Histopathology - Pulmonary Pathology

Front 1

The airways serve as conduits for ?

Back 1

1. Air traveling to and from alveoli;

2. For evacuation of material along the mucociliary escalator;

3. And for immunologic, protective, air-moisturizing, and warming functions

Front 2

How many generations of bronchial buds are?

Back 2

In a normal individual, there are approximately 20 generations of bronchial buds(~10-30 divisions, depending on the location in and distance from the trachea) extending from the trachea to the respiratory bronchioles.

Front 3

In health histologically, the diameter of an airway is ?

Back 3

In health histologically, the diameter of an airway ~ the same as its accompanying artery (and vice versa)

Disparities in size (of either airway or artery) suggest a pathologic condition.

Front 4

Define the airways

Back 4

Front 5

About the epithelium of the airways

Back 5

1. Vocal cords = stratified squamous epithelium

2. Except for the vocal cords, which are covered by stratified squamous epithelium,

the entire respiratory tree, including:

The larynx, Trachea And bronchioles is lined by pseudostratified, tall, columnar, ciliated epithelial cells.

Front 6

About mucus secreting cells and submucosal

Back 6

Numerous mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of the trachea and bronchi (but not the bronchioles).

Front 7

List examples of congenital anomalies of the lung

Back 7

Developmental defects of the lung include the following:

1.Agenesis or hypoplasia of both lungs, one lung, or single lobes

2. Tracheal and bronchial anomalies (atresia, stenosis, tracheoesophageal fistula)

3. Vascular anomalies

4. Congenital lobar overinflation (emphysema)

5. Foregut cysts

6. Congenital pulmonary

7. airway malformation

8. Pulmonary sequestrations

Front 8

Definition -

Obstructive airway diseases Vs restrictive airway diseases

Back 8

(1) obstructive diseases (or airway diseases), characterized by an increase in resistance to airflow due to partial or complete obstruction at any level, from the trachea and larger bronchi to the terminal and respiratory bronchioles, and

(2) restrictive diseases, characterized by reduced expansion of lung parenchyma and decreased total lung capacity.

Front 9

Obstructive Vs restrictive airway diseases and pulmonary function tests

Back 9

In individuals with

1. diffuse obstructive disorders, pulmonary function tests show decreased maximal airflow rates during forced expiration, usually measured by forced expiratory volume at 1 second.

2. Restrictive diseases are identified by a reduced total lung capacity, and an expiratory flow rate that is normal or reduced proportionately

Restrictive defects occur in two general conditions:

(1) chest wall disorders

(2) chronic interstitial and infiltrative disease

Front 10

Restrictive defects occur in two general conditions: list them plus examples

Back 10

Restrictive defects occur in two general conditions:

1. Chest wall disorders

2. chronic interstitial and infiltrative diseases

(1) chest wall disorders

(e.g., neuromuscular diseases such as poliomyelitis, severe obesity, pleural diseases, and kyphoscoliosis)and(2) chronic interstitial and infiltrative diseases,

such as pneumoconioses and interstitial fibrosis of unknown aetiology.

Front 11

restrictive diseases, characterized by ?

Back 11

restrictive diseases, characterized by

1. reduced expansion of lung parenchyma and

2. decreased total lung capacity.

Front 12

Disorders associated with airflow obstruction - COPD

Back 12

1. At the bronchus

2. Bronchiole

3. Acinus

1. At the bronchus -

a. Chronic bronchitis

b. Bronchiectasis

c. Asthma

2. At the Bronchiole

a. Small airway disease

b. Bronchiolitis

3. At the acinus

a. Emphysema

Front 13

Kartagener syndrome

1. Inheritance?

2. Triad?

3. Cause?

Back 13

1. Autosomal recessive

2. Bronchiectasis, chronic sinusitis, situs invertus ( dextrocardia)

3. Cause is - immotile cilia due to defect of dynein arms

Front 14

What is situs invertus

Back 14

Organs are switched

Liver is on the left, stomach is on the right etc.. Normally, cilia move the organs during embryogenesis. So, with defect in dynein arms cilIa doesn't work and so, doesn't move the organs..

It's is one if the triad of Kartagener syndrome

Others being - Bronchiectasis, chronic sinusitis

Front 15

Define emphysema

Back 15

Emphysema is a condition of the lung characterized by irreversible enlargement of the airspaces distal to the terminal bronchiole, accompanied by destruction of their walls without obvious fibrosis

Front 16

Classify emphysema

1. On basis of ?

2. Types

Back 16

1. On the basis of its anatomic distribution within the lobule

2. Types -

a. Centriacinar

b. Panacinar

c. Paraseptal

d. Irregular

Front 17

What is a lobule

Back 17

A lobule is a cluster of acini , the terminal respiratory unit

Front 18

..... is the most common type of emphysema

Back 18

Centriacinar emphysema

Front 19

About Centrilobular / Centriacinar emphysema

Back 19

1. In this type of emphysema the central or proximal parts of the acini, formed by respiratory bronchioles, are affected, whereas distal alveoli are spared.

2. Both emphysematous and normal airspaces exist within the same acinus and lobule.

3. The lesions are more common and usually more severe in the upper lobes, particularly in the apical segments.

4. The walls of the emphysematous spaces often contain large amounts of black pigment.

5. Inflammation around bronchi and bronchioles is common.

6. Centriacinar emphysema occurs predominantly in heavy smokers, often in association with chronic bronchitis.

Front 20

About Panacinar / panlobular emphysema

Back 20

1. In this type, the acini are uniformly enlarged from the level of the respiratory bronchiole to the terminal blind alveoli

2. The prefix “pan” refers to the entire acinus but not to the entire lung.

3. In contrast to centriacinar emphysema, panacinar emphysema tends to occur more commonly in the lower zones and in the anterior margins of the lung, and it is usually most severe at the bases.

4. This type of emphysemais associated with α1-antitrypsin (α1-AT) deficiency.

Front 21

About Paraseptal emphysema / distal acinar emphysema

Back 21

1. The proximal portion of the acinus is normal, and the distal part is predominantly involved.

2. The emphysema is more striking adjacent to the pleura, along the lobular connective tissue septa, and at the margins of the lobules.

3. It occurs adjacent to areas of fibrosis, scarring, or atelectasis and is usually more severe in the upper half of the lungs.

4. The characteristic findings are of multiple, continuous, enlarged airspaces from less than 0.5 cm to more than 2.0 cm in diameter, sometimes forming cystlike structures.

5. This type of emphysema probably underlies many of the cases of spontaneous pneumothorax in young adults.

Front 22

The characteristic findings in Paraseptal emphysema

Back 22

The characteristic findings are of multiple, continuous, enlarged airspaces from less than 0.5 cm to more than 2.0 cm in diameter, sometimes forming cystlike structures.

Front 23

Morphology of emphysema

Back 23

Grossly

1. Lungs are voluminous, often overlapping the heart and hiding it when the anterior chest wall is removed.

2. Generally, the upper two thirds of the lungs are more severely affected.

3. Large apical blebs or bullae are more characteristic of irregular emphysema secondary to scarring and of distal acinar emphysema.

4. Large alveoli can easily be seen on the cut surface of formalin-inflated fixed lung.

Microscopically,

1. there are abnormally large alveoli separated by thin septa with only focal centriacinar fibrosis

2. There is loss of attachments of the alveoli to the outer wall of small airways.

3. The pores of Kohn are large

4. As alveolar walls are destroyed, there is decrease in the capillary bed.

Front 24

List other forms of emphysema

Back 24

1. Compensatory hyperinflation emphysema ( f/f surgical removal of a diseased ling or lobe )

2. Obstructive overinflation - subtotal obstruction by a tutor or foreign object

3. Bulbous emphysema - large subplural blebs or bullae

4. Interstitial emphysema

5.

6.

7.

Front 25

Define chronic bronchitis

Back 25

Chronic bronchitis is defined clinically as persistent cough with sputum production for at least 3 months in at least 2 consecutive years, in the absence of any other identifiable cause.

Front 26

Chronic bronchitis is not trivial it was once thought.

When persistent for years, it may lead to

Back 26

When persistent for years, it may

(1) progress to COPD,

(2) lead to cor pulmonale and heart failure, or

(3) cause atypical metaplasia and dysplasia of the respiratory epithelium, providing a rich soil for cancerous transformation

Front 27

....... Stimulate mucus secretion in chronic bronchitis

Back 27

Proteases released from neutrophils, such as

neutrophil elastase and

cathepsin, and

matrix metalloproteinases, stimulate this mucus hypersecretion.

Front 28

About Reid index

Back 28

1. In chronic bronchitis

2. Although the numbers of goblet cells increase slightly, the major change is in the size of the mucous gland (hyperplasia).

This increase can be assessed by the ratio of the thickness of the mucous gland layer to the thickness of the wall between the epithelium and the cartilage (Reid index).

The Reid index equals the maximum thickness of the bronchial mucous glands internal to the cartilage (b to c) divided by the bronchial wall thickness (a to d)

Front 29

Formula for the Reid index

Back 29

The Reid index equals the

maximum thickness of the bronchial mucous glands internal to the cartilage (b to c) divided by the bronchial wall thickness (a to d)

Front 30

What is the normal Reid index

Back 30

Normally, 0.4 ...

Front 31

Normal Reid index Vs in chronic bronchitis

Back 31

The Reid index (normally 0.4) is increased in chronic bronchitis, usually in proportion to the severity and duration of the disease.

The bronchial epithelium may exhibit squamous metaplasia and dysplasia.

There is marked narrowing of bronchioles caused by mucus plugging, inflammation, and fibrosis. In the most severe cases, there may be obliteration of lumen due to fibrosis (bronchiolitis obliterans

Front 32

...... & ...... COPD co-exist in most cases

Back 32

Emphysema and chronic bronchitis

Front 33

Define asthma

Back 33

Asthma is a chronic inflammatory disorder of the airways that causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough, particularly at night and/or in the early morning.

Front 34

Hallmark of asthma

Back 34

The hallmarks of the disease are:

1. Increased airway responsiveness to a variety of stimuli, resulting in episodic bronchoconstriction;

2. Inflammation of the bronchial walls; and

3. Increased mucus secretion.

Front 35

Many cells play a role in the inflammatory response in asthma..

List them

Back 35

Many cells play a role in the inflammatory response, in particular-

1. Lymphocytes,

2. Eosinophils,

3. Mast cells,

4. Macrophages,

5. Neutrophils, and

6. Epithelial cells

Front 36

What is status asthmaticus

Back 36

Rarely, a state of unremitting attacks, called status asthmaticus, proves fatal; usually, such patients have had a long history of asthma.

Between the attacks, patients may be virtually asymptomatic.

Front 37

Explain the lung in patients dying of status asthmaticus

Back 37

In patients dying of status asthmaticus the lungs are overdistended because of overinflation, with small areas of atelectasis

Front 38

Morphology in asthma

1. Macroscopy

2. Microscopically

Back 38

1. Macroscopy -

Occlusion of bronchi and Bronchioles by thick tenacious mucus

2. Microscopically -

a. Curschmann spirals ( mucus plugs contain whorls of shed epithelium

b. Numerous eosinophil

c. Charcot-leyden crystal - collections of crystalloids made up of an eosinophil lysophospholipase binding protein called galectin 10

Others ; collectively called airway remodeling;

1. Overall thickness of airway wall

2. Sub basement membrane fibrosis ( due to deposition of type I and III collagen beneath the classic basement membrane composed of type IV collagen and laminin

3. Increased vascularity

4. Increase in the size of the submucosal glands and mucous metaplasia of epithelial cells

Hypertrophy and / or hyperplasia of the bronchial wall muscle

Front 39

List the contents of airway remodeling

Back 39

The other characteristic histologic findings of asthma, collectively called “airway remodeling” include:

1. Overall thickening of airway wall

2. Sub-basement membrane fibrosis (due to deposition of type I and III collagen beneath the classic basement membrane composed of type IV collagen and laminin)

3. Increased vascularity

4. An increase in size of the submucosal glands and mucous metaplasia of airway epithelial cells.

Front 40

Chronic interstitial diseases are?

Back 40

Chronic interstitial diseases are a heterogeneous group of disorders characterized predominantly by inflammation and fibrosis of the pulmonary connective tissue, principally the most peripheral and delicate interstitium in the alveolar walls.

Front 41

What is the honeycomb 🍯 lung

Back 41

Although the entities can often be distinguished in the early stages, the advanced forms are hard to differentiate because they result in scarring and gross destruction of the lung, often referred to as end-stage lung or honeycomb lung

Front 42

Define pneumoconises

Back 42

The term pneumoconiosis was originally coined to describe the non-neoplastic lung reaction to inhalation of mineral dusts encountered in the workpl5ace. Now it also includes diseases induced by organic as well as inorganic particulates and chemical fumes and vapors.

Front 43

....... causes farmers lung

Back 43

Moldy hay

Front 44

Bagasse?

Back 44

Bagassosis, inhalation of dust from sugarcane processing

Manufacturing wallboard, paper

Front 45

....... causes byssinosis

Back 45

Cotton, flax, hemp... Textile manufacturing

Front 46

Asthma and pneumoconises

Back 46

Red cedar dust causes asthma while lumbering, carpentry

Front 47

Pathogenesis of pneumoconiosis

The development of a pneumoconisis depends on?

Back 47

(1) the amount of dust retained in the lung and airways;

(2) the size, shape, and therefore buoyancy of the particles

(3) particle solubility and physiochemical reactivity; and

(4) the possible additional effects of other irritants (e.g., concomitant tobacco smoking).

Front 48

The amount of dust retained in the lung is determined by?

Back 48

The amount of dust retained in the lungs is determined by

1. the dust concentration in ambient air,

2. the duration of exposure, and

3. the effectiveness of clearance mechanisms.

Any influence, such as cigarette smoking, that affects the integrity of the mucociliary apparatus significantly predisposes to the accumulation of dust.

Front 49

The most dangerous particles range from?

Because?

Back 49

The most dangerous particles range from 1 to 5 μm in diameter because they may reach the terminal small airways and air sacs and settle in their linings.