Interstitial Lung Diseases Flashcards
what is interstitial lung disease?
– Lung parenchymal disorders with common clinical, radiologic, physiologic and pathologic features; hallmark – Involvement of interstitium
synonyms of interstitial lung disease?
• Infiltrative lung disease -Infiltration of cellular and non-cellular
elements within alveolar septa and alveoli.
• Diffuse parenchymal lung disease (DPLD)
• Restrictive lung disease – Characterized by reduced total lung capacity in presence of a normal or reduced expiratory flow rate.
types of interstitial lung disease
• Acute interstitial lung disease – Acute interstitial pneumonia (ARDS)
• Chronic interstitial lung disease
– Fibrosing lung disorders (pneumoconioses)
– Granulomatous disorders (sarcoidosis)
– Idiopathic interstitial pneumonias (IIPs)
pathogenesis of “alveolitis”?
– Damage to pneumocytes and endothelial cells
• Leads to leukocytes releasing cytokines which mediate and stimulate interstitial fibrosis
• Interstitial fibrosis –
– ↓es lung compliance and elasticity
• ↓ed lung expansion during inspiration
clinical laboratory findings of interstitial lung disease
- Dry cough and dyspnea
- Late inspiratory crackles, bibasilar (Velcro crackles)
- Cor pulmonale
- Chest radiography – bilateral reticulonodular infiltrates
Pneumoconioses definition
Non- neoplastic lung diseases in response to inhalation of mineral dusts inhaled in the workplace.
• Now expanded to include diseases induced by organic and inorganic particulate matter/chemical fumes /vapors.
• Coal dust, silica, asbestos, beryllium
what percent of interstitial lung disease does pneumoconiosis cause?
• 25% cases of chronic interstitial lung disease
what does the development of pneumoconiosis depend upon?
• The amount of dust retained in the lung parenchyma and airways
• The size, shape and buoyancy of particles
– 1 – 5 μm – reach bifurcation of respiratory bronchioles and alveolar ducts
– < 0.5 μm – reach alveoli and are phagocytosed by alveolar macrophages (much worse!!)
• Particle solubility and physicochemical reactivity
• Possible additional effects of other irritants (e.g., tobacco smoking)
causes of fibrogenic pneumoconiosis
- coal worker’s pneumoconiosis (carbonaceous dust)
- silicosis (crystalline silica)
- silicatosis (talc, kaolin, fedspar, mica, muscovite)
- asbestosis (asbestos fibers)
- rare forms:
- metalloconiosis
- berylliosis (beryllium dust)
- hard metal lung disease (tungsten carbide)
- aluminosis (aluminum)
- thesaurosis (hair spray)
- metalloconiosis
types of Coal workers’ pneumoconiosis (CWP)
- Anthracotic pigment – coal mines, urban centers, tobacco smoke
- Pulmonary anthracosis
- Simple CWP
- Complicated CWP (progressive massive fibrosis)
Anthracosis findings
- Asymptomatic
* Anthracotic pigment in interstitial compartment and lymph nodes
findings of Simple coal workers’ pneumoconiosis
- Fibrous opacities < 1 cm
- Upper lobes and upper portions of lower lobes
- Characterized by coal dust deposits adjacent to respiratory bronchioles
findings of Complicated coal workers’ pneumoconiosis (progressive massive fibrosis)
• Fibrous opacities > 1 cm • With or without central necrosis • Massive fibrosis – crippling lung disease (Black lung disease) • Caplan syndrome – CWP with rheumatoid nodules in lung
complication of Complicated coal workers’ pneumoconiosis (progressive massive fibrosis)
• Complication – Cor pulmonale
does Complicated coal workers’ pneumoconiosis (progressive massive fibrosis) increase the risk of a patient developing TB or cancer?
• No increased incidence of TB or cancer.
prevalence of silicosis
• Most common occupational disease worldwide
cause of silicosis
• Crystalline silicon dioxide (quartz)
– Foundries (metal casting), sandblasting, silica mines
• Quartz activates alveolar macrophages after engulfment → cytokine release → fibrogenesis
what do you get from chronic exposure to silicosis?
– Nodular opacities with concentric layers of collagen
– Polarizable quartz particles can be seen
– “Egg-shell” calcification in hilar lymph nodes
complications of silicosis?
• Complications – cor pulmonale; association with Caplan syndrome
does silicosis increase the risk of a patient developing TB or cancer?
yes,
• Increased risk for TB (silicotuberculosis) and cancer
forms of asbestos
– Serpentine (e.g.–chrysotile)–curlyandflexible
– Amphibole (e.g. – crocidolite) – straight and rigid
deposition sites of asbestos-related disease
• Deposition sites – respiratory bronchioles, alveolar ducts and alveoli
sources of asbestos-related disease
• Sources –
– Insulation around pipes in old naval ships
– Roofing material used over 20 years ago
– Demolition of old buildings
tissue appearance of asbestos-related disease
• Tissue appearance –
– Ferruginousbodies–macrophages phagocytose asbestos fibers and coat them with ferritin (iron and protein)
asbestos-related disease clinical variations
• Benign pleural plaques (KEY findings!!)
– Not a precursor of mesothelioma
• Diffuse interstitial fibrosis (asbestosis)
• Bronchogenic carcinoma
– Additional risk with smoking
– 20 years after first exposure
• Mesothelioma
– No relationship to smoking
– Arises from lining mesothelial cells of pleura
– 25-40 years after first exposure
does asbestos-related disease increase the risk of a patient developing TB?
• No increased risk for TB
complications of asbestos-related disease
• Complications:
– Cor pulmonale
– Caplan syndrome
causes of Berylliosis
• Beryllium – Nuclear and airspace industry
findings of Berylliosis
• Granulomatous inflammation – TB and sarcoidosis (differential diagnosis)
complications of Berylliosis
• Complications – cor pulmonale and lung cancer
what is Sarcoidosis?
• Multisystem granulomatous disease of unknown etiology
how prevalence is sarcoidosis?
- 25% cases of chronic interstitial lung disease
* World wide occurrence; highest Scandinavia
who does sarcoidosis effect most often?
- AA: Whites – 10:1
- M: F – 1:2
- 70% < 40years
- Non-smokers
cause of Sarcoidosis
- Disorder of immune regulation
- Unknown antigen → Interaction with CD4 TH cells → cytokine release → recruitment of monocytes/histiocytes → non-necrotizing granuloma formation
- Diagnosis of exclusion
tissue involved in patients with sarcoidosis
lung, lymph nodes, spleen, liver, skin, eyes, joints, nervous system, myocardium
sarcoidosis manifestations in the skin
- Nodular granulomatous lesions
- Lupus pernio
- Erythema nodosum
sarcoidosis manifestations in the eye
• Uveitis
sarcoidosis manifestations in the liver
• Granulomatous hepatitis
other manifestations of sarcoidosis
- Enlarged salivary and lacrimal glands
- Diabetes insipidus
- Bone marrow and splenic involvement
Lab and radiologic findings of sarcoidosis
– ↑ed angiotensin converting enzyme (ACE) levels
• Marker of disease activity and response to steroids
– Hypercalcemia (5% cases)
– Polyclonal gammopathy
– Cutaneous anergy (lack of response to common skin antigens (candida) due to consumption of CD4 TH cells
CXR findings of sarcoidosis
- Bilateral hilar adenopathy
* Reticulonodular shadows in lungs
prognosis of sarcoidosis
– Variable – spontaneous remissions and relapses
– Progressive interstitial fibrosis with cor pulmonale and death in 10 – 15% of cases
causes of Hypersensitivity pneumonitis
• Inhaled antigen (known or unknown) producing granulomatous interstitial pneumonitis (extrinsic allergic alveolitis)
what type hypersensitivity reaction is hypersensitivity pneumonitis?
• Type III hypersensitivity reaction
how does the hypersensitivity pneumonitis reaction occur?
– First exposure –
• IgG antibodies in serum – Second exposure –
• Antibodies combine with inhaled antigens to form immune complexes → inflammatory response in lung (interstitial)
– Chronic exposure –
• Granuloma formation (Type IV hypersensitivity response)
important types of hypersensitivity pneumonitis
– Farmers’ lung – moldy hay – thermophilic actinomycetes bacteria – saccharopolyspora rectivirgula
– Silo fillers’ disease
• Inhalation of gases from plant material (oxides of nitrogen)
– Byssinosis
• Cotton, linen, hemp
• Textile factory workers
• “Monday morning blues”
clinical syndromes of hypersensitivity pneumonitis?
Acute, subacute, chronic
• Interstitial and alveolar infiltrates of inflammatory cells, peri-bronchiolar accentuation, ill-defined granulomas
Clinico-pathologic diagnosis od hypersensitivity pneumonitis
symptoms and physical findings, x-ray abnormalities, PFTs, immunologic features (Abs to suspected Ags); lung biopsy may be needed
prevalence of Idiopathic pulmonary fibrosis
• 15% of cases of chronic interstitial lung disease
what is Idiopathic pulmonary fibrosis
- Broad and all encompassing term including a number of types of Idiopathic interstitial pneumonias
- Usual interstitial pneumonia ~ Idiopathic interstitial fibrosis
who is affected most often by idiopathic pulmonary fibrosis?
- M> F
* 40 – 70 years
what are the clinical symptoms of idiopathic pulmonary fibrosis?
• Average duration of symptoms – 18 – 24 months
• Clinical manifestations – Dyspnea; non-specific constitutional symptoms
such as fever, weight loss, fatigue, arthralgias; cough
pathogenesis of idiopathic pulmonary fibrosis
• Repeated injury to the lung → alveolitis → cytokine release → interstitial fibrosis
• Interstitial fibrosis → irregular dilatation of adjacent airways → honeycomb lung (end stage interstitial fibrosis) (KEY finding!!)
-normal and “abnormal” areas give rise to a “patchwork” appearance
course of idiopathic pulmonary fibrosis
• Course – Progressive disease – end-stage lung; cor pulmonale.
prevalence of Collagen vascular disease
• 10% cases of interstitial lung disease
SLE and interstitial lung disease
• Systemic lupus erythematosus (SLE)
– Interstitial lung disease in 50% of patients
– Wide spectrum of pulmonary changes; common manifestation – pleural effusion (unexplained pleural effusion in a young woman likely to be SLE).
RA and interstitial lung disease
• Rheumatoid arthritis (RA)
– Wide spectrum of pulmonary changes
• Rheumatoid nodules (when associated with pneumoconiosis – Caplan syndrome)
• Interstitial fibrosis
• Pleural effusions
Systemic sclerosis (scleroderma) and interstitial lung disease
• Systemic sclerosis (scleroderma)
– Interstitial fibrosis with pulmonary vascular hypertrophy
– Commonest cause of death
