Respiratory Flashcards
What is COPD?
Progressively worsening, irreversible airflow obstruction
Types of respiratory failure and pathophysiology?
Type 1 = fibrosis related causes, lung fails to fill properly which results in ↓PaO2, ↓PaCO2 Type 2 = obstructive causes. Lung fails to remove CO2 properly which results in ↓PaO2 + ↑PaCO2.
Conditions that cause type 2 respiratory failure?
Asthma and COPD
Treatment for type one respiratory failure?
CPAP - continuous positive airway pressure
Treatment for type 2 respiratory failure?
BIPAP - bi positive airway pressure
Types of COPD?
Chronic Bronchitis Emphysema A1AT deficiency
Risk factors for COPD?
Cigarettes Air pollution Genetics (A1AT deficiency = auto recessive) Older males
Pathophysiology of chronic bronchitis?
- Hypertrophy + hyperplasia of mucous glands (mucous is protective against damage) - Chronic inflammation cells infiltrate bronchi and bronchioles - This causes: - mucus hypersecretion - ciliary dysfunction - narrowed lumen (thus increased infection risk + airway trapping)
Typical presentation of chronic bronchitis?
Chronic purulent cough, dysponea for 3+months, over 2 years with sputum “blue bloater” (blue tint of skin and lips due to cyanosis and typically overweight- not a respectful term to use nowadays)
Pathophysiology of Emphysema?
Destruction of elastin layer in alveolar ducts/alveolar sacs/respiratory bronchioles - elastin keeps walls open during expiration (bernouli principle) - decreased elastin = air trapping distal to blockage
Types of Emphysema?
Centriacinar Emphysema Panacinar Emphysema Distal Acinar Irregular Emphysema
Most common type of Emphysema?
Centracinar emphysema very common in smokers
Most severe type of emphysema?
Panacinar emphysema caused by A1AT deficiency
What area of the lungs does centriacinar emphysema effect?
Respiratory bronchioles only
What area of the lungs does Panacinar emphysema effect?
respiratory bronchioles - alveolar ducts - alveolar sacs - alveoli
Pathophysiology of A1AT deficiency?
A1 antitrypsin degrades NE (neutrophil elastase) which protects excess damage to elastin layer especially in lungs - Deficiency (decreased liver production) = ↑NE = panacinar emphysema and liver issues
What is A1AT deficiency caused by?
Autosomal codominant inheritance
Typical patient presentation to suspect A1At deficiency in?
Younger/middle aged men with COPD symptoms but no smoking history
Symptoms of COPD?
Typically: - older patient - chronic cough - with (often) purulent (infectious) sputum - extensive smoking history (exception A1AT) - constant dyspnoea (not episodic)
Presentation of a pink puffer?
Minimal cough - Pursed lip breathing - Cachectic (muscle wastage) - Barrel Chest - Hyperesonant percussion
Complication of pink puffer patients?
Bullae rupture - if subpleural = pneumothorax
Do patients present with only blue bloater or pink puffer?
These aren’t separate conditions and most patients present with a mix of both
Dyspnoea grading scale MRC 1-5?
1- strenuous exercise 5- can’t do daily activities without SOB eg. change clothes
Main investigation to diagnose COPD?
Pulmonary function test: - Increasing fractional expired number indicates lung damage - FEV1:FVC <0.7 = obstruction on PFT spirometry