Resp path - COPD (emphysema)

Question 1

What is obstructive lung disease?

Answer 1

It is a diffuse airway disease (at any level of the respiratory tract) resulting in an increase in resistance to airflow (FEV1/FVC<0.7)

Question 2

Examples of COPD

Answer 2

COPD (Emphysema & chronic bronchitis)
Asthma
Bronchiectasis

Question 3

What is COPD?

Answer 3

• Characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities caused by exposure to noxious particles or gases.

Question 4

risk factors for COPD (5)

Answer 4

Strongly associated with cigarette smoking.
Poor lung development early in life,
Exposure to environmental and occupational pollutants,
Airway hyperresponsiveness and
Genetic polymorphisms

Question 5

2 Major clinicopathologic manifestations of COPD

Answer 5

Emphysema
Chronic bronchitis
(can be found together in the same patient)

Question 6

What is emphysema

Answer 6

Permanent enlargement of airspaces distal to terminal bronchiole with destruction alveolar septae and walls of airways.

Question 7

Class of emphysema that affects the respiratory bronchioles and involves the upper lobes. Associated with smoking.

Answer 7

centriacinar emphysema

Question 8

Class of emphysema that affects the alveoli and alveolar ducts and eventually the respiratory bronchioles and involves the lower lobes.

Answer 8

Panacinar emphysema

Question 9

What is panacinar emphysema associated with?

Answer 9

Associated with α1antitrypsin deficiency. Exacerbated by smoking

Question 10

What class of emphysema manifests as spontaneous pneumothorax in young adults?

Answer 10

Paraseptal emphysema

Question 11

which types of emphysema cause clinically significant airflow obstruction?

Answer 11

Centriacinar and Panacinar emphysema?

Question 12

Pathogenesis of emphysema (alpha1 antitrypsin deficiency and Smoking)

Answer 12

alpha1-antitrypsin defieciency» decreased antielastase&raquo_space;> elastic damage»> emphysema

Smoking»» increased elastase AND decereased antielastase&raquo_space;> elastic damage&raquo_space;» emphysema

Question 13

Explain how emphsema occurs

Answer 13

Toxic injury from inhaled smoke and other noxious particles damage respiratory epithelium and cause inflammation as well as oxidative stress, resulting in parenchymal destruction.

Question 14

Centriacinar and panacinar emphysema is caused by what?

Answer 14

caused by an imbalance in protease-antiprotease
and oxidant -antioxidant.

Question 16

the role of nicotine in the development of emphysema

Answer 16

Nicotine is a chemoattractant of neutrophils by induction of nuclear factorκβ and resultant production of tumor necrosis factor (TNF) and interleukin8 (IL8).
TNF and IL8 activate neutrophils, which release damaging proteases.
Nicotine causes inactivation of antiproteases.
Nicotine causes production of reactive oxygen species, which inactivate proteases and deplete antioxidants.

Question 17

What is the normal allele encoding for alpha1 antitrypsin?

Answer 17

PiMM, but a minority of the population has a PiZZ allele, which associated with a significant decrease in the amount of alpha1 antitrypsin

Question 18

What is the function of alpha1 antitrypsin?

Answer 18

Protease inhibitor, esp elastase which is secreted by neutrophils during inflammation

Question 19

Explain the mechanism of emphysema (4)

Answer 19

The loss of pulmonary parenchyma results in a loss of elastic tissue and recoil, increased lung compliance, increased pulmonary residual volume ,increased total lung capacity
Airway obstruction results from loss of elastic tissue in the alveolar walls that surround respiratory bronchioles, leading to decreased radial traction and functional collapse of the respiratory bronchioles during expiration.
There is decreased diaphragmatic excursion and increased use of accessory muscles for breathing.
Over time, with reduced ventilation and air trapping, the partial pressure of arterial oxygen (Pao2) decreases, the partial pressure of carbon dioxide (Paco2) increases, and respiratory acidosis ensues, with renal compensation. This is exacerbated by small airway changes in smokers .

Question 20

What are the signs and symptoms of emphysema? (9)

Answer 20

Dyspnoea, hypoxemia, hypercapnia, hyperventilation (referred to as “pink puffers”).
Pursed lips
Digital clubbing.
Decreased volume of breath sounds and longer (increased)expiratory phase on auscultation.
Chronic respiratory acidosis with compensatory alkalosis
Weight loss(pulmonary cachexia: utilises lots of calories just to breath)

Question 21

What causes barrel-shaped chest in emphysema?

Answer 21

Hyperinflation
Trapped air

Question 22

What does a CXR of emphysema pt show?

Answer 22

Chest radiograph: Flattened diaphragm , increased AP Diameter , and expanded hyperlucent lung fields.

Question 23

Microscopic features of emphysema

Answer 23

Loss of distal airspaces,bronchioles, alveolar ducts, and alveoli.
Remaining airspaces become dilated as shown.
There is less surface area for gas exchange..

Question 24

How are the ABGs of an emphysema patient?

Answer 24

Over time, with reduced ventilation and air trapping, the
partial pressure of arterial oxygen (pao2) decreases,
the partial pressure of carbon dioxide (paco2) increases, and
respiratory acidosis ensues, with renal compensation.

Question 25

Gross appearance of centriacinar emphysema

Answer 25

The central lobular loss of lung tissue with intense black anthracotic pigmentation (←) is apparent as “dirty holes.”

Question 26

gross appearance of panacinar emphysema

Answer 26

Pan acinar emphysema occurs with loss of all portions of the acinus from the respiratory bronchiole to the alveoli.
The bullae seen here are most prominent in the lower lobe (→) on theleft

Question 27

Gross appearance of paraseptal (distal acinar) emphysema

Answer 27

Peripheral location of the bullae, along septa may lead to rupture into the pleural space =spontaneous pneumothorax
>/= 2 cm in size or more,.
Two small bullae (→↓) are seen here just beneath the pleural surface.