Pathology - Lecture 3 ( Restrictive Diseases ) Flashcards
General features of parenchymal disease
- Diffuse parenchymal lung disease (DPLD) - most accurate
- Characterized by normal FEV1:FVC, reduced DLCO & increased A-a gradient
Extra-parenchymal
Chest wall disorders
o Kyphoscoliosis
o Neuromuscular diseases (e.g. Myasthenia gravis)
o Obesity
- Pleural disorders (effusions/pneumothorax)
- Characterized by normal FEV1:FVC, normal DLCO & normal A-a gradient
Interstitial lung disease
—involves the interstitium
-inflammation and fibrosis of the alveolar septa
• “Alveolitis” – Damage to pneumocytes and endothelial cells
• Leads to leukocytes releasing cytokines which mediate and stimulate
interstitial fibrosis Decreased lung compliance (stiff)
Complications of ILD
-Hypoxia
-pulmonary vasoconstriction
-pulmonary htn and cor pulmonale
Idiopathic pulmonary fibrosis (usual interstitial pneumonia)
Clinicopathologic syndrome marked by progressive interstitial pulmonary fibrosis and respiratory
• Males > Females
• Older age group (55-75 yrs)
-presents as dry cough and dyspnea on exertion ,cyanosis ,cor pulmonale and clubbing
Gross appearance of IPF
-Cobble stone appearance of pleural surface-Retraction of scars along interlobular septa
• Firm, fibrotic parenchyma markedly in lower lobe and subpleural regions
• Honeycomb cysts
-patchy interstitial fibrosis
Nonspecific Interstitial Pneumonia(NSIP)
-Younger demographic; female non-smokers
-histology: uniform fibrosing process
-cellular variant /fibrosing variant
-lung architecture is preserved
-some respond to steroids
Cryptogenic Organizing Pneumonia
Also called: Bronchiolitis obliterans organizing pneumonia (BOOP)
-Patchy sub-pleural or peri-bronchial areas of airspace consolidation.
-histology: Polypoid plugs of loose organizing connective tissue(called Masson bodies) in alveoli, alveolar ducts and often bronchioles
• All lesions are of the same age, and the underlying lung architecture is normal
• There is no interstitial fibrosis or honeycomb lung
Pneumoconiosis etiology
common- coal dust, silica (most common) and asbestos
ASBESTOS RELATED DISEASES
• Inhalation of asbestos fibers (fibrous silicates)- pro inflammatory
• Serpentine (more common) and amphibole (more pathogenic) forms
-worsening dyspnea which appears 10- 20 years after exposure
Pathogenesis of asbestos related diseases
-asbestos fiber deposition in lungs
-asbestos body formation
-asbestos body leads to iron catalyzed reactions forming free radicals (on histo : golden brown roots with translucent center )
-DNA damage
-carcinogens
Asbestos gross appearance
-thickened visceral pleura
-interstitial fibrosis affecting the lower lobe
-pleural plaques
Pleural plaques
• Contain dense collagen and calcification
• No asbestos bodies seen
• Most frequently on the anterior and posterolateral
aspects of the parietal pleura and over the domes of the diaphragm
SILICOSIS
-Caused by inhalation of proinflammatory crystalline silicon dioxide (silica)
-they interact with the epithelial cells and macrophages
-leads to fibrosis
- Increased risk of Pulmonary Tuberculosis - Crystalline silica inhibits the ability of pulmonary macrophages to kill phagocytosed mycobacteria.
Morphological changes in silicosis
• Collagenous nodule/ scar
(usually in the hilar lymph nodes
and upper lung field).
• Eggshell calcification – sheets
of calcification in the lymph
nodes- Radiographic finding.
• Progressive massive fibrosis
Microscopy of silicosis
• Central area of whorled collagen
fibers with dust-laden
macrophages
• Weakly birefringent silica in the
centre under polarized microscopy
Coal workers pneumoconiosis
-Inhalation of coal particles and other admixed forms of dust
- coal contains mainly carbon , metallic , silica and organic compounds
CWP morphology- anthracosis
Accumulation of carbon pigment mostly in peri lymphatic regions and lymph nodes
Asymptomatic, no appreciable pathologic changes
CWP morphology- simple CWP
Macules ( 1-2 mm) and nodules Aggregates of dust-laden macrophages Fibrosis minimal or absent
Little or no pulmonary dysfunction
CWP morphology- complicated
Coalescence of nodules into fibrous scars (Blackened scars 1 cm&>)
• Impaired pulmonary function
• Probably < 10% of simple CWP progress to complicated
Sarcoidosis
-characterized by noncaseating granulomatous inflammation in many tissues and organs
-less than 40 years of age
Pathogenesis of sarcoidosis
-genetic involvement
-Cell mediated (Type IV) hypersensitivity reaction to unidentified antigen
Morphology of Sarcoidosis
-non necrotizing epitheloid granulomatoma
-hyalinized scar
-some progress and diffuse interstitial fibrosis and honeycomb king
-Schumann bodies
-asteroid bodies
Schumann bodies
laminated concretions of calcium and protein
Asteroid bodies
stellate inclusion in giant cells
Clinical features sarcoidosis
-fever
-asymptotic for a long time
- other organ systems involved
Diagnosis of sarcoidosis
-hypercalcemia
-elevated ACE
-CD4:CD8 increased
-Typical bilateral hilar lymphadenopath
Hypersensitivity Pneumonitis
Immunologically mediated, predominantly interstitial lung disorders caused by intense, often prolonged exposure to inhaled organic antigens -primarily involving alveolar walls
-acute : signs and symptoms show up 4-8 hours after exposure
-chronic : onset of cough, dyspnea, malaise, and weight loss
Etiology of hypersensitivity pneomonotis
• 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”
Pathogenesis of hypersensitivity pneomonitis
Both type III and type IV hypersensitivity reaction patterns
1st exposure : IgG
2nd exposure : inflammatory response
Chronic exposure - granuloma formation
Morphology of hypersensitivity pneomonitis
-Airway centered process
• Chronic inflammatory infiltrate
• Organizing pneumonia
• Poorly formed non- necrotizing granulomata with giant cells
Pulmonary Alveolar Proteinosis
-Rare disease caused by defects in pulmonary macrophage function due to deficient granulocyte-macrophage colony-stimulating factor (GM-CSF) signalling, which results in the accumulation of surfactant in the intra-alveolar and bronchiolar spaces
-Autoimmune
Pulmonary alveolar proteinosis presentation
-accumulation of intra-alveolar precipitates containing surfactant proteins, causing focal-to confluent consolidation of large areas of the lungs with minimal inflammatory reaction
-bilateral patchy asymmetric pulmonary opacifications
-gelatinous sputum
Acute Interstitial Pneumonia-Hamman Rich syndrome
-Very aggressive form of interstitial lung disease
-May also occur as an acute phase of acceleration of IPF
-Presents with diffuse alveolar damage and hyaline membranes
