UWorld Sets x4 6.28.23

Question 1

8yr F for eval of skin rash on upper back. Not painful, mildly pruritic. No PMH, update vaccines. Vitals WNL. R scapular area of skin shows patches of tinea corporis. Rest of exam WNL. What is the most likely cause of this pt’s condition?

Answer 1

infection limited to keratinized structures (attacks the strat corneum)» a patient w/ a mildly pruritic, polycyclic rash w/ raised, scaly border w/ central clearing= tinea corporis. typically Trichophyton rubrum, cutaneous fungus, branching septate hyphae. KOH+, blue fungal stain+

**patches of tinea corporis are typically round/ovoid but may become confluent to form “flower petal” shape. generally warm/humid skin contacts is common risk factor.

Question 2

66yr M w/ progressive vision impairment–unable to see road signs at night, excessive glare from oncoming cars. PMH HTN, DM2. Fundoscopy reveals a diminished red reflex b/l w/ obscuration of retinal detail. Pt’s condition is partly due to the intracellular accumulation of sorbitol. In healthy cells, this sugar alcohol is metabolized to what substance?

Answer 2

fructose»

glucose (fast)-> sorbitol-> (slow) fructose
*aldose reductase (w/ NADPH)
**sorbitol dehydrogenase (w/ NAD+)

NOTE: congenital cataracts is the increased about galactitol

risk factors for cataracts: age, smoking, excessive light exposure, DM, glucocorticoids.

Question 3

47yr M ER w/ fever and fatigue. PMH HIV+ inconsistent antiRTs. Exam is notable for hepatosplenomegaly + multiple erythematous papules. Labs show pancytopenia. Histoplasma +. IV amphotericin B tx is initiated for disseminated histoplasmosis. A day later, pt develops palpitations + weakness. ECG reveals frequent premature ventricular beats. If these are new signs of drug toxicity, they are most likely related to?

Answer 3

renal tubular dysfunction» most dangerous adverse effect is nephrotoxicity, w/ dec in GFR and direct toxic effects on tubular epithelium» nephrotoxicity leads to anemia (no EPO), & hypokalemia (leads to arrhythmias). electrolytes due to DCT permeability incr

**hypoK= weakness, arrhythmias= T wave flat, ST DEPRESS, prominent U waves, premature atrial/ventricle contractions.

ampho B is drug of choice for most disseminated fungi; most toxic antifungal med.

Question 4

ampho B doesn’t cause damage to cardiac muscle cell damage. But what meds are associated w/ cardiotoxicity?

Answer 4

doxorubicin & danurubicin are associated w/ irreversible DOSE-dependent cardiotoxicity.

**other meds affect the electrolytes, and then they affect the heart.

Question 5

34yr old electric company worker w/ skin rash on R leg. Not eaten new foods, changed detergent, etc. Pt recalls recently did a repair job in an unmaintained, wooded area. Had atopic dermatitis as child, but no other illnesses. Exam shows lungs clear b/l and his heart sounds normal. Leg shows erythema, excoriation rash, w/ linear vesicles , but overall haphazard fashion. What is the cell responsible for tissue damage?

Answer 5

T lymphocytes» pt has poison ivy (urushiol hapten)= CD8+ primary effector cells, directly destroying keratinocytes expressing the haptenated proteins

contact dermatitis is HSR 4= mediated T cell. occurs in 2 phases:
1) sensitizations: creation of the hapten-specific T cell= 10-14 days> cutaneous dendritic cells expressed on MHC1/2, take to lymph> CD4/CD8+ activation + clonal expansion.
2) elicitation: 2-3days f/u REEXPOSURE, hapten is taken up by skin cells, activation of hapten-sensitized T cells in dermis/epidermis= clinical manifestations of contact derm.

Question 6

what cells are responsible for HSR 1?

Answer 6

mast cells, IgE, basophils/eosinophils (host defense)>

**mast cells play a role in modulating the response of contact dermatitis (HSR4) by affecting antigen presentation, and T cell recruitment & activation.

Question 7

what are the main effector cells for HSR 2?

Answer 7

plasma cells» directly responsible for the synthesis of IGs.

Question 8

what are the main effector cells for HSR 3?

Answer 8

plasma cells (IGs), neutrophils (deposited complexes> complement+>neutrophil-mediated damage)

Question 9

what are the main clinical features of nocardiosis?

Answer 9

bronchopneumonia (similar to TB)
CNS involvement, generally multiloculated brain abscesses> seizures

**differs from Actinomyces in that it’s partially AFP+ & aerobic (vs Actinomyces is anaerobic)

Question 10

24yr F w/ bloody emesis. 2 episodes of vomitting bright red blood & feels lightheaded, dizzy. Pt was recently diagnosis w/ factitious disorder. Exam shows scattered ecchymoses, soft abdomen. Rectal exam shows maroon-colored, guaiac+ stool. She admits to having ingested rat poison several days ago. Immediate tx of this pt should include?

Answer 10

fresh frozen plasma» rat poison contains brodifacoum= superwarfarin> hella depleted her VitK dependent clotting factors> GI bleds, bruises> needs rapid reversal of warfarin effects= FFP (factors 2/7/9/10) + vit K.

Question 11

when does someone need cryoprecipitate?

Answer 11

fibrinogen def, factor 8 dec, vWF def

Question 12

when does someone need protamine sulfate?

Answer 12

heparin overdose

Question 13

when would desmopressin be used?

Answer 13

hemophilia A, vWF» desmopressin encourages the release of vWF/F8 from Weible pallided bodies.

Question 14

what is given in the immediate for warfarin overdose?

Answer 14

fresh frozen plasma + Vit K

**vit K can be given alone if the person just has prolonged bleeding times (abnormal coagulation), w/o evidence of bleeding. effect takes days, so not usually given alone for someone w/ acute bleeding risk management

Question 15

68yr F w/ worsening fatigue, SOBm dry cough for 1mon. Worsened w/ lying flat + exertion. No angina, palpitations, lightheadness. PMH HTN, breast caner in remission w/ doxorubicin-tx 15yrs ago. BP 110/62, pulse 94. Exam shows crackles, b/l pedal edema. What does her RA pressure and LV end-diastolic pressure look like?

Answer 15

RA pressure increased (evidence of advanced heart failure)
LV EDP increased» dilated cardiomyopathy, now pt in acute decompensated heart failure (via doxrubicin tx damage).
**problem started w/ direct damage to RV in dilated cardiomyopathy.

increased LV volume is initially compensated via Frank-Starling, then eccentric hypertrophy to maintain CO> overwhelming stress=impaired myocardial contractile fxn> reduced CO> sympt decomp heart failure.

Question 16

what are the signs of increased pulmonary capillary wedge pressure?

Answer 16

PCWP= LA pressure
pulmonary edema
orthopnea
cough
paroxysmal nocturnal dyspnea

Question 17

what are the signs of increased central venous pressure?

Answer 17

CVP= RA pressure
JVD
hepatomegaly
lower extremity edema

Question 18

an increased RA pressure w/ a normal LV end diastolic pressure suggests?

Answer 18

R heart failure, in the absence of L heart failure» look for someone w/ pulmonary HTN, or hypoxic lung disease (interstitial lung disease).

RV output is impaired, causing reduced BF thru lungs to LA.

Question 19

Pt is started on oseltamivir for her influenza+ test. What is most likely impaired in this pt’s infected cells?

Answer 19

virion particle release» it is neuraminidase inhibitor, known as “tamiflu”

Question 20

what inhibits the viral/foreign protein synthesis?

Answer 20

alpha/beta interferons» they induce synthesis of proteins that have antiviral effects> promote degrade of RNA= no viral protein translation

Question 21

31yr previously healthy man comes in w/ myalgias, anorexia, and skin rash. He’s been eating large amt of raw eggs for several months» exam shows macular dermatitis of extremities. A water-soluble vit def is suspected. What biochemical conversion is most likely uses the def vit as a cofactor?

Answer 21

pyruvate to oxaloacetate» pt is def in VitB7 (biotin), which is needed for pyruvate carboxylase.
Biotin is a CO2 carrier.

Note: for acteyl-CoA carboxylase (Acetyl CoA to malonyl-CoA= FA synthesis)
& propionyl-CoA carboxylase (propionyl CoA to methylmalonyl-CoA= FA oxidation)
**biotin individuals can also dev met acidosis w/ increased conversion of pyruvate to lactic acid (w/ this def enzyme fxn)

Question 22

35yr F w/ fever, headache, severe muscle aches, sore throat for last 4 days. Pharyngeal erythema + nasal congestion on exam. Influenza+ test. Pt improves over next few days w/ only sympt tx. In response to influenza virus, infected resp epithelial cells begin secreting increased interferons. The specific interferons secreted by these cells will most likely cause what?

Answer 22

decreased protein synthesis by infected cells (alpha/beta interferon)

**antiviral enzymes from interferons only becomes active in presence of dsRNA, which forms as result of viral replication= allowing it to only selectively inhibit viral infected cells.

INFg= Type II interferon that improves intracellular killing ability of macrophages.

Question 23

23yr M w/ painful, growing lesion on chest from a laceration that happened 6 months ago. A pink, firm plaque on exam, diagnosed as keloid. What is responsible for pt’s lesion

Answer 23

overexpression of TGFB> proliferation of fibroblasts> excessive collagen production

overexpression of IGF1, PDGF1 would also contribute to keloid formation.

Question 24

12yr M eval for excessive bleeding from tooth extraction. Pt also develops large bruises after minor injuries, no mjr bleeding in past. Maternal uncle died from intracranial hemorrhage. Labs show dec F8. Referral is made to geneticist– suspects a deletion mutation in enhancer sequence of F8 gene. Mutation resulted in dec TF of F8 by RNA polymerase 2. What is accurate regarding pt’s abnormal genetic sequence?

Answer 24

mutation (in enhancer) can be located upstream/downstream/or within introns of the gene» bind activator proteins that facilitate bending of DNA= interact w/ general TF and RNA poly2, to increase rate of transcription

**silencers work the opposite way, to decrease rate transcription, but bind repressor proteins

**promoter sequences directly bind to general TF and RNA poly2> necessary for initiation of transcription

Question 25

1wk bot for 1st PCP visit since del at 40wks. Exam shows grade II/VI harsh, holosystolic murmur best heard at L mid to L lower sternal border. Records show no indication of murmur at birth. This patient’s findings are most likely due to what embryological event?

Answer 25

insufficient develop of interventricular septum» pt has VSD

**harsh, holosystolic murmur characteristic for VSD, and generally not audible immediately after birth due to high pulm vascular resistance: limits L>R shunting thru VSD. as PVR declines over next few days, murmur becomes audible, and eventually undergo spontaneous closure.

vs. moderate/large VSD lead to pulm overcirculation, L overload> L heart failure, diaphoresis, failure to thrive. generally unrestricted flow= soft, no murmur; eventual shunt reversal w/ pulm HTN= cyanosis

Question 26

what is the patent ductus arterious murmur?

Answer 26

failed obliteration of vascular connection btw pulm artery/aorta> L>R shunt= GAINS murmur intensity as PVR declines.

continuous machine like murmur best heard at L upper sternal border.

Question 27

what is the atrial septal defect murmur?

Answer 27

failed fusion of septum primum & endocardial cushions (or arrested growth of septum secundum)> L>R shunting» systolic ejection murmur over 2nd intercostal space (PULM valve) caused by R volume overload and increased flow over pulm valve.

Question 28

what is the murmur heard in TofF?

Answer 28

malialignment of infundibular septum> various degrees of RVOT obstruction» generally have large VSD, and murmur created by flow thru partially obstructed RVOT:

cresendo-decresendo murmur at L mid to upper sternal border.
(vs aortic stenosis: C-D murmur at R upper sternal border)

Question 29

45yr M w/ chronic insomnia. Trouble sleeping at night since he must remain alert to protect himself from workers at a nearby chemical plant. They are constantly trying to poison him w/ toxic waste. Pt’s wife says this has been going on 10yrs, and the numerous soil toxicity tests have all been negative. Pt has been working as a taxi driver for the same company for over 20yrs. No PMH of psych tx or disorders. What is the most likely diagnosis?

Answer 29

delusional disorder» more than 1+ delusion for 1+ months, w/ other psychotic symptoms absent (or not prominent). Pt’s ability to fxn apart from delusion is intact.

tx: antipsychotics, CBT.

**not a personality disorder since this isn’t a persistent pattern of behavior, and didn’t arise in early adulthood. also not pervasive across all situations. and personality disorders generally don’t have specific delusions.

Question 30

what cytokine is most likely for a pt’s clinical regression of inflammation?

Answer 30

IL-10, TGFB» via T reg cells

Question 31

7yr boy w/ eval of neck mass. 1wk ago pt was taken to urgent care for nasal congestion/sore throat. Parent’s noticed persistent neck swelling. The patient has no prior PMH, vaccines WNL. Neck exam shows mildly tender, 2cm, ant midline mass moves upward when pt swallows. Most likely cause of patient’s lesion?

Answer 31

incomplete obliteration of duct (thyroglossal duct cyst)»

**lateral neck mass= abnormal migration of neural crest cells> paraganglioma, arising from carotid body
**L side deep to SCM mass= cervical implantation of thymic tissue> cystic neck mass
**lateral, ant to SCM= branchial cleft structures> branchial cleft cysts= DOES NOT move w/ swallow

Question 32

56yr M w/ chronic fatigue, cough. Heavy smoker. Cyanosis & expiratory wheezes scattered thru lungs. Eval for long term O2 tx, RR dec shortly after begins nasal O2. Pt’s reduced RR is most likely caused by sudden dec in stimulation of what sensory receptors?

Answer 32

carotid body»peripheral chemo senses PaO2 (hypoxemia)= carotid (glossphary)/aortic body (vagus)

central chemo @ medulla responsible for CO2 (hypercapnia)» O2-induced hypercapnia can occur in COPD pts, but it’s effect is minor contribution.

Question 33

32yr M eval for 2wks fever, malaise, arthralgia. 100.8, pulse 102. Exam reveals several enlarged cervical, axillary, inguinal lymph nodes + diffuse maculopapular skin rash. Inc ALTs. Pt’s serum is added to a mixture of cardiolipin, cholesterol, lecithin, leading to extensive clumping and flocculation. Eval for antibodies directed against what is the best next step in mangement?

Answer 33

treponema pallidum» “RPR: rapid plasma reagin” or “VDRL: Venereal disease research laboratory” use the CCLantigen= lower sensitivity

FTA-ABS, TP-EIA detect antibodies to treponemal antigens= greater sensitivity

pt has 2 syphilis: fever, arthralgias, diffuse lymphadenopathy, elevated ALTs, widespread rash.

note: the anticardiolipin antibodies make the VDRL nonspecific> as other diseases (yaws, pinta, bejel, TB, SLE) make it> giving FP results

Question 34

what serologic testing can aid in the diagnosis of Lyme Disease?

Answer 34

IgM/IgG against Borrelia burgdorferi

Question 35

what serologic testing can aid in the diagnosis of RA?

Answer 35

rheumatoid factor (antibody) targeting Fc portion of IgG» but is seen in RA and other autoimmune diseases

Question 36

what antibodies are most predominant in primary biliary cholangitis/

Answer 36

anti-mitochondrial antibodies

fatigue, pruritis, hepatomegaly, elevated ALK PHOS

Question 37

44yr M f/u on DM2. Dx 4yrs ago and since been taking metformin. 6 months ago, new antiDM med was added b/c of suboptimal control. Today, pt lost weight, has occasional symptoms of n/v, prolonged fullness. Vitals WNL. HA1c 7.2%. Normal renal fxn, normal cardio, lung, sensory exam. If this patient’s weight loss is solely med related, what is the most likely agent?

Answer 37

glucagon-like-peptide 1 agonist (exexatide, liraglutide)» slow gastric emptying, suppress glucagon, incr glucose-dependent insulin release= low risk for hypoglycemia.

**DPP4 inhibitors affect this pathway as well, but act indirectly on GLP1 receptors, so their effects on weight loss are less pronounced» considered weight neutral.
**SGLT2 inhibitor would also cause weight loss, but would have glucosuria (inc UTI), and no effect on GI related symtptms.

Question 38

50yr M for routine f/u. Heavy smoker, occasional alcohol. Diet is fried foods, red meat several times/week. Not very active. FMhx HTN mom, bladder cancer dad. 160/90. Labs show glucose 155mg/dL. What intervention is likely to have the greatest effect on reducing pt’s mortality risk?

Answer 38

smoking cessation»
has substantially increased risk for microvascular (retinopathy, nephropathy) complications in DM. smoking not only worsens complications of diabetes, but also increases the likelihood of developing diabetes.
**focus on prevention, early cessation.

risk factors reducing mortality: smoking cessation» aspirin» lipid reduction/BP control/lifestyle modifactions

**smoking is the #1 most effective, most preventable intervention for all patients, but esp for diabetics.

Question 39

78yr M eval for headaches relieved by OTC acetaminophen. No meds, nonsmoker. BP 180/70. Prior visit, BP 175/68. Exam shows S4, but otherwise unremarkable. CT scan of head reveal no abnormalities. What age-related changes best explains the pt’s BP?

Answer 39

increased arterial collagen deposition»

pattern of elevated systolic, w/ low diastolic= elevated pulse pressure» isolated systolic HTN, commonly seen in elderly pt (>65yr), 60-80% cases.
aging is associated with inc aortic stiffness caused by endothelial dysfxn & change in extracellular matric composition (replacement of elastin w/ collagen)» dec aortic compliance(slight dec DBP)= inc pulse pressure (directly related to SV, inverse of aortic compliance). increased load on LV, seen as inc SBP.

Question 40

what happens to pt’s SBP, DBP, pulse pressure in renal arterial resistance?

Answer 40

renal artery atherosclerosis= inc renal arterial resistance (can happen w/ aging)> RAAS+ (Na retention, arteriolar vasoconstriction)> increased DBP, incre SBP, no pulse pressure change.

Question 41

58yr M eval for skin lesions on forehead. Noticed lesions when rubbing forehead b/c of roughness. PMH HTN w/ chlorthalidone. Farmer for 30yrs. Exam shows scaly, erythematous papules w/ sandpaper texture on forehead. What is the most likely diagnosis?

Answer 41

actinic keratosis» precursor lesion for squamous cell carcinoma, but less than 1% develop malignancy.
AK common in face, ears, scalp, and dorsa arms/hands; “sun exposed”

notable for being for “felt than seen”, usually not more than 10mm, hyperkeratosis in lesions may become prominent and form “cutaneous horns”.

Question 42

what is pityriasis rosea?

Answer 42

solitary pink/brown scaly plaque w/ central clearing on trunk, neck, extremities= “herald patch”. then develops into ovoid maculopapular rash w/ lesions oriented in oblique direction along skin tension lines on back= “Christmas tree” pattern

Question 43

56yr M in ED w/ persistent L wrist pain. Fell forward onto ground and landed on outstretched hand. Exam shows mild, L wrist swelling w/ preserved ROM. Point tenderness over dorsolateral aspect of wrist btw tendons of extensor pollicis longus, extensor pollicis brevis. XRay as shown. This patient is at greatest risk for developing what complication?

Answer 43

avascular necrosis (of scaphoid)»
persistent wrist pain and tenderness localized to anatomical snuffbox w/ main blood supply as dorsal scaphoid branch of radial artery.

Question 44

how would a fall on outstretched hand give carpal tunnel syndrome?

Answer 44

palmer dislocation of lunate into carpal tunnel space» though median n, nontraumatic compression at wrist is most common.

Question 45

how would a fall onto an outstretched hand lead to guyon canal syndrome?

Answer 45

fracture of hook of hamate> compression of ulnar n w/in guyon canal.

Question 46

what is the best management of a suspicious scaphoid fracture, but x-rays don’t show it?

Answer 46

treat scaphoid fracture appropriately» they are known to be missed on xray, and avascular necrosis w/ nonunion is a common complication.

**MRI or ultrasound are commonly used to better diagnosis a scaphoid fracture.

Question 47

23yr F in ED w/ chest wound. She was in her house when large tree branch fell thru window during thunderstorm. Window shattered glass fragments and struck the pt. She did not LOC, but family found her bleeding profusely. BP 80/50, pulse 130. Pt appears in severe distress. Exam shows deep penetrating wound in 4th intercoastal space along L sternal border. What structure is most likely injured in patient?

Answer 47

RV»
composes the mjr of anterior heart surface, and at risk of injury w/ penetrating trauma at mid/lower L sternal border. the parietal pleura would be injured too, but the L lung would remain intact since no middle lobe exists on L w/ heart.

L sternal border injury at 4th intercostal space: skin> pect mjr> external intercostal membrane> internal intercostal m>internal thoracic artery/vein> transversus thoracis m> parietal pleura> pericardium> RV myocardium.

Question 48

an injury at what level would impact the IVC?

Answer 48

penetrating wound to back immediately R of T8= IVC

remember that it passes thru central tendon of dia at T8.

Question 49

an injury at what level would impact the LV?

Answer 49

stab wound angled medially in 4th intercostal space at MID CLAVICULAR line would capture both LV (but would also have to go thru L lung= collapse).

LV is the L lateral heart.

Question 50

an injury at what level would impact the pulmonary trunk?

Answer 50

penetrating injury to 2nd intercostal space at L sternal border.

Question 51

an injury at what level would impact the LA?

Answer 51

LA makes up most of the posterior heart surface» it would not be likely to be injured from any direction. BUT it is the most readily viewed on the transesophageal echo (TEE).

Question 52

72yr W w/ persistent headaches, fatigue, muscle pain. PMH HTN, OA. Her father had subarachnoid hemorrhage from ruptured berry aneurysm. She is treated w/ prednisone, leading to marked and rapid improvement of symptoms. What pathologic process is most likely responsible for pt’s condition?

Answer 52

granulomatous inflammation of media» mediated by T cells.
histology: focal granulomatous inflammation in media w/ intimal thickening, elastic lamina fragmentation, and giant cell formation.

elderly F w/ headaches (temporal headache), muscular pains, rapid response to steroids= giant cell arteritis, which also commonly presents w/ polymyalgia rheumatica, achy shoulder/hip pain.
**if this was in a younger pt= Takayasu arteritis, at aortic arch

Question 53

what is the vascular histology for diabetes?

Answer 53

hyaline arteriolosclerosis= homogenous hyaline material in intima & media of small arteries/arterioles.
(same as advanced age)

Question 54

what is the vascular histology for advanced age?

Answer 54

hyaline arteriolosclerosis= homogenous hyaline material in intima & media of small arteries/arterioles.
(same as diabetes)

Question 55

what is the vascular histology for HTN?

Answer 55

hyaline arteriolosclerosis= homogenous hyaline material in intima & media of small arteries/arterioles.
(same as advanced age, diabetes)

Question 56

what is the vascular histology for severe HTN?

Answer 56

hyaline arteriolosclerosis= homogenous hyaline material in intima & media of small arteries/arterioles.

& hyperplastic arteriolosclerosis= onion-like concentric thickening of arteriole walls.

Question 57

what is the common presentation for polyarteritis nodosa? what is the vascular histology?

Answer 57

present: young adult w/ intermittent episodes of abd pain, peripheral neuropathy, renal insufficiency, severe HTN.

histology: transmural inflammation of arterial wall w/ fibrinoid necrosis

Question 58

64yr M eval for nagging R shoulder pain radiating to i/l arm. Weakness in RU arm. Started 2 months ago, progressively worsened. Heavy smoker. Pt is awake, alert, follows commands. Partial R sided ptosis w/ fully intact extraocular movements. Pupils are asymmetic, but both reactive to light. Dec R UE strength, absent DTR. Pt’s autonomic dysfunction is most likely due to an injury where?

Answer 58

autonomic ganglia» pt has Horner’s syndrome from a Pancoast lung tumor (superior sulcus= groove of the subclavian artery).

Question 59

78yr M f/u of chronic medical problems. PMH HTN CAD DM2, takes meds. Follows diet/exercise. He hesitates, laughs nervously, but adds “I can’t get an erection anymore, and my wife says I have to ask you about getting the blue pill”. What is the most appropriate response?

Answer 59

“This is a very common problem for men as they age. It is good that you mentioned it”» primary concern w/ this pt is making them feel comfortable talking about it (via reassurance), and denoting that it’s an appropriate subject for discussion.

**NOT “I can see that you feel uncomfortable talking about this. It can be a sensitive subject for some men.”

Question 60

67yr M w/ sudden-onset AMS. Pt was working alongside 17yr old grandson on hot summer day. Exam shows 105.8F, BP 90/60, pulse 120, RR 24; warm, dry skin. Pt is not oriented at all. DTR, muscle tone normal. What most likely explains why pt developed symptoms while his grandson remained asymptomatic?

Answer 60

dec effective epidermal area available for heat transfer= loss of rete pegs & dermal capillaries» pt has heat shock (hyperthermia + CNS dysfxn: encephalopathy)

elderly at higher risk w/:
1. tonic contraction of peripheral vasculature (limits heat transfer)
2. reduced sweat gland density (limits ability to dissipate heat)
3. reduced effective epidermal area for heat transfer w/ loss of rete pegs/dermal capillaries
4. MEDS: beta blockers (limited CO), anticholinergics, diuretics, alcohol

**note: normal response w/ vasoconstriction of splanchnic vasculature (BF to skin), peripheral vasodilate for heat dissipation.

Question 61

68yr M w/ Parkinson is hospitalized for pneumonia + sepsis. Tx w/ IV fluids + antibiotics. Also started on IV dopamine for hemo support. Although manifestations of Parkinson disease are attributed to dopaminergic neuron degeneration in SN, IV dopamine doesn’t improve these symptoms. What cell junction structure is responsible for this lack of responsiveness?

Answer 61

tight junctions» at BBB, preventing paracellular passage of fluids/solute. aka zonulae occludentes of transmembrane proteins (claudins/occludins) that associate with actin filaments, forming a ‘beltlike seal’ around the apical intercellular space.

Question 62

A genetic study performed on a 10yr boy reveals a single base substitution mutation involving a DNA segment that encodes a cellular protein. (Patient coding strand shows a T>G mutation that results in a -25bp loss upstream from a +1bp, of a TATAAA sequence in the normal coding strand). This mutation is most likely to affect which of the following processes?

Answer 62

transcription initiation» pt’s mutation happens w/in the TATA box of the normal coding strand, most likely leading to altered gene transcription when RNA poly 2 attached to the altered promoter (TATA) sequence.

**altered heat shock proteins> polypeptide folding
*altered snRNPs> posttranscriptional RNA splicing
*altered enhancer> rate transcription varies

Question 63

54yr M HIV+ diagnosed 5yrs ago. Blood samples for a clinical study perform sequencing analysis of viral genome. Current tests reveal a large # of isolates w/ mutation in the pol gene compared to previous analyses. This finding is most closely related associated with what characteristic of the virus?

Answer 63

HIV RT’s inability to proofread» allowing virus to rapidly accumulate mutations> making it resistant to antiRT monotheraphy.

BUT consistent use of combo antiRT tx contains meds that target multiple steps of viral process> allowing for limited replication, limited newly acquired resistances.

Question 64

what does the pol gene of HIV encode for?

Answer 64

protease, RT, integrase

Question 65

what does the nef gene of HIV encode for?

Answer 65

a protein that downregulates MHC1 proteins>reduced ability of cytotoxic T cells to recognize host cells infected w/ HIV.

Question 66

42yr weightlifter is preparing for upcoming strength competition. After a lifting series of progressively heavier weights, he decides to increase the weight on the exercise bar to 385lbs, the heaviest ever attempt. He is able to hold the weight over his head for several seconds. However, his arms suddenly & involuntarily give way and he drops weight on ground. What structure is most likely responsible for the sudden muscle relaxation?

Answer 66

golgi tendon organ» sensory receptors located at the jxn of the muscle & tendon that are innervated by group 1b sensory axons; connected in series w/ contracting extrafusal skeletal muscle fibers.

the golgi tendon circuit is a neg feedback system that regulates and maintains muscle tension> when too much force is applied, GTOs inhibit contraction of muscle= sudden muscle relaxation, preventing damage to MSK.

Question 67

what is the role of the intrafusal muscle fibers?

Answer 67

connected in parallel w/ extrafusal fibers, intrafusal fibers are sensitive to changes in muscle length> muscle spindles mediate the stretch reflex, tested w/ DTRs.

when stretched, there is a monosynaptic reflex activation of alpha motor neuron (w/in same muscle)= contraction that resists the stretch

Question 68

where are Pacinian corpuscles located, what are they?

Answer 68

RAPIDLY adapting mechanoreceptors in subQ skin, mesentery, peritoneum, joint capsules» touch, proprioception, vibration, innervated by myelinated AB fibers.

Question 69

where are Ruffini’s corpuscles located, what are they?

Answer 69

SLOW adapting mechanorecptors in skin, subQ tissue, joint capsule» touch, proprioception, vibration, innervated by myelinated AB fibers.

Question 70

what are A-delta fibers for?

Answer 70

thin, myelinated nerve fibers whose FREE NERVE endings detect temp + nociceptive stimuli. also associated with acute sharp pain in the afferent reflex arc (retracting hand from hot stove)

Question 71

45yr M w/ R ankle pain for past 2 days. Pt twisted ankle downhill going inward. There’s swelling and pain, but able to walk unassisted. Bluish discoloration over lateral aspect of joint. Maximal tenderness to palpation at the anterolateral aspect of ankle joint. Forced inversion also causes pain. What is the structure most likely injured?

Answer 71

talofibular L, specifically the anterior talofibular L.

Question 72

what ligament is involved w/ a high ankle sprain?

Answer 72

tibiofibular L> dorsiflexion/eversion, w/ unstable ankle joint, but no swelling.

Question 73

27yr F w/ increased paranoid and disorganized behavior over the past year. Pt works as a housekeeper and has had progressive difficulty performing her work responsibilities. Become increasingly secretive over the past 6 months, recently started talking in a whisper b/c she believes that listening deceives are planted in walls. Past month started hiding food and clothes under beds. Vitals WNL, exam normal. With interview, she changes topics frequently, rambles about voices harassing her. Which of the following mental status findings is most likely?

Answer 73

decreased facial expressiveness (or other negative symptoms)» pt has schizophrenia: paranoid delusions, disorganized speech/behavior, auditory hallucinations, functional decline 6+ months.

flat affect, apathy, poverty of speech, social withdrawal.

**pressured speech= bipolar, mania

Question 74

25yr F in ED 45mins after being stung by several wasps. Reports throat tightness and dizziness. BP 80/40, pulse 120, RR 32. Exam shows diffuse erythematous plaques over the trunk and 1+ pitting edema of the ankles. What is the most likely cause of pt’s hypotension?

Answer 74

chemical mediator-induced increased vascular permeability» HISTAMINE baby, postcapillary venules! (and the other inflammatory mediators: leukotrienes, PGE)

pt has anaphylaxis, HSR 1 to wasp venom> production of allergen-specific IgE

Question 75

68yr M w/ long history of chewing tobacco for f/u of squamous cell carcinoma of oral cavity. 1 month ago, pt was diagnosed w/ SCC of L lateral tongue. Specimen on resection showed clear margins, and he started addn tx. The patient recently noticed a 2nd ulcerative lesion on R lateral tongue. Biopsy is performed and it also shows SCC. The 2nd tumor most likely arose by which mechanism?

Answer 75

field cancerization» large area of cells w/in a ‘field’ are primed to develop cancer b/c of widespread exposure to mutagens, eventually leading to multiple primary malignancies.

**carcinoma usually spreads lymph, but it’s unlikely that the lymph would drain, and then bring back to other side of mouth> would just go elsewhere.

Question 76

5yr M due to bed-wetting. Stayed dry during day since age 3, but continues to wet bed 4-5 night/week. Urinated approx 5 times during the day; stream is continuous and strong. Bowel movements healthy. Height/weight 75th percentile. Vitals WNL. UA unremarkable. This patient’s bed-wetting is most likely caused by what?

Answer 76

brain maturational delay» pt has primary nocturnal enuresis; child 5yrs+ who has never achieved prolonged period of nighttime urinary continence.

maturational delay in development of bladder control in brain: awareness of bladder filling, suppression of bladder contractions in cerebral cortex, coordination of sphincter fxn in pontine micturition center.

**other reasons: dec ADH, excessive fluid consumptions at night.

Question 77

38yr F G3P2 35wks w/ sudden-onset visual changes and headache. Pt reports “spots” in vision for few hours + occipital headache. Acetamin did not help. Preg complicated by gestational DM requiring insulin. BP 168/114, pulse 90. Pupils normal, movements intact. Visual field shows partial loss of vision b/l. What is the most likely cause?

Answer 77

retinal artery vasospasm» placental ischemia of preeclampsia triggers widespread endothelial dysfxn causing dysregulation vascular tone, increased vascular permeability, and dec end-organ perfusion.

pt has preeclampsia: HTN 20+wks w/ headache and visual changes: commonly blurry vision, “seeing sparks”, scotomata (partial vision loss=blind spots)= all due to retinal artery vasospasm, optic nerve ischemia.

symtoms of vision loss resolve w/ delivery usually.

Question 78

what is the presentation & pathophys of wet macular degeneration?

Answer 78

painless, u/l vision loss
choroidal neovascularization> abnormal vessel growth beneath the retina= age-related wet macular degeneration

Question 79

42yr F G4P4 w/ heavy & painful menses bleeding over past 3 months. LMP 3wks ago. Sexually active w/ spouse, no pain w/ intercourse. b/l tubal ligation 3yrs ago. BMI 24. Vital WNL. On bimanual exam, the uterus is uniformly enlarged and tender. Ptest is negative. What is the most likely cause of pt symptoms?

Answer 79

endometrial glands/stroma w/in myometrium» pt has adenomyosis= multiparous + dysmenorrhea + heavy menses + uniformly enlarged uterus

endometrial gland proliferation + cyclic bleeding> dysmenorrhea, uterine tender
abnormal myometrial hyperplasia + hypertrophy> uniformly enlarged uterus
uterine enlarged=increased endometrial surface area> regular, heavy menstrual bleeding

definitive tx is hysterectomy, which allows for histologic dx too

**not leiomyomas (fibroids)> uterus is non-tender & irregularly enlarged
**not endometrial polyps> painless intermenstrual bleeding, no uterus tenderness.

Question 80

75yr M w/ acute onset profuse vomiting of bright red blood. Had intermittent, dull epigastric pain for 3months. PMH COPD w/ multiple exacerbations and L spinal stenosis. Heavy smoker. BP 70/40, pulse 120. Exam shows epigastric tenderness; pt dies 1hr later. Autopsy shows deep peptic ulcer localized proximally on the lesser curvature of stomach. Ulcer most likely penetrated what artery?

Answer 80

L gastric> runs along and perfuses the lesser curve of stomach> common hemorrhage of penetrating gastric ulcer.

other complications: penetration into biliary tract/colon, gastric outlet obstruction, free wall perforation w/ peritonitis.

Question 81

ulcers in the posterior duodenal bulb erode into what artery?

Answer 81

gastrodudodenal

Question 82

if an ulcer were to erode the greater curvature of stomach (unlikely), what artery would be damaged?

Answer 82

R gastroepiploic> serves the distal greater curvature (L gastroepiploic serves upper portion)

Question 83

what is the most common site of an Hpylori gastric ulcer?

Answer 83

transition zone from body to antrum> parietal cells (HCl + IF) and G cells (gastrin) most at risk.

microenvironment (pH, host immune factors) are optimal>inflam leads to mucosal atrophy & ulcer formation

Question 84

what arteries come off the celiac trunk?

Answer 84

splenic> goes to spleen
L gastric> lesser curvature
common hepatic> to liver as proper hepatic.

Question 85

67yr man w/ inc fatigue, weight gain over 6months. PMH HTN w/ CCB. 2yrs ago exam was unremarkable, lipid tests normal. Today, BP 135/98, pulse 62. Thyroid mildly enlarged, irregular and firm in consistency. Labs inc TSH, low T4, high total & LDL, mild inc triglycerides. What is the most likely underlying mech for elevated cholesterol in pt?

Answer 85

decreased LDL receptor gene expression»

pt has hypothyroidism, which causes LDL receptor expression to dec> dec clearance of blood LDL, also dec biliary excretion of cholesterol, elevated triglycerides via dec LPL expression= inc risk for coronary atherosclerosis.
» HTN from inc peripheral vascular resistance= inc BP too

**increased LDL receptor degradation can lead to inc LDL too, but it isn’t associated w/ hypothyroidism.

Question 86

A group of researchers conduct a study to evaluate pharm properties of new drug. As part of study they inc oral doses admin to their healthy volunteers. Data is collected for pharmacokinetic profile. A total of 20 volunteers participated. What phase best describes this study?

Answer 86

phase 1 clinical trial most likely.

preclinical studies= non-humans
phase 0= very small # of healthy humans, initial trial of pharm profile
phase 1= slightly bigger, w/ safety
phase 2= diseased pts, does it work?
phase 3= improvement over standard?
phase 4= long term effect @ market

Question 87

A healthy couple who emigrated from europe w/ 3yr son for eval of eczematous rash. Child shows signs of intellect disability, gait abnormalities + musty body odor. What is the likelihood this couple’s next child will have same disease?

Answer 87

1/4» pt has PKU, AR inheritance.

w/ unaffected parents, affected child> parents are carriers> 1/4 probably normal kid, 1/2 probably carriers, 1/4 affected.

**the probability of having 2 kids w/ same disorder is (.25)(.25)= 1/16

Question 88

what is the mutation that leads to PKU?

Answer 88

intellectual disability + gait changes + musty odor + eczema= PKU
mutation in single gene encoding for phenylalanine hydroxylase> build up of tyrosine leads to CNS dysfxn. in USA this is caught on newborn screening.

Question 89

2wk infant in ER w/ fever, lethargy, grunting, poor feeding. Pt born at full term s/p normal pregnancy. Cultures grow EColi. Pt’s condition developed due to exposure to bacterial LPS which +KFKB> cytokines TNFa, IL1, IL6. This bacterial component most likely interacted w/ what immune cells of the patient?

Answer 89

TLR»
DCs & macrophages of innate (+ adaptive) immunity express pattern recognition receptors (PRRs) on DAMPs/PAMPs> LPS is the common PAMPs for gram- bacteria, binds TLRs> inductions NFKB» inflammation cascade.

Question 90

what is the pattern recognition receptor that recognizes microbial carbohydrates?

Answer 90

mannose-binding lectin> activates the lectin complement pathway

Question 91

32yr M PMH bipolar disorder in ER w/ wife for inability to sleep for more than 3hr/night/wk. Pt been irritable, argumentative, racing thoughts, rapid speech, stopped his job, and decided to stay home ‘to unravel the secrets of the universe’. He’s also been drawing shapes on the walls. He is prescribed multiple meds to address this. 5 days later, pt is calm but has difficulty moving spontaneously or getting out of bed. He doesn’t respond appropriately to questions/newly disorientated. 102.9F, 162/98, pulse 98, RR 20. Dysregulation of which NT is most likely to be primary cause of new symptoms?

Answer 91

dopamine»
pt has an acute manic episode, most likely received antipsych meds to target agitation/psychosis.
5 days later develops neuroleptic malignant syndrome: hyperthermia, muscular rigidity, AMS, autonomic dysfxn. this is thought to be due to dysregulation of dopamine (D2 antagonism is MOA for all 1st gen, most 2nd gen).

**D2 anatgonism in nigrostriatal pathway= diffuse “lead pipe” rigidity

**5HT + NE cause SSS: look for hyperreflexia, neuromuscular irritability

Question 92

63yr M w/ routine preventative exam. No PMH, no meds. Pt takes vitamins, but is concerned she’s “looking old”, esp around her eyes w/ the wrinkles. A decrease in what is most likely responsible for pt complaint?

Answer 92

collagen fibril production
(would be increased crosslinking collagen)

UVA penetrate deeper into skin causing photoaging>produce ROS>inflammatory cell-surface receptors + nuclear transcription factors>decreased collagen fibril production, upregulation of matrix metalloproteinases> degrade type 1/3 collagen + elastin.

*triple helix instability w/o VitC= scurvy

Question 93

what is the characteristic histology of photoaging?

Answer 93

epidermal atrophy w/ flatting of rete ridges

Question 94

what are the derivatives of neural crest (name them all)

Answer 94

1. neural ganglia
2. adrenal medulla
3. Schwann cells
4. pia & arachnoid mater
5. aorticopulmonary septum
6. endocardial cushions
7. branchial arches (bones/cartilage)
8. skull bones
9. melanocytes

**parafollicular C cells are no longer considered neural crest

Question 95

what are the “odd” derivatives of endoderm?

Answer 95

parafollicular C cells
thymus
parathyroids
middle ear epithelium

**GI tract + liver + pancreas + bladder + urethra makes sense

Question 96

what are the “odd” mesoderm derivaties?

Answer 96

adrenal cortex
serosal linings (peritoneum)
spleen

**others makes sense GU/kidney/ureters + CT + muscle + cardiovascular/lymph system

Question 97

what are the “odd” surface ectoderm derivatives?

Answer 97

sweat glands
mammary glands
lens
cornea
salivary glands
anterior pituitary

**other makes sense: nasal + oral epithelium, inner ear, epidermis

Question 98

what are the derivaties of neural tube?

Answer 98

brain + spinal cord
posterior pituitary gland
pineal gland
retina

Question 99

19yr F comes to office to discuss tx options for seasonal sneezing, rhinorrhea, and nasal congestion. She’s had symtoms every spring/summer, now willing to try anything to allow her to concentrate on her upcoming finals. No PMH, no meds. Vitals WNL. Exam reveals mild b/l pale, boggy nasal turbinates w/ copious clear mucus. Fluticasone, a glucocorticoid, is prescribed. What is the most likely MOA of this drgu?

Answer 99

apoptosis of tissue eosinophils»

glucocorticoids bind cytoplasmic receptors and translocate to nucleus where they inibit transcription of genes that encode inflammatory mediators> decrease immune cell survival and propagation via:
1. dec tissue production of PGE, LOX> inhibits phospholipase A2
2. dec synthesis of all proinflammatory cytokines
3. impaired macrophage activation, neutrophil emigration
4. increased apoptosis of eosinophils, T cells, monocytes via dec BCL2 expression

**note: would affect leukotrienes, but not the receptors (that’s montelukast for allergic rhinitis)

Question 100

Ghon complex vs. Ranke complex

Answer 100

Ghon complex: areas of initial infection (lower lobe, hilar lymph nodes)
Ranke complex: calcified & fibrosed Ghon complex

Question 101

Potts disease vs Miliary TB

Answer 101

Potts disease: hematogenous spread to distant areas (also meningitis TB at brain base)
Miliary TB: widespread, massive hematogenous dissemination> innumerable, small, millet seed-like lesions in multiple organs (liver, lungs)

Question 102

4month boy w/ failure to thrive & developmental delay, evaluation for hereditary metabolic disorder. Born outside USA, had severeal seizures during neonatal period. Exam shows abnormal head shape w/ large ant fontanelle, widely splayed cranial sutures. Profound hypotonia + hepatomegaly. Elevated levels of VLCFAs and phytanic acid. Skin fibroblasts show impaired ability to oxidize VLCFAs. Pt’s condition best explained by dysfxn of what cellular structure?

Answer 102

peroxisomes»
pt has inability to undergo mitochondrial beta-oxidation (VLCFA + branched chain fatty acids), which occurs win/ peroxisomes. H2O2 degradation also happens w/in them

pt most likely has Zellweger syndrome: defective peroxisomal biogenesis. death usually occurs w/in months of initial presentation.

Question 103

what cellular functions happen in mitochondria?

Answer 103

TCA cycle
fatty acid oxidation
ATP synthesis (ETC)
apoptosis

Question 104

what cellular functions happen in lysossomes?

Answer 104

digestion of cellular debris/pathogens

Question 105

what cellular function of golgi apparatus?

Answer 105

protein modification, sorting, transport

Question 106

what cellular fxn of sER?

Answer 106

drug detoxification
lipid, phospholipid, steroid synthesis

Question 107

what is the common presentation of X-linked adrenoleukodystrophy?

Answer 107

presenting in childhood/adulthood w/ neurological deterioration + adrenal insufficiency as VLCFAs accumulate in CNS + adrenal glands
**deficit is also w/ VLCFAs, but it’s their defective transport into peroxisomes vs Zellwneger is inability due to peroxisomal biogeneis.

Question 108

What is the timeline and presentation of acute stress disorder?

Answer 108

symtpoms of re-experience, avoidance, neg mood, dissociation, and hyperarousal from 3 days to 1 month s/p LIFE-THREATENING traumatic event.

essential the precursor lesion to PTSD.

Question 109

36yr F w/ several months of tingling & numbness in R hand and fingers w/ progressive dull, achy pain. Initially intermittent, but now pain worsens overnight. Pt is a typist at work, has difficulty holding phone, weakness of thumb opposition, atrophy of thenar eminence. Pt attempted conservative management, but is not referred to surgery. During surgery, incision of what structure will most likely improve her symtpoms?

Answer 109

transverse carpal L (flexor retinaculum)» pt has carpal tunnel syndrome

Question 110

57yr M in ER s/p generalized tonic-clonic seizure. Wife reports he has no hx of seizures. But has been complaining of intermittent headaches, memory loss, vision disturbances for past 2wks. Brain image shows solitary mass w/in R temporal lobe. What is the visual field defect of pt?

Answer 110

mass w/in temporal lobe> affects inferior optic radiation (Meyer’s loop)> pt will have superior visual field loss: c/l homonymous superior quadrantanopia (c/l superior quadrant defect)

Question 111

what does an injury to the R optic tract/R occipital cortex do to visual field defect?

Answer 111

L homonymous hemianopia> can’t see the L visual field from either eye (L no peripheral vision, R no medial vision)

Question 112

how does an injury to the parietal lobe affect the visual field?

Answer 112

pt will have c/l homonymous inferior quadrantanopia> superior optic radiations (inf visual field) affected in parietal lobe.

Question 113

65yr F w/ COPD DM2 in ER w/ profound fevers and malaise. Pt is hospitalized for septicemia. Cultures show lactose-containing media grow rapidly dividing gram- bacteria. Replication of these microbial cells requires synthesis of two daughter strands of DNA using the parent strands as templates. What process will differ most btw the 2 daughter strands formed at each fork?

Answer 113

joining of DNA fragments by ligase»

DNA synthesis can only occur 5>3 direction, synthesized continuously toward the replication fork (leading strand); but the other strand is discontinuously away from fork (lagging strand), Okazaki fragments> short stretches of new DNA are separated by RNA primers> later joined together by DNA ligase more than leading strand

Question 114

24yr M evaluated for nerve block procedure. Pt has intermittent burning, stabbing pain in L groin since undergoing mesh repair of an inguinal hernia 1yr ago. Pain is bad w/ cough, physicial activity. Exam shows no weakness of ant abd or lower extremity muscles. Lightly touching medial thigh + upper scrotum gives burning pain. Cremasteric reflex normal. Clinical dx is entrapment of nerve transvering the superficial inguinal ring w/ spermatic cord. Blockade of what n w/ local anesthestic injection is most likely to relieve pt’s symtoms?

Answer 114

ilioinguinal> pt had recent hernia surgery, commonly regional nerves can be injured, or s/p inflammation and fibrosis (nerve entrapment).

nerve w/in internal ring following spermatic cord is illioinguinal> supplies anterior scrotum (mjr lab), base of penis (mons pubis), medial thigh.
**note: if the cremasteric reflex were injured, then genitofemoral would be more appropriate

Question 115

What neuronal property is likely decreased as a direct result of demyelination?

Answer 115

length (space) constant decreased> shorter impulse conductions

time constant increased> slower changes in membrane voltage

Question 116

what is the reversal for anticholinergic toxicity?

Answer 116

physostigmine» easily cross BBB (3 amine, lipophilic) for central reversal.

4 amines: neostigmine, edrophonium, pyridostigmine are hydrophilic + polar= no readily cross BBB, but would reverse peripheral symptoms

Question 117

70yr F w/ acute midT back pain after ground level fall. Weakness + weight loss for past 2 months. 150/70, pulse 110. Sweaty palms + hand tremor. Labs normal Ca, Cr, Vit D, low TSH. Xray reveals compression fracture of T7 w/ diffuse mineralization of bones. What is most likely responsible for bone abnormalities?

Answer 117

incr bone resorption due to osteoclast+ (hyperthyroid>T3 inc>direct osteoclastic+)

pt has osteoporosis
*thyroid has no effect on bone mineralization
*if this was lytic bone lesions of MM, then diffuse bone loss due to interleukin-1 induced uncoupling of bone resorption & formation.

Question 118

Newborn girl admitted to NICU w/ jaudince, big liver, edema. Minimal prenatal care. Lab reveals Hb 6, +direct Coombs test. Smear shows many nucleated RBCs. Infant in significant resp distress w/ pleural effustion + ascities= death. Autopsy shows extramedullary hemat in many tissues. What is the most likely cause of pt’s condition?

Answer 118

RBC opsonization by maternal antibodies» pt has hemolytic disease of newborn. Sensitized Rh(-) mother kills Rh(+) baby.

*fetus w/ homozygous alpha-thalassemia (Hb Barts) have no alpha chains= G4 w/ high O2 affinity> severe fxn anemia + tissue hypoxia + heart failure + nonimmune hydrops fetails (neg Coombs test)

Question 119

A scientist is conducting research to discover novel drug targets for antiRT against HIV. CD4 lymph extracted. The protein becomes glycoslyated b4 being proteolytically cleaved into 2 smaller proteins in the Golgi. Which of the following describes the fxn of these 2 proteins?

Answer 119

virion attachment to target cells> only glycosylated HIV polyprotein is gp160> forms gp120 + gp41> both function to attach to hose cell + immune evasion

Question 120

62yr M in ED w/ severe colicky upper abd pain, n/v. Reports similar episodes before. Immigrated from East Asia several years ago. Imaging shows several gallstones in common bile duct + GB. Gallstones are dark brown, soft, primarily calcium bilirubinate w/ variable amts of cholesterol. What enzymes most likely played role in pathogenesis of condition?

Answer 120

beta-glucuronidase» pt has infectious gallstones (likely from EColi/liver fluke being in Asia) 2/2 infection of biliary tract, which releases beta-g by injured hepatocytes and bacteria.

**C sinesnsis is most common cause of pigmented stones in East Asia> prolonged phase before symtpms

Question 121

24yr M w/ painful swelling in his L groin, noticed 2 days ago. Progressively more tender, more painful. Sustained a puncture wound on sole of L foot. Exam shows nonfluctant L inguinal lymph node + red skin. Small wound on foot expresses pus w/ mild pressure. What is the histology likely in pt groin mass?

Answer 121

formation of multiple germinal centers» pt has puncture would leading to inflammatory lymphadenopathy> adaptive response» large, foriegn antigens displayed on follicular DCs in draining lymph» T cells then differentiate into T helper> promote the survival of of antigen-specific B cells»> generation of germinal centers (somatic hypermutuation)

Question 122

36yr M under general anesthesia. Pt inhaled isoflurance to achieve the desirable depth of CNS depression. An increase in what parameter is most likely to happen during the anesthesia of this patient?

Answer 122

cerebral blood flow»
fluorinated anesthetics dec vascular resistance> incr cerebral BF> inc ICP

apart from CNS depression affects:
1. cardiovascular depression (hypotension 2/2 dec CO)
2. resp depression (sevoflurane have bronchodilation and preferred in asthma)
3. kidneys> inhaled anesthetics dec GFR, inc vascular resistance, dec renal plasma flow
4. fluinated dec hepatic BF

Question 123

12yr girl w/ recurrent episodes of self-limited colicky abd pain w/ nausea lasting several days. Recent hospitalization for difficult breathing. Lab reveals dec serum complement C4 and C1 esterase inhibitor levels. What drug is contraindicated in pt?

Answer 123

captopril» no ACE- for this kid, pt has hereditary angioedema

Question 124

32yr F in ER w/ lightheadedness & SOB while at supermarket. Last 6 months> increasing SOB and had to adjust her daily activities. No PMH, no FMhx. BMI 25. After assessment pt “feels fine”, refuses further eval, insists discharge. Pt dies 1 month later. Heart at autopsy shows thickened RV free wall, nearly 2cm. Most likely diagnosis?

Answer 124

thickened free RV wall + progressive dyspnea in young F> pulmonary arterial HTN (PAH)…which led R heart failure w/ circulatory collapse + resp failure (cor pulmonale)

Question 125

when should you suspect Wolff-Parkinson-White, and what does it look like on histology?

Answer 125

suspect in any case of sudden cardiac death of healthy young person> there’s a small accessory AV impulse conduction pathway anatomically separate from the AV node= creates the AV node conduction, noticeable on EKG.

Question 126

72yr M w/ long-standing dyspnea seen in clinic after experiencing an episode of syncope. Exam shows weak & slowly rising arterial pulses. Cardiac shows harsh, midsystolic murmur at 2nd R intercostal space w/ dec intensity of 2nd heart sound. EKG confirms severe aortic stenosis. 2 month later, pt in ED w/ palpitations, inc SOB. 90/60, 130/min, w/ new onset-AFib, no significant ST/T wave changes. CXR shows b/l pulm edema. What hemodynamic change is most likely associated w/ patient’s current presentation?

Answer 126

sudden decrease in LV preload via loss of contraction in AFib

> > severe aortic stenosis impairs LV output, inc systolic P (LV hypertrophy), makes stiff LV> in order to fill stiff LV, you need contraction» once this AFib hits, pt gonna have no contracrtion>drops LV filling> low BP, pulm edema= sudden onset heart failure.

tx: cardioversion to stop the AFib

**pt had no ST changes on EKG, so no evidence of myocardial ischemia= LV systolic fxn would remain unchanged, leaving dec CO a result of low LV preload.

Question 127

what are the lab values that make you suspect vWF?

Answer 127

prolonged bleeding time (impaired platelet fxn)
prolonged PTT (dec F8)= intrinsic, heparin

**inherited AD w/ variable penetrance
**differs from HemoA= X-linked R, prolonged PTT, normal bleeding time; HemoB= prolonged PTT, normal bleeding time
*Vit K dec> prolongs PT w/ normal bleeding time