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Usmle > Block 3 > Flashcards

Block 3 Flashcards

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USMLE® Step 1 flashcards
1
Q

Foramen rotondum transmits >
Foramen ovale transmits>
Optic canal transmits>

A
  • Foramen rotundum transmits V2 (maxillary branch of CN V)
  • foramen ovale transmits V3 (mandibular nerve)
  • optic canal transmits optic nerve CN II
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2
Q

In case of Vit D excess (compensation)

A

Cycle shift towards 24,25 dihydroxycholecalciferol instead of 1,25 . This leads to inactive form of vitamin D

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3
Q

Cough in ACEI cause:

A

ACE normally degrades bradykinin and substance P. Inhibition of ACE leads to elevated bradykinin and substance P levels –> nonproductive cough

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4
Q

Intrapartum ampicillin is given in

A
  • universal prenatal screening for group B streptococci colonization in vagina and rectum is recommended at 35-37 weeks of gestation.
  • in women who culture positive for GBS or in women who have had infant infected with GBS before intrapartum antibiotic prophylaxis is indicated.
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5
Q

MAC (minimal anesthetic concentration)

A

This term is used in inhaled anesthetics, is defined as the concentration of inhaled anesthetic at which 50% of the patients do not respond to surgical stimulus.
- the more lipid soluble the anesthetic the lower the MAC and the greater the potency.

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6
Q

Carcinoid tumor treatment

A

Octerotide for symptomatic patients, surgery for liver metastases

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7
Q

Organophosphate intoxication signs and symptoms

A

DUMBELS

  1. Diarrhea, diaphoresis
  2. Urination
  3. Miosis
  4. Bronchospasm and Bradycardia
  5. Emesis
  6. Lacrimation
  7. Salivation
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8
Q

Chronic bronchitis effect on airways and mucus

A
  • airway inflammation

- mucus hypersecretion

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9
Q

Effect of solubility on the onset of gas anesthetic

A

Poorly soluble gas = low blood/gas coefficient
Highly soluble gas = high blood/gas coefficient
- the speed at which the blood becomes saturated depends on the solubility of the gas in the blood. Highly soluble anesthetics dissolve easily and requires larger amounts before blood becomes saturated.
-

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10
Q

Symptoms of advanced aortic stenosis include

A

Syncope, angina, dizziness or heart failure

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11
Q

Carcinoid syndrome features

A

Clinical:
Skin: flushing, telengectasis
GI: watery dirrhea,cramping
Pulmonary : bronchospasm, dyspnea, wheezing
Cardiac: valvular fibrous plaques ( right> left)
Diagnosis:
Elevated 24 hrs urinary excertion 5-HIAA , CT/MRI of abdomen and pelvis to localize tumor

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12
Q

White reflex in the eye indicates ->

A

Retinoblastoma

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13
Q

Acute HIV presentation

A

Rash, lymphadenopathy, fever , and painful oral ulcers on tongue.

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14
Q

Cavernous hemangioma

A
  • Vascular malformation, involves the deeper tissues of the body such as liver and brain.
  • gross exam: “mulberry-like” appearance due to their purple vascular clusters.
  • Histologically: they are composed of abnormal, dilated blood vessels with a thin adventitia lacking elastic fibers and smooth muscle.
  • reduced structural support gives them a tendency to leak causing recurrent hemorrhage.
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15
Q

Medications associated with osteoporotic fracture

A
  • Anti convulsant that induce CYP450 (phenobarbital,phenytoin, carbamazepine) . (Increase VIT D catabolism)
  • aromatase inhibitors and medroxyprogesterone ( decrease Estrogen)
  • GnRh agonist (decrease testosterone and estrogen)
  • glucocorticoids, unfractioned heparin and thazolidineiones (decrease bone formation)
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16
Q

Acne pathophysiology and association

A

Cause are:
1. Follicular epidermal hyper proliferation
2. Excessive sebum production
3. Inflammation
4. Propionibacterium acnes
Drugs: methyltestosterone, lithium and HER-1 receptor blocker

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17
Q

Pneumonia with non-productive cough

A

M.pneumoniae

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18
Q

Hyper-acute rejection occurs within

A
  • Minutes of transplantation. Performed antibodies against ABO or HLA are the cause.
  • Graft blood vessel spasm and diffuse intravascular coagulation with ischemia.’
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19
Q

Cataracts in diabetes

A
  • sorbitol accumulation increase cellular osmotic and oxidative stress
  • contribute to diabetic retinopathy, neuropathy and nephropathy.
  • in lens cells the increased stress leads to development of hydropic lens fibers that degenerate eventually resulting in lens opacification and cataract formation
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20
Q

How are NK cells activated

A

By interferon gamma and IL-12

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21
Q

What is frameshift mutation

A

Frameshift mutation are caused by deletion or insertion of any number of nucleotides that are not multiples of 3. This leads to the formation of entirely different protein as all amino acids after the affected area are pushed and changed .

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22
Q

Pralidoxime

A

Anti cholinergic that can be given in the early course of organophosphate intoxication. can act on muscarinic and nicotinic receptors

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23
Q

Alanine to pyruvate , enzyme and requirement

A

Enzyme is alanine transaminase (ALT)

And requirement are vitamin B6

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24
Q

Perforins and granzymes mechanism of action.

A

Perfoirn produce a hole in the target cell membrane and granzyme induce target cell apoptosis

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25
Q

Oculomotor nerve palsy, along with worse headache of my life

A
  • posterior communicating cerberal artery saccular(berry) aneurysm.
  • pcca is between MCA and PCA(image)
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26
Q

Single sarcomere is between ?

A

Two Z lines

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27
Q

Saccular aneurysm

A

Berry aneurysm

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28
Q

Farmers and agricultural workers are exposed to

A

Oraganophosphate intoxication –> excessive amounts of pesticides

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29
Q

Legionella diagnosis

A
  • sputum diagnosis is unreliable –> many neutrophils and no colonies, since unique lipopolysachharides chain on outer membrane inhibits gram staining
  • diagnosis is most commonly made by testing for legionella antigen in urine.
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30
Q

Vitamin B5 pantothenic acid

A

Essential for CoA

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31
Q

B6 is required for

A

ALT and AST, heme ,NE and epinephrine, dopamine, GABA, niacni , histamine, serotonin, , glycogen synthesis.

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32
Q

Rates of onset and recovery after inhaled anesthesia depends on;

A

Blood-gas ratio:

  • The more soluble the anesthetics in blood- the slower the anesthesia.
  • anesthetics with high blood/gas ratio are associated with slow onset
  • anesthetics with high blood/gas ratio are associated with slow recovery
  • low blood/gas ratio = faster onset and recovery.
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33
Q

Aldose reductase function

A
  1. Glucose –> sorbitol

2. Galactose –> galactitol

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34
Q

COPD signs

A

Wheezing, diminshed breath sound, barrel shaped chest

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35
Q

Cavernous hemangioma in the brain - clinical

A
  • most patients are assymptomatic
  • may cause neurological deficits and seziures due to compression of the surrounding tissue and irritation from recurrent bleeding.
  • surgery indicated in case of symptoms
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36
Q

Superior fissure contain

A

Oculomotor nerve, CN VI, CN IV, V1(ophthalmic nerve)

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37
Q

Gustatory innervation

A

Anterior 2/3 : chorda tympani branch of facial nerve
Posterior 1/3 : glossopharyngeal
Posterior area of the tongue root, and taste buds of larynx and upper esophagus : vagus nerve

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38
Q

Diffusion impairment

A

Not common cause of hypoxemia, occurs in patients with end stage interstitial lung disease

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39
Q

Acute rejection

A
  • occurs within 1-2 weeks after receiving the transplant. Its the recipient reaction to HLA of the graft. This is cell-mediated immune response, and CD8 T cells play a central role.
  • in lung transplant acute rejection manifests with dyspnea, dry cough and low grade fever.
  • immunosuppressant can prevent
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40
Q

General sensation of the tongue ( touch, pain, pressure, and temperature sensation)

A

Anterior 2/3 of the tongue : mandibular branch of trigiminal nerve
Posterior 1/3 : glossopharyngeal
Posterior area of tongue root: vagus nerve

41
Q

Emphysema effect on interalveolar walls and elastic recoil

A

-destruction of interalveolar walls and diminished lung elastic recoil–> trapping in enlarged distal airspaces

42
Q

Fat embolism

A

Etilogy :
1. long bone and pelvic fractures .
2. Orthopedic surgery
Classic triad :
A> respiratory distress (hypoxia,dyspnea,tachypnea)
B> neurological symptoms (altered mentation, seizures)
C> petechial rash (typically over head, neck, thorax and axillae)

43
Q

Anabolic steroids use( methyltestosterone) can predispose to

A

ACNE- comedonal and inflammatory eruption on face back and chest.
Also- hepatic adenoma

44
Q

FAS receptors is essential for

Deficiency leads to

A

Apoptosis
-fas ligand –> binds to Fas receptor –> Fas-associated death domain (FADD) –> stimulate capases that initiate apoptosis.
- the Fas receptor is expressed on T-lymphocytes and plays important role in numerous diseases such as cancer and autoimmune diseases. Mutation involving Fas or FasL impair the process of tolerance and may lead to self reactive T cell and development of autoimmune diseases,
Deficiency leads to autoimmune lymphoproliferative syndrome

45
Q

Polyol pathway

A

Its an alternative route of glucose metabolism.
This process is slow , in long standing hyperglycemia, sorbitol accumulates in tissue with lower sorbitol dehydrogenase activity such as retina, lens, kidney and peripheral nerves.
Glucose (by aldose reductase)—> sorbitol .
Sorbitol (by sorbitol dehydrogenease) –> fructose.

46
Q

Brown sequard syndrome: clinically

A

(Hemisection of spinal cord)
Clinically characterized by :
1. Flaccid paralysis at level of the lesion (anterior horn)
2. Ipsilateral spastic paralysis below level of lesion (corticospinal tract)
3. Ipsilateral loss of touch, vibratory sensation and proprioception (dorsal column) .
4. Contralateral loss of pain and temperature sensation 1-2 levels below the lesion.

47
Q

Thrombotic occlusion of pulmonary circulation leads to

A

increased blood flow to remainder of lung –> leading to V/Q mismatch.
the resulting ischemic injury –> inflammation –> surfactant deficiency and atelectasis in surrounding lung regions.
Results in –> high volume of deoxygenated blood traversing poorly ventilated lung regions causing –> right to left intrapulmonary shunt –> hypoxemia

48
Q

The etiology of transposition of great arteries (TGA)

A

Is due to linear rather than spiral development of the aortico-pulmonary septum in utero, resulting in anteriorly positioned aorta connected to the right ventricle and posteriorly positioned pulmonary artery connected to the left ventricle.

49
Q

Acute intermittent prophyria clinical and treatment

A

Clinical : GI and CNS symptoms, red urine –> (after 24 hours) –> dark urine

Treatment: inhibitoion of ALA synthase, which is upregulated by CYP450 and downregulated by heme and glucose.
(Avoiding drugs is important for preventing acute attacks)

50
Q

Legionella treatment

A

Fluroquinolones or newer macrolides such as azithromycin

51
Q

Apoptosis triggering mechanisms

A
  1. Deprivation of growth factors.
  2. DNA damage.
  3. Intracellular accumulation of misfolded proteins.
  4. Mediation by cytotoxic T cell.
  5. Activation of receptors in the TNF receptor family such as FAS.
52
Q

Leginella pneumophilia clinical

A
  • Legionnaires disease include a very high fever in smokers accompanied by diarrhea, confusion, and cough that may initially be only slightly productive.
  • its a common cause of CAP
  • symptoms can be inconclusive along with fever, accompanying GI, such as diarrhea.
53
Q

L.monocytogenes characteristics:

Shape, hemolysis, resembles what? ,

A
  • gram + rod
  • very narrow zone of beta-hemolysis
  • tumbling immotile at 22C˙, immotile at 37 C˙.
  • can also multiply as low as 4C˙(can contaminate refreigated food )
54
Q

Fibrocystic breast changes

A

Normal varian in which breast feel dense and lumpy on examination, commonly present with cyclic mastalgia

55
Q

Dimercaprol and succimer

A

Treatment for arsenic poisoning, mercury, and lead( EDTA also used )

56
Q

Organophosphate antidote

A
  • Atropine is the main antidote, it can almost treat all the symptoms except the muscle paralysis as atropine have no effect on nicotinic receptor.
  • pralidoxime is the only medication that reverse muscarinic and nicotinic effects (its effective only if given early)
57
Q

Familial hypercholesterolemia

A

Autosomal dominant mutation of LDL receptor gene

-MI at young age

58
Q

The motor /sensory component of corneal reflex is carried primarily by ?

A

Motor :Temporal branch of facial nerve

Sensory: nasociliary nerve of V1

59
Q

HIDA scan

A

Radionuclide biliary scan

60
Q

Sudden onset tachypnea and chest pain in hospitalized patients raise suspicion for

A

Pulmonary embolism

61
Q

Common disease causing intracellular organisms

A 
Bacteria:
1. Chlamydia.
2.legionella.
3.L.monocytogenes
4.myobacterium
5. N.meningitidis
6. Nocardia
7. Rickettsia
8. S.typhi
fungi: 
A> cryptocucs neoformans, H.capsulatum, P.jirovecii 
Parasites: plasmodium , T.gondii
62
Q

H band in muscle and I band

A

The area of the muscle where myosin doesnt overlap actin and I band is the area that actin doesnt overlap myosin.
During muscle contraction both H and I bands decrease in length

63
Q

APC gene is found in

A

Familial polyposis syndromes, sporadic colon caner and melanomas

64
Q

Pseudopalisading necrosis is present in

A

Glioblastoma

65
Q

A band in muscle:

M-line

A

A band corresponds to myosin filaments

M line lies at the center of A bands

66
Q

Acute intermittent porphyria (AIP)

A

AD disorder, caused by prophobilinogen deaminase deficiency.
AIP causes the nervous system dysfunction due to the accumulation of early heme pathway intermediates.

67
Q

Cardiovascular changes during exercise

A

Cardiac output increased , LV EDV and EDP increases, pulmonary artery systolic pressure increases and systemic systolic BP increase.
On the contrary total systemic vascular resistance decrease

68
Q

Perivascular pseudorosettes in found in

A

Ependymoma,
Children mostly
Hydrocephalus common

69
Q

B2 (riboflavin) is required for

A

FAD and FMN

70
Q

TH1 and TH2 formation

A

IL-4 stimulate TH2

IFN-¥ and IL-12 stimulate TH1

71
Q

Imaging studies in cholecystitis

A
  • ultrasound

- HIDA scan - in case of inconclusive results (nuclear medicine hepatobilliary scanning)

72
Q

Biotin is required for which enzymes

A
  1. Pyruvate carboxylase : – > pyruvate to oxaloacetate (in gluconeogenesis)
  2. Actyl-coA carboxylase –> actyl-CoA to malonyl CoA
  3. Propionyl CoA carboxylase –> propionyl CoA to methelmalonic acid
73
Q

What are the risk factors for developing PE

A
  1. Immobilization (venous stasis)
  2. Recent surgery (inflammation induces hyper-coagulable state)
    Risk for PE can be as high as 50% after orthopedic surgery.
74
Q

Arterio-venous concentration gradient in inhaled anesthesia

A
  • its the difference between concentration of gas anesthetic in arterial and venous blood.
  • the soulbility of the anesthetic in the peripheral tissue is the major factor in determining the size of the arteriovenous gradient.
  • if solubility is high –> larger anesthetic taken by blood –> low venous concentration. And vice versa.
  • this means the higher the arteriovenous concentration gradient, the slower the onset of action. (It has no affect on potency)
75
Q

Causes of aortic stenosis (3)

A
  1. Congenital: bicuspid aortic stenosis
  2. Normal valve with calcification (senile)(more common in USA)
  3. Rheumatic heart disease.
76
Q

Vitamin A defeciancy

A
  1. Nyctalopia
  2. Xerosis cutis
  3. Keratomalacia
  4. Bitot spots on conjunctiva
  5. Immunosuppression
77
Q

Rifaximin

A

Nonabsorbable antibiotic that alters GI flora to decrease intestinal production and absorption of ammonia. (Its a primary source of ammonia in the body, normal flora responsible ) .
In pts with cirrhosis. Its generally used with lactulose which is catabolized by intestinal bacterial flora.

78
Q

Motor innervation of the tongue is provided by

A
  • hypoglossal nerve with the exception of palatoglossus muscle which is innervated by vagus nerve
79
Q

CF pathogenesis and clinical

A
  • CFTR protein is found normally in airways, intestine, salivary glands (absorbs Cl- from the saliva making it hypotonic –> sodium follows)
  • Thick mucus in epithelial cells of the airways –> chronic cough, recurrent pneumonias, and pancreatic damage.
80
Q

Which bacteria can grow well at refrigeration tempreture

A

Listeria monocytogenes

81
Q

Most common pituitary adenoma

A

Prolactinoma- can cause galactorrhea, amenorrhea, loss of libido, and infertillity in women.

82
Q

what cell is responsible for the destruction of infected cell/tumor cell with decreased or absent MHC class I

A

NK cell

83
Q

Anti pseudomonal drugs

A
  1. Penicilins : ticracillin, piperacillin
  2. Cephalosporins: cefepime
  3. Amino-glycosides: amikacin, gentamicin, tobramycin
  4. Fluroquinolones : ciprofloxacin and levofloxacin (not moxifloxacin)
  5. Monobactam : aztreonam
  6. Carbapenem: impenim, meropenem
84
Q

Avascular necrosis is a side effect of (osteonecrosis)

A

Bisphosphonate

85
Q

Vitamin E deficiency

A
  1. Hemolytic anemia
  2. Acanthocytosis
  3. Muscle weakness
  4. Posterior coulmn and spinocerbellar tract demyelination
86
Q

Vitamin A - used in drugs as

A
  1. Oral isotretinoin to treat severe acne
  2. All trans retinoic acid to treat Acute Protomeylotic leukemia
  3. Measles
87
Q

Which process is defected in vitamin D metabolism in CKD

A

Conversion of 25 hydroxycholecaliferol –> 1,25 dihydroxycholecaliferol .

88
Q

CF transmembrane conductance regulator (CFTR)

A

2 ATP bind to channel –> channel opens –> Cl- transport down gradient –> Na+2 and water follows as a result of membrane potential. –> this leads to hydration of mucosal surfaces in the airways and bowel.

89
Q

Rifaximin is indicated in

A
  • liver cirrhosis encephalopathy

- travelers diarrhea

90
Q

I band and Z line

A

I band corresponds to the light chain

Z line: actin are bound to structural protien at the Z line

91
Q

Transposition of great arteries is a deficiency in

A

Spiraliation

92
Q

Isotype switching requires the attachment of

A

CD40 (on B cell) to CD40L (on TH cell)

93
Q

Niacin is essential for

A
  • NAD+ , NADP +
  • derived from tryptophan
  • lowers VLDL and raise HDL
94
Q

Cresecndo decrescendo systolic ejection murmur

A

Aortic stenosis= heared best in the right sternal border

95
Q

Inhaled Anesthetics

A

before inhaled anesthetic can reach the target organ (brain) , they must move through a number of compartments (inhaled air–>lung–>blood–>brain . The onset of anesthesia occurs when sufficient quantity of anesthetic is transferred to the brain .

96
Q

Anergy

A

State of prolonged unresponsiveness that occurs in T lymphocyte as form of immune tolerance

97
Q

Rheumatic fever, MR or MS more common

A

MR

98
Q

Excessive perspiration effect on acne

A

It excacerbate it but doesnt cause it

99
Q

Chronic transplant rejection

A

Occurs months or years after transplantation.

  • Its the major cause of mortality in lung transplantation.
  • Chronic rejection causes inflammation of the small bronchioles (bronchiolitis obliterates ).
  • in heart transplant accelerated atherosclerosis is seen
  • in kidney :chronic graft nephropathy
  • in liver : vanishing bile duct syndrome

Usmle (45 decks)

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