Respiratory

Question 1

Describe the components of the alveoli wall.

Answer 1

1. Capillary endothelium and basement membrane.
2. Pulmonary interstitum (composed of fine elastic fibers, collagen bundles, fibroblasts, smooth muscles, mast cells)
3. Alveolar epithelium

Question 2

What are two types of alveolar epithelium cells?

Answer 2

Type I: covers 95% of alveoli surface.

Type II: Produces surfactant

Question 3

What are pulmonary acini?

Answer 3

Distal part of terminal bronchioles. Made up of respiratory bronchioles that differentiate into alveolar ducts.

Question 4

What is atelectasis?

Answer 4

Lung collapse due to inadequate expansion of air spaces.

Question 5

What are 3 causes of atelectasis?

Answer 5

1. Resorption atelectasis: obstruction prevents air from reaching distal airways, leading to alveolar collapse (e.g. mucous plugs, foreign bodies)
2. Compression atelectasis: associated with accumulation of blood, fluid, or air within pleural cavity (e.g. pleural effusion, pneumothorax)
3. Contraction atelectasis: local or diffuse fibrosis affecting lung expansion.

Question 6

Define Acute Respiratory Distress Syndrome (ARDS)

Answer 6

Respiratory failure occurring within 1 week of a known clinical insult with bilateral opacities on chest imaging. Life threatening respiratory insufficiency, cyanosis, hypoxia.

Question 7

What are common triggers of ARDS?

Answer 7

Pneumonia
Sepsis
Aspiration
Trauma
Pancreatitis
Transfusion reaction

Question 8

Describe pathogenesis of ARDS.

Answer 8

Neutrophils enter the alveolar space and release leukotrienes/oxidants/proteases, which contribute to tissue destruction, accumulation of edema fluid, loss of surfactant, scar tissue formation.

Question 9

Describe emphysema.

Answer 9

Alveolar wall destruction, air space enlargement. Common in smokers. Signs include: dyspnea, cachexia, barrel chested, tripoding, hyperventilation, “pink puffers”

Question 10

Describe bronchiectasis

Answer 10

A consequence of an underlying infection, obstruction, or other pathology that causes permanent dilation of bronchioles. Signs would include cough, purulent sputum, fever.

Question 11

Describe chronic bronchitis.

Answer 11

Mucous gland hypertrophy, hyperplasia and hypersecretion. Common in smokers. Signs include cough and sputum production.

Question 12

What are 4 types of emphysema?

Answer 12

1. Centriacinar: Central part of acini affected, most common in smokers, associated w/chronic bronchitis.
2. Panacinar: Acini are uniformly enlarged, commonly in lower lung zones, associated w/ a1-anti-trypsin deficiency.
3. Distal acinar: Distal part of acini affected, idiopathic, young adults at risk for pneumothorax.
4. Irregular: Acinus irregularly involved, associated w/ scarring from inflammatory disease, most common form.

Question 13

What is the difference between a pink puffer and blue bloater?

Answer 13

Pink puffer: lower body mass index, fewer cardiovascular co-morbidities, less muscle mass, hyperinflation, more dyspnea, decreased exercise capacity, worse health status.
Blue bloater: Higher body mass index, more metabolic co-morbidities, cardiac compromise, obstructive sleep apnea/COPD overlap, more chronic bronchitis, increased exacerbations.

Question 14

What is bullous emphysema?

Answer 14

Any form of emphysema that produces large subpleural blebs or bullae which can cause pneumothorax if they rupture.

Question 15

What is alpha 1-anti-trypsin deficiency?

Answer 15

A genetic disease that causes destruction of elastic tissue, giving rise to emphysema.

Alpha 1-anti-trypsin normally protects the lungs from destructive enzymes.

Question 16

Describe pathogenesis of asthma.

Answer 16

Genetic predisposition to type I hypersensitivity, chronic airway inflammation, and bronchial hypersensitivity are contributors. Eosinophils are responsible for airway damage.

Question 17

What are hallmark features of chronic interstitial lung disease?

Answer 17

The hallmark of these disorders is reduced compliance (stiff lungs), which in turn necessitates increased effort to breathe (dyspnea) – damage to the alveolar epithelium and interstitial vasculature produces abnormalities in the ventilation-perfusion ratio, leading to hypoxia.

Question 18

What is idiopathic pulmonary fibrosis?

Answer 18

Refers to a pulmonary disorder of unknown etiology that is characterized by patchy, progressive bilateral interstitial fibrosis. Males are affected more often than females, and it is a disease of aging, virtually never occurring before 50 years of age.

Question 19

Define pneumoconiosis.

Answer 19

Lung disorders caused by inhalation of mineral dusts. Includes diseases induced by organic and inorganic particles. 3 most common are coal dust, silica, and asbestos.

Question 20

Describe pathogenesis of silicosis.

Answer 20

Caused by inhalation of silica, common in mining. Particles interact with epithelial cells and macrophages and cause inflammation. Xrays show fine nodularity in upper zone of lung. Progressive massive fibrosis causes shortness of breath, pulmonary hypertension, susceptibility to tuberculosis.

Question 21

Describe pathogenesis of asbestosis.

Answer 21

Asbestos phagocytized by macrophages, cause inflammation, function as tumor initiator. Xrays show pleural plaques as circumscribed densities. Worsening dyspnea 10-20 years after exposure, can lead to congestive heart failure, cor pulmonale, mesothelioma.

Question 22

What is sarcoidosis?

Answer 22

Restrictive chronic disease characterized by non-necrotizing granulomatous inflammation. Causes bilateral hilar lymphadenopathy, most of lungs evolved and may eventually become fibrosed. Dry eyes and erythema/subcutaneous nodules are associated symptoms.

Question 23

What is pulmonary hypertension?

Answer 23

Pulmonary arteries become hypertrophied, atherosclerized. Heart has right ventricular hypertrophy. Causes pulmonary pressure of 25 mmHg or greater. Can be caused by left sided heart disease, COPD, interstitial lung disease.

Question 24

What organisms cause community-acquired bacterial pneumonia?

Answer 24

Strep pneumoniae.
Haemophilus influenzae.
Moraxella catarrhalis.
Staph aureus.
Legionella pneumophila.
Enterobacteriacae (klebsiella pneumoniae).
Mycoplasma pneumoniae.
Chlamydia pneumoniae.
Coxiella burnetii.

Question 25

What organisms cause community-acquired viral pneumonia?

Answer 25

Respiratory syncytial virus.
Human metapneumovirus.
Parainfluenza A virus.
Influenza A and B.
Adenovirus.

Question 26

What organisms cause nosocomial pneumonia?

Answer 26

Gram-negative rods (Enterobacteriacae, Klebsiella spp., Serratia marcescens, E coli.) Psudomonas spp. S. aureus.

Question 27

What organisms cause aspiration pneumonia?

Answer 27

Anaerobic oral flora (bacteroides, prevotella, fusobacterium, peptostreptocuccus), mixed with aerobic bacteria (S. pneumoniae, S. aureus, H influenza, Pseudomonas aeruginosa)

Question 28

What organisms cause pneumonia in an immunocompromised host?

Answer 28

Cytomegalovirus.
Pneumocystis jiroveci.
Mycobacterium avium complex.
Invasive aspergillosis.
Invasive candidiasis.
"Usual" bacterial, viral, fungal organisms.

Question 29

What are four stages of lobar pneumonia?

Answer 29

1. Congestion: lung is heavy, bogged, red.
2. Red hepatization: massive confluent exudation, lobe is red/firm/airless. Liver like consistency.
3. Gray hepatization: progressive disintegration of red cells and persistent fibrinosuppurative exudate.
4. Resolution: exudate in alveolar spaces broken down by enzymatic digestion, resorbed, ingested by macrophages.

Question 30

What are features of bronchopneumonia?

Answer 30

Consolidated area of acute suppurative inflammation. 1 lobe but more often multilobar, frequently bilateral and basal because secretions gravitate to lower lobes.

Question 31

List the clinical features of viral pneumonia.

Answer 31

1. Viruses invade epithelium more, cause interstitial swelling, less productive cough, increasing SOB.
2. Macroscopically, affected areas are red-blue, congested, subcrepitant.
3. Histological exam: inflammatory reaction confined to walls of alveoli.

Question 32

What are epidemiology and risk factors of tuberculosis?

Answer 32

1. Most common cause of death resulting from a single infectious agent.
2. TB flourishes under conditions of poverty, crowding, chronic illness.
3. (In US) older adults, urban poor, patients with AIDS, minority communities.
4. Diabetes, Hodgkin lymphoma, chronic lung disease, chronic renal failure, malnutrition, alcoholism, immunosuppression increase risk.

Question 33

Regarding tuberculosis, explain infection.

Answer 33

Infection: implies seeding of a focus with organisms, which may or may not cause clinically significant tissue damage (disease). Droplet transmission. Usually TB infection is asymptomatic, though it can develop with fever and pleural effusions.

Question 34

Explain the PPD test and delayed hypersensitivity.

Answer 34

Infection with M. Tuberculosis typically leads to development of delayed hypersensitivity which can be detected by the TB (Mantoux) test.
2-4 weeks after infection, .1 mL of sterile purified protein derivative (PPD) causes induration in 48-72 hours.
Positive TB test signifies cell-mediated hypersensitivity to TB antigens but doesn’t differentiate between infection and disease.

Question 35

Describe the pathogenesis of tuberculosis.

Answer 35

1. Inahled bacilli implant in distal airspaces of lower part of upper lobe or upper part of lower lobe to form 1-1.5 cm inflammation with caseous necrosis called Ghon focus.
2. Spreads to lymph nodes and caseates, creating Ghon complex.
3. Infection typically controlled, Ghon complex undergoes fibrosis to become Ranke complex.

Question 36

Define primary vs secondary tuberculosis.

Answer 36

Primary: form of disease that develops in previously unexposed and unsensitized patient. Only sign of infection is tiny fibrocalcific nodule. Remains dormant.
Secondary: Pattern of disease in sensitized host. Reactivation of dormant primary lesions decades after infection when resistance is weakened. Cavities form that erode lung tissue, patient becomes contagious.

Question 37

What are symptoms of mycobacterium avium and who is particularly at risk?

Answer 37

Symptoms: Fever, night sweats, weight loss, hepatosplenomegaly, lymphadenopathy, diarrhea, malabsorption, pulmonary symptoms mimicking TB. No granulomas but macrophages “stuffed” with atypical mycobacteria.

HIV patients are particularly at risk.

Question 38

Describe epidemiology of histoplasmosis.

Answer 38

Endemic to Ohio/Mississippi River valleys and Appalachia. Infection caused by soil-dwelling thermally dimorphic fungus Histoplasma capsulatum. Infection results from inhalation of aerosolized spores.

Question 39

Describe epidemiology of coccidiodomyosis.

Answer 39

Caused by soil-dwelling, dimorphic fungi coccidioides immitis and coccidioides posadasii, which are found in southwestern and western US. “Valley fever”

Question 40

Describe epidemiology of blastomycosis.

Answer 40

Systemic pyogranulomatous infection, arises after inhalation of conidia of blastomyces dermatitidis or blastomyces gilchristii a fungus. Endemic in Ohio/Mississippi river valley and Appalachia.

Question 41

What are the 3 major histological classifications of lung cancer?

Answer 41

1. Adenocarcinoma: Most common, most common primary tumors arising in women, never smokers, individuals younger than 45.
2. Squamous cell carcinoma: Strong association with smoking. Arise in major bronchi
3. Small cell carcinoma: Strong association with smoking. Extend into lung parenchyma

Question 42

What are 6 most common paraneoplastic syndromes associated with lung cancers?

Answer 42

1. hypercalcemia
2. Cushing syndrome
3. Syndrome of inappropriate secretion of antidiuretic hormone.
4. Neuromuscular syndromes (myathenic syndrome, peripheral neuropathy, polymyositis)
5. Clubbing of fingers/hypertrophic pulmonary osteoarthropathy
6. Coagulation abnormalities (thrombus, nonbacterial endocarditis)

Question 43

What is a pulmonary carcinoid tumor? What are its symptoms?

Answer 43

Malignant tumor that contain dense-core neurosecretory granules that may secrete active hormones.
SYMPTOMS: cough, hemoptysis, recurrent bronchial/pulmonary infections, carcinoid syndrome (diarrhea, flushing, cyanosis)

Question 44

What is pleural effusion?

Answer 44

Fluids in pleural space of the lungs, can be either transudate or exudate. Transudate suggests osmotic/hydrostatic imbalance. Exudate suggests pleuritis due to infection or cancer.

Question 45

What is the difference between a primary and secondary pneumothorax?

Answer 45

Primary: simple, spontaneous pneumothorax that occurs in healthy adults, usually men, without known pulmonary disease.
Secondary: consequence of rupture of pulmonary lesion situated close to pleural surface that allows inspired air to gain access to pleural cavity. Can result from thoracic or lung disorder.

Question 46

What is pyopneumothorax?

Answer 46

AKA infected hydropneumothorax or empyemic hydropneumothorax. Pleural collection of pus and air.

Question 47

What is a chylothorax?

Answer 47

Pleural collection of a milky lymphatic fluid containing microglobules of lipid. Implies obstruction of major lymph ducts, usually by intrathoracic cancer.

Question 48

What is a hydropneumothorax?

Answer 48

Serous fluid collects in the pleural cavity

Question 49

What is a ball-valve leak? (due to pneumothorax)

Answer 49

Tension pneumothorax shifts mediastinum. Leads to compromise of pulmonary circulation that can be fatal. If lung is not re-expanded within a few weeks so much scarring may occur that prevents lung from ever re-expanding.