Transcript Pathology Laboratory Air exchange Diseases

Pathology Laboratory
Air exchange Diseases:
Interstitial diseases
Air Exchange Diseases
• Infectious Pneumonias
– Bacterial, Mycobacterial, Viral and Fungal
• Interstitial Lung Diseases
– Pneumoconiosis, Sarcoidosis, Fibrosis etc.
• Pulmonary “Vascular” Diseases
– Pulmonary Embolism, pulmonary edema,
ARDS
OBJECTIVES
• Describe the normal interstitium and the
changes in cells and lung architecture that may
occur in interstitial lung disease.
• Describe the key pathologic features of the
common idiopathic interstitial lung diseases.
• Describe the pathologic features of common
secondary interstitial lung diseases: sarcoidosis,
pneumoconiosis, and collagen vascular disease
and compare and contrast their pathological
features.
• Describe the key pathologic features of
pulmonary vascular diseases.
Interstitial Lung Diseases
• The clinician, radiologist and pathologist all
approach ILD differently
• Each approach provides unique insight
– But this can be confusing as each specialty has its
own terminology:
• Clinician: Disease causing breathlessness and
restriction on lung function
• Radiologist: Disease producing extra lines/dots
on radiographs
• Pathologist: Disease involving the interstitium
Pulmonary Interstitium
Structure
Axial Interstitium
Peribronchial
Perivascular
Peripheral Interstitium
Interlobular
Interstitium
Pleural Interstitium
Septal Interstitium
Pathophysiology
• Why is having extra stuff in your
pulmonary interstitium bad?
– Impairment of Lung Mechanics
• Compliance of the lungs is reduced
• Increases work of breathing
• Reduces Lung volumes
– Impairment of Gas Exchange
• Smaller lung volumes mean less surface area for
gas exchange
• Extra stuff in interstitium impedes transfer of gas
oxygen from alveoli to pulmonary capillaries
Interstitial lung diseases
• Acute vs chronic
• Known vs Unknown etiology
• Primary vs secondary
• Pathologic patterns
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Interstitial Lung Diseases
• Primary
– Sarcoidosis (20%)
– Idiopathic Interstitial Pneumonia - IPF (15%)
• Secondary
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Congestive Heart Failure / Pulmonary Edema
Infection (Pneumonia)
Malignancy (Lymphangitic Carcinomatosis)
Pneumoconiosis (25%)
Connective Tissue Disease (10%)
Hypersensitivity Pneumonitis (5%)
Drugs / Radiation (5%)
Primary Interstitial Lung
Diseases
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Sarcoidosis
• Systemic disease of unknown etiology
• Often Involves lung and lymph nodes
• Etiopathogenesis: type IV hypersensitivity
reaction with granulomatous inflammation
along the lymphatic routes
• Progressive disease presenting symptoms
only late in its course
• Unpredictable outcome
Sarcoidosis
Granulomas
Granulomas
Artery
Bronchiole
Interlobular septum
Sarcoidal Granuloma
Histiocytes
Granuloma
Giant cell
Idiopathic Pulmonary Fibrosis
• Unknown etiology
• Middle-age to elderly individuals
• Chronic interstitial pneumonia evolving to
lung fibrosis
Idiopathic Pulmonary Fibrosis
End-Stage Lung
(Honeycombing)
Fibrous septa
Honeycombing
Idiopathic Pulmonary Fibrosis
Cystic spaces
Septal fibrosis
Idiopathic Pulmonary Fibrosis
Inflammatory cells
Septal fibrosis
Normal septum
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Secondary Interstitial Lung
Diseases
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Pneumoconioses
• Known etiology: Inorganic particulate matter
• Usually fibrogenic:
– Silica
– Asbestos
• Usually non-fibrogenic
– Coal
– Berylium (granulomatous)
Silicosis
• Subacute or chronic presentation
• Intra-histiocytic short needle-shaped
particles
• Histiocytic aggregates along lymphatic
routes and within lymph nodes
• Fibrous silicotic nodules, predominantly
upper lobes
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Pulmonary Silicosis
Silicotic Nodule
Asbestosis
• Chronic presentation
• Long slender fibres coated by iron
(ferruginous body/asbestos body)
• Peribronchiolar fibrosis
• Fibrous thickening of the alveolar septa
• Predominantly lung bases and subpleural
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Asbestos Body
Pulmonary Fibrosis
Septal thickening
Pleural Plaques
Collagen Vascular Diseases
• Collagen diseases frequently involve the
lung and cause interstitial pneumonia :
– Rheumatoid Arthritis
– Systemic Sclerosis
– Systemic Lupus Erythematosis
– Sjögren Syndrome
– Mixed Connective Tissue Disease
• The histological features are
indistinguishable from idiopathic forms
Hypersensitivity Pneumonitis
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Known etiology: organic matter (e.g. fungal)
Acute, subacute or chronic presentation
Centrilobular inflammation (peribronchiolar)
Poorly-formed granulomas in the alveoli
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Hypersensitivity Pneumonitis
Septal thickening
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Hypersensitivity Pneumonitis
Giant cell
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Pulmonary Vascular Diseases
Types of Diseases
• Obstruction to the venous outflow (pulmonary
congestion )
– Congestive heart failure → pulmonary edema
• Increase in the pulmonary artery resistance
(pulmonary hypertension)
– Primary or secondary (e.g. systemic sclerosis)
• Pulmonary artery obstruction (pulmonary
thromboembolism)
– Emboli (common) or thrombosis (uncommon)
• Vascular inflammation (vasculitis)
– Wegener’s granulomatosis, Churg-Strauss
Pulmonary Thromboembolism
• Pulmonary artery embolism (common)
– More than 95% associated to deep venous
thrombosis of the lower limbs in either
hypercoagulability state or bed ridden
patients.
• Pulmonary artery thrombosis (uncommon)
– Large vessels: rare, associated to pulmonary
hypertension or atherosclerosis.
– Small vessels: vasculitis, inflammation,
diffuse intravascular coagulation (DIC)
Pulmonary Embolism
• Acute morphologic changes
– Luminal obstruction with endothelial damage
– Small vessels: Alveolar hemorrhage in the
correspondjng irrigated area (e.g. lobule) and
possible infarct
– Larger vessels: hemorrhagic infarction in the
center and hemorrhage in the periphery
• Chronic morphologic changes
– Infarcted areas become fibrotic
– Chronic micro pulmonary embolism: pulmonary
hypertension
Thrombosis
Pulmonary Embolism
Pulmonary
Embolism
Pulmonary Embolism
Embolus
Artery
Respiratory bronchiole
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Hemorrhagic pulmonary infarct
Alveolar hemorrhage
Alveolar septa
Complete Obstruction
Organized thrombosis
Internal elastic layer (short arrows)
Recanalized Thrombus
New lumen
Organized thrombus
ARDS
• Associated with the systemic release of
inflammatory mediators :
– Systemic inflammatory response syndrome
(SIRS)*
– Sepsis
– Infectious Pneumonias
– Mechanic Trauma (shock)
– Extensive burns
– Pancreatitis
– Toxic fumes inhalation
ARDS
• Pathogenesis
– Diffuse alveolar damage (DAD) to the
epithelial and endothelial cells, increased
vascular permeability, interstitial and alveolar
oedema, septal inflammatory infiltrate,
fibrinous exudate and hyaline membranes
formation (diffuse alveolar damage)
– Neutrophils are the main cells involved
– Difficult repair, frequently evolving to death or
fibrosis
ARDS - Pathogenesis
Diffuse Alveolar Damage
Diffuse Alveolar Damage
Early septal fibrosis
Hyaline membranes
OBJECTIVES
• Describe the normal interstitium and the
changes in cells and lung architecture that may
occur in interstitial lung disease.
• Describe the key pathologic features of the
common idiopathic interstitial lung diseases.
• Describe the pathologic features of common
secondary interstitial lung diseases: sarcoidosis,
pneumoconiosis, and collagen vascular disease
and compare and contrast their pathological
features.
• Describe the key pathologic features of
pulmonary vascular diseases.