MB preparation - week 3

Hillegass, Chapter 6

COPD = chronic pulmonary obstructive disease

• it’s a term given to a cluster of problems that affect the airways and the lung parenchyma that produce obstruction to the expiratory airflow

Airflow obstruction can be related to:

• Retained secretions

• Inflammation of mucosal lining of airway walls

• Bronchial constriction related to increased tone or spasm of bronchial smooth muscle

• Weakening of the support structure of airway walls

• Air sac destruction and air sac overinflation with destruction of surfactant

Differences between COPD and OLD

COPD = chronic pulmonary obstructive diseases

• combination of diseases “emphysema“

• chronic bronchitis

• bronchoconstriction

• asthma

OLD = obstructive lung disease

• cystic fibrosis

• bronchiectasis

• bronchopulmonary dysplasia

OLD decrease the size of the bronchial lumen , increase size of alveolar sac and increase resistance of the expiratory flow

Characteristics

• incomplete emptying of the lung → lung hyperinflation

• reduced lung function

RLD different than OLD

In common they have:

• shortness of breath

• dyspnea

Etiology, Pathology and Pathophysiology of COPD and OLD

COPD

Causes:

• 1) Inhalation factors:

  • Cigarette smoke (active and passive)

  • Exposure to chemicals and air pollution

  • Occupational dust and fumes

Pathophysiology (how it happens)

1. Inflammatory response activation:

   • Triggered by inhalation of harmful substances

   • Leads to an increase in protease and decrease in antiprotease

   • Protease breaks down elastin and connective tissue, causing structural damage

2. Long-term consequences:

   • Irreversible lung damage due to chronic inflammation

   • Increased risk of infections

   • Cilia dysfunction, impairing mucus clearance

   • Destruction of macrophages, reducing immune defense in lung tissue

3. Airway obstruction mechanisms:

   • Excessive mucus production and mucus plugging

   • Edema of the mucosal lining

   • Increased airway reactivity, leading to bronchospasms

   • Fibrosis and destruction of terminal airways

4. Lung function impairment:

   • Loss of elastic recoil, leading to airway collapse

   • Hyperinflation of lungs due to trapped air

   • Ventilation/perfusion (V/Q) mismatch, causing hypoxemia (low oxygen levels) → saturation?

   • Potential development of hypercapnia (high CO₂ levels)

2) Genetic Factors:

• α1-Antitrypsin (AAT) deficiency

  • Affects surfactant production, reducing lung protection

  • Leads to early-onset emphysema, even without smoking

Lung Function in Obstructive Lung Disease (OLD)

Lung Hyperinflation and Its Effects

Lung hyperinflation impacts:

1. The mechanical function of respiratory muscles.

2. Gas exchange efficiency.

Signs of OLD

• Horizontal ribs

• Barrel-shaped thorax (increased anteroposterior diameter)

• Low, flattened diaphragms

To confirm the diagnosis, medical assessments: (do we need to ask them as physio?)

• Chest X-ray

• Spirometry

• CT scan

• Examination of arterial blood gases (e.g., oxygen saturation levels)

Symptoms

• Dyspnea on exertion (DOE) – difficulty breathing during ADLs, stair climbing, or walking long distances/fast.

• Increased secretion production

• Chronic coughing

• Anxiety (understandable, you almost dying bruh).

COPD

Structural Changes and Their Consequences

• Loss of elastic recoil → Lung hyperinflation → Changes in the thorax, leading to a "barrel-shaped" chest.

• Altered rib movement – disrupts the normal "pump-handle" and "bucket-handle" motion of the ribs.

• Diaphragm flattening due to structural adaptations (loss of sarcomeres), altering its tension and impairing ventilation mechanics.

• Increased intra-abdominal pressure (IAP) → Elevated pelvic floor pressure → Possible urinary incontinence.

Respiratory Muscle Adaptations

• Impaired inspiration → Increased reliance on accessory muscles.

• Over time, these muscles undergo hypertrophy and shortening, contributing to postural deviations.

• Patients may assume a forward-leaning posture to facilitate expiration.

Skeletal Muscle Changes

• Shift from Type I (endurance) to Type II (fast-twitch) muscle fibers, reducing endurance capacity.

• Decline in anaerobic metabolism, affecting energy efficiency (We like breathing CO2 cause oxygen, what is oxygen)

• Muscle weakness and fatigue are common due to chronic oxygen deprivation.

Psychological Aspects of COPD/ OLD

• Anxiety and depression – common due to the chronic struggle to breathe.

• Cognitive impairment – chronic hypoxemia (low oxygen levels) can negatively affect brain function.

Because it’s not clear, here a table with the differences between COPD, OLD and RLD

Using the values, we can express these changes between OLD and COPD

(note to self: you read from the book and the info come from there than God but you ask chat to semplify it cause wtf was that)

why?

question to ask: how deep do we need to know OLD (like we said before, it’s a group of diseases) do we have to know each one?