restrictive lung disease

Major Findings in Lung Function Tests

• FVC (Forced Vital Capacity) is significantly low.

• Total Lung Capacity (TLC) is low.

• FEV1/FVC ratio is greater than 0.7.
    - This indicates a restrictive pattern of lung disease.

Causes of Restrictive Lung Disease

• Disorders causing restriction include:
    - Neuromuscular disorders:
      - Example: Guillain-Barre Syndrome (GBS), Myasthenia Gravis
    - Obesity
    - Pleural disease (e.g., pleural effusion)
    - Interstitial Lung Diseases (ILD) - Major topic of discussion
    - Anatomical problems:
      - Example: Kyphoscoliosis, Ankylosing Spondylitis

Interstitial Lung Diseases (ILD)

• Definition:
    - Interstitial lung disease refers to inflammation and fibrosis of the lung interstitium.
    - Interstitial refers to the area between the alveoli and pulmonary vessels.

• Pathological changes include inflammation and involvement of alveolar septa and capillary endothelium, leading to:
    - Pulmonary fibrosis
    - Reduced lung compliance
    - Impaired gas exchange

Stages of ILD Progression

1. Inflammation

2. Fibrosis

3. Irreversible scarring

Classification of Interstitial Lung Diseases

1. Idiopathic Interstitial Pneumonia (IIP)
      - Most commonly examined type in exams:
        - Idiopathic Pulmonary Fibrosis (IPF)
          - Common in elderly, male-prevalent, smokers
          - Characterized by reticular pattern and honeycombing on imaging
      - Other types:
          - Nonspecific Interstitial Pneumonia (NSIP)
          - Cryptogenic Organizing Pneumonia (COP)

2. Connective Tissue Disorders
      - Examples include Rheumatoid Arthritis (RA), Sjögren's Syndrome, scleroderma.

3. Occupational Exposures
      - Examples include asbestosis, silicosis, coal worker pneumoconiosis, and berylliosis.

4. Hypersensitivity Pneumonitis (EAA)
      - Important to discuss in subsequent slides.

5. Drug-Induced ILD
      - Culprit drugs include Amiodarone, Nitrofurantoin, Methotrexate.

6. Smoking-Related ILD

7. Sarcodosis

Clinical Presentations of ILD

• Common patient presentations include:
    - Dyspnea on exertion: Shortness of breath that worsens with activity
    - Dry cough: Progressive over months to years
    - Auscultation Findings:
      - End inspiratory crackles that sound similar to Velcro
      - Bilateral predominant, reduced chest expansion
    - Other symptoms:
      - Tachypnea (rapid breathing)
      - Clubbing
      - Cyanosis
      - Pulmonary hypertension

Diagnostic Imaging in ILD

• X-ray findings:
    - Reticular opacities or shadows
    - Reduced lung volume
    - Basal predominance

• High-Resolution CT (HRCT): Gold standard for diagnosis
    - Findings may include:
      - Ground glass opacities
      - Honeycombing pattern
      - Traction bronchiectasis
    - Ground glass appearance likened to broken glass on the ground.

Spirometric Findings in ILD

• Reduced FVC and TLC

• Normal or high FEV1/FVC ratio (often >0.7)

• DLCO (Diffusing Capacity of the Lung for Carbon Monoxide) is markedly reduced
    - Early abnormality due to fibrosis affecting gas exchange

• Exercise desaturation assessed via the six-minute walk test.

Summary of ILD Types

• IPF:
    - Affects elderly, predominant male and smokers.
    - Reticular pattern with honeycombing, common near pleura.

• NSIP:
    - Affects younger individuals, often female, associated with CT disorders.
    - Ground glass opacities, subpleural sparing observed.

• COP:
    - Often presents post-respiratory infection with fever.
    - Represents organizing pneumonia with consolidative pathology.

Treatment Approaches for ILD

• Remove exposure to offending agents (occupational, drugs).

• Manage underlying connective tissue disorders.

• Inflammatory ILDs:
    - Corticosteroids for conditions like NSIP and COP
    - Immunosuppressants in severe cases (e.g., Azathioprine, Mycophenolate, Cyclophosphamide)

• IPF Management:
    - Antifibrotic agents like Nintedanib, Pirfenidone
    - Supportive care includes long-term oxygen therapy, pulmonary rehabilitation, and lung transplantation for progressive disease.

Hypersensitivity Pneumonitis (EAA)

• Non-allergic extrinsic agents leading to inflammation of the alveoli.

• Classically presents with:
    - Fever, dry cough, dyspnea, and crackles (acute phase)
    - Chronic phase leads to fibrosis and respiratory failure.

• Diagnosis includes:
    - Serum IgG antibodies
    - Reticular nodular changes on X-ray or HRCT.

• Specific antigen exposures associated include:
    - Farmer's lung, moldy hay exposure (Saccharopolyspora rectavigula)

Sarcoidosis

• A multisystem granulomatous inflammatory disease with non-caseating granulomas.

• Primarily involves the lungs and lymph nodes.

• Age group affected is usually 20-40 years, predominately in Afro-Caribbeans.

• Common presentations:
    - Dry cough, dyspnea, fine inspiratory crackles
    - Can initially be asymptomatic.
    - Extrinsic signs may include:
      - Erythema nodosum (tender nodules), lupus pernio (facial lesions), uveitis.

• Investigations:
    - CXR to identify bilateral hilar lymphadenopathy (BHL)
    - Transbronchial biopsy as gold standard demonstrating non-caseating granulomas.

Staging of Sarcoidosis (based on imaging)

• Stage 0: Normal chest X-ray.

• Stage 1: Bilateral hilar lymphadenopathy.

• Stage 2: BHL plus pulmonary infiltrates.

• Stage 3: Only peripheral infiltrates, no BHL.

• Stage 4: Fibrosis, lung volume loss, honeycombing.

Types of Sarcoidosis Syndromes

1. Lofgren's Syndrome:
     - Triad: Erythema nodosum, BHL, arthritis; often self-limiting with excellent prognosis.

2. Heerfordt's Syndrome:
     - Parotid enlargement, facial palsy, uveitis.

3. Mikulicz's Syndrome:
     - Involves both parotid and lacrimal glands, causing dry mouth/eyes.

Prognostic Factors in Sarcoidosis

• Favorable indicators:
    - Erythema nodosum, Lofgren's syndrome.

• Poor prognostic factors:
    - Lung involvement, cardiac involvement, neural involvement, persistent symptoms lasting more than six months.
    - Severe hypercalcemia, chronicity, and stages 3 and 4 on imaging results.

Management of Sarcoidosis

• Often self-resolving; treatment only for symptomatic advanced stages or organ involvement.

• First-line therapy: Corticosteroids.

• Alternatives include:
    - Methotrexate, Hydroxychloroquine.
    - Third line: TNF-alpha inhibitors (Infliximab, Adalimumab).