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pulmonary fibrosis

Etiology: 1) idiopathic (most common) 2) pharmacologic agents a) amiodarone b) bleomycin c) cyclophosphamide d) nitrofurantoin 3) connective tissue disease a) lupus erythematosus b) rheumatoid arthritis c) scleroderma 4) sarcoidosis 5) histiocytosis X 6) occupational exposure a) asbestos b) silicosis b) pigeons c) cotton dust 7) inherited diseases a) neurofibromatosis b) tuberous sclerosis 8) post-infectious a) bacterial - Legionella, Mycoplasma, tuberculosis b) viral- adenovirus 10) lymphangitis carcinomatosis a) breast cancer b) lung cancer 11) radiation Hamman-Rich syndrome: rapidly progressive pulmonary fibrosis Clinical manifestations: 1) dyspnea 2) dry cough 3) clubbing (most common cause of clubbing) 4) absence of orthopnea 5) inspiratory rales (Velcro-like sound) 6) tachypnea 7) augmented P2 heart sound Laboratory: 1) complete blood count: normocytic anemia 2) erythrocyte sedimentation rate 3) antinuclear antibody 4) rheumatoid factor 5) antibodies to: a) avian antigens b) actinomycetes 6) serum Ca+2 (sarcoidosis) 7) angiotensin-converting enzyme (ACE) may be elevated in sarcoidosis 8) urinalysis (sediment) Goodpasture's syndrome Special laboratory: 1) pulmonary function testing a) restrictive lung disease b) restriction combined with obstruction - sarcoidosis c) decreased diffusion capacity of CO 2) bronchoscopy & bronchoalveolar lavage a) Pneumocystis b) fungus or tuberculosis c) alveolar proteinosis d) lymphangitis carcinomatosis e) histiocytosis X f) pulmonary hemorrhagic syndrome (Goodpasture's) g) exclude cancer 3) open lung or thorascopic biopsy 4) ambulatory pulse-oximetry exercise-induced hypoxemia Radiology: 1) may be normal 2) reticulonodular pattern (most common) 3) upper lobe a) sarcoidosis b) histiocytosis X c) silicoisis 4) lower lobe a) idiopathic b) asbestosis c) connective tissue disease 5) pleural effusion a) connective tissue diseases b) asbestosis 6) computed tomography (high resolution) of thorax - obtain prior to biopsy to delineate distribution of disease & direct selection of site for biopsy Differential diagnosis: 1) congestive heart failure (CHF) may masquarade as pulmonary fibrosis 2) Goodpasteur's syndrome 3) pneumocystis pneumonia Complications: 1) respiratory failure (infectious) 39% 2) heart failure 14% 3) exposure to particulate matter <= 2.5 um in diameter is associated with worse baseline severity, disease progression, & mortality [3] Management: 1) pirfenidone for idiopathic pulmonary fibrosis 2) steroids: unclear if steroids alter course of disease 3) prophylaxis against respiratory infection a) PneumoVax b) influenza vaccine 4) calcium channel blockers may be of benefit 5) nitrates may be of benefit 6) colchicine 0.5 mg PO BID may be of benefit

Related

drug-induced interstitial lung disease

Specific

acute interstitial pneumonia; Hamman-Rich syndrome; idiopathic alveolar fibrosis; rapidly progressive pulmonary fibrosis (IAF) chronic pulmonary fibrosis idiopathic pulmonary fibrosis (IPF); usual interstitial pneumonitis (UIP) progressive massive fibrosis

General

interstitial lung disease; diffuse parenchymal lung disease (DPLS, ILD) fibrosis

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 790
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 19 American College of Physicians, Philadelphia 1998, 2022.
  3. Goobie GC, Carlsten C. Johannson KA et al Association of Particulate Matter Exposure With Lung Function and Mortality Among Patients With Fibrotic Interstitial Lung Disease. JAMA Intern Med. 2022;182(12):1248-1259. PMID: 36251286 PMCID: PMC9577882 Free PMC article https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2797557
  4. National Heart, Lung, and Blood Institute (NHLBI) Idiopathic Pulmonary Fibrosis https://www.nhlbi.nih.gov/health-topics/idiopathic-pulmonary-fibrosis