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2	Interstitial lung diseases Chronic lung disease in which the interstitium is altered by inflammation and/or fibrosis 180 diseases: 70% unknown Clinico-radiologic correlation
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6	USUAL INTERSTITIAL PNEUMONIA Idiopathic UIP = Interstitial Pulmonary Fibrosis = Cryptogenic Fibrosing Alveolitis UIP-pattern - Collagen vascular disease - Drugs - Radiation - Pneumoconiosis (e.g., asbestosis)
7	USUAL INTERSTITIAL PNEUMONIA Clinical Features Gradual onset of dyspnea on exertion and dry cough 40 - 70 years Restrictive pattern on PFTs Mean survival 4 - 6 years
8	USUAL INTERSTITIAL PNEUMONIA Chest Radiograph Bilateral, symmetric irregular linear opacities causing a reticular pattern Ground glass opacities, honeycombing, decreased lung volume Mainly lower lung zones in 80% Normal in 10 - 15%
9	USUAL INTERSTITIAL PNEUMONIA High-Resolution CT Irregular lines (reticular pattern) and honeycombing, mainly subpleural Honeycombing in 80 - 90% Progressive fibrosis
10	USUAL INTERSTITIAL PNEUMONIA Pathologic Features Gross: - Cobble-stone appearance of pleura - Patchy fibrosis of lung, lower lobes, subpleural, along inter-lobular septa Microscopic: - Fibrosis varies in time and intensity - Mild to moderate inflammation - No granulomas
11	NONSPECIFIC INTERSTITIAL PNEUMONIA (NSIP) Diagnosis of exclusion Dyspnea and cough (average 8 months) 46 and 55 years Cellular and fibrosing patterns (Cellular pattern: younger and better prognosis) Better prognosis than UIP
12	NSIP, Cellular Pattern Mild to moderate interstitial chronic inflammation (lymphocytes, few plasma cells) Uniform or patchy Focal organizing pneumonia No dense or honeycomb fibrosis
13	NSIP, Fibrosing Pattern Dense or loose interstitial fibrosis Lack of temporal heterogeneity Inconspicuous or no fibroblastic foci Diffuse or patchy involvement Foci of honeycomb fibrosis and lymphoid aggregates Mild to moderate chronic interstitial inflammation
14	SURVIVAL UIP NSIP, FP NSIP, CP 5 yr. 43% 90% 100% 10 yr. 15% 35% 100%
15	CRYPTOGENIC ORGANIZING PNEUMONIA Cough and dyspnea (< 3 months) H/O flu-like illness 4 - 6 weeks ago 55 years Respond to oral corticosteroids Idiopathic or OP pattern associated with specific disease
16	CRYPTOGENIC (IDIOPATHIC) ORGANIZING PNEUMONIA Patchy air space consolidation, subpleural or peribronchial, and air bronchograms Small or large nodules Polypoid plugs of loose organizing connective tissue, with or without bronchiolar intraluminal polyps Same age, preserved lung architecture
17	ACUTE INTERSTITIAL PNEUMONIA (AIP) Widespread acute lung injury Rapidly progressive clinical course Unknown etiology Histology is that of diffuse alveolar damage (DAD); however, DAD is associated with known causes
18	ACUTE INTERSTITIAL PNEUMONIA 50 years Acute respiratory failure after upper respiratory tract infection Requires mechanical ventilation 50% mortality Acute and organizing phases
19	RESPIRATORY BRONCHIOLITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE Cigarette smokers (> 30 pack-years) Mild symptoms/incidental finding 2:1 male predominance Dusty brown macrophages Mild peribronchiolar fibrosis Centrilobular emphysema
20	DESQUAMATIVE INTERSTITIAL PNEUMONIA Cigarette-smoking related lung disease 4th and 5th decade 2:1 male predominance Insidious onset of dry cough and dyspnea Good prognosis
21	DESQUAMATIVE INTERSTITIAL PNEUMONIA BAL: macrophages with pigment Diffuse, uniform involvement Intra-alveolar pigmented macrophages Mild inflammation and fibrosis, interstitial
22	LYMPHOCYTIC INTERSTITIAL PNEUMONIA Not all cases of LIP are lymphoma Few idiopathic cases Diffuse dense infiltration of septa by lymphocytes Defining criterion for AIDS in < 13 y EBV+ in lung lesions