Chronic Obstructive Pulmonary Disease🦋 Flashcards
What’s the function of lungs
What does gas exchange depend on?
Where can gas exchange occur
- Gas exchange
- depends on compliance( stretchability) of lungs
- in alveoli that are both ventilated and perfused
What are ventilation+perfusion defects
- when alveoli are ventilated but not perfused, this is ventilatory dead space
- when alveoli are perfused but not ventilated and this leads to shunting on non-oxygenated blood from pulmonary to systemic circulation causing cyanosis
What causes respiratory failure
- ventilation defects( CNS, neuromuscular defects, drugs)
- perfusion defects(cardiac failure,pulmonary emboli)
- gas exchange defects(fibrosis, consolidation, emphysema)
What are risk factors for COPD
- nutrition
- infections
- socio-economic status
- aging population
- genes( a decrease in alpha 1 anti-trypsin)
- cigarette smoking
- occupational dust and chemicals(silica)
- environmental tobacco smoke
- indoor and out door pollution
What is chronic bronchitis
It’s a persistent productive cough for at least 3 consecutive months in at least 2 consecutive years
What are the forms of chronic bronchitis
- simple chronic bronchitis
- chronic asthmatic bronchitis
- chronic obstructive bronchitis
Describe the features of the different forms of chronic bronchitis
Simple chronic bronchitis- the productive cough raises mucoid sputum but airway not obstructed
Chronic asthmatic bronchitis- has hyper responsive airways with irregular bronchospasms and wheezing
Chronic obstructive bronchitis- develops chronic outflow obstruction and is associated with emphysema
What cell changes take place in chronic bronchitis
- mucus gland hypertrophy
- smooth muscle hypertrophy
- goblet cell hyperplasia
- inflammatory infiltrate
- excessive mucus production
- squamous metaplasia
What is the morphology for chronic bronchitis
The trachea in the mid upper field is hyperemic
The bifurcation and bronchi contain mucopurulent exudate secretion
What are complications of chronic bronchitis
- pulmonary hypertension and cardiac failure
- recurrent infections
- respiratory failure
What are signs and symptoms of chronic bronchitis
- cough
- sputum
- frequent infections
- intermittent dyspnea
- wheeze
- some patients develop COPD with outflow obstruction causing, hypercapnia, hypoxemia, cyanosis
What is emphysema
It is the permanent enlargement of air spaces distal to terminal bronchioles, accompanied by destruction of their walls(septa), reducing surface area of alveoli
What causes emphysema
- smoking
- deficient of alpha 1 anti trypsin
What does alpha 1 antitrypsin do
It coats lungs,protecting them from neutrophil elastase
What produces neutrophil elastase
What does neutrophil elastase do
By white blood cell (neutrophil)
Neutrophil elastase breaks down harmful bacteria but damages lungs at the same time if they are exposed
What happens to alpha 1 antitrypsin when it’s deficient
It’s trapped in the liver causing liver cirrhosis and this leaves neutrophil elastase uninhibited causing lung damage
What 2 imbalances cause emphysema and increase elastase
Protease- antiprotease imbalance
Oxidant-antioxidant imbalance
What are the types of emphysema and their features
- centriacinar (involves central/proximal parts of the acini, lesions are more common and severe in the upper lobe, this type is caused by cigarette smoking)
- panacinar (occurs more in lower lung zones and because of alpha 1 antitrypsin deficiency)
- distal acinar (the distal part of acinus is involved, it’s seen adjacent to pleura,along lobular margins and has cyst like structures called bullae)
- irregular acinar (the acinus is irregularly involved, is associated with scarring, clinically asymptomatic and is the most common emphysema)
What are complications of emphysema
-pulmonary hypertension (resulting in hypoxia induced pulmonary vascular spasms and loss of capillary surface area due to alveolar wall destruction)
- right side heart failure
- respiratory failure
What is bronchiectasis
Is the abnormal fixed dilation of the bronchi
What causes bronchiectasis
fibrous scarring following infection such us pneumonia, tb, cystic fibrosis (diseases that cause chronic inflammation)or it’s seen with chronic obstruction(tumour)
What do the dilated airways in bronchiectasis do
Accumulate purulent secretions which can’t be removed because of damaged bronchi( cilia don’t work efficiently )
Bronchiectasis affects which lobes normally
Lower lobes
Chronic recurring infections from bronchiectasis can lead to what
Finger clubbing
