L2: Resp. Path: Bronchitis, Bronchiolitis, Atelectasis, Emphysema (Castleman) Flashcards
2 main components of bronchi
cartilage (to prevent collapse) and glands
T/F: very small changes in bronchi diameter increases resistance markedly
T
chronic inflammation of bronchi –> dilation or shrinkage?
dilation
role of THICK connective tissue in bronchi
prevents infection spread into surrounding alceolar parenchyma
T/F: ciliated cells are terminally differentiated
T
which cells have capacity for regenerating bronchi epithelium?
mucous cells, basal cells, other nonciliated cells (Clara cells)
Do bronchioles have cartilage or glands?
NO
-patency maintained by interalveolar septa on bronchiolar wall
chronic inflammation –> bronchioles
stenosis of lumen
infection spread in bronchioles vs. bronchi
THIN CT of bronchioles allows spread to surrounding alveoli
Clara cells rich in what enzyme
cytochrome monooxygenase (cytochrome P450)
primary lobule
pulmonary tissue supplied by terminal bronchiole
secondary lobule
composed of many primary lobules. Constitute grossly visible lobules
-cattle have most
components of interalveolar septa
- epithelial cells (type 1 and 2)
- capillary endothelium
- fibroblasts (composed of elastin and collagen)
- macs
chars. of type 1 epithelial cells
- large SA
- susceptible to damage
- incapable of division
- terminally diff.
chars. of type 2 epithelial cells
- cuboidal
- produce surfactant and other mediators**
- effect epithelial repair
- stem cells
- diff. into type 1 cells
Q: Which of the following is NOT a stem cell for epithelial repair in bronchi/bronchioles?
a) mucous cells
b) ciliated cells
c) nonciliated cells
ciliated cells
Q: which serve as stem cells for epithelial repair in the interalveolar septum?
a) type 1
b) type 2
c) mucous cell
type 2
causes of bronchitis and bronchiolitis
- infectious (viral, bacterial, fungal, parasitic)
- toxic (plant toxins)
- hypersensitivity
functional consequences of bronchitis/iolitis
- inc. airway resistance –> obstruction, ventilation/perfusion abnormality –> hypoxemia
- dec. mucociliary clearance –> 2ary bacterial infection
sequelar of bronchitis/iolits
- resolution/repair
- extend to alveoli –> pneumonia
- chronic localized inflamm. in bronchi –> bronchiectasis or bronchioles –> bronchiolitis obliterans
- post-obstructive atelectasis
bronchiectasis
dilation of bronchi beyond normal physiological limits due to destruction of the bronchial wall
path. of bronchiectasis
1) chronic infection (usually bact.)
2) neut-mediated tissue destruction of glands/cartilage, fibrosis
gross morphology of bronchiectasis
1) airway dilation (saccular or cylindrical)
2) thick wall
3) luminal exudate
fx significance of bronchiectasis
1) inc. airway resistance
2) poor mucociliary clearance
3) aspiration of infective material to alveoli
sequelae of bronchiectasis
- irreversible!
- progression of inflamm. –> continued bronchial damage, pneumonia
bronchiolitis obliterans
obstruction of the bronchiolar lumen by fibrous connective tissue
atelectasis
collapse of the lung
2 types of atelectasis
1) neonatal (inadequate surfactant)
2) acquired (compressive or obstructive)
compressive atelectasis
fluid, air, mass compress lung or results in loss of neg. pleural pressure
why are cattle most easily affected by obstructive atelectasis?
don’t have collateral circulation in lungs.
post-obstructive atelectasis most common in cattle
path. significance of atelectasis
- segment of lung underventilated
- if widespread –> hypoxemia
sequelae of atelectasis
1) resolution of cause: reinflation
2) alveolar edema
3) secondary bacterial pneumonia
4) fibrosis and irreversible collapse
pulmonary emphysema
enlarged gas-filled space in the lung
-can be alveolar or interstitial
path. significance of alveolar emphysema
- decreased alveolar/capillary SA
- loss of radial support for airways: early closure
- decreased elastic properties; increased compliance and residual lung capacity
- pulmonary hypertension
which type of emphysema is irreversible?**
alveolar
interstitial emphysema
excess gas in the pulmonary interstitium
-occurs in species w/ extensive interlobular septa
pathogenesis of interstitial emphysema
1) forced expiration against obstructed airways
2) gas dissects into interstitial tissue (interlobular septa, perivascular areas, subpleural tissues)
pathological significance of interstitial emphysema
compression of lobules decreases ventilation (restrictive lung disease)
interstitial emphysema sequelae
1) resolution
2) progression: mediastinum and subcutis (gas bubbles)
3) secondary infection of pockets
4) fibrosis and parenchymal loss
5 most common things that lead to edema in the lung
1) inc. hydrostatic pressure assoc. w/ CV abnormalities
2) inc. permeability of vessels assoc. with inflamm. or injuries
3) obstruction of lymphatics
4) hypoalbuminemia/decreased oncotic pressure
5) increased sodium
Q: most common cause of bronchiectasis
a) viral infection
b) chronic dust inhalation
c) chronic bacterial infection
C)chronic bacterial infection
Q: which is reversible?
a) bronchiectasis
b) bronchiolitis obliterans
c) atelectasis
d) alveolar emphysema
c) atelectasis
pneumonia
inflamm. of the pulmonary gas exchange parenchyma
- causes: infectious, toxic, immunologic, mixed
distr. of aspiration pneumonia
cranioventral
4 distribution types of pneumonia
focal
multifocal
locally-extensive
diffuse
4 main morphologic classifications of pneumonia
1) bronchopneumonia
2) interstitial pneumonia (rare)
3) focal or multifocal (embolic)
4) mixed (ie bronchointerstitial)
slide 26 chart
:)
pathogenesis of bronchopneumonia
- deposition of causative agent in terminal bronchioles and alveoli
- early damage in proximal acinar areas w/ spread into surrounding alveolar parenchyma
gross morph. of bronchopneumonia
-cranioventral
+/- fibrinous pleuritis, lobar distribution
-chronic –> fibrosis and lymphadenomegally
histo of bronchopneumonia
- abundant exudate in alveoli including neuts, fibrin, necrotic debris
- airway oriented lesions initially
pathophysiologic significance of bronchopneumonia
- airway obstruction
- infiltration of walls and filling of alveoli –> stiffer lungs
- exudate and alveolar wall thickening –> dec. diffuse capacity
- pleuritis may contribute to restrictive disease
bronchopneumonia sequelae
- resolution
- death
- septicemia
- chronic bronchopneumonia w/ bronchiolitis obliterans and bronchiectasis +/- pleural adhesions
interstitial pneumonia pathogenesis
- primary injury to elements of the interalveolar septum: epithelial, endothelial
- causes: infectious, toxic, hypersensitivity
gross morph. of interstitial pneumonia
diffuse or locally extensive firm, large, red
histo morph. of interstitial pneumonia
- acute: type 1 epithelial necrosis
- subacute: type 2 hyperplasia, alveolar septa thickening, mononuclear cells
- chronic: fibrosis
pathophys. significance of interstitial pneumonia
- -> decreased compliance, increased stiffness
- dec. diffusion capacity –> hypoxemia
interstitial pneumonia sequelae
- resolution
- death
- fibrosis of interalveolar septa and progressive restrictive lung dz
Q: if distr. of pneumonia is cranioventral, it is most likely:
a) aspiration pneumonia
b) fungal pneumonia
c) viral pneumonia
d) bronchopneumonia
e) interstitial pneumonia
d) bronchopneumonia
Q: most likely causes of bronchopneumonia
a) bacteria
b) virus
c) aspiration
d) A and B
e) A and C
A and C
Q: if pneumonia is diffuse, the least likely cause is:
a) virus
b) protozoa
c) toxins
d) aspiration
e) bacterial septicemia
d) aspiration
if it ain’t firm…
…it ain’t pneumonia
pathogenesis of acute viral pneumonia
- virus replicates in resp. airway and alveolar epithelial cells
- induces inflamm. and immune response
- inflamm. in parenchyma is focused on interalveolar septa
- viral replication is effectively halted before diffuse interstitial pneumonia develops
morph. features of acute viral pneumonia
virus-induced epithelial injury and inflamm. manifesting as:
- rhinitis
- tracheitis/bronchitis
- bronchiolitis
- patchy interstitial pneumonia
chars. of chronic viral pneumonia
- assoc. with viruses that replicate in macs and/or depress or escape antiviral immunologic mechs.
- virus spreads throughout the lung and induces diffuse interstitial pneumonia
ex. of chronic viral pneumonia viruses
ovine progressive pneumonia
canine distemper virus
