Usmle Respiratory

Front 1

Physical findings in bronchial obstruction

Back 1

Breath sounds absent/decreased over affected area
Decreased resonance
Decreased fremitus
Tracheal deviation toward side of lesion

Front 2

Physical findings in Pleural effusion

Back 2

Decreased breath sounds over effusion.
Dullness on resonance
Decreased fremitus

Front 3

Physical findings in lobar pneumonia

Back 3

May have bronchial breath sounds over lesion.
Dullness on resonance
Increased fremitus

Front 4

Physical findings with pneumothorax

Back 4

Decreased breath sounds
Hyperresonant on resonance
Absent fremitus
Tracheal deviation away from side of lesion.

Front 5

Location, Characteristics and Histology of Squamous Cell Lung Cancer

Back 5

Central Location

Hilar Mass arising from bronchus. Cavitation. Clearly linked to Smoking, Parathyroid-like activity PTHrP

Keratin pearls and intercellular bridges.

Squamous Sentral Smoking

Front 6

Location, Characteristics and Histology of Adenocarcinoma.

Bronchial and bronchioalvelar

Back 6

Peripheral location.

Developes in site of prior pulm inflammation or injury. most common lung cancer in nonsmokers and females.

Bronchioloalveolar - not linked to smoking

Both types: Clara cells --> type II pneumocytes; multiple densities on x-ray of chest.

Front 7

Location, Characteristics and Histology of small cell (oat cell) carcinoma.

Back 7

Central location.

Undifferentiated, very aggressive. often associated with ectopic production of ACTH or ADH, may lead to Lambert-Eaton syndrome (autoantibodies against calcium channels). responsive to chemotherapy

Neoplasm of neuroendocrine Kulchitsky cells --> small dark blue cells.

Front 8

Location, Characteristics and Histology of large cell carcinoma

Back 8

Peripheral location.

Highly anaplastic, undifferentiated tumor; poor prognosis; less responsive to chemotherapy. Removed surgically.

Plemorphic giant cells with leukocyte fragments in cytoplasm

Front 9

Location, Characteristics and Histology of Carcinoid tumor

Back 9

Secretes serotonin, can cause carcinoid syndrome (flushing, diarrhea, wheezing, salivation).

Front 10

Location, Characteristics and Histology of Metastasis.

Back 10

Very common.
Brain - epilepsy
Bone - pathologic fracture
Liver - jaundice, hepatomegaly

Front 11

Drugs associated with interstitial fibrosis

Back 11

1. Amiodarone
2. Bleomycin and busulfan
3. Cyclophosphamide
4. Methotrexate and methysergide
5. Nitrosourea and nitrofurantoin.

Front 12

Muscles of active inspiration

Back 12

external intercostals
scalenes
sternomastoids
(diaphragm)

Front 13

Muscles of active expiration

Back 13

rectus abdominis
internal and external obliques
transversus abdominis
internal intercostals

Front 14

Vital capacity formula

Back 14

= IRV + TV + ERV

(everything but RV)

Front 15

Functional residual capacity formula

Back 15

= ERV + RV

volume in the lungs after normal expiration

Front 16

Inspiratory capacity formula

Back 16

= TV + IRV

Front 17

Physiological dead space

formula and definition

Back 17

Vd = Vt x ( (PaCO2 - PeCO2) / (PaCO2)

anatomical dead space of conducting airways plus functional dead space in alveoli.

Volume of inspired air that does not take part in gas exchange.

Front 18

Factors that cause a right shift of the hemoglobin-O2 dissociation curve

Back 18

Inc CO2
Inc Acid, Altitude
Inc 2,3-DPG
Inc Exercise (metabolic needs)
Inc Temperature

Right shift - CADETs face Right

Front 19

Molecules that are perfusion limited

Back 19

O2 (healthy), CO2, N2O

Gas equilibrates early along capillary

Diffusion can be increased only if blood flow increases

Front 20

Molecules that are diffusion limited

Back 20

CO, O2 (emphysema, fibrosis)

Gas does not equilibrate by the time blood reaches end of capillary

Front 21

Pulmonary hypertension

Back 21

> 25 mmHg in pulm artery
normally 10-14 mmHg

1 - unknown etiology, poor prognosis
smooth mm hypertrophy, fibrosis of intima, inc endothelial cells
Rx - Bosentan

2 - usually caused by COPD, can also be caused by L--> R shunt

Front 22

Pulmonary vascular resistance equation

Back 22

PVR = (pulm artery pressure - left atrium (PCWP) ) / CO

Front 23

Oxygen content

Oxygen delivery

Back 23

O2 content = (O2 binding capacity x % saturation) + dissolved O2

O2 delivery to tissues = CO x O2 content of blood

Front 24

Alveloar gas equation

Back 24

PAO2 = 150 - (PaCO2/ 0.8)

Front 25

Haldane effect

Back 25

oxygenation of Hb promotes dissociation of H+ from Hb

Shifts equilibrium toward CO2 formation, so CO2 is releasd form RBCs

Front 26

Bohr effect

Back 26

In peripheral tissue, H+ from tissue metabolism shifts curve to right unloading O2

Front 27

Responses to high altitude

Back 27

Acute/Chronic increase in ventilation
Inc erythropoietin resulting in increased Hct and Hgb
Inc 2,3 DPG (inc unloading)
Cellular changes (inc mitochondria)
Inc renal excretion of bicarb to compensate for respiratory alkalosis
Chronic hypoxic pulm vasoconstriction results in RVH

Front 28

PFT changes seen in obstructive lung disease

Back 28

obstruction of air resuling in air trapping in lungs
airways close prematurely at high lung volumes
Inc RV, dec FVC
DEc FEV/FVC < 80%
V/Q mismatch

Front 29

Chronic bronchitis

Back 29

Blue bloater

hypertrophy of mucus-secreting glands in bronchioles
Reid index = gland depth/total thickness of wall
here, > 50%

Productive cough for > 3 consecutive months in > 2 years

Disease of small airways
Wheesing, crackles, cyanosis

Front 30

Emphysema

Back 30

Pink puffer - barrel-shaped chest

Enlargement of air spaces and dec recoil resulting from destruction of alveolar walls

Centriacinar - caused by smoking
Panacinar - alpha-antitrypsin deficiency
Paraseptal emphysema - associated with bullae - can rupture, cause spontaneous pneumothorax in young, otherwise healthy males

lung compliance due to loss of elastic fibers.
exhale through pursed lips to increase airway pressure and prevent airway collapse during exhallation

dyspnea, dec breath sounds, tachycardia, dec I/E ratio

Front 31

Asthma

Back 31

Bronchial hyperresponsiveness causes reversible bronchoconstriction

Smooth muscle hypertrophy and Curschmann's spirals (shed epithelium from mucus plugs)

Triggered by viral URIs, allergens, stress

Cough, wheezing, dyspnea, tachypnea, hypoxemia, Dec I/E ratio, pulsus paradoxus, mucus plugging

Front 32

Bronchiectasis

Back 32

Chronic necrotizing infection of bronchi:
permanently dilated airways, prurulent sputum, recurrent infections, hemoptysis

Assoc w/ bronchial obstruction, CF, poor ciliary motility, Kartagener's. can develop aspergillosis

Front 33

Restrictive lung disease

Back 33

Dec lung volumes - FVC, TLC
FEV/FVC > 80%

Due to:
1. Poor breathing mechanics - extrapulmonary, peripheral hypoventilation
- poor muscular effort, poor structural apparatus

2. Interstitial lung diseases (pulmonary, lowered diffusing capacity)
- ARDS, NRDS, pneumoconiosis, sarcoidosis, IPF, Goodpasture's, Wegener's, eosinophilic granulomas (histiocytois X), drugs

Front 34

Beta agonists used in the treatment of asthma

Back 34

Isoproterenol - nonspecific - relaxes bronchial smooth muscle b2, tachycardia b1

Albuterol - b2 selective, use in acute exacerbation

Salmeterol - long acting agent for prophylaxis. adverse effects - tremor, arrhythmia

Front 35

Methylxanthines

Back 35

Theophylline - likely causes bronchodilation by inhibiting phosphodiesterase, decreasing cAMP

narrow therapeutic index
p450 metabolism

Front 36

Muscarinic agonist used for asthma

Back 36

Ipratopium - competitive block of muscarinic receptors, preventing bronchoconstriction

Front 37

Corticosteroids used for asthma

Back 37

Beclomethasone, prednisone - inhibit the synthesis of all cytokines by inactivating NFkB

First line for chronic asthma

Front 38

Antileukotrienes used for asthma

Back 38

Zileuton - a 5 - lipoxgenase pathway inhibitor.
Blocks conversion of arachadonic acid to leukotrienes

Zafirlukast, montelukast - block leukotriene receptors.
Especially good for aspirin-induced asthma