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bronchiolitis obliterans; constrictive bronchiolitis; cryptogenic organizing pneumonia; bronchiolitis obliterans with organizing pneumonia (BOOP)

Bronchiolitis with or without organizing pneumonia (BOOP). Cryptogenic organizing pneumonia is the idiopathic form of BOOP. [2,4] BOOP is a non-specific histologic diagnosis. The diagnosis is one of exclusion. Etiology: 1) connective tissue diseases (disease associations) a) rheumatoid arthritis b) systemic lupus erythematosus c) polymyositis/dermatomyositis d) mixed connective tissue disease 2) silo-filler's lung 3) exposure to noxious gases, hazardous inhalents - burn-pit combustion products, desert dusts, explosive blasts. polluting industries, microbial aerosols 4) pharmaceutical agents a) bleomycin b) amiodarone c) penicillamine d) inhaled cocaine 5) radiation therapy 6) infection a) viral 1] cytomegalovirus 2] influenza virus 3] respiratory syntitial virus (RSV) - most common cause of bronchiolitis in young children 4] HIV b) bacterial 1] Legionella 2] Nocardia 3] Mycoplasma c) Fungal 1] Cryptococcus 2] Pneumocystis carinii 7) organ transplantation a) heart transplantation b) bone marrow transplantation c) lung transplantation 8) chronic eosinophilic pneumonia 9) Wegener's granulomatosis 10) pulmonary infarcts 12) pulmonary granulomas 13) vasculitis [2] 14) lymphoma [2] 15) adenocarcinoma [2] 16) pulmonary neoplasms 17) idiopathic (BOOP) Epidemiology: - veterans returning from Iraq & Afghanistan Pathology: 1) inflammatory infiltrate of terminal bronchioles 2) intraluminal fibrosis in distal airways, alveolar ducts or perialveolar spaces 3) obliteration of small airways 4) organizing pneumonia in the absence of infection (BOOP) a) extension of exudate & granulation tissue into respiratory bronchioles, alveolar ducts, & alveolar walls - patchy bilateral alveolar filling with loose plugs of granulation tissue b) a distinct entity without organizing pneumonia is considered separate from BOOP [2] 5) airflow obstruction Clinical manifestations: 1) may follow upper respiratory tract infection 2) resembles a flu-like syndrome with acute or subacute onset, or community acquired pneumonia 3) patients may be initially treated for pneumonia - failure to respond to antibiotics 4) development of a subacute process - cough, fever, malaise for 6-8 weeks [2] 5) exertional dyspnea 6) cough 7) fever may or may not be present 8) crackles 9) sputum uncommon Special laboratory: 1) bronchoscopy: a) bronchial alveolar lavage (BAL) b) lung biopsy* 2) Pulmonary function testing: a) restrictive pattern b) diminished DLCO c) generally poorly responsive to bronchodilators * lung biopsy may not be needed for diagnosis if clinical presentation & CT consistent with cryptogenic organizing pneumonia [2] Radiology: 1) chest X-ray a) patchy, diffuse, migratory ground-glass alveolar infiltrates b) patchy air-space consolidation in the lung periphery c) often involves the lower lung fields [2] d) may mimic infectious pneumonia [2] 2) high-resolution computed tomography - mosaic pattern - ground glass infiltrates with areas of hyperinflation - centrilobular nodules - airway thickening Differential diagnosis: - recurrent pneumonia Management: 1) remove offending agents 2) treat underlying disorders 3) high-dose glucocorticoids a) generally beneficial with idiopathic form b) 6-12 months in duration, occasionally longer c) relapses common with glucocorticoid taper, but they general respond to a dose increase with slowertaper [2,4] d) adjunct immunosuppressive agents may be needed 4) erythromycin may be of value 5) prognosis a) generally good with idiopathic form b) may be less favorable when associated with specific disorders

General

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

References

  1. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 748, 763
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018, 2022.
  3. Journal Watch, Mass Med Soc 19(23):187 (Dec) 1999
  4. Drakopanagiotakis F, Paschalaki K, Abu-Hijleh M et al Cryptogenic and secondary organizing pneumonia: clinical presentation, radiographic findings, treatment response, and prognosis. Chest. 2011 Apr;139(4):893-900 PMID: 20724743
  5. Montesi SB, Nance JW, Harris RS, Mark EJ. CASE RECORDS of the MASSACHUSETTS GENERAL HOSPITAL. Case 17-2016. A 60-Year-Old Woman with Increasing Dyspnea. N Engl J Med. 2016 Jun 9;374(23):2269-79. PMID: 27276565 http://www.nejm.org/doi/full/10.1056/NEJMcpc1516452
  6. Lazor R, Vandevenne A, Pelletier A et al Cryptogenic organizing pneumonia. Characteristics of relapses in a series of 48 patients. The Groupe d'Etudes et de Recherche sur les Maladles "Orphelines" Pulmonaires (GERM"O"P). Am J Respir Crit Care Med. 2000 Aug;162(2 Pt 1):571-7. PMID: 10934089
  7. NEJM Knowledge+ Question of the Week. Jan 26, 2021 https://knowledgeplus.nejm.org/question-of-week/269/ - Epler GR et al. Bronchiolitis obliterans organizing pneumonia. N Engl J Med 1985 Jan 17; 312:152 https://www.nejm.org/doi/full/10.1056/NEJM198501173120304 - Drakopanagiotakis F et al. Cryptogenic and secondary organizing pneumonia: clinical presentation, radiographic findings, treatment response, and prognosis. Chest 2010 Aug 21; 139:893 PMID: 20724743 - Cottin V, Cordier JF. Cryptogenic organizing pneumonia. Semin Respir Crit Care Med 2012 Oct; 33:462. PMID: 23001801