamin E deficiency leads to degeneration of:
- spinocerebellar tracts
- dorsal column of spinal cord,
- peripheral nerves



- damage to anterior horn cells and leads to paralysis


Creutzfeldt- Jacob disease

- prion disease
- progressive dementia and myoclonic jerks of extremities
- multiple vacuoles are seen in gray matter of brain (spongiform encephalopathy)


Thiamine deficiency signs

- periperhal neuropathy
- high output cardiac failure (due to AV shunts)
- Wernicke encephalopathy
** ataxia, confusion and abdominal pain



- antifungal by binding to ergosterol in cell membrane to promote pore formation in cell membrane
- drug of choice for oral candiasis in an immunosuppressant patient


Genomic imprinting

selective inactivation of genes in either maternal or paternal origin
- occurs in Prader-Willi and Angelman syndromes


Virulence factors for E.coli

- K-1 capsule: associated with pneumonia and meningitis
- fimbriae: virulence factor that allows bacteria to adhere to target tissue
- Lipid A: septic shock from endotoxin in outer membrane



- shooting pain down posterior thigh and leg that results from impingement of spinal nerves as it leaves spinal column
- compression of S1 is associated with pain in posterior thigh and dimunition of ankle reflex


Damage to L4

L4 provides sensation ot posterior thigh or left
- damage to L4 would result in damage to knew reflex



- gene exchange that occurs through crossing over double stranded DNA molecules

- two defective viruses co-infecting same cell can result in cytopathic wild type genome


Pseudomonas aeruginosa

- Oxidase positive, motile gram negative rod

- cause of external otitis media (esp. in elderly) - hich presents as LOTS of ear pain and draining and granulation tissue


Wallerian degeneration

occurs in segment of axon that lost connection with cell body
- initially, swelling and irregularity noticed in distal axon
- within week, axon is destroyed and fragments are digested by Schwann cells and macrophagees


Axonal reaction

changes in body of neuron after axon has been severed
- increased protein synthesis that facilitates axonal repair
- enlarged, rounded cells with peripherally located nuclei and dispered Nissl substance


Signs of compression of atrophy

- result of increased intracranial pressure or mass lesion
- decrease in size and number of cells


Buccopharyngeal fascia

extends from carotid sheath to surround pharyngeal constrictor muscles
- space between buccopharyngeal and prevertebral fascia is retropharyngeal space


Deep cervical fascia

INVESTING- surrounds neck like a collar, investing deeper parts of neck
PRETRACHEAL - encloses viscera of neck (thyroid, parathyroid, larynx, esophagus, trachea)
PREVERTEBRAL - surrounds vertebral column and spinal muscles



calcified cystic tmors
- arise from Rathke's pouch
- can cause headaches, growth failure and bitemporal heminopsia


Coagulative necoris

occurs following hypoxic death in all tissues EXCEPT CNS
- acute denaturation of cellular proteins following irreversible cell injury


Fibrinoid necrosis

pattern of injury seen in walls of blood vessels affected by immune complex vasculitis and related processes


Liquefactive necoris

irreversible ichemic injury to BRAIN
- infarcted tissue eventually replaced with cystic astroglial scar


Caseous necrosis (in brain)

results from tuberculosis


Nonenzymatic fat necrosis

describes necrosis of fat tissue after trauma
- female breast is common site of trauma


Facial flushing and mydriasis after taking medication to cure asthma

- due to muscarinic blockade

1st generation antihistamines (e.g. diphenhydramine, neuroleptics, and antiparkisoninan drugs often have muscarinic blockade)


Pilocytic astrocytomas

- usually arise in cerebellum, brainste
- well differentiated neoplasms comprised of hair-like glial processes associated with microcysts
- show mixed Rosenthal fibers and granular eosinophilic bodies



- 2nd most common posterior fossa tumor in children
- cells are small and poorly differentiated with scant cytoplasm and little stroma
- high mitotic index
- Classic Homer-Wright rosettes



- common extracranial solid tumors in children
-composed of round blue-cell tumors
- neuropil, neuritic process, is pathognomonic feature of neuroblastoma ecells
- neuroendocrine markers (synaptophysin, NSE, chromagranin, S100 +_
- have elevated HVA and VMA levels



- 10% of posterior fossa tumors in children
- often occur in roof of 4th ventricle in children vs. spine in adults
- ependymal pseudorosettes
-GFAP + processes tapering toward blood vessels


Fracture to pterion hits what artery?

Pterion - where frontal, parietal, temporal, and sphenoid bones meet
- thin in this region and can hit middle meningeal artery which can cause EPIDURAL HEMATOMA


Occipital artery

serves posterior scalp and sternocleidomastoids
- runs posteriorly


Ophthalmic artery

first branch of internal carotid
- serves eye, orbital contents, and eyelids


Middle cerebral artery

- branch of internal carotid
- supplies parietal and temporal regions of brain
- injury causes subarachnoid and intercerebral hemorrhage


Transtentorial (uncal) herniation

- complication of ipsilateral mass lesion (e.g. hemorrhage or brain tumor)
- associated with ipsilateral FIXED AND DILATED pupil
- ipsilateral paralysis of occulomotor muscles, contralateral
- ipsilateral hemiparesis and contralateral homonymous hemiaopsia with macula sparing may occur


Signs of uncal herniation

- Ipsilateral fixed and dilated pupil (due to compression of CN III)
- Contralateral homonymous hemianopsia with macula sparing (due to compression of ipsilateral PCA
- Ipsilateral hemiparesis due to compression of contralateral corticospinal tract


Fragile X Syndrome

- trinucleotide repeats within FMR1 gene on X chromosome
- signs include mental retardation, facial deformities, and macroorchidism


C. neoformans

- fungus associated with CNS infection (meningitis) in immunocompromised individuals
- found in soil and pigeon droppings
- transmitted via respiratory route with lungs primary site of entry
- found with Indian ink stain, Methanmine silver, Methacarmine


Tabes dorsalis

- manifestation of neurosyphillis
- affects dorsal columns - causing loss of proprioception and vibration
- affects dorsal sensory routes - loss of pain and sensation
- Argyll-Robertson pupil (involvement of periaqueductal gray matter of brain) -


Argyll-Robertson pupil

loss of response to light, but still accomodates


Progressive multifocal Leukoencephalopathy

- results of JC virus infection
- demyelination of CNS due to oligodendrocyte destruction
- rapidly progressive and atal


Multiple scleoris

- self-limiting neurological symptoms in patients 20-30 yeears old
- associated with optic neuritis
- internuclar opthalmoplegia
- sensory deficits


HIV fenome

- structural gene (gag, pol, env) poduces nucleocapsid p24 and p7
- envelope glycoproteins (e.g. gp120 and gp41)
- viral replicaiton (tat and rev)


Defects in first branchial arch can affect which structures

- Mandible
- Maxila
- Malleus
- Incus
- Masseter
- associated with trigeminal nerve (CN V)


Mechanisms of diabetic neuropathy

1. Non-enzymatic glycosylation of proteins - leads to increased thickness, hyalinization and narrowing arteriolar walls

2. Intracellular hyperglycemia occurs in peripheral nerves - accumulated glucose is converted into sorbitol and fructose by aldose reductase. Sorbitol inc. cell osmolarity and increases water influx which causes osmotic damage to nerves


Liquefactive necrosis

- characterized by complete digestion and removal of necrotic tissue by cystic cavity
- Hypoxic CNS injury followed by liquefactive necrosis
- Abscess formation due to this type of injury is due to this type of necross



neuraminidase inhibitor usedful for treatment of both influenza A and B viruses
- impairs release of newly formed virions from infected host cells
- impairs viral penetration of mucous secretions that overlie respiratory epithelium
- best if taken after 48 hours



impairs uncoating or dissembly of influenza A after host cell endocytosis


Niemann-Pick disease

deficiency of sphingomyelinase
- causes abnormal accumulations of ceramide phospholipid sphingomyelin and neurologic deterioriation within 1st year of life
- foamy appearing, sphingomyelin histocytes accumulate in liver and spleen --> hepatosplenomegay


Niemann-Pick disease

- deficiency in sphingomyelinase
- progressive neurodegeneration
- hepatosplenomegaly
- cherry red macula
- foamy macrophages filled with sphingomyelin


Interferons alpha and B

produced by eukaryotic cells in response to viral infectios
- act on neighboring cells to stimulate production of antiviral proteins that would impair viral protein synthesis


Non-pathogenic corynebacterium

- can cause severe pseudomembranous pharyngitis after acquiring Tox gene via lysogenization by temperate bacteriophage


Bacteria that can acquire bacterial toxins via lysogenic phase

A= ShigA-like toxin
B = Botilinium toxin
C = Cholera toxin
D = Diptheria
E = Erythrogenic toxin of Group B Strep


Virulence factors in N. meningitidis that's responsible for meningitis and meningococecemia

- LOS (Meningococcal lipoligosaccharide)
- it's analgous to the LPS seen in many gram negative bacteri


Drugs associated with the redistribution of fat from extremities to trunk

- Medication induced body fat redistribution (fat from extremities to creation of buffalo hump) is usually done by:
- Glucocorticoids - causes Cushing's syndrome
- HAART - causes lipodystrophy


Huntington's disease

- AD
- manifests with progressive dementia anc choreiform movements
- loss of neurons in caudate nucleus and putamen is characteristis
- decrease in GABA, ACh, and substance P
- CAG repeats in chromosome 4
- Anticipation is frequently seen


Varicella Zoster Virus

- typically infects children and causes "chickenpox"
- present with fever, vescicular rash, and pruritic rash
- vaccine recommended for children aged 12-18 months


IgG antibodies

delayed response to antigen
- most abundant isotupe
- fixes complement
- crosses the placenta anc provides infants with passive immunity
- opsonizes bacteria



produce in the first exposure to antigen
- fixes complement but DOESN'T cross placenta
- antigen receptor on surface of B cell
- monomer of B cell and pentamer
- pentamer allows it to efficiently trap free antigens out of tissue while humoral resopnse



prevents attachment of bacteria and viruses to mucous membranes
- does not fix complement
- monomer in circulation or dimer when secreted
- crosses epithelial cells via transctytosis
- picks up secretory component from epithelial cell before secretion



binds mast cells and basophils when exposed to allergen
- mediated type I hypersensitivity through release of inflammatory mediators such as histamine
- mediates immunity to worms by activating eosinophils
- lowest concentration in serum



unclear function
- found on surface of many B cells and in serum



protein found on presynaptcic vesicles of neurons, neuroendocrine and neuroendocrine cells
- CNS tumors of neuronal origin stain for synaptophysin


CNS tumors of glial origin

- Astrocytomas
- Ependymomas
- Oligodendrogliomas
** stain positively for GFAP


Guillain Barrre syndrome

- acute demyelinating peripheral neuropahy
- affects young adults and is preceded by febrile illness
- segmental demyelination of peripheral nerves
- endoneural inflammatory infiltrate


Subarachnoid hemorrahge

- occurs due to rupture of saccular aneurysm and AV malformation
- severe vasospasm 4 - 12 days after initial insult is major cause of morbidity and mortality in patients recovering from this


Treatment of vasospasma associated with subarachnoid hemorrahge

- Nimodipine - selective Ca channel blocker


Corynebacterum diptheriae

Gram positive rod
- found in clumps that look like Chinese letter
- cytoplasm contain metachromatic granules that stain with aniline dyes like methylene blue
- produces two subunit AB toxin


Discuss toxins associated with C. diptheriae

toxin B - binds to heparin binding epidermal growth factors on cardiac and neural cells - explains affinity for heart and neural tissues
B subunit induces endocytosis of toxin
- A (Active subunit) - inhibits cell protein synthesis by catalyzing ADP- ribosylation of protein EF-2 which causes cell death



transplanting one's unacceptable impulses or affect to another person or situation
- immature defense mechanism


Reaction formation

redirection of unacceptable impulse into its opposit
- ex. former alcoholic trying to ban alcohol sales


Acting out

expressing unacceptable thoughts or impulses
(e.x. throwing a tandrum)



unconscious beleife that people are wholly good or wholly bad



modeling one's behavior after someone who is perceived more powerful
- may be admirable or non-admirable
- classic example is child of an abusive father become a child abuser


Common signs of Turner Syndrome

- Lymphedema in hands/feet
- Coarctation of aorta
- Horseshow kidney


Syringomyelia presentation

presents with chronic loss of upper extremity pain and temp sensation
- upper extremity weakness and hyporeflexia
- low extremity weakness and hyperreflexia
- kyphoscloiosis



caused by central cystic dulation in cervical spinal cord (syrinx) that slowly enlarges
- damages anterior white commissure and anterior horns
- injures lateral spinothalamic tract and ventral horns
- most common at C8 - T1 levels


C. diptheriae

Gram-positive, catalase +, club shaped ros
- cultured in cysteine-tellurite agar in which colonies are black
- produces metachromatic granules that can be detected with methylene blue staining


Rabies encephalitis

- caused by rhabdoviridae (rabies)
- agitation, disorientation, pharyngospasm leading to coma and denth
- initially flu-like prodrome that leads to acute neurologic syndrome



- single stranded RNA viruses enveloped by bullet-shaped capsule
- studdded by glycoprotein spokes that bind to nicotinic ACh receptors
- once inside women, virus can stay local for days to weeks before binding to ACh receptors on perpipheral nerves



- binds to cellular intergrins


Epstein- Barr virus

binds to CD21



binds to CD4 and CXCR4/CCR5



binds to ICAM1 (CD54)


Pathogenesis of Alzheimer's disease

- decreased ACH in nucleus basalis of Meynert and hippocampus
- diminshed activity of choline acetyltransferase is that cause


Symptoms of Alzheimers

- slow progressive memory loss
- mild to moderate brain atrophy
- neurofibrillary tangles, senile plaques, and amyloid angiopathy
- decreased ACh levels in basalis nucleus of Meynert and hippocampus



- formed in raphe nucleus
- loss leads to anorexia, depression, and sleep disorders


Locus cereleus

- site of NE production and located in pontine central
- implicated in panic attacks and panic disosorder


Conductive hearing loss testing

Rinne test: (mastoid process test) - sounds louder in mastoid near affected ear (bone > air)
Webber test: sounds loudest in the affected ear


Sensorial hearing loss testing

Rinner test: sounds normal - don't hear sound in abnormal ear
Webber test: sounds loudest in unaffected ear


Conductive hearing loss

- due to obstruction of external sound vibrations to the inner ear
- can be caused by cerumen impaction, tympanic membrane rupture, severe otitis meia


Sensorineural hearing loss

- due to involvement of inner ear, cochlea, and auditory nerve
- can be caused by Meniere's disease, acoustic neuromoa, ototoxic drugs (e.g. aminoglycosides0


Duchenne muscle dystrophy

- onset is between 3 -6 years old
- affects proximal muscles of shoulder, lower back and pelvic girdl
- waddling gait, may appear clumsy
- Gower's sign positive - to get up out of chair child must support weight with hands
- Distal muscles of extremities enlarge due to PSEUDOHYPERTROPHY
- Asymmetric weakening of muscles leads to kyphoscoliosis


Mitochondrial myopathies

associated with ragged red fibers (muscle fibers with irregular contours and blotchy red appearance)


Multiple sclerosis

autoimmune demyelinating disease
-within plaques, loss of myelin sheaths adn depletion of oligodendrocytes
- oligoclonal bands of IgG may be seen in CSF fluid


Common peroneal nerve injury

- most common injury of leg
- trauma to head of fibula
- presents with plantarflexted and inverted posture of affected foot
- loss of sensation to anterolateral leg
- associated with "foot drop" - affected foot slaps the ground with each step


Tibial nerve injury

causes dorsiflexion and eversion of the foot with sensory loss on sole of foot


Dorsal column

- affects pressure, vibration, proprioception, fine touch
- medial leminiscal pathway


DC-ML Pathway (neurons and synapses)

1st order neurons: Sensory nerve ending to DRG --> enters spinal cord and ascends ipsilaterally
Synapse 1: ipsilateral nucleus cunneatus or ipsilateral fasisculus
2nd order neurons: Decussates in medulla ascends CONTRALATERALLY in ML
Synapse 2: VPL of thalamus
3rd order neurons: Sensory cortex


Spinothalamic tract
Lateral: pain and temperature
Anterior: crude touch and pressure

1st order neurons: sensory nerve ending (A-delta and C fibers) - cell body in DRG --> enter spinal cord
Synapse 1: Ispilateral gray matter
2nd order neurons: Decussates at anterior white commisure --> ascends CONTRALATERALLY
Synapse 2: VPL of thalamus
3rd order neurons: Sensory cortex


Lateral corticospinal tract
- descending voluntary movements

1st order neuron: UMN -cell body in 1 motor cortex --> descends ipsilaterally (through internal capsule_ until decussating at caudal medulla (pyramidal decussation) --> descends CONTRALATERALLY
Synapse 1: Cell body of anterior horn (spinal horn)
2nd order neuron: LMN leaves spinal cord
Synapse 2: Neuromuscular Junction


Primary CNS lymphomas

- occur in immunocompromised patients
- tumors arise from B cells and are associated with EBV
- high grade tumors with poor prognosis


Common causes of asceptic meningitis

- Coxsackievirus
- Echovirus


Viral meningitis

- commonly caused by enteroviruses
- WBC count < 500 cells
- lymphocytic predominance
- Glucose levels are normal/ slightly reduced
- Elevated protein but < 150 mg/dL
- no organisms identified


Bacterial meningitis

- S. pneumonie and N. meningitidies - common in adults
- Group B Strep and Gram-negative bacilli in kids
- WBC count > 1000 cells
- Neutrophil predomniance
- Glucose levels < 70 mg/gL but may be lower
- Elevated protein
- Often positive for certain protein


S. epidermidis

- coagulase negative Staph species
- associated with foreign bodies (e.g. catheters, procedures, IV lines)
- can form biofilms


Elderly patient with progressive memory loss.
Congo red staining shows patchy amyloid deposition in temporal cortex and hippocampus. Likely diagnosis

Alzheimer's disease
- associated with amyloid deposits (Congo red)
- parenchymal, extracellular deposits in brain are senile plaques - composed of AB amyloid
- amyloid angiopathy - amyloid deposition in media and adventitia of cerebral vessels and cause thickening of BM and vessel stenosis


Paraneoplastic syndromes-

- associated with systemic caner
- tumors produce substances that induce AUTOIMMUNE reaction and cause damage and degeneration of health tissue
- Paraneoplastic cerebellar degeneration are thought to be autoimmune


Wernicke Encephalopathy

- Confusion
- Ataxia
- Opthalmoplegia


Medical treatments that can precipitate Wenicke's encephalopathy

- Infusion of glucose without thiamine in patient with chronic thiamine deficiency can precipitate encephalopathy
-** Thiamine needed for glucose metabolism


Low frequency sounds are best heard where in ear?

At apex of cochlea near the helicotrema


High frequency sounds are best heard where in ear?

At base of cochlea near round and oval windows


General sensation from anterior 2/3 of tongue

Mandibular division of Trigeminal nerve


Gustatory innervation of anterior 2/3

Chorda tympani branch of facial nerve


Innervation of posterior 1/3 of tongue

Glossopharyngeal nerve - transmits pain, temperature and touch from posterior 1/3 of tongue


Innervation of far posterior innervation of tongue root

Vagus nerve - transmits gustatory and general sensory stimuli


Rabies encephalitis

- restlessness, agitation, and dysphagia progressing 30 to 50 days following exposure to bats, rabid pets
- manifests with flu-like prodrome and then subacute neuro symptoms (agitation, persistent fever, and painful spasms upon inspiration or with swallowing)
- associated with rhabdoviridiae


Merniere's disease

triad of tinnitus, vertigo, and sensorineural hearing loss
- related to increase in volume and increase in endolymph in vestibular apparatus



- occurs often in children 1-3 years old
- seen in Tzanck pereparation - ulcer scraping in Wright-Giemsa stain
- presence of giant multi-nucleated cells
- presents with ulcerative gingivitis and cervical lymphadenopathy


Common clinical manifestation of primary infection of HSV-1

Herpetic gingivostomatitis


Cause of anopia (no vision in one eye)

- Injury to ipsilateral optic nerve
- seen in renal artery occlusions


Cause of bitemporal hemianopia

- lesion in optic chiasm
- seen in craniopharyngoma, pituitary tumors, ACA aneurysms


Cause of (right) nasal hemianopis - no vision in inner right half of right eye

- lesion in (right) -IPSILATERAL peri-chiasmal lesion
- calcificatino or aneurysm of internal carotid artery impinging on UNCROSSED lateral retinal fibers


Cause of (left) homonymous hemianopia

- lesion in (right) -CONTRALATERAL optic tract or optic radiation

Optic tract: occlusion of anterior choroidal artery
Optic radiation: occlusion of MCA or lesion in posterior limb of internal capsule


Cause of left (homonymous) superior quandrantanopia ("pie in the sky")

- lesion in (right) CONTRALATERAL temporal lobe (Meyer's loop)
- lesion or stroke in


Cause of left homonymous inferior quandrantaopia ("pie on the floor")

- Lesion in (right) CONTRALATERAL primary visual cortex
- Lesion in parietal lobe


Cause of left homonymous heminanopia with macular sparing

- Lesion in primary visual cortex (occipital lobe)
- Occlusion of PCA. Macula is spared due to colateral blood from MCA


Which viruses can undergo reassortment

Viruses with segmented genomes (e.g. orthomyxoviruses and rotaviruses)


Red neuron

- signs of irreversible neuronal injury 12-24 hours after event
- shrinkage of cell body
- eosinophilia of cytoplasm
- pyknosis of nucleus and loss of Nissl substance