Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

USMLE Step 1 > Neuro - Stuff Missed > Flashcards

Neuro - Stuff Missed Flashcards

1
Q

Tabes dorsalis

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

JC virus

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Histo changes in brain 12-48 hours after infarct

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Histo changes in brain 24-72 hours after infarct

A

Necrosis and neutrophilic infiltration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Histo changes in brain 3-5 days after infarct

A

Macrophage infiltration and phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Histo changes in brain 1-2 weeks after infarct

A

Microscopic: reactive gliosis and vascular proliferation around necrotic area

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Histo changes in brain > 2 weeks after infarct

A

Microscropic changes: Glial scar

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pupillary light reflex

A

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

-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Nerves responsible for pupillary light reflect

A

Afferent limb: CN II (optic nerve)

Efferent limb: CN III (occulomotor nerve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

CN III

A

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

Parasympathetic fibers: contract iris sphincter and ciliary muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Signs of CN III palsy

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

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

A 
CN V1 (afferent limb)
CV VII (efferent limb)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A

CN VI - result of unopposed action of CN III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Meningiomas

A

located to cerebral surface

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Tinnitus and unilateral hearing loss are associated with which tumors?

A

Cerebellopontine angle tumor (e.g. acoustic neuroma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Headache and anosmia associated with which tumors

A

Meningioma located in olfactory groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Bitemporal heminopia associated with which tumors?

A

Pituitary adenomas and craniopharyngiomas

due to compression of central part of optic chiasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Meningiococcal pilli

A

responsible for epithelial attachment to nasopharynx

- responsible for preventing invasion and disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Common causes of Down’s Syndrome

A
  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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Uniparental disomy

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Symptoms associated with pineal tumors

A
  1. Precocious puberty - caused by B-hcG production
  2. Parinaud syndrome
  3. Obstructive hydrocephalus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Precocious puberty

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Parinaud syndrome

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Lateral medullary syndrome (Wallenberg(

A
  • 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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Medially medullarysyndrome

A
  • due to lesions on medial side of medulla

causes contralateral spastic paralysis and ipsilateral paralysis of tongue (CN XII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

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

A

Radial nerve

  • innervates the extensor compartment of the arm
  • innervates the dorsal portions of 1st half of 1st to 3rd fingers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Phenotyping mixing

A

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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Reassortment

A

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)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Recombination

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Conversion disorder

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Malingering

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Body dysmorphic disorder

A

patient believes body part is pathologically flawed

  • develops mostly in adolescence and affects men and women
  • high rate of depressive disorder and suicide attemps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

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

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Which Vitamin deficiency resembles Friedrich’s ataxia?

A 
Vitamin E
Like Friedrich's Ataxia, Vitamin E deficiency leads to degeneration of:
- spinocerebellar tracts
- dorsal column of spinal cord, 
- peripheral nerves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Poliomyelitis

A
  • damage to anterior horn cells and leads to paralysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Creutzfeldt- Jacob disease

A
  • prion disease
  • progressive dementia and myoclonic jerks of extremities
  • multiple vacuoles are seen in gray matter of brain (spongiform encephalopathy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Thiamine deficiency signs

A
  • periperhal neuropathy
  • high output cardiac failure (due to AV shunts)
  • Wernicke encephalopathy
    • ataxia, confusion and abdominal pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Nystatin

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Genomic imprinting

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Virulence factors for E.coli

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Sciatica

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Damage to L4

A

L4 provides sensation ot posterior thigh or left

- damage to L4 would result in damage to knew reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Recombination

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Pseudomonas aeruginosa

A
  • NONLACTOSE-FERMENTING
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Wallerian degeneration

A

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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Axonal reaction

A

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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Signs of compression of atrophy

A
  • result of increased intracranial pressure or mass lesion

- decrease in size and number of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Buccopharyngeal fascia

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Deep cervical fascia

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Craniopharyngioma

A

calcified cystic tmors

  • arise from Rathke’s pouch
  • can cause headaches, growth failure and bitemporal heminopsia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Coagulative necoris

A

occurs following hypoxic death in all tissues EXCEPT CNS

- acute denaturation of cellular proteins following irreversible cell injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Fibrinoid necrosis

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Liquefactive necoris

A

irreversible ichemic injury to BRAIN

- infarcted tissue eventually replaced with cystic astroglial scar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Caseous necrosis (in brain)

A

results from tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Nonenzymatic fat necrosis

A

describes necrosis of fat tissue after trauma

- female breast is common site of trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Facial flushing and mydriasis after taking medication to cure asthma

A
  • due to muscarinic blockade

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Pilocytic astrocytomas

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Medulloblastomas

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Neuroblastomas

A
  • 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
  • N-MYC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Ependymomas

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Fracture to pterion hits what artery?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Occipital artery

A

serves posterior scalp and sternocleidomastoids

- runs posteriorly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Ophthalmic artery

A

first branch of internal carotid

- serves eye, orbital contents, and eyelids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Middle cerebral artery

A
  • branch of internal carotid
  • supplies parietal and temporal regions of brain
  • injury causes subarachnoid and intercerebral hemorrhage
65
Q

Transtentorial (uncal) herniation

A
  • 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
66
Q

Signs of uncal herniation

A
  • 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
67
Q

Fragile X Syndrome

A
  • trinucleotide repeats within FMR1 gene on X chromosome

- signs include mental retardation, facial deformities, and macroorchidism

68
Q

C. neoformans

A
  • 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
69
Q

Tabes dorsalis

A
  • 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) -
70
Q

Argyll-Robertson pupil

A

loss of response to light, but still accomodates

71
Q

Progressive multifocal Leukoencephalopathy

A
  • results of JC virus infection
  • demyelination of CNS due to oligodendrocyte destruction
  • rapidly progressive and atal
72
Q

Multiple scleoris

A
  • self-limiting neurological symptoms in patients 20-30 yeears old
  • associated with optic neuritis
  • internuclar opthalmoplegia
  • sensory deficits
73
Q

HIV fenome

A
  • structural gene (gag, pol, env) poduces nucleocapsid p24 and p7
  • envelope glycoproteins (e.g. gp120 and gp41)
  • viral replicaiton (tat and rev)
74
Q

Defects in first branchial arch can affect which structures

A
  • Mandible
  • Maxila
  • Malleus
  • Incus
  • Masseter
  • associated with trigeminal nerve (CN V)
75
Q

Mechanisms of diabetic neuropathy

A
  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
76
Q

Liquefactive necrosis

A
  • 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
77
Q

Oselatamivir

A

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
78
Q

Amantadine

A

impairs uncoating or dissembly of influenza A after host cell endocytosis

79
Q

Niemann-Pick disease

A

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
80
Q

Niemann-Pick disease

A
  • deficiency in sphingomyelinase
  • progressive neurodegeneration
  • hepatosplenomegaly
  • cherry red macula
  • foamy macrophages filled with sphingomyelin
81
Q

Interferons alpha and B

A

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

82
Q

Non-pathogenic corynebacterium

A
  • can cause severe pseudomembranous pharyngitis after acquiring Tox gene via lysogenization by temperate bacteriophage
83
Q

Bacteria that can acquire bacterial toxins via lysogenic phase

A 
"ABCDE"
A= ShigA-like toxin
B = Botilinium toxin
C = Cholera toxin
D = Diptheria
E = Erythrogenic toxin of Group B Strep
84
Q

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

A
  • LOS (Meningococcal lipoligosaccharide)

- it’s analgous to the LPS seen in many gram negative bacteri

85
Q

Drugs associated with the redistribution of fat from extremities to trunk

A
  • 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
86
Q

Huntington’s disease

A
  • 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
87
Q

Varicella Zoster Virus

A
  • typically infects children and causes “chickenpox”
  • present with fever, vescicular rash, and pruritic rash
  • vaccine recommended for children aged 12-18 months
88
Q

IgG antibodies

A

delayed response to antigen

  • most abundant isotupe
  • fixes complement
  • crosses the placenta anc provides infants with passive immunity
  • opsonizes bacteria
89
Q

IgM

A

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
90
Q

IgA

A

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
91
Q

IgE

A

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
92
Q

IgD

A

unclear function

- found on surface of many B cells and in serum

93
Q

Synaptophysin

A

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

94
Q

CNS tumors of glial origin

A
  • Astrocytomas
  • Ependymomas
  • Oligodendrogliomas
    • stain positively for GFAP
95
Q

Guillain Barrre syndrome

A
  • acute demyelinating peripheral neuropahy
  • affects young adults and is preceded by febrile illness
  • segmental demyelination of peripheral nerves
  • endoneural inflammatory infiltrate
96
Q

Subarachnoid hemorrahge

A
  • 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
97
Q

Treatment of vasospasma associated with subarachnoid hemorrahge

A
  • Nimodipine - selective Ca channel blocker
98
Q

Corynebacterum diptheriae

A

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
99
Q

Discuss toxins associated with C. diptheriae

A

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

100
Q

Projection

A

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

101
Q

Reaction formation

A

redirection of unacceptable impulse into its opposit

- ex. former alcoholic trying to ban alcohol sales

102
Q

Acting out

A

expressing unacceptable thoughts or impulses

e.x. throwing a tandrum

103
Q

Splitting

104
Q

Identification

A

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
105
Q

Common signs of Turner Syndrome

A
  • Lymphedema in hands/feet
  • Coarctation of aorta
  • Horseshow kidney
106
Q

Syringomyelia presentation

A

presents with chronic loss of upper extremity pain and temp sensation

  • upper extremity weakness and hyporeflexia
  • low extremity weakness and hyperreflexia
  • kyphoscloiosis
107
Q

Syringomyelia

A

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
108
Q

C. diptheriae

A

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
109
Q

Rabies encephalitis

A
  • caused by rhabdoviridae (rabies)
  • agitation, disorientation, pharyngospasm leading to coma and denth
  • initially flu-like prodrome that leads to acute neurologic syndrome
110
Q

Rhabdoviridae

A
  • 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
111
Q

Cytomegalovirus

A
  • binds to cellular intergrins
112
Q

Epstein- Barr virus

A

binds to CD21

113
Q

HIV

A

binds to CD4 and CXCR4/CCR5

114
Q

Rhinovirus

A

binds to ICAM1 (CD54)

115
Q

Pathogenesis of Alzheimer’s disease

A
  • decreased ACH in nucleus basalis of Meynert and hippocampus
  • diminshed activity of choline acetyltransferase is that cause
116
Q

Symptoms of Alzheimers

A
  • 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
117
Q

Serotonin

A
  • formed in raphe nucleus

- loss leads to anorexia, depression, and sleep disorders

118
Q

Locus cereleus

A
  • site of NE production and located in pontine central

- implicated in panic attacks and panic disosorder

119
Q

Conductive hearing loss testing

A

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

120
Q

Sensorial hearing loss testing

A

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

121
Q

Conductive hearing loss

A
  • due to obstruction of external sound vibrations to the inner ear
  • can be caused by cerumen impaction, tympanic membrane rupture, severe otitis meia
122
Q

Sensorineural hearing loss

A
  • due to involvement of inner ear, cochlea, and auditory nerve
  • can be caused by Meniere’s disease, acoustic neuromoa, ototoxic drugs (e.g. aminoglycosides0
123
Q

Duchenne muscle dystrophy

A
  • 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
124
Q

Mitochondrial myopathies

A

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

125
Q

Multiple sclerosis

A

autoimmune demyelinating disease

  • within plaques, loss of myelin sheaths adn depletion of oligodendrocytes
  • oligoclonal bands of IgG may be seen in CSF fluid
126
Q

Common peroneal nerve injury

A
  • 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
127
Q

Tibial nerve injury

A

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

128
Q

Dorsal column

A
  • affects pressure, vibration, proprioception, fine touch

- medial leminiscal pathway

129
Q

DC-ML Pathway (neurons and synapses)

A

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

130
Q

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

A

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

131
Q

Lateral corticospinal tract

- descending voluntary movements

A

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

132
Q

Primary CNS lymphomas

A
  • occur in immunocompromised patients
  • tumors arise from B cells and are associated with EBV
  • high grade tumors with poor prognosis
133
Q

Common causes of asceptic meningitis

A

Enteroviruses

  • Coxsackievirus
  • Echovirus
134
Q

Viral meningitis

A
  • 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
135
Q

Bacterial meningitis

A
  • 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
136
Q

S. epidermidis

A
  • coagulase negative Staph species
  • associated with foreign bodies (e.g. catheters, procedures, IV lines)
  • can form biofilms
137
Q

Elderly patient with progressive memory loss.

Congo red staining shows patchy amyloid deposition in temporal cortex and hippocampus. Likely diagnosis

A

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
138
Q

Paraneoplastic syndromes-

A
  • 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
139
Q

Wernicke Encephalopathy

A
  • Confusion
  • Ataxia
  • Opthalmoplegia
140
Q

Medical treatments that can precipitate Wenicke’s encephalopathy

A
  • Infusion of glucose without thiamine in patient with chronic thiamine deficiency can precipitate encephalopathy
  • ** Thiamine needed for glucose metabolism
141
Q

Low frequency sounds are best heard where in ear?

A

At apex of cochlea near the helicotrema

142
Q

High frequency sounds are best heard where in ear?

A

At base of cochlea near round and oval windows

143
Q

General sensation from anterior 2/3 of tongue

A

Mandibular division of Trigeminal nerve

144
Q

Gustatory innervation of anterior 2/3

A

Chorda tympani branch of facial nerve

145
Q

Innervation of posterior 1/3 of tongue

A

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

146
Q

Innervation of far posterior innervation of tongue root

A

Vagus nerve - transmits gustatory and general sensory stimuli

147
Q

Rabies encephalitis

A
  • 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
148
Q

Merniere’s disease

A

triad of tinnitus, vertigo, and sensorineural hearing loss

- related to increase in volume and increase in endolymph in vestibular apparatus

149
Q

HSV-1

A
  • 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
150
Q

Common clinical manifestation of primary infection of HSV-1

A

Herpetic gingivostomatitis

151
Q

Cause of anopia (no vision in one eye)

A
  • Injury to ipsilateral optic nerve

- seen in renal artery occlusions

152
Q

Cause of bitemporal hemianopia

A
  • lesion in optic chiasm

- seen in craniopharyngoma, pituitary tumors, ACA aneurysms

153
Q

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

A
  • lesion in (right) -IPSILATERAL peri-chiasmal lesion

- calcificatino or aneurysm of internal carotid artery impinging on UNCROSSED lateral retinal fibers

154
Q

Cause of (left) homonymous hemianopia

A
  • 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

155
Q

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

A
  • lesion in (right) CONTRALATERAL temporal lobe (Meyer’s loop)
  • lesion or stroke in
156
Q

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

A
  • Lesion in (right) CONTRALATERAL primary visual cortex

- Lesion in parietal lobe

157
Q

Cause of left homonymous heminanopia with macular sparing

A
  • Lesion in primary visual cortex (occipital lobe)

- Occlusion of PCA. Macula is spared due to colateral blood from MCA

158
Q

Which viruses can undergo reassortment

A

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

159
Q

Red neuron

A
  • 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

USMLE Step 1 (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions