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STEP1 Uworld > Deck 5 > Flashcards

Deck 5 Flashcards

0
Q

Tetrolagy of fallot results from failure of what embryologic process?

*what other 2 cyanotic heart disease arise from the same type of error?

A
  • migration of neural crest cells into the truncal and bulbar ridges of the truncus arteriosus and bulbus cordis
  • These would normally grow grow in a spiraling fashion to separate the aorta and pulmonary arteries

*Truncus arteriosus and TGA

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1
Q

patau syndrome clinical appearance results from defect in what?

A
  • Prechordal mesoderm development

* Non-disjunction in meiosis 1 is original error

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2
Q

The carotid sinus’ afferent fibers run with the ______ nerve, while the aortic sinus’ afferents run with the _______ nerve. They both end up at the ________ nucleus of the ________.

A
  • glossopharyngeal
  • Vagus
  • Solitary nucleus
  • Medulla
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3
Q

WHat are the specific skin findings in dermatomyositis? What about lab findings?
Pts who develop it after age 50 have incr risk of _______

A
  • Grotton papules = red or violaceous, flat topped papules, often with light scale, OVER BONY PROMINENCES, usually over MCP, PIP, and DIP joints.
  • Heliotrope rash = erythematous or violaceous edematous eruption on the upper eyelids and periorbital skin

Labs:

  • Incr CK
  • Positive ANA (antinuclear antibodies), but not specific
  • Anti-Jo1 antibodies = specific!

-Over 50 = incr risk of underlying malignancy

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4
Q

What is the triad in Ménière’s disease and how can you differentiate it from a CPA tumor?

A
  • Tinnitus, Vertigo, Hearing loss (caused by incr volume of endolymph)
  • pts often also describe a sensation of “fullness”

-It is episodic with exacerbations and remissions! Vs. CPA tumor which would be progressive and constant

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5
Q

What does a carcinoid tumor look like on microscopy?

A
  • Uniform shape and size of cells

- Kind of looks like a fly’s eye

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6
Q

Incr solubility of a gas in the blood require ________ amounts in order to become saturated and affect the brain maximally

*High solubility = ______ blood/gas partitioning coefficient

A
  • Larger
  • takes longer to reach desired effect bc more gas must be administered
  • incr solubility = High partitioning coefficient
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7
Q

As mitral stenosis becomes more severe, the S2 to opening snap time interval becomes _______

A

Shorter!

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8
Q

For each of these virion, what is their virulence ability? (what do they bind to?

A
  • CMV = cellular integrins
  • EBV = CD21
  • HIV = CD4 and CXCR4/CCR5
  • Rabies = Nicotinic AcH receptor
  • Rhinovirus = ICAM-1
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9
Q

Other than Flagyl and Vanc, what other drug can you use for C. Diff colitis? What are some of its properties?

A
  • Fidaxomicin
  • Oral, bacteriocidal, minimal systemic absorption
  • used for recurrent c diff (minimal effect on colonic fluora)
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10
Q

Of the HIV structural genes, which one’s product is glycosylated and cleaved in the ER? What does this create?

A
  • Env
  • glycosylated to gp160
  • Cleaved to gp120 and gp41 —> facilitate virion absorption by target cells
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11
Q

How can HepA virus be inactivated?

A
  • Water chlorination
  • Bleach
  • Formalin
  • UV irradiation
  • Boiling to 85 deg for one minute
  • Autoclave at 120 deg for 20 minutes
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12
Q

What is the 5 –> 3 and the 3 –> 5 exonuclease activity responsible for?

A
  • 5 –> 3 = removes RNA primers and damaged DNA segments

- 3 –> 5 = proofreading function that removes and replaces mismatched nucleotides on the newly formed daughter strands

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13
Q

A high _____/_______ ratio in the pancreatic Beta cells results in the closure of the ________ channel, which causes insulin secretion by opening the voltage-gated calcium channels.

A
  • ATP/ADP

- Potassium (KATP)

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14
Q

What enzyme serves as a major glucose sensor for the pancreatic Beta cell? It’s increased activty leads to release of insulin, and it is the major rate limitor

A

-Glucokinase

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15
Q

When is HCG detectable in maternal serum? why?

A
  • no earlier than 6 days after ovulation (sometimes up to 11 days)
  • Because successful impantation in the uterus must occur before HCG is detectable in the serum (which takes a few days)
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16
Q

What is the MDR-1 gene in tumor cells, what does it produce, and what does it accomplish?

A
  • Multi-drug resistance gene
  • Produces P-glycoprotein, a transmembrane ATP-dependent efflux pump, normally expressed in intestinal and renal tubular epithelial cells
  • functions to eliminate foreign compounds from the body
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17
Q

Atheromatous plaque stability depends significantly on mechanical strength of _______. This is made primarily out of _______. Inflammatory macrophages in the intima may reduce plaque stability by secreting ________.

A
  • the fibrous cap
  • Made mostly of collagen
  • metalloproteinases, which degrade collagen —> weaken fibrous cap
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18
Q

Differentiating DIC with TTP/HUS

A

DIC:

  • Bleeding
  • Coag cascade involved (incr PT and PTT)
  • Low fibrinogen
  • high D-dimer

*All opposite for TTP/HUS

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19
Q

Acute intermittent porphyria is an autosomal ________ condition, caused by deficiency of _________.

A
  • Autosomal dominant

- Porphobilinogen deaminase deficiency (PBG deaminase)

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20
Q

How does acute intermittent porphyria present?

What makes it worse? What makes it better?

A
  • Acutely with variable GI and neurological symptoms…abd pain, vomiting, peripheral neuropathy, neuropsych derrangements
  • Reddish urine —-> darkens on exposure to light and air via oxidation of excess PBG
  • Worsening factors: upregulating ALA-synthase (P450 inducers, alcohol, smoking)
  • Improving factors: Heme and glucose, to tx with IV heme and dextrose
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21
Q

how is TPR calculated in vassels arranged in paralell?

A

1/TPR = 1/R1 + 1/R2 etc…

  • Parallel = total body circulation
  • Series = individual organ
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22
Q

Which 2 arteries to other tissues branch off from the splenic artery? Which of these tissues is succeptible to ischemia is the splenic artery is occluded?

A
  • Short gastric A. to the fundus of stomach, and Left Gastroepiploic A. to the greater curvature
  • The gastric fundus, bc of poor anastamoses of short gastric artery
  • L gastroepiploic has good anastamoses with R. gastroepiploic
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23
Q

Gastric EROSIONS are defined as mucosal defects that do not extend through the ________

A
  • Muscularis mucosa

* Gastric ULCERS penetrate mucosa and go into sub-mucosa

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24
Q

HIT is more commonly caused by _______. Treatment is ______

A
  • Unfractionated heparin compared to LMW heparin

- Direct thrombin inhibitors (Argatroban, Hirudin, Lepirudin)…but obviously 1st stepis to stop heparin

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25
Q

What kind of bias occurs when ther eis significant “loss to followup” which is disproportional (i.e: a greater number of one group was lost) ?

A

-Attrition bias, which is a form of selection bias

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26
Q

How do you define PAH, and What is the genetic cause for inherited pulmonary arterial hypertension?

A
  • PAH defined as PA pressure > 25 mmHg

- Abnormal BMPR-2 (bone morphogenic protein receptor type 2)….then a second insult (infection, drugs, etc ) —-> PAH

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27
Q

Other than back pain, what systems are affected in Ankylosing spondylitis?

A
  1. MSK - Also get enthesitis…pain at insetion of muscles
  2. Respiratory - enthesopathies of costochondral joints, etc…decr chest wall expansion….MONITOR THIS….rarely fibrosis of lung
  3. Cardiovascular - ascending aortitis –> dilation of aortic ring with aortic insufficiency
  4. Eye - anterior uveitis in 30-40% (pain, blurred vision, photophobia, conjunctival erythema)

**remember: RF is negative!!

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28
Q

All protease inhibitors have what side effects?

A
  1. Lipodystrophy - central obesity, buffalo hump, etc
  2. Hyperglycemia - from incr insulin resistance
  3. Inhibition of P450 (dont use rifampin in pts of HAART…it increases P450 and thus decreases protease ……use rifabutin instead)
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29
Q

The Urachus is a remnant of the _______ that connects the ______ to the yolk sac in fetal life. Failure of the urachus to obliterate by birtch results in patent urachus, and presents with _______

A
  • Allantois
  • Bladder
  • Urine discharge from the umbilicus
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30
Q

How is Attributable risk % calculated?

A

ARP = (risk in exposed - risk in unexposed) / risk in exposed

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31
Q

Diff in nucleotides in frameshift vs nonsense mutation?

A
  • Frameshift = deletion of non-multiples of 3

- Nonsense = single base substitution —> premature stop codon

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32
Q

Graft vs host dz usually happens ______ after transplant. Most commonly affected sites are _______

A
  • within one week

- can affect anywhere, but most common is skin, Liver, GI tract

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33
Q 
Each MHC class 1 molecule is composed of what 2 things?
WHat about MHC class 2?
A
  • Heavy chain
  • Beta-2-microglobulin

-Alpha and beta polypeptide chains

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34
Q

WHat is the histology seen in lacunar infarct areas?

A
  • Small vessel Lipohyalinosis and atherosclerosis

- grossly = small cavities filled with clear fluid (5-6 mm)

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35
Q

Dx for someone with fixed segmental loss of UE pain+T sensation, UE lower motor neuron signs, and/or LE upper motor neuron signs….in the setting of SCOLIOSIS?

A

-Syringomyelia

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36
Q

What is the mechanism of staph scalded skin syndrome?

A

-Exotoxin acting as protease in the superficial epidermis by cleaving desmoglein in desmosomes

37
Q

WHat conditions are associated with carpal tunnel syndrome?

A
  • Hypothyroid
  • DM
  • RA
  • dialysis-associated amyloidosis
38
Q

What is a common mutation in non-small cell lung carcinoma that results in constitutively active tyrosine kinase activity?

A

-EML4-ALK fusion gene

39
Q

Integrin-mediated adhesion of cells to basement membrane and ECM involves the binding of integrins to what 3 molecules?

A
  • Fibronectin
  • Collagen
  • Laminin
40
Q

Which anti-arrythmics have been implicated with QT prolongation and torsades?

A
  • Quinidine
  • Procainamide
  • Disopyramide
  • ibutilide
  • dofelitide
  • Sotalol
41
Q

Describe the findings seen in Pulm Silicosis

A

CXR:

  • Nodular densities, most prominently in Apical region
  • Calcified Hilar lymph nodes (eggshell)

Node sampling:
-Birefringent particles surrounded by dense collagen fibers

42
Q

From what cells does RCC usually originate from?

What are RCC risk factors?

A
  • PCT

- Smoking and obesity

43
Q

What appetite suppressants have been shown to cause pulmonary hypertension?

A
  • Fenfluramine
  • dexFenfluramine
  • phentermine
44
Q

Which drugs for BPH work on the dynamic component of obstruction (muscular tension)? And which work on fixed component (decreasing prostate size)?

A
  • Dynamic = alpha 1 antagonists (terazosin, tamsulosin) –> work in days to weeks
  • Static = 5-a-reductase inhibitors (finasteride, dutasteride) –> can take up to 6-12 months to work
45
Q

What drug is used to treat Hairy-cell leukemia? What class is it in, how does it work, etc?

A
  • Cladribine
  • purine analog, resistant to degradation by adenosine deaminase
  • able to reach high intracellular concentrations –> incorporated into DNA and causes DNA strand breaks
  • Can penetrate the CNS well, excreted in the urine
46
Q

What structures are in the retroperitoneum?

A
  1. major vessels - abd aorta, IVC and their branches
  2. solid organs - Pancreas (except tail), kidneys, adrenals
  3. Hollow organs - parts 2,3 of duodenum (part of 4 too), ascending and descending colon, rectum, ureters, bladder
  4. Vertebral column and spinal muscles
47
Q

What enzyme is relatively specific to Mast cells, and can be used as a marker of mast-cell activation?

A

-Tryptase

48
Q

How is Menotropin useful in the treatment of infertility in women? WHat else is needed after menotropin administration and why?

A
  • Menotropin acts like FSH and forms a dominant follicle

- hCG is then needed in a large dose in order to induce an LH surge –> Ovulation

49
Q

What is seen in the brain (at autopsy) of a child with PKU?

A

-pallor of the substantia nigra, locus ceruleus, and vagal nucleus dorsalis

50
Q

What is seen on muscle biopsy in Polymyositis? WHat lab value is specific?

A
  • inflammation, necrosis, regeneration, fibrosis of muscle fibers
  • infiltration of endomysium by macrophages and CD8+ T cells

Lab: Anti-Jo-1 antibodies

51
Q

When looking at a near object, the lens accommodates….this happens when the the ciliary muscles ______, causing ______ of the zonular fibers, allowing the lens to relax and assume a more ________ shape

A
  • contract
  • relaxation of zonular fibers
  • Convex shape (lens thickening)

*with age, lens gets less elastic and ciliary muscles weaker —> harder to see close objects

52
Q

What segment of bowel is ALWAYS involved in Hirschsprung’s disease?

A
  • Rectum and anus

* sigmoid is 75% of the time

53
Q

The chemotherapeutic effect of methotrexate is overcome by _______ supplementation. This is not true for what similar drug?

A
  • Leucovorin (N-5-formyl-THF)

- 5-FU

54
Q

What is the presentation of an infant with testicular feminization syndrome?

A
  • Aka androgen insensitivity syndrome

- 46XY infants appear to be phenotypically normal females with blind-ended vaginal pouch and no uterus

55
Q

How do you calculate maintenance dose of a drug?

A

Maint dose =
(steady state plasma conc mg/L x Clearance mg/L) / Bioavailability

  • for IV drugs, bioavailability can be assumed to be 1
  • answer is in mg/min….so need to multiply accordingly (ex: for drug given every 3 hours…..multiply by 60 for 1 hr, then by 3)
56
Q

What happens on a molecular level to cause Factor 5 Lieden mutation?

A

-Single AA substitution of glutamine for arginine near the protein C cleavage site on factor 5 gene product

57
Q

What are treatment options for pts on anti-psychotics who develop Akithisia?

A
  • Decrease dose of antipsychotic

- Beta blockers or Benzos

58
Q

Describe the steps involved in dysplastic cells eventually invading basement membrane –> carcinoma.

A
  1. Detachment
    - decr expression of adhesion molecules such as E-Cadherins
  2. Adherence to Basement membrane
    - incr expression of Laminin and others
  3. Invasion
    - secretion of proteolytic enzymes such as metalloproteinases
    - also Cathepsin D protease
59
Q

Crohn’s dz inflammation is mediated mostly by ______ cells and ______ cytokines

What about UC?

A

Crohn’s:

  • Th-1 T cells
  • IL-2, IFN-gamma, macrophages secrete TNF

UC:

  • Th-2 T cells
  • IL-4, IL-5, IL-6, IL-10
60
Q

What are the histological findings associated with Hydronephrosis?

A

grossly:

  • dilation and deformation of calices and renal pelvis
  • atrophy and scarring or renal parenchyma and distortion of architecture

LM:

  • interstitial fibrosis with patches of mononuclear infiltration
  • tubular atrophy
61
Q
  • What nerve is damaged in pts with positive trendellenbug sign?
  • WHat muscles are innervated by this nerve?
  • What does positive trendellenburg look like?
A
  • Superior Gluteal nerve
  • Gluteus medius and minimus, tensor fascia latae (stabilize pelvis and Abduct thigh)
  • Pelvis sags down on UN-affected side….patients will often lean toward affected side when walking to maintain a level pelvis
62
Q

What is the clinical presentation of Granulomatosis with polyangitis (aka Wegner’s)?

A
  1. Pulmonary
    - cough and/or hemoptysis
    - focal necrotizing granulomas…sometimes coalesce into nodules and cavitate
  2. Upper resp tract
    - chronic sinusitis
    - mucosal ulcers and/or granulomas
  3. Renal disease
    - RPGN (crescenteric GN)
    - no immunoglobs or complement deposits…unlike Goodpastures
63
Q

What elevated serum marker is diagnostic for Wegner’s?

A

-c-ANCA

64
Q

In atelectasis, the trachea deviates ________ the affected side, and in Pleural effusion the trachea deviates ________ the affected side

A
  • Towards

- away from

65
Q

How do patients with familial Hyperchylomicronemia present? What is the pathology? Associated complications?

A
  • Presents in childhood: marked hypertriglyceridemia, recurrent acute pancreatitis, and milky plasma appearance. Also eruptive xanthomas
  • Autosomal recessive, LPL deficiency—> body is unable to clear dietary lipid loads due to defective hydrolysis of serum triglycerides
  • No incr risk of premature CAD!! Pancreatitis
66
Q

What is a common cause of unilateral nasal hemianopia?

A

-Aneurysm or atherosclerotic calcification of the internal carotid artery —> laterally impinges on optic chiasm

67
Q

What type of hemoglobin binds poorly with 2,3-BPG?

A

HgF

-allows it to bind oxygen more avidly

68
Q

What is the underlying mechanism of a BRAF mutation and what is the result?
What drug targets BRAF mutation?

A
  • Valine replaced by glutamate at position 600 (V600E)
  • protein kinase overactivation –> incr signaling pathway stimulus for melanocyte proliferation

-Vemurafenib

69
Q

What should yu suspect in a pt with sore throat and fever who has Hx of Hyperthyroid?

A
  • Rule out agranulocytosis (caused by PTU and methimazole)

- D/c those meds and check CBC with diff

70
Q

Why are NSAIDS an inappropriate choice for fever tx in a pt with hyperthyroid?

A

-They can displace thyroid hormones from binding proteins, thereby worsening thyrotoxic state

71
Q

Clinical presentation of homocystinuria?

Supplementation with what can significantly improve outcomes?

A
  • Marfanoid, lens dislocation, developmental delay, THROMBOEMBOLIC EPISODES
  • Vitamin B6 (required cofactor for cystathionine synthetase) which turns homocysteine into cystathionine
72
Q

How can you tell EHEC (O157:H7) in the lab compared to other strains?

A
  • Does not ferment sorbitol
  • does not produce glucoronidase

*remember: toxin is encoded by a phage

73
Q

What do the HIV structural genes, gag, pol, and env code for?

A

gag- nucleocapsid proteins p24 and p7 (group specific antigens in the virion core)

pol - Reverse transcriptase, integrase, protease

env - indirectly encodes envelope glycoproteins gp120 and gp41

74
Q

What markers are commonly seen in Small cell carcinoma of the lung?

What about non-small cell?

A

Small cell:
-Neurofilaments, synaptophysin, neuron-specific enolase, chromogranin

Non-small cell:
-EGF-receptors, mucin, surfactant-associated proteins

75
Q

Do not give _______ to patients with Hyperkalemia from Digoxin toxicity.

A
  • Calcium gluconate

* remember: HYPOkalemia worsens Digoxin toxicity, bc digoxin competes with K+ for Na/K/ATPase

76
Q

Most common presentation of MEN type 1 is _______

A
  • Hypercalcemia from hyperparathyroidism
  • 70% also have endocrine pancreatic tumors, usually gastrin…..but occasionally insulin or VIP
  • some will have pituitary adenoma
77
Q

In acute hepatitis B, what are some of the histologic changes seen?

A
  • ballooning degeneration
  • hepatocyte necrosis
  • portal inflammation
  • cytoplasm filled with spheres and tubules of HBsAg –> cytoplasm takes on FINELY GRANULAR, EOSINOPHILIC APPEARANCE
78
Q

What are the 3 main groups of veins in early embryonic development, and what do they form?

A
  • Umbilical = degenerate
  • Vitelline = veins of the portal system
  • Cardinal = systemic circulation
79
Q

WHat is the histological appearance of Medullary thyroid cancer?

A
  • Uniform polygonal or spindle-shaped cells

- extracellular Amyloid deposits —> stain with congo red

80
Q

Other than for reducing glutathione, what else is NADPH used for?

A
  • as an electron donor for anabolic reactions like making cholesterol, FA, steroids……also drug metabolism
  • High need in liver and adrenals
81
Q

Why do certain adenocarcinomas cause a hypercoagulable state?

A

-They produce a thromboplastin-like substance capable of causing chronic intravascular coagulations that are disseminated and tend to migrate

82
Q

Injections given in the superomedial part of the buttock risk injury to the ______ nerve.

Injections in the superomedial, inferomedial, and inferolateral regions of the buttock risk injury to the ______ nerve

A
  • Superior gluteal

- Sciatic

83
Q

WHich nerve provides cutaneous sensation to the posterior external auditory canal? What nerve does the rest of the ext aud. canal?

A
  • Vagus nerve

- Trigeminal (V3)

84
Q

WHat is the pathophysiology involved in formation of an aortic aneurysm from syphyllis?

A

-Vasa vasorum endarteritis and obliteration –> inflammation, ischemia, weakening of aortic adventitia

85
Q

In an atheromatous plaque, what provides stimulus for SM to migrate from the media into the intima and for proliferation?

A
  • PDGF

* released locally by platelets, endothelial cells, and macrophages

86
Q

Which anti-epileptic can cause an exaggerated response to vasopressin?

A
  • Carbamazapine

- dizziness, confusion, hyponatremia

87
Q

What gives Elastin its characteristic elastic properties? And what are the primary amino acids used for its production?

A
  • Interchain crosslinks involving Lysine
  • NO TRIPLE HELIX unlike collagen
  • Non-polar AAs glycine, alanine, valine (also proline and lysine…but a lot less than collagen)
88
Q

What is the progression of EKG changes seen in acute transmural MI?

A
  • Peaked T waves are first sign
  • ST elevations within minutes to hours
  • Q-waves appear within hours to days
89
Q

Particles entering the respiratory tract are cleared by different mechanisms based on their size….what are the size categories and how is each one removed?

A
  • 10-15 um –> upper airway trapping
  • 2.5 - 10 um –> mucociliary transport
  • less than 2 um —> reach terminal bronchiolo and alveoli –> phagocytosis by macrophages

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