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UWorld 2 Flashcards

1
Q

Part of brain responsible for

(a) Pupillary light reflex
(b) Oculocephalic reflex

A

(a) Pupillary light reflex mediated by upper midbrain. CN II brings signal to pretectal nuclei, communicates w/ Edinger-WEstphal nucleus to shoot out CN III fibers
- midbrain

(b) Oculocephalic (Doll’s eye) reflex mediated by horizontal eye center of the pons

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2
Q

Part of brain responsible for

(a) Gag reflex
(b) Corneal reflex

A

(a) Gag reflex: CN IX and CN X both in the medulla

(b) Cornel reflex: CN V and VII both in the pons

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3
Q

Part of brain that contains the majority of

(a) Dopaminergic neurons
(b) Serotonergic neurons

A

(a) Dopaminergic neurons in the substantia nigra
- involved in Parkinsons

(b) Serotonergic neurons (aka neurons that release serotonin) primarily located in the Raphe nuclei

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4
Q

Involvement in disease

(a) Caudate nucleus
(b) Locus ceruleus

A

(a) Caudate nucleus is part of the striatum (caudate plus putamen = striatum). Loss of ACh and GABA in the striatum = Huntingtons
(b) Locus ceruleus = contains NE-releasing neurons, potentially overactive in anxiety

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5
Q

Involvement in disease

(a) Nucleus basalis of Meynert
(b) Raphe nuclei

A

(a) Nucleus basalis of Meynert hold the cell bodies of cholinergic neurons which undersecrete ACh in Alzheimers
(b) Raphe nuclei houses serotonergic neurons which may undersecrete 5-HT in depression/anxiety

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6
Q

3 mechanism of actions of anti-emetics used for chemo-induced nausea

A
  1. 5-HT3 inhibitors = Onadestron
  2. Dopamine receptor inhibitors = Metocloprmaide
  3. Neurokinin 1 (NK1) inhibitor = Aprepitant, Fosaprepitant
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7
Q

The following are major virulence factors of what organisms?

(a) Polyribosylribitol phosphate
(b) Lecithinase

A

(a) PRP = virulence factor on the capsule of H. influenzae B (think epiglottitis)
- this PRP is conjugated to the toxoid vaccine = HiB vaccine

(b) Lecithinase (also called alpha toxin or phospholipase C) is the virulence factor of C. perfinges (gas gangrene)

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8
Q

Two bacteria whose toxins inhibit EF-2

A

Both Diptheria toxin and pseudomonas toxin ribosylate (and therefore inhibit) elongation factor 2 to kill cells

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9
Q

Explain why rocuronium is a better paralytic than succinylcholine in burn victims

A

Succinylcholine (depolarizing blockade) binds to nicotinic ACh receptors to depolarize the motor end plate, acts continuously b/c not degraded by ACh-ase. However this n-AChR are upregulated in burn victims (and crush victims) and are non-selective cation channels => along w/ Na+ outflux they can allow a dangerous outflux of K+ => hyperkalemia and lethal arrhythmias

So due to risk of hyperkalemia w/ succinylcholine, use rocuronium (non-depolarizing agent) in burn, crush, and denervating injury victims

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10
Q

27 yo M w/ foot pain after stepping on a nail

  • imaging shows gas in the tissues
  • Cx shows G pos rods

Mechanism of the toxin causing his pain

A

G pos rods causing gas gangrene = C. perfinges

C. perfinges toxin = lecithinase (also called alpha toxin or phospholipase C) that catalyzes splitting of phospholipids to cause cell lysis

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11
Q

Which class I antiarrhythmic is specifically helpful on ischemic myocardium

A 
IB (Lidocaine, Mexiletine, Tocainide) is more selective for ischemic myocardium 
-IB has the lowest dependence of the class I, and ischemic myocardium spends the most amount of time in the inactivated state so that IB has time to bind
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12
Q

What class of antiarrhythmic:

(a) Flecainide
(b) Disopyramide
(c) Quinidine
(d Lidocaine
(e) Tocainide
(f) Propafenone
(g) Procainamdide
(h) Mexiletine

A

Recall: IC > IA > IB

(a) Flecainide = IC
(b) Disopyramide = IA
(c) Quindine = IA
(d) Lidocaine = IB
(e) Tocainide = IB
(f) Propafenone = IC
(g) Procainamide = IA
(h) Mexiletine = IB

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13
Q

Antiinflammatory cytokine

A

IL-10 = antiinflammatory cytokine

  • inhibits Th1 cytokines
  • reduces MHC II expression
  • suppresses activated macrophages and dendritic cells
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14
Q

Main fxn of

(a) IL-1
(b) IL-5
(c) TNF-alpha

A

Main fxn

(a) IL-1- proinflammatory and fever induction
(b) IL-5 (by Th2 cells)- stimulates B cells and eosinophils
(c) TNF-alpha- promotes leukocyte recruitment and increases adhesion molecule expression on endothelium

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15
Q

Main fxn of

(a) IL-12
(b) IL-10

A

Main fxn

(a) IL-12 = secreted by macrophages to induce differentiate of Th1 and activate NK cells
(b) IL-10 = antiinflammatory that inhibits Th1 cytokines

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16
Q

Mode of inheritance

(a) Rett syndrome
(b) Hemophilia B
(c) Classic galatosemia

A

(a) Rett syndrome = X linked dominant
- no males b/c lethal for males in utero

(b) Hemophilia B (factor IX deficiency) = X linked recessive
(c) Classic galatosemia (absence of galatose-1-phosphate uridyl transferase) = autosomal recessive

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17
Q

Which fatty acids cannot be metabolized if there is a peroxisome defect?

A

Very long chain fatty acids or fatty acids w/ branching points at odd-number carbons cannot undergo mitochondrial beta-oxidation => metabolized by a special reaction in peroxisomes

So inborn error of metabolism of dysfunctional peroxisomes => neurologic defects from improper CNS myelination

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18
Q

4 lactose fermenters

A

Klebsiella
E. Coli
Enterobacter
Serratia

Pink colonies on MacConkey agar

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19
Q

How to differentiate the lactose non-fermenting, oxidase negative gram negative rods

A

Gram negative rods

Lactose fermenters: Klebsiella, E. Coli, Enterobacter, Serratia

Then non-lactose fermenters (white colones on MacConkey agar), split by oxidase test

  • oxidase positive = pseudomonas
  • oxidase negative dif by TSI agar
  • -no H2S production = Shigella
  • -H2S production (black color) = Salmonella and Proteus
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20
Q

Lactose-fermenting, indole positive gram negative rods

A

E. coliiiiiiii

Indole positive = can convert tryptophan to indole
-distinguishes from Enterobacter cloacae

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21
Q

2 MC clinical side effects of Lithium toxicity

A
  1. nephrogenic diabetes insipidus

2. hypothyroidism: pt p/w constipation, hair loss, wt gain, fatigue

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22
Q

Describe the histologic change from bronchi to bronchioles

A

At terminal bronchioles airway epithelium changes from pseudostratified ciliated columnar to ciliated simple cuboidal

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23
Q

Differentiate the location of the

(a) Cilia
(b) Goblet and mucous glands
(c) Cartilage

A

(b,c) Submucosal mucus and serous glands travel within cartilage, all of which terminate at the smallest bronchi => no goblet cells, glands, or cartilage in the bronchioles

(a) While cilia go down into bronchioles, terminate so not in alveolar ducts or alveoli
- presence of cilia beyond most distal mucus-producing cells prevents bronchiolar mucus accumulation and airflow obstruction

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24
Q

45 yo construction worker p/w fatigue, constipation x4 mo
-microcytic anemia w/ normal ferritin and serum iron

(a) Dx
(b) Peripheral blood smear finding

A

(a) Lead poisoning, Pb inhibits ALA dehydratase and ferrochelatase in heme synthesis pathway causing microcytic, hypochromic anemia
(b) Basophilic stiplling on peripheral blood smear

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25
Q

52 yo alcoholic p/w skin rash worsened by sun exposure, disorientation, and diarrhea

(a) Dx
(b) Cause of symptoms

A

(a) Pellagra (diarrhea, dermatitis, dementia)

(b) Lack of B3 (pellagra) needed for synthesis of NAD+ coenzyme

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26
Q

What can the following precursors be used to produce?

(a) Arginine
(b) Tryptophan
(c) Orotic acid
(d) Phenylalanine

A

(a) Arginine –> NO, urea, creatinine
(b) Tryptophan can endogenously synthesis niacin (B3) required for NAD synthesis
(c) Orotic acid –> pyrimidine
(d) Phenylalanine is the precursor to tyrsoine = AA necessary for catecholamine formation

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27
Q

Speculum in ear causes sudden lightheadedness and fainting- which nerve is involved?

A

Vasovagal syncope 2/2 manipulation of vagus nerve- parasympathetic outflow via vagus => decreased HR and BP

Vagus innervates small posterior part of the external auditory canal

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28
Q

Why does verapamil not work on skeletal muscle?

A

Verapamil (nondihydropyridine) blocks L-type calcium channels b/c cardiac and smooth muscle cells depend of influx of extracellular calcium to cause contraction

While skeletal muscles get their Ca from the SR => don’t depend on extracellular Ca influx => aren’t inhibited by Verapamil

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29
Q

2 parts of the nephron that are particularly susceptible to hypoxia

A

Proximal tubule and thick ascending limb of loop

B/c they’re using ATP to transport O2 => have high O2 demand

So in ATN (usually caused by decreased renal perfusion) the straight proximal tubules and thick ascending limb are the most commonly affected portions of the nephron

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30
Q

Heterophile antibodies used for what?

A

Dx of EBV/mono, detect heterophile IgM Abs that react w/ antigens on the horse erythrocytes

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31
Q

Mechanism of local tissue necrosis 2/2 NE infusion extravasation

(a) How to prevent this

A

Potent alpha1 mediated vasoconstriction

(a) Prevent by giving phentolamine = alpha receptor blocker

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32
Q

Differentiate a pericardial knock from an S3 heart sound

A

Pericardial knock 2/2 constrictive pericarditis is sharper and earlier in diastole

S3 due to sudden deceleration of incoming blood as ventricle reaches its elastic limit is later in diastole and not as severe

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33
Q

Explain Kussmaul’s sign in constrictive pericarditis

A

Kussmaul’s sign = paradoxical rise in JVP w/ inspiration

Occurs in constrictive pericarditis b/c the restricted RV can’t accommodate the inspiratory increase in venous return

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34
Q

Name the protein that damages the bronchial epithelium in atopic asthma?

(a) Name another fxn of this protein

A

Major basic protein is thought to be responsible for bronchial epithelium damage in atopic asthma

(a) Secreted by eosinophils to kill helminths

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35
Q

Hct 43%
Prolonged bleeding time and PTT
Normal PT, thromin time, and D-dimer

Dx

A

Dx = von Willebrand disease

Prolonged bleeding time (impaired plt fxn) and impaired extrinsic pathway (factors VIII, IX, XI, XII) b/c vWF needed for plt adhesion and as carrier protein for factor VIII

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36
Q

14 yo boy p/w delayed puberty and inability to distinguish smells despite good visual acuity

(a) Location of defect

A

Precocious puberty and anosmia = Kallman syndrome from failure of GnRH secreting neurons to migrate from origin in the olfactory placode

(a) Central hypogonadism (reduced hypothalamic GnRH secretion)

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37
Q

Gram positive rod w/ tumbling motility

(a) Abx of choice

A

Listeria monocytogenes- distinctive flagellar-based tumbling motility

(a) Abx of choice for listeria monocytogenes = Ampicillin

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38
Q

MC cause benign

(a) bloody nipple discharge
(b) Green-brown nipple discharge

A

(a) Intraductal papilloma- papillary cells w/ fibrovascular core
- has both layers as opposed to intraductal carcinoma which is lacking myofibroblast layer

(b) Green-brown discharge = mammary duct ectasia

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39
Q

Differentiate the roles of the three key hormones in male sexual tract embryologic development

A

Anti-mullerian hormone/mullerian inhibiting factor from embryonic testes (from sertoli cells)- causes regression of paramesonephric (mullerian) ducts that would otherwise give rise to internal female genitalia

Testosterone (from Leydig cells) mediates development of male internal genitalia
-epidiymis and vas deferens

DHT mediates development of male external genitalia
-penis and prostate

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40
Q

What nerve innervates the muscles of mastication

(a) Exits the skull thru which structure

A

V3 = mandibular division of the trigeminal nerve

(a) Exits thru foramen ovale

V1,2,3 (‘standing room only’): superior orbital fissure, rotundum, ovale

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41
Q

Which ions form the resting membrane potential of an isolated muscle cell?

A

Resting membrane determined by ions that are most permeable to the cell membrane => high K efflux and some Na influx cause the resting potential of about -70 mV

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42
Q

Which diuretic has a beneficial effect on calcium homeostasis in an osteoporotic F

A

HCTZ/thiazide diuretics
-enhance Ca reabsorption in the distal tubule
While loop diuretics actually increase urinary calcium loss

Hence why thiazides are a good agent for tx HTN in pts at risk for osteoporosis

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43
Q

3 causes of myopathy w/ elevated CK

A
  1. Autoimmune inflammatory conditions: polymyositis, dermatomyositis
  2. Statin-induced
  3. Hypothyroidism

While glucocorticoid-induced and polymyalgia rheumatic myopathy would have normal CK

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44
Q

Main distinction btwn bulimia and bing eating/purging subtype of anorexia nervosa

A

Pts w/ bulimia maintain body weight at or above normal level => don’t experience signs of malnutrition or starvation

While if BMI is under 18.5 = anorexia

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45
Q

What lab value needs to be checked before starting pt on statin

A

LFTs

-common side effects of statins are muscle and liver toxicity

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46
Q

Which bacteria are visualized by the following

(a) Bordet-Genogou
(b) VCN medium

A

(a) Bordet-Genogou medium to visualize Bordetella pertussis (whooping cough)

(b) VCN medium: Neisseria
= chocolate agar supplemented w/ Vanc, Colistin (polymyxin), and nystatin to restrct growth of other Gram pos, gram neg, and yeast

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47
Q

Bacteria visualized by

(a) Blood agar containing bile and hypertonic saline
(b) Cysteine-tellurite agar

A

(a) Blood agar containing bile and hypertonic saline grows enterococci to differentiate E. faecalis and E. faecium (growth in bile salts and 6.5% hypertonic saline) from Strep bovis and strep equinis
(b) Cysteine-tellurite agar cultures C. diptheriae

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48
Q

Clinical features of classic dengue fever

A

Flu-like febrile illness w/ marked myalgias and joint pains

  • retro-orbital pain**
  • rash

Can also be hemorrhagic where get thrombocytopenia, petechiae

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49
Q

Explain what happens in the brain after neuron degeneration

A

Gliosis!

Proliferation of astrocytes in the area of the degeneration = gliosis. Forms glial scar that compensates for the volume loss

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50
Q

Location of PBC vs. PSC

(a) Demographic

A

PBC- only intrahepatic interlobular ducts- gramulomatous inflammation
(a) Middle-aged F w/ insidious onset of pruritis and fatigue

PSC- intra and extrahepatic ducts w/ periductal concentric (onion skinning) fibrosis
(b) 40 yo M w/ long h/o ulcerative colitis

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51
Q

SLE Ab w/ protein complexed w/ small nuclear ribonucleic acid- fxn of this complex?

A

Protein w/ snRNA = snRNP, snRNPs are used at the spliceasome to remove introns during intra-nuclear mRNA processing

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52
Q

2 protein mutation associated w/ early-onset familial Alzheimer’s

A

Presenillin and amyloid precursor protein- both of which play a role in production of amyloid beta (deposited in Alzheimers)

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53
Q

Differentiate HSL and LPL

(a) Which is activated during starvation?

A

Hormone sensitive lipase is in adipose tissue to break down TG –> glycerol and FFA

While LPL is on endothelium of BV work on chylomicrons and VLDL in the blood stream

(a) So its HSL in adipose tissue that is activated by stress hormone and starvation to break down TG stored in adipose (not LPL)

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54
Q

Kartagener’s

(a) Associated CXR finding
(b) Explain female infertility

A

Kartagener’s = primary ciliary defect 2/2 defect in dynein arm

(a) Dextrocardia (heart on the right side)
(b) Male sperm can’t swim, females have immotility of fallopian tube cells

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55
Q

Differentiate conduct d/o and ODD

A

Conduct d/o more severe. ODD is just defiant w/o the physical aggression, stealing, or destruction of property

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56
Q

MC antibody cause of ITP

A

Immune thryombocytopenic purpura: IgG antibody against GPIIbIIIa platelet surface protein

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57
Q

Lab test to confirm menopause

A

Elevated FSH confirms menopause

B/c Ovarian follicles are burnt out = no estrogen to negate feedback on GnRH

58
Q

Mechanism by which Strep Viridans adheres to surfaces

A

Strep viridans (gram positive cocci) adheres to both tooth enamel and fibrin-platelet aggregations on damaged heart valves by synthesizing dextrans from sucrose

So infective endocarditis w/ a species that synthesizes dextrans from sucrose = S. Viridans (includes S. mutans and S. sanguinis)

59
Q

Clinical presentation of defect in type I interferons

A

Type I interfrons = alpha and beta secreted by virally infected cells

Defect => increased susceptibility to viral infections

60
Q

Kleinfelter Syndrome

(a) Genetic composition
(b) Clinical features

A

Kleinfelters

(a) 47XXY
(b) Cryptoorchidism (small firm testes b/c reduced T from dysfunctional Leydig cells), long legs, sparse body/facial hair, gynecomastia (reduced T and inhibin from dysfunctional Sertoli and Leydig cells reduces feedback on FSH/LH, so high FSH/LH increases aromatase activity => elevated estrogen => gynecomatsia)

61
Q

Pt w/ Kayer-Fleischer rings also likely to have what CNS finding?

A

Kayer-Fleischer rings due to copper deposition in cornea 2/2 Wilson’s disease. Copper acts as pro-oxidant that induces free radical damage to hepatocytes, then leaks out of hepatocytes and gets deposited in cornea and basal ganglia

Get basal ganglia atrophy

62
Q

Thrombosed external hemorrhoids cause pain by which nerve?

A

Inferior rectal vein, branch of the pudendal

63
Q

2 things transmitted by the Ixodes tick

A
  1. Lyme disease

2. Babesiosis

64
Q

2 diseases that make intra-RBC forms

A
  1. Plasmodium (malaria)- transmitted by misquito

2. Babesia (babesiosis)- transmitted by Ixodes tick

65
Q

Differentiate Janeway lesions and Osler nodes seen as systemic signs of infective endocarditis

A

Janeway lesions = vascular lesions, painless embolic microthrombi on palms of hands or soles of feet

Osler nodes = immunologic (immune complex) painful lesions on fingers or toes

66
Q

Two mechanisms of medication tx for metastatic prostate cancer

A

Prostate cancer is responsive to testosterone => can give Leuprolide (GnRH agonist- inhibits LH/FSH b/c not pulsatile GnRH) or Flutamide

Flutamide = competitive testosterone receptor antagonist = non-steroid anti-androgen

67
Q

Mechanism of acute transplant rejection

A

Acute transplant rejection = host T cells sensitized against graft MHC
-seen weeks after transplant

Different from graft vs. host seen in bone marrow transplant where host has no functional T cells left

68
Q

Prevention of

(a) Acute transplant rejection
(b) Chronic transplant rejection

A

Prevention of

(a) Acute transplant rejection w/ calcineurin inhibitors (cyclophosphamide and tacrolimus)
(b) Chronic transplant rejection- cant prevent :-(

69
Q

One organ that chronic glucocorticoid therapy induces protein synthesis at

A

Chronic glucocorticoids is generally catabolic: reduces protein synthesis at lymphoid tissue (immunosuppression), skeletal muscle (myopathy => weakness), skin (striae, impaired wound healing)

But it increases protein synthesis at the liver => increases gluconeogenesis and glycogenolysis => hyperglycemia

70
Q

Distinguish Bulemia from binge eating d/o

A

Bulemia = binge w/ compensatory behavior (exercise, vomiting)

While Binge eating d/o has no compensatory behavior- just feeling of lack of control w/ binge but w/o compensation of starvation exercise or throwing up

71
Q

2 key features of TCA overdose

A

TCA overdose

  1. Prolonged QRS
  2. Anticholinergic findings: so dry mouth, flushed face etc
72
Q

Afferent limb of reflex arc for

(a) DTRs
(b) Removal from noxious stimuli

A

(a) DTRs: group Ia and group II of intrafusal muscle fibers that respond to change in muscle length

(b) Removal from noxious stimuli mediated by thin myelinated fibers - A-delta fibers that respond to temperature and nociceptive stimuli
ex: remove hand from hot stove

73
Q

Main fxn

(a) Pacinian corpuscle
(b) Ruffini end organs
(c) Meissner’s corpuscles
(d) Merkel’s discs

A

4 types of mechanoreceptors

(a) Pacinian = fast-adapting for vibration
(b) Ruffini end organ = slow adapting for tension
(c) Meissner’s = fast-adpating for light touch and changes in texture
(d) Merkel’s disc = slow adapting to detect sustained pressure

74
Q

Mechanism of death 2/2 cyanide poisoning

A

CN- causes toxicity by inhibiting crucial ETC enzyme cytochrome c oxidase, so w/o ETC cells => lactic acidosis and death from only anaerobic metabolism

75
Q

Clinical presentation of cyanide poisoning

A

Reddish skin discoloration (can’t remove O2 from Hb) b/c ETC enzyme inhibited
Lactic acidosis (b/c no aerobic metabolism occurring)
Narrowed venous-arterial PO2 gradient b/c tissues can’t extract O2

76
Q

Mechanism of inhaled amyl nitrite in tx of cyanide poisoning

A

Amyl nitrate oxides ferrous (Fe2) to ferric (Fe3) oxide
Fe3 = methemoglobin which can’t carry O2 but has super high affinity for CN-, so draws CN- out of mitochondria off cyt c oxidase so aerobic metabolism can continue

77
Q

Cells cultured from kid w/ immunodeficiency shows high rate of radiation-induced genetic mutation

Dx?

A

DNA hypersensitivity to ionizing radiation 2/2 inefficient DNA repair seen in ataxia-telangiectasia (aut recessive)

Ataxia 2/2 cerebellar atrophy
Severe immunodeficiency w/ recurrent sinopulmonary infxns
Oculocutaneous telangiectasias

78
Q

Formula for absolute risk

A

AR = risk in exposed population explained by exposure to the RF

AR = (RR-1) / RR

Where RR = (risk in exposed) / (risk in unexposed)

79
Q

Granulomatosis w/ Polangiitis

(a) LM finding
(b) IF finding
(c) Serum marker

A

Granulomatosis w/ Polyangiitis = Wegener’s

(a) LM: crescentic (it’s a type of rapidly progressive glomerulonephritis)
(b) IF: absent of deposits (pauci-immune)
(c) c-ANCA

80
Q

FFP vs. cyro

A

FFP = all coagulation factors
vs.
Cryoprecipitate- only contains cold-soluble proteins: factor VIII, fibrinogen, vWF, vitronectin

81
Q

3 groups of embryologic veins and what happens to them in the fetus

A

3 groups:

  1. umbilical veins- degenerate
  2. vitelline veins- forms the portal system
  3. cardinal veins- forms the systemic venous circulation
82
Q

Acid fast bacteria that grows optimally at 41 C

A

MAC = mycobacterium avium complex

83
Q

Clinical presentation of fulminant hepatitis 2/2 halothalne

A

Inhaled anesthetics (mainly halothalne) carries risk of lethal fulminant heptatitis

-clinically indistinguishable from acute viral hepatitis (but obv history is dif): see elevated LFTs, prolonged PT (b/c factor VII has the shortest half life of the procoagulant factors)

84
Q

HIV ppx at

(a) CD4 under 200
(b) CD4 under 150
(c) CD4 under 100
(d) CD4 under 50

A

HIV ppx

(a) CD4 under 200: Bactrim for pneumocystis jiroveci
(b) Under 150: Itraconazole for histoplasma capsulatum
(c) Under 100: Bactrum for toxo
(d) Under 50: Azithromycin for MAC

85
Q

76 yo w/ long standing DM p/w severe cataract formation, which is the end product in the lens cell that he is not producing?

A

Glucose –> (aldolase reductase) –> Sorbitol

Then sorbitol –> (sorbitol reductase) –> Fructose, but low sorbitol reductase in retina, renal papillae, and Schwann cells

86
Q

How long after ischemic stroke do you expect

(a) Reactive gliosis
(b) Macrophage infitration
(c) Red neurons
(d) Glial scar formation
(e) Neutrophil infiltration

A

(a) Reactive glisosis seen w/ liquefactive necrosis after 1-2 weeks
(b) Macophages infiltrate in 3-7 days
(c) Red neurons w/in 12-24 hrs
(d) Glial scar forms after 2 weeks, 3-4 weeks usually
(e) Neutrophils infiltrate in 24-72 hrs

87
Q

6 yo boy w/ persistent epistaxis- where to apply silver nitrate cautery?

A

Vast majority of nose bleeds are anerior in the anteroinferior part of nasal septal mucosa known as Kiesselbach’s plexus

Where 3 important (anterior ethymoidal, sphenopalatine, and superior labial) arteries anastomose

88
Q

Target of trastuzumab

A

Trastuzumab = Herceptin = monoclonal Ab against tyrosine kinase receptor overexpressed in 20% of breast cancer pts

-downregulates cell proliferation and promotes apoptosis

89
Q

In addition to water, what does ADH impact renal excretion of?

A

ADH also increases reabsorption of urea

Vasopressin activates urea transporters in the medullary collecting duct to decrease renal urea clearance

90
Q

Gram positive cocci, catalase negative, able to grow in hypertonic (6.5%) saline

(a) And bile
(b) And not bile

A

Gram positive, catalase negative = streptococci
Grown in 6.5% NaCl

(a) And bile = enterococcus
(b) And not in bile = Strep bovis

91
Q

Antipsychotic of choice for treatment-resistant schizophrenia

A

Clozapine!!!

Not clonazepam (benzo) or chlorpromazine (low potency first gen) or aripiprazole (good choice for first try at tx but not for tx refractory)

92
Q

12 yo boy p/w ST seg elevations in inferior leads and increased serum methionine

(a) Dx
(b) Cause of thromboembolic event

A

(a) Homocystineuria, MC 2/2 defect in cystathionine synthase => can’t synthesize cystine from homocystine
(b) Homocystine (prothrombotic substance) builds up, is converted to methionine => elevated serum methionine
- these pts need dietary cysteine

93
Q

Clinical distinction btwn B12 and folate deficiency

A

Folate deficiency- just megaloblastic anemia

While B12 deficiency p/w megaloblastic anemia and neurologic dysfunction

94
Q

Extensive LN dissection during mastectomy increases risk of what skin lesion of the ipsilateral arm?

A

Chronic lymphedema is a RF for cutaneous angiocarcoma

95
Q

42 yo M BIB wife for losing temper, moving extremities w/o control and grimacing involuntary

Neuronal damage in what location?

A

Dx = Huntingtons

Damage to nucleus caudatus (caudate nucleus)- basically striatum = caudate and putamen

96
Q

Mechanism of eosinophil fxn against parasitic infxns

A

When parasite gets into bloodstream it’ll be marked by IgG or IgE, which then bind to Fc region of eosinophil causing release of major basic protein and ROS

So: Antibody-dependent cell-mediated cytotoxicity

97
Q

Clinical features of Fragile X vs. Kleinfelters

A

Fragile X = trinucleotide repeat d/o: ID, macroorchidism, long narrow face w/ prominent facial features (protruding ears, large jaw and forehead)

Kleinfelters = 47XXY: small firm testes, tall from long legs, gynecomastia

98
Q

Amniotic fluid w/ elevated acetylcholinesterase indicates what?

A

ACHE elevation indicates similar finding as elevated AFP = failure of fusion of the edges of the neural plate

Anencephaly if rostral, spina bifida if caudal

AFP and AChE leak from persistent opening btwn neural tube and amniotic cavity

99
Q

35 yo F after trip to Cancun p/w diffuse pruritic rash of oxidase positive G- rod that produces pigmented culture on medium

Dx

A

Pseudomonas: hot tub folliculitis

100
Q

Antiviral for ganciclvoir-resistant CMV that can cause seizures

A

Foscarnet- causes electrolyte abnormalities

-Foscarnet can chelate calcium and cause renal Mg wasting

(Cidofovir is only topical)

101
Q

Trisomy due to defect in fusion of prechordal mesoderm

A 
Patau syndrome (trisomy 13) => midline defects
-holoprosencephaly, cleft lip/palate, omphalocele
102
Q

What are the following openings in?

(a) Superficial inguinal ring
(b) Deep inguinal ring
(c) Which are the testes reduced thru during orchiopexy?

A

(a) Superficial inguinal ring is an opening in the aponeurosis of the external oblique
(b) Deep inguinal ring is an opening in the transversalis fascia
(c) Testes reduced thru the superficial inguinal ring (external oblique aponeurosis) during orchiopexy

103
Q

Mechanism of drugs given to reduce host T cells from sensitizing to graft HLA

A

Calcineurin inhibitors (cyclosporine and tacrolimus), b/c calcineurin activates NFAT to cause IL2 release to amp up T-cell response

104
Q

S3 vs S4

(a) Timing
(b) Cause

A

S3

(a) Heart just after S2, early diastolic sound
(b) High volume

S4

(a) Just before S1, end diastole
- heard immediately after atrial contraction (b/c volume being forced into ventricles)
(b) High LV wall tension

105
Q

S3 vs S4

(a) In who may be physiologic
(b) Cause

A

S3

(a) Physiologic in high volume states; children/young adults and pregnancy
(b) turbulent flow due to high volume

S4

(a) May be physiologic in older adults
(b) Blood forced into still ventricle

106
Q

What type of channel is CFTR

A

ATP-gated Cl- channel

107
Q

First line tx for RLS

A
  1. DA agonist (Ropinorole, Pramepexole): dysfunction of dopaminergic pathway
    - SSRI would make it worse!!!!
  2. Fe supplementation (associated w/ Fe deficiency)
108
Q

Explain the concept of heteroplasmy

A

Heteroplasmy = coexistence of distinct versions of mitochondrial genomes in an individual cell, causing variable clinical expressions

Basically different offspring cells have different ratio of normal to mutant mitochondria

109
Q

26 yo F w/ inherited d/o, h/o GTCs
-partial vision loss 2/2 occipital infarction
-mother w/ intermittent muscle weakness and lactic acidosis
-maternal uncle hemiplegia
skeletal muscle bx: ragged-appearing muscle fibers

(a) Dx
(b) Mode of inheritance

A

(a) Mitochondrial encephalomyophaty
(b) Mitochondrial d/o- maternal inheritance pattern b/c embryo’s mitochondria are all inherited from ovum

-variable phenotypic expression b/c of heteroplasmy = different number of mutant mitochondria in each cell

110
Q

Pts w/ aldolase B deficiency- can they handle breast milk?

A

Aldolase B needed to breakdown fructose (and therefore sucrose)

Breast milk contains lactose (glucose and galactose) and maltose (2 glucoses) so no problem for fetuses until they’re switched off just breast milk

111
Q

ATN recovery phase

(a) How long after inciting event
(b) Serious complication

A

ATN recovery phase = high volume diuresis b/c tubules (aka reabsorption of water) still recovering

(a) Starts about 1-2 weeks after inciting injury
(b) Serious complication = hypokalemia, low Mg

112
Q

Cause of sepsis in neisseria meningitis

(a) Location

A

LOS = lipooligosaccharide
-similar to LPS of enteric gram negative rods

(a) Outer membrane
Works as endotoxin

113
Q

How to reduce vertical transmission of GBS

A

Penicillin or Ampicillin intrapartum!!! (at the time of delivery) or shortly before (like week 38)

Giving penicilin at week 30 isn’t enough!! only lasts about 4 weeks then mother can just recolonize

114
Q

Volume of the following based on drug clearance

(a) Half life
(b) Maintenance dose

A

(a) t1/2 = (Vd x 0.7) / CL
Vd = volume of distribution
CL = clearance

(b) Maintenance dose = (Cpss x Cl) / (bioavailability fraction)
Cpss = plasma steady state concentration
BA fraction = 1 when administered IV

Ex: if want plasma concentration at 4 mg/L, drug dosed q6h and has Vd of 70L, clearance of .5L/min
Maintenance dose = (4mg/L) x (.5L/min) = 2mg/min for 360 min (6hrs) = 720 maintenance dose

115
Q

How many half lives until drug reaches steady state

A

4-5 half lives until steady stage (or elimination) is achieved

116
Q

Distinguish volume to calculate loading dose and maintenance dose of a medication

(a) How to account for renal or hepatic impairment

A

Maintenance dose = (Cpss x Cl) / (bioavailability fraction)
Cpss = plasma steady state concentration
BA fraction = 1 when administered IV

Loading dose = (Vd x Cpss) / (bioavailability fraction)
Vd = volume of distribution

(a) Loading dose RTS, but reduce maintenance dose

117
Q

Mechanism by which TG over 1,000 can cause acute pancreatitis

A

Direct tissue toxicity! FFA concentration exceeds the binding capacity of albumin in serum => directly injures the pancreatic acinar cells

So remember hypertriglycerides and acute pancreatitis

118
Q

Bethanechol vs. Oxybutynin

A

Bethanechol = muscarinic agonist, improves bladder emptying in pts w/ post-surgery urinary retention

Oxybutynin = antimuscarinic that would worsen post-op retention, used for urge incontinence

119
Q

First line drug for post-op urinary retention

A

Bethanechol = muscarinic agonist b/c muscarinic cholinergic activity stimulates detrusor muscle contraction

Goal of post-void residual volume under 50cc

120
Q

Explain mechanism by which annual flu vaccine prevents symptoms

A

Prevents live virus from entering via endocytosis

  • doesn’t cause CD8 immune response, that would only be from a live attenuated vaccine
  • inactivated (killed) vaccine causes neutralizing Abs against hemaglutinin antigen of the selected influenza strains, then Ab inhibits binding of HA to siaclylated receptors on the host membrane to prevent live virus entry
121
Q

Endocrine effects of amiodarone

A

Amiodarone (dirty class III antiarrhythmic) is 40% iodine by weight, can cause both hyper and hypothyroidism

Get TFTs before starting a pt on Amiodarine

122
Q

Describe the mechanism of type I vs. type II hypersensitivity rxn

A

Type I = cell surface-bound antibodies bridging by antigen

  • interaction btwn allergen and preexisting IgE on basophils and mast cells
  • so no cytotoxicity, more crosslinking basophils/mast cells which release granules of shit

Type II = Ab-dependent cell mediated cytotoxicity

123
Q

Name the 5 main catalase positive organisms

A

5 main catalase positive organisms (increased risk in CGD pts)

  1. S. aureus
  2. B. cepacia
  3. Serratia
  4. Nocardia
  5. Aspergillus
PLACESS for your cats
Pseudomonas
Listeria
Aspergillus
Candida
E Coli 
S. Aureus
Serratia
124
Q

Best agent solely for raising HDL

A

Niacin (B3)

But still statin better for preventing CV events

125
Q

Adrenergic tone effect on insulin release

A
  • beta2 tone increases insulin release via Gs
  • alpha2 tone inhibits/decreases insulin release via Gi

Sympathetic tone overall usually alpha2 predominates causing overall decrease in insulin release

126
Q

Mnemonic for cyt p450 inducers

A

Chronic alcoholics steal phen-phen and never refuse a greasy carb

  • chronic EtOH
  • St. John’s wart
  • Phenytoin
  • Phenoparbitol
  • Nevirapine (NNRTI)
  • Rifampin
  • Griseofulvin (antifungal for ringworm)
  • Carbamazepine
127
Q

Zumab vs. Ximab

A

Zumab is humanized

While ximab is chimeric monoclonal antibody

128
Q

Composition of final collagen molecule

(a) Mechanism of defect causing Ehler-Danlos

A

Final collagen molecule is 3 alpha helixes held together by H-bonds

(a) Ehler Danlos 2/2 defective N-terminal propeptide removal- deficency in enzyme that cleaves the terminal pro-peptides from procollagen in the extracollagen space
- so collagen production is normal but it doesn’t properly cross-link => joint laxity, hyperextensible skin, tissue fragility

129
Q

Name 2 long acting benzos

A

Diazepam

Chlordiazepoxide

130
Q

Differentiate clinical presentation of intoxication w/ phencyclidine and LSD

A

PCP- buzzword is nystagmus
Also aggression/violence, ataxia, amnesia

LSD- buzzword is visual hallucinations
Also euphoria, panic, tachy/HTN

131
Q

MR vs. MS in ARF

A

ARF: first causes MR- regurg in pts under 40ish

Then later on (like 50s up) causes MS

132
Q

Holosystolic murmur at L mid to lower sternal border

A

VSD

133
Q

Mechanism of IgA protease virulence

(a) Name three species that produce IgA protease

A

IgA protease facilitates mucosal adherence of bacterial, b/c IgA normal functions to bind pili and other bacterial adhesion proteins to prevent colonization

(a) Neisseria, Strep pneumo, H. influenza

134
Q

Why do pregnant women not lactate despite super high prolactin levels?

A

Progesterone (from corpus luteum then placenta) keeps negative feedback on anterior pituitary (inhibits FSH/LH)

So after birth when placenta is loss, inhibitory effect of progesterone is lost => lactation

Not beta-hCG!!! that would drop after corpus luteum degenerated

135
Q

MC organism implicated in perforated appendicitis

A

Bacteroids fragilis = gram negative bacillus that has a unique surface polysaccharide that favors abscess formation

Not S. Aureus which is associated w/ cutaneous (not intra-abdominal) abscess

136
Q

Explain how amphotericin toxicity can cause premature A/V contractions

A

Amphotericin main toxicity = nephrotoxicity from reduced GFR and direct effect on tubules

Renal dysfunction => hypokalemia (less K reabsorption) and anemia (reduced EPO)

Hypokalemia => EKG changes: T wave flattening, ST depressions, prominent U-waves, premature A/V contractions

137
Q

Pneumoconiosis associated w/

(a) Calcification of hilar LN
(b) Pleural plaques
(c) Noncaseating epitheliod granulomas

A

Pneumoconiosis = interstitial lung disease from inhalation of mineral dusts

(a) Calcification of hilar LN = ‘egg shell calcifications’ seen in silicosis
(b) Pleural plaques = asbestosis- lower lung fields involved, see ferruginous (Fe containing) bodies on histology
(c) Beryllium has the noncaseating granulomas confusable w/ sarcoid

138
Q

MC complication of vericose veins

A

Overlying skin changes: ulceration, superficial infections 2/2 poor blood flow

NOT PE- which are from the deep (not superficial) veins of the leg

139
Q

Contrast mechanisms of

(a) Cyclosporin
(b) Sirolimus
(c) Mycophenolate

A

Common immunsuppressants

(a) Cyclosporin (calcineurin inhibitor) inhibits transcription factor needed for IL-2
(b) Sirolimus inhibits mTOR signaling pathway, blocking IL-2 signal transduction
(c) Mycophenolate = inhibits enzyme required for de novo purine synthesis

140
Q

45 yo M w/ cellulitis 2/2 gram-positive cocci in clusters

Mechanism of the virulence factor?

A

Gram positive cocci in clusters causing cellulitis = Staph aureus

Virulence factor = protein A on the S. aureus cell wall which binds Fc portion of IgG at the complement binding site, preventing complement activation

=> decreased C3b production => impaired opsonization and phagocytosis

141
Q

Type of back pain that

(a) Relieved w/ rest
(b) Relieved w/ exercise
(c) Worse at night

A

(a) Degenerative (ex: OA) better w/ rest
(b) Spondyloarthropathy (associated w/ HLA-B27) relieved w/ exercise
(c) Worse at night, not responsive to positional change, doesn’t improve w/ rest = think spinal mets

142
Q

Molecular cause of polycythemia vera

A

JAK2 mutation that renders hematopoietic stem cells more sensitive to growth factors

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