Chronic Obstructive Pulmonary Disease - Pathoma Flashcards
What type of obstruction occurs in Chronic Pulmonary Obstructive Disease?
Obstruction to getting air out of the lung?
What is the hallmark of Chronic Pulmonary Obstructive Disease?
Airway obstruction
What changes in spirometry are seen in patients with Chronic Pulmonary Obstructive Disease?
- Decreased FVC (↓)
- Decreased FEV1 (↓↓ more)
- Decreased FEV1:FVC ratio
- Total Lung Capacity is increased (due to air trapping)
How is Chronic Bronchitis defined?
Clinically:
- Chronic productive cough lasting at least 3 months over a minimum of 2 years
- Cough up “cups” or “buckets” of mucous
- Highly associated with smoking
What causes the excess mucous production associated with Chronic Bronchitis?
- Smoking exposes airways to pollutants
- Hypertrophy of mucinous glands (increased thickness of mucus glands relative to overall bronchial wall thickness, Reid index >50%)
- Increased glandular production of mucus to trap pollutants
What causes the obstruction in Chronic Bronchitis?
Mucus travels down airway and plugs up some smaller bronchioles.
What are the clinical features in Chronic Bronchitis?
- Productive cough
- Cyanosis, ↑PaCO2, ↓PaO2
- Increased risk of infection or Cor Pulmonale
What is Cor Pulmonale?
Diffuse pulmonary arteriole constriction causing right ventricular hyperplasia and eventually right ventricular failure.
What leads to the air trapping in Emphysema?
- Destruction of alveolar sacs
- Lose elastic recoil
- Collapse of small airways
What causes the destruction of alveolar sacs in Emphysema?
Imbalance of proteases and antiproteases.
- alveolar macrophages => eat pollutants in alveoli => inflammation => produces proteases
- body produces alpha-1-antitrypsin to balance proteases
- EMPHYSEMA: overproduction of proteases OR underproduction of antiproteases
What is the most common cause of Emphysema?
Smoking… duh
What happens in the lungs when Emphysema is due to smoking?
- Overproduction of inflammation proteases that destroy lungs
- Results in centriacinar emphysema, more severe in upper lungs (affects the central part of acinous)
What is the functional unit of the lung?
Acinous:
- terminal bronchiole
- alveolar sacs
What is a rare cause of Emphysema?
Alpha-1 Antitrypsin Deficiency
What kind of emphysema does Alpha-1 Antitrypsin Deficiency cause?
Panacinar emphysema => more severe in lower lobes
liver cirrhosis may also be present
What are the genetic considerations in Alpha-1 Antitrypsin Deficiency?
Disease severity is based on degree of A1AT deficiency.
- PiM = normal allele (PiM/PiM)
- PiZ = is most common clinically relevant mutation (misfolded protein accumulates in Endoplasmic Reticulum of hepatocytes)
What happens if Alpha-1 Antitrypsin Deficiency is a heterozygote?
PiMZ Heterozygotes:
- usually asymptomatic with decreased circulating levels of A1AT
- significant risk for emphysema with smoking
What happens if Alpha-1 Antitrypsin Deficiency is a homozygote?
PiZZ Homozygotes:
-Significant risk for panacinar emphysema and cirrhosis
(misfolded protein accumulates in Endoplasmic Reticulum of hepatocytes)
What are the clinical features of Panacinar Emphysema?
- Dyspnea and cough with minimal sputum production
- Prolonged expiration with pursed lips (“pink-puffer”)
- Weight loss
- Increased AP diameter of chest (“barrel chest” due to reset FRC)
What are late complications of emphysema?
-Hypoxemia (PaO2
Why is Asthma a Chronic Pulmonary Obstructive Disease?
Results in airway bronchoconstriction.
but it is reversible!
Asthma is most often due to what?
ALLERGIC STIMULI => Type I Hypersensitivity Reaction
What is asthma most offten associated with?
- Presents in childhood
- Allergic rhinitis
- Eczema
- Family history of ATOPY
What is the pathogenesis of Asthma?
- Allergens induce Th2 phenotype in CD4+ T-cells of genetically susceptible individuals
- Th2 cells secrete IL-4, IL-5, and IL-10
