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USMLE Step 1 > Respiratory - Stuff Missed > Flashcards

Respiratory - Stuff Missed Flashcards

1
Q

Major component of pulmonary surfactant

A

Phosphatidylcholine (aka lecithin) - it is measured to gauge fetal lung maturity

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2
Q

How to assess fetal lung maturity

A 
When lecithin (phosphatidylcholine) to sphingomyelin ratio (L/S ration) in amniotic fluid is =/ > 2
- measured in cases of premature labor or premature of rupture of membranes
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3
Q

How to assess fetal neural tube defect

A

amniotic fluid is sampled to measure alpha fetoprotein (AFP)

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4
Q

Anaphylaxis

A

systemic version of local allergenic response due to cross-linking of surface IgE to signal degranulation
- systemic vasodilation
- increased vascular permeability
- airway constriction
- mediated by histamine, heparin, and vasoactive peptide
-

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5
Q

Conducting zone of respiratory tree

A 
Large airways (nose, pharynx, bronchi)
Smaller airways (bronchioles, terminal bronchioles)
  • warm, humidifies, and filiters air but NO GAS EXCHANGE
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6
Q

Respiratory zone of respiratory tree

A 
Respiratory bronchioles (mostly cuboidal)
Alveolar ducts
Alveoli (simple squamous)
- GAS EXCHANGE HAPPENS HERE
-
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7
Q

Which structural components end in bronchi

A

Cartilage

Goblet cells

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8
Q

Which structural components end in terminal bronchioles

A

Pseudostratified columnar cells - to beat mucous out of lungs
Smooth muscle of airway walls

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9
Q

Cystic fibrosis

A
  • phenylalanine removal at base pair 508
  • mutation impairs post-translational processing of CFTR transcript and degrades protein before it can transported to cell surface
  • aka abnormal transport of protein to cell surface
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10
Q

Secondary reactivation tuberculosis

A

occurs in patients previously infected by tuberculosis

  • occurs in immunosuppressed patients
  • characterized by apical lesions and hemoptysis
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11
Q

Primary tuberculosis

A

formation of Ghon foci (calcified granulomas) in lower lung fields

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12
Q

Common signs of sarcoidosis

A
  • Erythema nodosum
  • Hilar lymphadenopathy
  • Elevated serum AVCe levels
  • liver biopsy usually shows scattered granulomas
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13
Q

Discuss peak expiratory flow rates

A

Decreased in obstructive lung disease

  • FEV1 is decreased
  • FVC is very decreased
  • leads to decreased FEV1/FVC
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14
Q

Systemic response to patient with COPD (remember: smoker and chronic cough)

A
  • Patient has hypoxia, thus may have increased erythopoietin production
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15
Q

Type I pneumocytes

A
  • line 97% of alveolar surfaces
  • line alveoli
  • thin for optimal gas diffusion
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16
Q

Type II pneumocytes

A
  • secrete surfactant
  • cuboidal and clustered
  • precursors for type I pneumoncytes
  • these cells proliferate during damage
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17
Q

Surfactant

A

secreted by type II pneumocytes

- decrease alveolar surface tension and prevent alveolar collapse

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18
Q

Clara cells

A

non-cilliated

  • columnar with secretory granules
  • secrete component of surfactant
  • degrade toxins
  • act as reserve cells
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19
Q

When does surfactant synthesis begin?

A

Week 26 of gestation, but mature levels not reached until week 35

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20
Q

Meconium ileus

A
  • commonly caused by Cystic Fibrosis

- abnormalities in Cl, Na, water transport by ductal epithelium causes isotonic dehydration of lumen

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21
Q

Signs of small bowel obstruction

A

bilious vomiting
abdominal distention
air fluid levels
small bowel dilatation

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22
Q

Meconium illeus

A
  • signs of small bowel obstruction (bilious vomiting, abdominal distention, air fluid levels, and small bowels)
  • INSPISSATED GREEN MASS (distal ileum obstructed by dehydrated meconium)
  • associated with CF
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23
Q

Common complications of cystic fibrosis

A
  • Treatment resistant pneumonias
  • Bronchiectasis
  • Bronchitic obstructive disase
  • Cor pulmonale
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24
Q

What makes the pulmonary vascular bed unique in its response to hypoxia?

A

In times of hypoxia, pulmonary vascular bed VASOCONSTRICTS to divert blood flow away to more ventilated areas

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25
Q

Patients with asbestos risk exposure are at risk for which cancer?

A
  • Bronchogenic carcinoma

- Mesothelioma (is second)

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26
Q

Asbestosis

A
  • calcific plaques in parietal pleura
  • diffuse pleural thickening of lower lung lobes
  • interstitial lung fibrosis and asbestos bodies are seen
  • asbestos bodies are coovered in iron
  • symptoms appear until 15-20 years after initial exposure
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27
Q

Smoking + Asbestos increases risk for what cancer

A
  • Give 55x increased risk for bronchogenic cancers in comparison to non-smokers with asbestos exposure
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28
Q

Normal tracheal pO2
Normal alveolar pO2
Normal alveolar pCO2

A

Tracheal pO2 = 150 mmHg
Alveolar pO2 = 104 mmHg
Alveolar pCO2 = 40 mmHG

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29
Q

The equilibration of between venous blood and alveolar air is dependent on what?

A

The O2 equilibration is perfusion limited

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30
Q

Recurrent pulmonary infections
Exocrine gland fibrotic atrophy
Mucus plugs

A

THINK CF!!!`

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31
Q

Vitamin A

A
  • fat soluble
  • maintains orderly differentiation of specialized epithelia, which includes mucous secreting epithelia, respiratory tracts, pancreatic tracts
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32
Q

Vitamin deficency

A
  • can cause night blindness

- squamous metaplasia of epithelia

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33
Q

Risk factors for asthma

A
  • genetic predisposition to have more Th2 cells than Th1 cells
  • environmental irritants (e.g. smoking) triffer bronchospasm
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34
Q

Ethambutol

A

antimycobacterial agent that inhibits carbohydrate polymerization, thus preventing peptidoglycan wall sythesis

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35
Q

Side effect of ethambutol

A

Optic neuritis

- presents in conjunction with decreased visual acuity, central scotomas, and color blindness

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36
Q

Rifampin

A

directly inhibits DNA-dependent RNA polymerase
- disrupts transcription of DNA into RNA

associated with hepatotoxivity and red-orange discoloration of bodily secretions

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37
Q

Isoniazid

A

inhibits mycolic acid syntehsis

  • associated with liver toxicity and peripheral neuropathy
  • may cause Vitamin B6 deficiency
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38
Q

Common consequences of left ventricular infarction

A
  • Cardiogenic acute pulmonary edema
  • Pulmonary hypertension (due to congestion)
  • Transudate of plasma into lung interstitium
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39
Q

Hemosiderrin-containing macrophages in alveoli

A
  • suggestive of prior episodes of pulmonary congestion and edema from chronic LHF
  • when RBC extravasate into alveoli due increased intravascular pressure, hemosiderin collegct
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40
Q

Focal necrosis of alveolar walls

A

associated with pulmonary hemorrhage syndromes (e.g. Goodpastures, Wegner’s and SLE

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41
Q

Azoles

A

inhibit synthesis of ergosterol by fungal cytochrome P450 enzymes
- suppress P450 system resulting in many drug-drug interactions

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42
Q

Amphotericin B

A

polyene antifungal that binds to ergosterol in fungal cell membrane
- leads to pore formation and cell lysis

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43
Q

Griseofulvin

A

enters fungal cells and binds microtubules

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44
Q

Theophylline intoxication

A

Seizures
Abdominal pain
Vomitting
Tachyarrhythmias

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45
Q

Treatment of theophylline toxicity

A

gastric lavage and administering charcoal

- treat cardiac arrhythmias with B-blockers

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46
Q

Cystic fibrosis

A
  • autosomal RECESSIVE
  • defect in CFTR gene in chromosome 7
  • most common defect leads to protein degradation before it gets cell surface
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47
Q

Unaffected person with unaffected parents who has a sibling with an autosomal recessive disease (e.g. cystic fibrosis) has what chance of carrying the disease?

A

2/3

- both parents must be Aa
Aa x Aa will create the following possibilities
1 AA
2 Aa,
 aa (affected sibling)
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48
Q

Blastomycosis

A
  • dimorphic fungus found in Great Lakes, MS, and OH River basins
  • transmitted by respiratory route, entering lungs and transforms into yeast
  • causes flu-like illness or productive cough
  • may become chronic infection and associated with granulomas
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49
Q

Aspergillus fumigatus

A
  • opportunistic pathogen
  • causes invasive aspergillosis in immunocompromised patients
  • aspergillomas in patients with lung cavities (e.g. TB)
  • allergic bronchopulmonary aspergillosus in asthma
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50
Q

Cryptococcus neoformans

A
  • only fungus with pathogenic capsule
  • inhaled and causes meningitis via hematogenous spread to meninges
  • affects immunocompromised patients (e.g transplant patients, AIDS patients, diabetics??)
  • stained with methanmine silver and muscarimine (detects polysaccharide)
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51
Q

Hemoptysis in elderly smoker

A

Likely lung cancer

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52
Q

Pancoast tumor

A
  • lung cancer tumor found in lung apex in superior sulcus
  • Characterized by:
  • severe pain in shoulder that radiates towards axilla and scapula
  • Horner’s syndrome (ptosis, anhydrosis, miosis)
  • upper extremity edema (compression of subclavian vessels)
  • spinal cord compression/ paraplegia
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53
Q

Pancoast syndrome

A
  • ispilateral Horner’s syndrome
  • rib destruction
  • atrophy of hand muscles
  • pain in C8, T1, T2 nerves
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54
Q

S. pneumoniae

A 
Gram positive diplococci
Lancet shaped
Optochin sensitive
Bile soluble (unable to grow in bile)
Alpha hemolytic
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55
Q

Transformation

A
  • ability to uptake and express naked DNA made available when another bacterial cell dies
  • SHiN bacteria can do this (S. pneumoniae, H. influenzae, Neisseria)
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56
Q

Irritation of mediastinal or diaphragmatic parietal pleura will transmitted by which nerve

A 
Phrenic nerve (C3-C5)
- may cause sharp pain worsened upon inspiration
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57
Q

Legionella pneumophila

A

Gram negative (but difficult to stain)

  • use silver stain
  • contaminates water sources and air conditioning systems
  • grows on charcoal yeast and aerosilized water
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58
Q

Cause of green discoloration of pus or sputum during bacterial infections

A

Associated with release of myeloperoxidase (MPO) from neutrophil azurophilic granules
- MPO contains heme

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59
Q

Myeloperoxidase

A
  • heme containing molecules contained with azurophilic granules of neutrophiles that catalyze HOCl from chloride and H2O2 during respiratory burst
  • responsible for green color of sputum or pus in bacterial infections
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60
Q

Acid fast staining

A

carried out by applying an aniline dye (e.g. carbolfuchsin) to a smear and then decolorizing with acid alcohol to reveal whether organisms are acid fast

(e.g. Mycobacterium and Nocardia species)

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61
Q

Discuss work of breathing and patietns with increased elastic resistance (e.g pulmonary fibrosis)

A

Work of breathing is MINIMIZED in patients with increased elastic resistance (e.g pulmonary fibrosis) when their respiratory rate is high and tidal volume in low (fast, shallow breaths)

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62
Q

Discuss work of breathing and patients with decreased elastic resistance (e.g. asthma, COPD)

A

Work of breathing is MAXIMIZED in patients with decreased elastic resistance (e.g. asthma or COPD) at lower respiratory rate/higher tidal volume to minimize work of breathing

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63
Q

Pathogenecity of H. influenzae

A
  • depends on presence of antiphagocytic polysaccharide capsule
  • type b is most invasive and virulent (with ribose capsule instead of the hexose seen in other)
  • Unencapsulated H. influenzae are part of normal intenstinal flora
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64
Q

Metaplasia

A

adaptive change that occurs in response to chronic irritation
(e.g. Barrett’s esophagus - due to longstanding GERD & Smoking which can cause squamous bronchial metaplasia)

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65
Q

Discuss high altitude - in terms of CO, HR, pO2, and pCO2

A
  • Condition of hypoxia so increases CO, HR to improve oxygen delivery
  • pO2 and pCO2 would be lower than normal
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66
Q

Discuss pulmonary embolism - in terms of CO, HR, pO2, and pCO2

A
  • Causes low blood flow to left side of heart
  • Decreased CO thus compensated tachycardia takes place
  • Hypoxemia and lung vagal stimulation produces hyperventilation and respiratory alkalosis
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67
Q

Discuss carotid sinus massage - in terms of CO, HR, pO2, and pCO2

A

causes reflex vagal discharge to SA node, atrial myocytes, and AV node

  • HR and CO are reduced
  • would not affect pO2 and pCO2
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68
Q

Discuss panic attack - in terms of CO, HR, pO2, and pCO2

A
  • sympathetic stimulation causes increase in CO and HR

- but hyperventilation causes lowered pCO2 and respiratory alkalosis

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69
Q

Discuss exercise - in terms of CO, HR, pO2, and pCO2

A
  • increased heart rate, increased cardiac output, and increased respiratory rate balance the increased oxygen consumption and CO2 production
  • arterial blood gases remain the same, BUT VENOUS oxygen is decreased and VENOUS CO2 is increased
70
Q

Tissue destruction caused by M. tuberculosis

A
  • associated with granulomatous inflammation with caseating necrosis
  • due to T-lymphocyte mediated delayed type of hypersensitivity
  • stems from Th1 lymphocyte simulation of both macrophages and CD8 T lymphocytes
71
Q

Signs of exudation and alveolar hepatization

A

associated with S. pneumoniae

72
Q

Churg-Strauss Syndrome

A
  • necrotizing GRANULOMATOUS inflammation with EOSINOPHILS
  • associated with ASTHMA, palpable purpura, peripheral neuropahty
  • p-ANCA
73
Q

Idiopathic pulmonary fibrosis

A

insiduous onset progressive exertional dyspnia

  • restrictive lung disease profile
  • biopsy with honeycomb lung (fibrosis with paraseptic and subpleural enlargement
74
Q

Acute Respiratory Distress Syndrome ARDS

A

diffuse injury to alveolicapillary membraine results in interstitial and intraalveolar edema, acute inflammation, and alveolar hyaline membranes

  • acute necrotizing pancreatitis is major risk factors
  • commonly caused by:
  • gastric aspiration, shock, trauma, or infection
75
Q

Negative Predictive Value

A

probability of not having a disease when a given a negative test results
- is dependent on prevalence
- inversely dependent on prevalence of disease
-

76
Q

Adenocarcinoma

A
  • most common lung cancer in general population
  • common in women and non-smokers
  • located peripherally and consists of tumor cells that form glandular structures
77
Q

Squamous cell carcinoma

A
  • found centrally
  • necrosis & cavitation are common
  • associated with hypercalcemia (due to secretion of PTHrP
78
Q

Large cell carcinoma

A
  • locately peripherally

- associated with gynecomastia and galactorrhea

79
Q

Small cell carcinoma

A
  • located centrally
  • may produce ACTH or ADH or cause Lambert-Eaton syndrome (anti-bodies against presynaptic Ca channels, prevents ACh release)
80
Q

Acute epiglottis

A

associated with rapidly progressive fever, sore throat, progressive airway obstruction

  • associated with H. influenzae type b
  • vaccine has dropped incidence of this disease
81
Q

Describe Mycobacterial resistance to isonizaid

A
  • Non-expression of catalase-peroxidase enzyme OR

- genetic modification of isoniazid binding site on mycolic acid synthesis enzyme

82
Q

CMV

A
  • interstitial pneumonia in transplant patient
  • has cytoplasmic inclusion bodies
  • contains double stranded DNA genome
83
Q

Most common side effect of inhaled glucocorticoids (e.g. albuterol)

A
  • Development of oral candidiasis (as result of immunosuppression)
84
Q

Systemic ieffects of inhaled glucocorticoids

A
  • Increased intraoccular pressure
  • Cataracts
  • Growth retardation in children
  • Bone loss
  • Suppression of Hypothalamus-Pituitary Axis (HPA Axis)
85
Q

Primary infection of TB

A
  • occurs after inhaling aerosilized secretions of patient infected with TB
  • characterized by Ghon complex (lower lung lesion) and ipsilateral hilar adeopathy (calcified hilar lymph node)
86
Q

Hematogenous dessimation of TB

A

associated with extrapulmonary symptoms

  • Pott disease
  • tuberculous meningitis
  • psoas abcess
  • miliary tuberculosis ( small, scattered seed-like foci of infection throughout body)
87
Q

Most effective anti-inflammatory agents for chronic prevention of asthma

A

Corticosteroids (e.g Fluticasone)
- don’t have direct bronchodilatory effect, but minimize airway hyperresponsiveness by reducing inflammation (inducing apoptosis of inflammatory cells)

88
Q

Hamartomas

A

common benign lung tumors

  • present as asymptomatic peripherally located “coin lesion” with “popcorn calcifcaitions” in patients 50-60 years old
  • composed of disorganized hyaline cartilage, fibrous tissue, and adipose tissue
89
Q

Fat embolism

A
  • occurs within days of long bone fractures
  • associated with
    respiratory distress
    diffuse neurological impairment (e.g. confusion)
    upper body diffuse petichial rash (due to thrombocytopenia)
    ** multiple fat emboli stain black with osmium tetroxide
90
Q

Virchow’s triad

A
  • associated with development of deep vein thrombosis
    Endothelial injury
    Venous stasis
    Hypercoaguable state
91
Q

Major risk factors for deep venous thormbosis

A
  • older age
  • major lower extremity surgery (e.g hip surgery)
  • subsequent immobility
92
Q

Mycoplasma pneumonia

A
  • causative agent of walking pneumonie
  • has no peptipglycan cell wall, only has phospholipid bilaer
  • shares antigen with human RBCs so when body immune response mount, it also lyses RBCs which lead to anemia
  • associated with COLD AGGLUTININS
93
Q

Pulmonary hypertension and Scleroderma

A
  • pulmonary hypertension in patients with scleroderma caused by damage to pulmonary arterioles
  • manifests with accentuated pulmonary component of 2nd heart sound
  • signs of right-sided heart failure
94
Q

Scleroderma

A

associated with increased deposition of collagen in tissues

- affected tissue secrete cytokines (e.g. TGF-beta) that increased collagen production and ECM proteins by fibroblasts

95
Q

Pneumoccocal vacine

A
  • recommended for all adults > 65 years and for patients with COPD, asplenia, or immune suppression
  • is an unconjugated polysaccharide vaccine that does not stimulate T-cell response
96
Q

Examples of inactivated toxin vaccines

A

Diptheria and Tetanus vaccines

97
Q

Bosentan

A
  • competitive antagonist for endothelial receptors used for primary (idiopathic) pulmonary arterial hypertension
  • used for treatment of pulmonary hypertension
98
Q

Clopidogrel

A
  • inhibits ADP induced platelet aggregation
99
Q

Blastomyces dermatidis

A

dimorphic fungus - changes due to temperature

  • fungus outside of body
  • yeast inside of the body
  • in tissue as round yeast with doubly refractive walls and broad based budding
  • can cause flu-like illness or pneumonia
  • diagnosed by KOH preparation
100
Q

Hyperacute rejection

A

occurs within minutes of transplantation

  • performed antibodies against ABO or HLA are the cause
  • can cause blood vessel spasm and intravascular coagulation
  • rare and IRREVERSIBLE
101
Q

Acute rejection

A

occurs 1-2 weeks after receiving transplant

  • represents recipient reaction to HLA to graft
  • CELL MEDIATED IMMUNE RESPONSE
  • causes vascular damage
  • microscopy shows lymphocytes
  • IMMUNOSUPPRESSANTS CAN TREAT THIS
102
Q

Chronic rejection

A

occurs months or years after transplant

- associated with fibrosis

103
Q

Chronic reject in lung transplantation

A
  • cuases inflammation of small bronchioles
  • inflammation of bronchiolar wall leads to narrowing and obstruction
  • patients present with dyspnea, non-productive cough and wheezing
104
Q

In the lung, which cells release elastase?

A
  • Alveolar macrophages (specifically in lysosome)

- Neutrophils (in azurophilic granules)

105
Q

Clara cells

A

non-cilliated secretory cells which liver in terminal respiratory bronchioles

  • secrete protein which inhibits neutrophil recruitment and activation
  • associated with surfactant
106
Q

Thoracocenteis should be performed where to avoid hitting abdominal strucures

A
  • above 7th rib in mid-clavicular line
  • above 9th rib along midaxillary line
    above 11 rib along paravertebral line

** hitting below rib risks hitting subcostal neurovascular bundle

107
Q

Superior vena cava syndrome

A
  • due to compression of SVC that impairs drainage from head, often caused by malignancy (e.g lung cancer) or thrombossis from indwelling catheters

presents with facial swellign, conjunctiva

  • JVP
  • upper extremity edema
  • heart sounds are fine
108
Q

Complications associated with SVC syndrome

A
  • Headaches, dizziness, and increased risk of rupture/aneurysm of cranial arteries
109
Q

Amphotericin B

A

binds ergosterol of fungal cell membrane to exert antifungal effects

110
Q

Amphotericin B side effects

A
  • binds to cholesterol, which can cause toxicity
  • important side effects are nephrotoxicity (dose dependent because it can decrease GFR) , hypokalemia, and hypomagnesmia
111
Q

Which enzymes / cells are responsible for formation of abcesses and tissue damage

A

Lysosomal enzymes released by neutrophils and macrophages

-

112
Q

IFN-gamma

A

reponsible for phagolysosome formation
inducible NO synthase relase
- development of granulomas and caseous necrosis

113
Q

IL-12

A

stimulates natural killer cells and is responsible for T helper cell secretion of IFN-gamma

114
Q

Stages of Lobar pneumonia

A
  1. Congestion (first 24 hours)
  2. Red hepatization (day 2-3)
  3. Gray hepatization (day 4-6)
  4. Resultion
115
Q

Congestion stage of lobar pneumonia

A
  • occurs within first 24 hours
  • affected lobe in red, heavy and boggy microscopically
  • vascular dilation
  • alveolar exudate contains mostly bacteria
116
Q

Red hepatization stage of lobar pneumonia (4)

A
  • occurs within 2-3 days
  • lung looks red, firm (liver-like consistency)
  • alveolar exudate contains erythrocytes, neutrophils, and fibrin
117
Q

Gray hepatization stage of lobar pneumonia

A
  • occurs within 4-6 days
  • gray-brown firm lobe
  • RBC disintegrate
  • Alveolar exudate filled with neutrophills and fibrin
118
Q

Resolution stage of lobar pneumonia

A

Restoration of normal architecure

- enzymatic digestion of exudate

119
Q

Culture requirements of H. influenza

A
  • Chocolate agar with factor V (NAD+) and factor X (Hemati)

** can’t grow in sheep agar because it lacks the nutrients and has enzymes which inhibit factor V

120
Q

H. influenzae

A

small gram negative coccobaccilli
EMOP (Esophagitis, Meningitis (in young kids) , Otitis Media, Pneumonia)
- requires chocolate agar with factor V and factor X

121
Q

Discuss S. aureus and H. influenzae sattelite phenomenon

A

H. influenzae can only grow in sheep agar in the presence of S. aureus because S. aureus produces factors X and factors V

122
Q

Pathogenesis of centriacinar emphysema

A

associated iwth chronic, heavy smoking predominantly involves intraalveolar release of protease (e.g. elastase) from infiltrating neutrophils

123
Q

Presentation of Bronchoalveolar carcinoma

A
  • patients (non-smoker or woman) presents with cough and dyspnea
  • coughs up lots and lots of tan-colored fluid
  • biopsy reveals columnar mucin-secreing cells that fill alveoli without invading stroma or vessels
124
Q

Bronchoalveolar carcinoma

A
  • subtype of adenocarcinoma
  • occurs in non-smokers and arises from alveolar epithelium
  • located in peripheral parts of lung and is multi-focal
  • composed of tall, columnar mucin secreting cells that don’t invade stroma or vesels
125
Q

Coccidioides immitis

A

can be asymptomatic

  • can cause pulmonary disease ranging from flu-like illness to chronic pneumonia
  • can cause disseminated disease in immunocompromised patients
  • SPHERULES containing endospores are found in tissue samples
126
Q

Discuss rifampin as monotherapy

A

best used as prophylaxis for people exposed to Meningitis

  • can eliminate carrier state and prevent active infection
  • ** used alone, bacteria acquire resistance through spontaneous mutations of bacterial DNA dependent RNA polymerase
127
Q

Mycoplasma pneumoniae

A
  • cause of “walking pneumonia” where patients look better than labs present
  • lack cell wall, capsule, or cell envelope so require cholesterol in rowth medium
128
Q

Coxiella burnetti

A
  • causes Q fever (mild pneumonia-like illness) that results from inhaling C. burnetti spores found in animal hides
129
Q

Small cell carcinoma

A

associated with smoking that is usually centrally located

  • arises from primitive cells in bronchial epithelium
  • stains are positive for neuroendocrine markers: neuron specific endolase, chromogranin, synaptophysin
130
Q

Neuroendocrine markers found in small cell carcinoma

A
  • Neuron specific enolase
  • Chromogranin
  • Synaptophysin
131
Q

Isoniazid

A
  • similar to pyroxidine
  • can increase urinary excretion of pyroxidine and cause deficiency of B6 and competes for binding sites with pyroxidine
  • B6 deficiency leads to defective synthesis of NTs like GABA- can induce neuropathy
132
Q

Isoniazid induced neuropathy

A
  • can be cured by pyroxidine supplementation
133
Q

Primary virulence factor of S. pnuemoniae

A

S. pneumoniae expresses polysaccharide capsule that inhibits phagocytosis by macrophages and PMNs (neutrophils)

134
Q

Diffusion limitation gas-exchange

A
  • caused by hypoxia that caused by pulmonary fibrosis, ARDS, emphysema
  • blood pO2 does NOT equilibrate with the alveolar pO2
135
Q

Perfusion limited gas ecxchange

A

occurs in resting sate

- blood equibrilation with alveolar gas is complete by the time blood crosses 1/3 of pulmonary capillary

136
Q

Apex of lung (Zone 1) in terms of V and Q

A
  • Wasted ventilation
  • V/Q =3
  • alveolar PO2 > blood pO2 > venous pO2
137
Q

Base of lungs (Zone 3) in terms of V and Q

A
  • Wasted perfusion
  • V/Q = .6
  • both ventilation and perfusion are higher in the base of the lung, BUT THE V/Q RATIO IS BIGGER IN APEX
  • arteriolar pO2 > venous pO2 > Alveolar pO2
138
Q

Middle of lung (Zone 2) in terms of

A
  • arteriolar pO2 > Alveolar pO2 > venous pO2
139
Q

Echinocandins (e.g. caspofungins and micafungin)

A

inhibit synthesis of polysaccharide glucan in ufngal cell walls

  • most active against Candida and Aspergillus
  • NOT EFFECTIVE in C. neoforms
140
Q

Terbinafine

A

accumulates in skin and nails and used to treat dermatophytosis
- inhibits squalene 2,3 epoxidase

141
Q

Griseofulvin

A
  • binds microtubules in fungi and inhibit mutosis

- effective against dermatophyte fungi as it accumulates in keratin containing tissues

142
Q

Allergic Bronchopulmonary Aspergillosis

A
  • caused by Aspergillus fumigatis
  • may complicate asthma
  • may result in recurrent pulmonary infiltrates
143
Q

Neutrophil chemotactic agents

A
  • Leukotriene B4
  • 5-HETE (leukotriene precursor)
  • complement component (5a)
144
Q

Side effects associated with ethambutol

A

causes optic neuritis that results in color blindness, central scotomas, and decreased visual acuity

145
Q

Side effects of aminoglycoside

A

Nephrotoxicity (dose dependent esp. when used with cephalosporins)
Neuromuscular blockade
Otoxicity (due to direct damage to CN VIII)
Teratogen

146
Q

Colonizing aspergillosis

A
  • occurs in old lung cavities (e.g. TB, emphysema or sarcoidosis)
  • does not invade lung tissue, but grows inside cavity to form “fungus ball”
  • may be asymptomatic or may present with hemoptysis
  • on X-ray, shifts when patient changes position
147
Q

Invasive aspergillosus

A
  • occurs in immunosuppressed patients
  • characterized by primary lung involvement, cough, hemoptysis
  • necrotizing pneumonia and granuloma formation may appear
  • biopsy shows lung invading tissue
148
Q

Hypersensitivity reactions to Aspergillosus

A
  • occurs in patients with asthma

- called allergic bronchopulmonary aspergillogosis (ABPA)

149
Q

ARDS

A
  • interstitial edema and alveolar edema associated with increased pulmonary capillary permeability
  • decreased in lung compliance
  • increase in work breath
  • worsened V/Q mismatch
  • CAPILLARY WEDGE PRESSURE STAYS NORMAL BECAUSE NOT HEART CAUSED PROBLEM
150
Q

Peptidoglycan layer in gram positives

A
  • protect them against osmotic stress and provide shape of bacterium
151
Q

Antiobiotics which disrupt cell wall syntheisis in gram-positive organisms

A

Penicillins
Cephalosportins
Vancomycin

152
Q

Chloramphenicol

A
  • anti-ribosomal antibiotic that inhibits the 50S bacterial ribosomal subunit
153
Q

Illnesses associated with cold agglutinins

A
  • Mycoplasma pneumonia
  • EBV infection
  • Hematologic infection
    • Cold agglutinins are antibodies that are antibodies for RBCs and cause clumping at low temps
154
Q

Pathogens most responsible for secondary bacterial pneumonia

A

S. pneumoniae
S. aureus
H. influenzae

** elderly are more likely to pick up new infections

155
Q

Ether and organic solvents can inactivated which type of viruses

A

“Enveloped viruses”

  • Ether dissolves lipid bipayer that makes up outer viral envelope
  • loss of infectivity is characteristic
156
Q

Nontypable strain of H. influenzae

A

strains that don’t form the antiphagocytic capsule

  • part of intestinal flora and cause EMOS
  • not conferred by vaccination
157
Q

Sarcoidoisis

A
  • affects young black women and presents with malaise, cough, and varied cutaneous findings
  • reveals bilateral hilar lymphadenopathy
  • non-caseating granulomas present in biopsy
158
Q

Absolute Risk Reduction

A

ARR = Event Rate (control) - Event Rate (studied treatment)

159
Q

H. influenzae type b vaccine

A
  • composed of polyribosyl-ribitol-phosphate (PRP)
  • conjugated with diptheria and tetanus toxoid
  • immune activation with antibody production and memory B-lymphocyte induction
160
Q

Polycythemias

A

Hct > 52% in men; Hct > 48% in women
may result of:
- true increase in RBC mass (Absolute polycythemia) OR
- decrease in plasma volume (Relative polycythemia)

161
Q

Relative polycythemia

A

normal RBC mass

- caused by dehydration or excessive diuresis

162
Q

Absolute polycythemia

A

true increase in RBC mass

- can result of polycythemia vera or secondaary erythrocytosis

163
Q

Primary erythrocytosis

A

e. g. polycythemia vera
- associated with LOW erythropoietin levels
- commonly caused by myeloproliferative disorders

164
Q

Secondary erythrocytosis

A
  • increased erythropoietin levels
    due to chronic hypoxia from high altitudes, smoking, or COPD OR
    due to abnormal secretion of erythropoetin
165
Q

Non enveloped RNA virususes

A
  • ENTEROVIRUSES (e.g. polioviruses, coxsackievirus, echovirus, hep A virus)
  • REOVIRUSES (e.g rotavirus)
  • NORWALK VIRUS
166
Q

Discuss viral protein synthesis for naked RNA viruses

A

Naked RNA viruses must be able to act directly as mRNA using host’s intracellular machinery for translatioj

167
Q

Which naked RNA viruses are more infectious?

Naked negative sense RNA viruses or Naked positive sense RNA viruses?

A
  • Naked viruses containing single stranded POSITIVE sense RNA can be infectious whereas
    naked viruses contaning single- or double stranded NEGATIVE SENSE RNA are not infectious
168
Q

Influenza

A

orthomyxovirus
SS - RNA
- to replicate in host cell, an RNA-dependent RNA polymerase within intact virion mus also gain entry into the host cell.

169
Q

HIV

A

retrovirus
enveloped and SS+ RNA
-packaged with reverse transcropatase
- RNA dependent DNA polymerase

170
Q

N-acetylcysteine

A

mucolytic agent used in treatment of CF

-works by cleaving disulfide bonds within mucus glycoproteins, thus loosening thick sputum

171
Q

Histoplasma capsulatum

A
  • can survive as small ovoid bodies intracellularly within macrophages
  • causes disseminated mycosis in immunocompromised patients
  • includes systemic mycosis (fever and weight loss), painful oral ulcers, HILAR lymphadenopathy, and hepatosplenomegaly

USMLE Step 1 (34 decks)

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