Pathophysiology of Respiratory Disease 1: Asthma & COPD Study Guide (2-3)

Describe Asthma

Hyperreactive airway and inflammation

Describe COPD

Alveolar destruction and chronic airway inflammation

What are the 2 types of obstructive lung disease?

Asthma & COPD

What are the statistics regarding asthma cases?

Cases are increasing, but deaths are decreasing

What are some of the risk factors for asthma deaths?

Not using inhaled steroid

Over-use of SABAs

Poor medication adherence

Hospitalization or multiple ER visits for asthma in past year

How many asthma deaths that occur outside the hospital are considered preventable?

8-9/10

What are some of the solutions to prevent asthma deaths?

Optimized treatment regimens

Adequate self-management (and team-based care)

Proper education, planning, assessment, and treatment, and follow-up care

How do you diagnose asthma?

PFTs

Fractional excretion of nitric oxide (FeNO)

provides an objective biomarker of airway inflammation

What do the standards of GINA 2022 say on FeNO?

start inhaled steroid independent of FeNO result

What do the standards of GINA 2023 say on FeNO?

Adding FeNO to those who started treatment based on symptoms did not decrease exacerbations.

(Questionable benefit to routinely add into assessment

What do the standards of GINA 2025 say on FeNO?

non-specific and variable given the fluctuation in readings from sleep/time of day

ICS use and comorbidities influencing the level

What do the standards of GINA 2026 say regarding FeNO?

Collect FeNO from the patient when PFTs and/or blood eosinophils cannot be collected so that the assessment is not based on symptoms alone

What does the American Thoracic Society 2021 say regarding 2021?

In patients with asthma where treatment is being considered, use FeNO in addition to usual care over usual care alone

What are the two types of asthma?

Allergic asthma/Type 2-high & non-allergic asthma/Type-2 low

What is allergic asthma (Type 2 high)?

Eosinophilic predominant version

What is non-allergic asthma type 2 low?

Non-eosinophilic

What causes the development of asthma?

genetics & environmental risk factors

Environmental risk factors of asthma?

low SES

allergen exposure

secondhand smoke exposure

air pollution

What is the hygiene hypothesis of asthma?

Artificial living environments do not expose children to enough antigens to get their immune systems trained to know the difference between a harmless vs. harmful threat and the immune system becomes hyperreactive, to the detriment of the lungs

What is the microflora hypothesis of asthma?

early life exposures influence gut bacterial colonization

With inadequate exposures, the microbiome suffers, causing immune dysregulation and hyperresponsiveness in the lungs

Course of asthma

Most patients will not die from asthma, few will develop severe asthma, new-onset asthma in adults can resolve and recently the number of asthma deaths in the US has decreased

What are the causes of obstruction in asthma?

Airway inflammation

Smooth muscle bronchospasm

Bronchial hyperresponsiveness

Mucus hypersecretion

What are the triggers of asthma attacks?

lung infections (viral > bacterial)

air pollution

emotions

drugs

exercise

weather changes

What are the statistics on the cases of COPD?

cases are increasing, deaths are increasing

What causes COPD to develop?

cigarette smoking & noxious particle exposure

alpha 1 anti-trypsin genetic deficiency (<1% of cases)

poor lung development in childhood

low SES plays an unclear role

longer life expectancy (higher cumulative exposure to noxious particles)

asthma

airway hyperresponsiveness

Environmental risk factors of COPD

smoking

wood & biomass fuel burning exposure

occupational exposures

How are the rates of pneumonia in smokers and non-smokers?

high

What all is higher with smokers vs. non-smokers?

COPD mortality

lung cancer risk

severity of respiratory symptoms

annual decline in FEV1

Is the likelihood of progression to respiratory failure high or low for both smokers and non-smokers?

high

Never smokers can still develop COPD, how many of them do?

1/4

Not all smokers develop COPD, how many of them actually do?

1/2

Course of COPD

progressive, does not resolve

Surgical options and lung transplants are last resorts

Pathogenesis of COPD

oxidative stress

protease/antiprotease imbalance

inflammation

fibrosis

Causes of COPD obstruction

chronic inflammation

parenchymal (alveolar) destruction

airflow limitation and gas trapping

gas exchange abnormalities

mucus hypersecretion

Triggers of COPD exacerbations

lung infections (leans bacterial over viral)

environmental pollutants

comorbidities (venous thromboembolism, heart failure exacerbation)

With patients who have both COPD and asthma, how do you treat them?

Using asthma guidelines

What are the structural changes of asthma?

normal elastic recoil + no or little emphysema

What is the structural changes of COPD?

loss of elastic tissue + alveoli destruction

What is the inflammation like in asthma?

Eosinophlic & some other differences in cytokines

What is the inflammation like in COPD?

Neutrophils in the inflammatory process predominantly & some other differences in cytokines

Features of asthma

airway hyperresponsiveness

atopy (allergic rhinitis, eczema, etc)

common night awakenings

uncommon to have chronic sputum production (dry cough)

Features of COPD

bronchitis

emphysema

normal prevalence of allergies

uncommon night awakenings

chronic sputum production & productive cough

airway hyperresponsiveness