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Flashcards in Pathology of Interstitial Lung Diseases Deck (25)
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pathologic patterns of interstitial lung disease

diffuse alveolar damage (DAD) - acute

organizing pneumonia (OP) - subacute

usual interstitial pneumonia (UIP) - chronic

non-specific interstitial pneumonia (NSIP) - chronic

granulomatous disease - acute, subacute, or chronic


diffuse alveolar damage

acute lung injury resulting from infections, drug reactions, collagen vascular diseases, vasculitis, aspiration and inhalational injuries, ionizing radiation, pancreatitis, and uremia

early exudative phase and organizing phase


pathogenesis of diffuse alveolar damage

damage to alveolar capillaries and epithelium

increased capillary permeability resulting in interstitial and intra-alveolar edema, fibrin exudation, and hyaline membrane formation


DAD early exudative phase

necrosis of pneumocytes, endothelial cells

hyaline membranes in alveolar ducts

collapse of alveolar parenchyma


organizing phase of DAD

organization of hyaline membranes

formation of airway space granulation tissue

dense collagenization of airway space granuation tissue


specific pathologic findings that point to etiologies in DAD

Infectious organisms (bacteria, viral, fungal, pneumocystis: special stains)

Neutrophils (imply infection)

Eosinophils (Acute eosinophilic pneumonia)

Granulomas (infection, aspiration & drug reaction)

Aspirated food particles (aspiration)

Drug associated changes (foamy macrophages amiodarone; granulomas in methotrexate)

Diffuse hemorrhage & capillaritis (vasculitis)


organizing pneumonia

sub-acute lung injury from any insult



drug reactions

minor component of many othe rdiseases cuh as hypersensitivity pneumonitis, NSIP, collagen vascular disease


cryptogenic organizing pneumonia

idiopathic organizing pneumonia

consists of proliferation of granulation tissue within small airways


usual interstitial pneumonia (UIP)

mostly idiopathic

caused by alveolitis, interstitial inflammation, patchy fibrosis with destruction of the underlying lung architecture

can be seen in collagen vascular diseases, drug reactions, familial/genetic disease, chronic hypersensitivity pneumonitis, and pneumoconiosis such as asbestosis


morphology of UIP

thickening of the interstitial wall alternation with normal lung

cobblestoned pleura

patchy fibrosis and traction bronchiectasis

lower lobe and subpleural predominence in the fibrosis

honeycomb lung - end stage lung


complications and causes of death in UIP

carcinoma of the lung

pulmonary hypertension/cor pulmonale

respiratory failure secondary to progressive fibrosis

pulmonary infections

acute exacerbations - acute lung injury superimpose don UIP (50% cause of death)


non-specific interstitial pneumonia

chornic process of hypersensitivity pneumonitis, drug reactions, or collagen vascular diseases

no significant architectural distortion

diffuse mild ot moderate interstitial chornic inflammation with preservation of underlying lung architecture

cellular and fibrotic types

fibrotic has worse prognosis


granulomatous disease

hypersensitivity pneumonitis

fungal and mycobacterial infections




sarcoidosis - idiopathic disease


hypersensitivity pneumonitis

extrinsic allergic alveolitis (EAA)

lung-limited hypersensitivity reaction to an inhaled antigen

known exposure to an offending agent

compatible clinical, radiologic, physiologic findings

BAL with lymphocytosis


symptoms of acute HP

dyspnea, chills, fevers, shortness of breath 4 to 6 hours after exposure, resolves by 48 hours


symptoms of sub acute HP

insiduous onset of SOB oer weeks to months, mild restrctive PFTs, marked lymphocytosis in BAL


symptoms of chronic (fibrotic) HP

insiduous onset of SOP

restrictive PFTs

clubbing sometimes present

features of fibrotic interstitial lung disease on biopsy

old dense fibrosis always present

fibrotic NSIP, UIP like, centrilobular

interstitial, non-necrotizing granulomas, giant cells


histologic features of HP

bilateral ground glass opacities and lobular areas of decreased attenuation and vascularity

interstitial inflammation with lymphocytes and plasma cells surrounding the bronchovascular bundles and extending into the surrounding interstitium

interstitial non-necrotizing granulomas or single giant cells, around bronchioles, in 2/3 cases


histologic features of sarcoidosis

follow lymphatic route in hilar lymph nodes

prominent concentric lamellar fibrosis around granulomas


nodular sarcoidosis

large nodules more than 1 cm in diameter

formed by aggregates of grnulomas

occasionally can show areas of necrosis


berylliosis histology

indistinguishable from sarcoidosis

history of beryllium exposure

beryllium lym lymphocyte transformation testing


aspiration pneumonia histology

organizing pnuemonia

aggregates of histiocytes surrounding food particle

not very well formed granulomas

food particle

presence of individual giant cells or foreign body granulomas


Wegeners Granulomatosis

acute necrotizing granulomas of the upper and lower respiratory tract

acute necrotizing or granulomatous vasculitis of small to medium sized vessels

renal disease - glomerulonephritis

limited wegener's in the absence of renal disease

pathogenesis is immune mediated


pulmonary eosinophilia

tropical eosinophilia - caused by infection with microfilariae

chronic esoinophilic pneumonia - idiopathic, secondary to infection in association with asthma


pulmonary alveolar proteinosis

unknown etiology - possible overproduction of surfactant by type 2 pneumocytes or its imparied clearance by alveolar macrophages

macrophage dysfunction

alveoli filled with dense, homogenous precipitate without any inflammation