what are the Interstitial lung diseases?
examples of ILDs?
ILDs cause obstructive or restrictive patterns?
restrictive
what is the interstitial space?
The interstitial space is defined as loose connective tissue throughout the lung (alveolar walls and septae)
what are the 3 subdivisions of the interstitial space of lung?
1) Bronchovascular: the area surrounding the bronchi, arteries, and veins from the root of the lung to the respiratory bronchiole
2) Parenchymal: situated between the alveolar and capillary basement membranes
3) Subpleural: situated beneath the pleura, as well as the interlobular septae
how ILD is diagnosed?
Interstitial lung disease is diagnosed by a combination of radiographic features in combination with clinical signs and symptoms, but can be diagnostically and therapeutically challenging!!
does interstitial space is visible radiographically?
The interstitium of the lung is not normally visible radiographically; it only becomes visible when it involved in a disease process, which increases its volume and attenuation.
what is the hallmark of ILDs?
Hallmark of this disease is FIBROSIS or SCARRING
what is the result of fibrosis and scarring in the lungs?
As the alveolar walls become fibrotic and scarred, diffusion of oxygen and carbon dioxide is impaired, resulting in lack of oxygen transfer to blood, causing hypoxaemia and dyspnoea.
what is the most common ILD?
- -Risk factors: cigarette smoking, environmental or occupational exposures, chronic aspiration, genetic predisposition
what are the occupational, environmental, and iatrogenic causes of ILD?
1) Pneumoconioses
- -Asbestosis
- -Silicosis
- -Rare pneumoconioses (e.g., berylliosis, anthracosis)
2) Radiation pneumonitis
what medications can cause lung fibrosis?
–Chemotherapeutic agents: bleomycin , methotrexate, busulfan
Other agents: amiodarone , nitrofurantoin, phenytoin, –penicillamine, cocaine, and heroin
what are the bleomycin and busulfan?
1) A metal-chelating, glycopeptide antibiotic that has a cytotoxic effect on nondividing tumor cells by causing fragmentation of DNA chains. Used to treat lymphomas, germ cell tumors, head and neck cancers, and squamous cell carcinoma. Adverse effects include fever, hypersensitivity reactions, skin changes, and severe pulmonary fibrosis.
2) An alkylating chemotherapeutic agent of the alkyl sulfonate class. Often used in bone marrow ablation prior to transplantation for chronic lymphocytic leukemia. Common adverse effects include severe myelosuppression, electrolyte imbalance, hyperpigmentation, cardiac, pulmonary, and hepatic toxicity.
what are the ILDs secondary to underlying disease?
1) Granulomatous ILD:
- -Sarcoidosis: noncaseating granulomas in multiple organs, including the lung
- -Pulmonary Langerhans cell histiocytosis
- -Granulomatosis with polyangiitis (formerly Wegener granulomatosis)
- -Eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome)
2) Infectious diseases (eg, tuberculosis, legionellosis)
3) Alveolar filling disease
4) Hypersensitivity reactions ( hypersensitivity pneumonitis and eosinophilic pneumonitis)
5) Connective tissue disorders
6) Bronchoalveolar carcinoma
the alveolar filling disease includes…
Includes Goodpasture’s syndrome, idiopathic pulmonary hemosiderosis, and pulmonary alveolar proteinosis (rare condition caused by accumulation of surfactant-like protein and phospholipids in alveoli)
what CTDs can cause ILDs?
rheumatoid arthritis, scleroderma, systemic lupus erythematosus, and mixed connective tissue disease
how ILDs are classified?
1) Etiology
2) Radiology
- -Based on zones of fibrosis
- -Upper, mid, lower, widespread
3) Histology
what are the ILDs that predominantly involve upper lung zones?
what are the ILDs that predominantly involve lung mid zones?
- -Chronic EAA
what are the ILDs that predominantly involve lung lower zones?
what are the pneumoconioses?
A group of restrictive interstitial lung diseases caused by the inhalation of certain dust, often affecting miners and agricultural workers. Asbestosis and silicosis are the most common types.
inorganic vs organic pneumoconioses?
1) Inorganic (mineral dust pneumoconioses)
- -Asbestosis, silicosis, coal, Beryllium
2) Organic
- -Extrinsic allergic alveolitis/hypersensitivity pneumonitis
- -Mouldy hay, bird feces, cotton fibers
In ILD, large particles (>10 mcm) are deposited in terminal bronchioles, alveolar ducts, and alveoli and result in fibrosis and granuloma formation. T/F
False Small particles (<10mcm)
what are the factors of particles that influence pathogenicity?
Particles1-5um may reach alveoli – most dangerous size
Particles >5-10um are unlikely to reach distal alveoli
<0.5um tend to act like gases and move into and out of alveoli without causing damage
Shape - > Long and thin eg asbestos