7.INTERSTITIAL LUNG DISEASE-DPLDs Year 4 Internal Medicine

7.INTERSTITIAL LUNG DISEASE-DPLDs Year 4 · Internal Medicine Collection: 4TH YEAR ALL NOTES / IMED / IMED 4.1 / NGUGI -- Slide 1 INTERSTITIAL LUNG DISEASES Slide 2 INTERSTITIAL LUNG DISEASES ILD is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs) of the lungs.\nare a heterogenous group of disorders characterized by inflammation which often leads to pulmonary fibrosis. Also referred to as Diffuse Pulmonary Lung Diseases (DPLDs) They share similar symptoms, physical signs, pulmonary function, abnormalities and radiological changes. Slide 6 initial and repeat epithelial injury, abnormal repair response \nprogression of tissue damage\nfibrotic lung changes. -lung damage is irreversible and gets worse over time Slide 7 CLASSIFICATION Slide 9 Classification Idiopathic interstitial pneumonias (IIP): \nIdiopathic pulmonary fibrosis (IPF) \nNonspecific interstitial pneumonia (NSIP)\nCryptogenic organizing pneumonia (COP)\nAcute interstitial pneumonia (AIP) Slide 10 Smoking-related ILD: \nRespiratory bronchiolitis-associated interstitial pneumonia (RB-AIP)\nDesquamative interstitial pneumonia (DIP)\nOthers of unknown cause Lymphangioleiomyomatosis Slide 11 Systemic diseases\nConnective tissue diseases (CTD)\nRheumatoid arthritis (RA)\nSystemic lupus erythematosus\nSystemic sclerosis\nSjogren’s disease\nDermatomyositis/polymyositis Slide 12 Granulomatous disease\nGranulomatosis with polyangiitis\nChurg-Strauss disease\nPulmonary Langerhans cell histiocytosis (PLCH)\nSarcoidosis\nHypersensitivity pneumonitis (HP) Slide 13 Exposure-related\nOccupational –Asbestosis, Silicosis, Gases/fumes\nRadiation Pharmacologic:\nMethotrexate, azathioprine, rituximab, tumor-necrosis factor blockers, amiodarone, nitrofurantoin, chemotherapeutics Slide 14 Features common in ILD- symptoms Shortness of breath- worsening and progressive\nDry cough chest discomfort Fatigue Gradual unintended weight loss Slide 15 Signs Clubbing-seen mostly in advanced IPF Fine crackles-typically bilateral and basal(velcro sound) Central cyanosis Signs of RHF Slide 16 Upper Lobe predominance Berylliosis Radiation Fibrosis Eosinophilic pneumonia and Hypersensitivity Pneumonia Allergic Bronchopulmonary Pneumonia/ Ankylosing Spondylitis Sarcoidosis TB Silicosis + Most pneumoconiosis Slide 17 LOWER LOBE PREDOMINANCE Asbestosis IPF Drug Induced Fibrosis- NAMB-Nitrofurantoin, Amiodarone, Methotrexate, Bleomycin Scleroderma. Slide 18 Idiopathic Interstitial Pneumonias (IIPs) Characterized by varying patterns of inflammation and fibrosis in the lung parenchyma Most common and most important is idiopathic Pulmonary Fibrosis. Accounts for 85% of new cases Slide 20 IDIOPATHIC PULMONARY FIBROSIS-IPF Refers to a form of DPLD characterized by evidence of Usual Interstitial Pneumonia Etiology Unknown- BUT, there are assumed factors Telomerase, mucin and surfactant disorders Viruses-EBV Occupational dusts-Metal and wood Chronic GERD There is a strong association with cigarette smoking Slide 21 Epidemiology Males affected more than females Commonly diagnosed in 5th and 6th decade 5 year survival rate is at 50% Slide 22 PATHOPHYSIOLOGY Repeated injury to the alveolar epithelium by antigen Triggers inflammation. Involvement of Il-8, Il-1 and 6, TNF alpha, TGF Beta, neutrophils and macrophages.\nAdaptive immune system is recruited Via Involvement of TH2\nInflammation persists but now, It is an autoimmune process Defective repair with activation of fibroblasts by TGF Beta. The repeated injury also induces apoptosis of the cells due to reduced telomeres 3 things-initial and repeat epithelial injury, abnormal repair response and progression of tissue damage and fibrotic lung changes. Slide 23 CLINICAL PRESENTATION S.O.B Non productive cough Tachypnea CLINICAL FINDINGS Finger clubbing Bi basal fine crackles In advanced cases- Peripheral cyanosis, Severe shortness of breath and symptoms of H.F Slide 24 INVESTIGATIONS No circulating marker for IPF Non specific findings +ve Rheumatoid factor Antinuclear factor Elevated LDH Pulmonary function test is similar to that of restrictive lung diseases.-Both FEV and FVC decline but FVC declines more. Hence FEV/FVC ratio rises. In advanced cases- Arterial hypoxemia present at rest Slide 25 CXR Bi-basal reticular and reticular nodular opacities Honey comb appearance seen in advanced stages. HRCT Subpleural reticulation-Patchy fibrosis of varying intensity Fibroblastic foci Honey comb fibrosis. (Subpleural and basal reticular pattern + subpleural cysts) Traction Bronchiectasis\nAlveolar collapse Do not biopsy if clinical evidence is typical and HRCT findings are clear. Slide 28 MANAGEMENT Steroids. Never monotherapy. Add Azathioprine or NAC Predisolone-0.5/kg combined with Azathioprine (2-3mg/kg) – Recommended for highly symptomatic, those with rapidly progressing disease, those with bilateral ground glass on CT or with a grater than 15% drop in their FVC in the past 3-6 months. Antifib