Lecture 11.1: Interstitial Lung Disease Flashcards
What are Interstitial Lung Diseases?
Heterogeneous group of diseases with similar
clinical presentations resulting in inflammation
and fibrosis of alveoli, distal airways and septal
interstitium of the lung
What are some known causes of ILD? (3)
- Exposure history: HP, Asbestosis, silicosis etc.
- Drugs: immunosuppressants, antibiotics, chemo
- Connective Tissue disorders: RA, SSc, etc
What are some “unknown” causes of ILD (meaning why those diseases developed is unknown)? (2)
- IPF
- Sarcoidosis
What is the “Interstitial Space” in a Lung?
The ‘interstitial space’ is a potential space between alveolar cells and the capillary basement membrane, which is only apparent in disease states, when it may contain fibrous tissue,
cells or fluid
The alveolar wall consists of…? What cell type?
- Type 1 Pneumocytes (provides surface for gas
exchange) - Closely opposed to capillary endothelial cells
What is the Role of Type 2 Pneumocytes? (1 + 3)
- Produce surfactant
- Lowering surface tension at the air–liquid
interface and thus preventing alveolar collapse
at end-expiration - Interacting with and subsequent killing of
pathogens or preventing their dissemination - Modulating immune responses
Most IDL are associated with extensive destruction and alteration of..? (3)
- Alveoli
- Airway Architecture
- Vasculature
What parts of the Lungs are affected by ILD? (4)
- Acini
- Alveolar Lumen
- Bronchiolar Lumen
- Bronchioles
What cell types are affected in ILD? (5)
- Epithelial Cells
- Endothelial Cells
- Mesenchymal Cells
- Macrophages
- Recruited Inflammatory Cells
Effects of Inflammation & Fibrosis
- Leads to temporary or permanent changes in
the interstitial tissues (development of fibrosis
tissue) - Interfere with diffusion of gases
- Change mechanics of breathing
- Stiff Lungs - The development of fibrous tissue
in the interstitium, makes lungs less compliant,
to produce a ‘restrictive’ ventilatory defect
Clinical Presentation of Interstitial Lung Disease (5)
- Progressive breathlessness
- Reduced exercise tolerance
- Dry cough
- Extrapulmonary symptoms: Fever,
joint pains, lethargy
Classification of ILD: Based on Aetiology (5)
- Occupational
- Treatment Related
- Connective Tissue Disease
- Immunological
- Idiopathic
Classification of ILD Based on Aetiology: Occupational Causes (3)
- Asbestosis
- Silicosis
- Coal Miners Pneumoconiosis
Classification of ILD Based on Aetiology: Treatment Related Causes (5)
- Radiation
- Methotrexate
- Nitrofurantoin
- Amiodarone
- Chemotherapy
Classification of ILD Based on Aetiology: Connective Tissue Disease Causes (5)
- Rheumatoid Arthritis
- Systemic Lupus Erythematosus (SLE)
- Polymyositis
- Scleroderma
- Sjogren’s
Classification of ILD Based on Aetiology: Immunological Causes (2)
- Sarcoidosis
- Hypersensitivity Pneumonitis
Classification of ILD Based on Aetiology: Idiopathic (6)
- CFA/IPF
- UIP/NSIP
- DIP
- LIP
- RB-ILD
- BOOP
Classification of ILD Based on Duration (3)
Acute (Days to Weeks Hx)
Subacute (Weeks to Months Hx)
Chronic (Months to Years Hx)
Classification of ILD Based on Duration: Acute Causes (4)
- AIP (Acute Interstitial Pneumonia)
- Acute Eosinophilic Pneumonia
- Acute HP (Hypersensitivity Pneumonitis)
- COP (Cryptogenic Organising Pneumonia)
Classification of ILD Based on Duration: Subacute Causes (5)
- Sarcoidosis
- Drug Induced
- COP
- CT –ILD
- Alveolar
Classification of ILD Based on Duration: Chronic Causes (3)
- IPF (Idiopathic Pulmonary Fibrosis)
- Sarcoidosis
- Chronic HP
Examples of Inhaled Inorganic Dust (4)
- Silica
- Asbestos
- Carbon (e.g. carbon pneumoconiosis)
- Metals (e.g. tin, aluminium, hard metal dust,
iron)
Examples of Inhaled Organic Dust (4)
- Thermophilic fungi (farmers lung, Grain handlers
lung, humidifier or air conditioners lung) - Bacteria (humidifiers lung)
- True Fungi
- Animal proteins (bird fanciers disease)
Examples of Other Inhaled Sources (5)
- Chemicals (e.g. synthetic fibres, Bakelite, vinyl
chloride) - Gases (e.g. oxygen, oxides of nitrogen, chorine
gas) - Fumes (e.g. oxides to metals such as zinc)
- Vapours (e.g. (hydrocarbons, thermosetting
resins, mercury) - Aerosols (e.g. oils, fats, pyrethrum)
How does Pneumoconiosis (fibrosis) secondary to inhalation of mineral dusts occur? (5 Steps)
- Exposure to inorganic dusts
- Particles less than 7 mm across reach terminal
bronchioles and alveolar ducts - Scavenged by macrophages
- Eventually trigger release of mediators
- Causing inflammation, tissue damage and
scarring (fibrosis)
What is Caplan’s Syndrome/RP? When does it occur?
- Occurs in people with rheumatoid arthritis who
have breathed in dust - Swelling (inflammation) and scarring of the
lungs
Simple Silicosis
- Multiple small nodules, 2-5 mm in diameter
accompanied by calcifications on CT - Hilar and mediastinal lymphadenopathy may
precede the parenchymal lesions - Eggshell pattern of calcification of lymph nodes
is common
Complicated Silicosis
- Aka progressive massive fibrosis
- Develops through confluence of individual
silicotic nodules
What happens to Lungs in Asbestos Exposure?
- Asbestos fibres breathed in and lodge in distal
air spaces - Scavenged by macrophages
