chronic obstructive lung disease

Question 1

Alveolar wall pneumocytes

Answer 1

Type 1 pneumocytes: cover 95% of alveolar surface

Type 2 pneumocytes: produce surfactant, repair alveolar epithelium

Question 2

Obstructive lung disease

Answer 2

Diseases that cause increased resistance to airflow out of the lung
Emphysema, chronic bronchitis, asthma, cronchiectasis

Question 3

Emphysema

Answer 3

Permanent enlargement of all or part of the respiratory unit ( respiratory bronchioles, alveolar ducts, alveoli) accompanied by wall destruction without obvious fibrosis
Males more
causes smoking, air pollution, a1 antitrypsin deficiency

Centriacinar (centrilobilar)- 95% cases
Panacinar

Question 4

Emphysema pathogenesis

Answer 4

Increased numbers of macrophages, CD8 T cells and PMNs

PMNs and Macrophages are activated by tissue damage from cigarette smoke

Elastase and free radicals derive from neutrophils and macrophages

Increased elastase and decreased antielastase (a1 antitrypsin), protease-antiprotease mechanism
Increased oxidants (free radical) and decreased antioxidants (oxidant antioxidants imbalance, oxidative injury inactivates native antiprotease)

destruction of elastic tissue, increased compliance and decreased elasticity

Question 5

emphysema pathophysiology

Answer 5

elastic tissue–> keeps airway lumen open by applying traction–> elastic destruction causes collpse of airways on expiration–> prevents exit of air (airflow obstruction)

Centriacinar before the alveolus

Panacinar in the actual alveolus

Question 6

Centracinar vs panacinar Emphysema

Answer 6

Centracinar: smokers emphysema, apical segments of upper lobes

Panacinar: a1-antitrypsin deficiency- autosomal dominant (phenotypes associated with severe deficiency PiZZ have marked under production of functional antiproteinases in the liver), lower lobes of the lungsm increased PMNs and smoking makes it much worse

Question 7

Emphysema clinical presentation

Answer 7

Dyspnea, pink puffers, coexistance with chronic bronchitis

CXR: increased AP diameter, hyperlucent lung fields, vertical heart, depressed diaphragms, club shaped or free floating septae

Question 8

Chronic bronchitis

Answer 8

Productive cough for 3 months for 2 years
Smoking and air pollutants
Pathogenesis: inhaled smoke (irritant)–> mucous hypersecretion in bronchi–> airflow obstruction in terminal bronchioles (more proximal than in emphysema). Infection, maintenance of disease, acute exacerbation, bronchospasm

Question 9

chronic bronchitis clinical presentation and morphology

Answer 9

Productive cough, cyanosis, blue bloater, expiratory wheezing and rhonci, corpulmonale

CXR: enlarged heart, horizontally oriented, increased bronchial markings

Morphology: hyperemia, swelling and edema of mucous membranes, mucinous and mucopurulent secretion

Question 10

REid index

Answer 10

Ration of the thickness of the mucous gland layer to the thickness of the wall between the epithelium and cartilage (normal=.4)

Question 11

Asthma

Answer 11

Chronic but reversible disorder of conducting airways caused by an immunologic reaction resulting in bronchoconstriction, inflammation and increased mucus secretion

Affects 8-10% of US pop
Types: Atomic (allergic) and non atopic

Wheezing, chest tightness, cough, dyspnea, peripheral eosinophilia, could lead to airway remodeling

Question 12

Atopic asthma

Answer 12

Type 1 (IgE mediated) hypersensitivity reaction
Begins in childhood, 2/3 pts diagnosed prior to 18, often coexisting allergic disorders (allergic rhinitis eczema etc)

Environmental allergens act synergistically with proinflammatory factors (viral infections)

Pathogenesis: exaggerated Th2 response to an Ag–> cytokine production (IL4, IL5, IL13)–> stimulation of B cells to produce IgE, activation og eosinophils–> IgE binds mast cells–> bronchoconstriction, mucus, vasodilation (early phase) and recruitment of more leukocytes (late phase)

Question 13

Non atopic asthma

Answer 13

No evidence of allergen sensitization, respiratory infections and inhaled pollutants are common triggers

Question 14

Bronchiectasis

Answer 14

permanent dilation of bronchi and bronchioles caused by destruction of smooth muscle and supporting elastic tissue- secondary disorder due to obstruction and chronic infection

Associated conditions: bronchial obstruction (tumor, foreign body, etc), hereditary condtions (cystic fibrosis, primary ciliary dyskinesia, immunodeficicency syndromes), necrotizing pneumonia (s aureus, klebsiella)

Question 15

Cystic fibrosis

Answer 15

inherited disorder of ion transport that affects fluid secretion in exocrine glands and lining of respiratory, GI, and reproductive tracts

AR mutaion in cystic fibrosis transmembrane conductance regulator gene

Increased Na and water reabsorption from luminal secretion and decreased Cl secretion from epithelial cells into lumen–> dehydration of body secretion due to lack of nacl

Defective mucocilliary action, pooling of secretion and obstruction of airways leading to secondary infection and inflammation (saureas, Hflu, p aeruginosa)
leads to bronchiectasis

Question 16

Bronchiectasis clinical presentation and morphology

Answer 16

Copious sputum, hemoptysis, digital clubbing, cor pulmonale

CXR: bronchial markings extending to the periphery of the lungs

Dilated airways with lots of mucus, lower lobes, dilated airways can be followed to pleural surfaces

Intense acute and chronic inflammatory exudate in bronchial walls, necrotizing ulceration, Squamous metaplasia of bronchial epithelium, hyperplasia of mucus cells, lung abscesses may be present, fibrosis of bronchial walls leading to bronchiolitis obliterans