asbestosis
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Etiology
- exposure to asbestos fibers (see asbestos)
- early massive exposure produces severe disease
- tobacco smoke greatly increases the risk of asbestos- related cancer
- all types of asbestos fibers have been implicated
Epidemiology
- construction, automotive servicing, ship-building & mining industries are most commonly affected[3]
Pathology
- pleural disease, multiple forms
- pleural plaques/fibrosis (hyalinosis simplex)
- most common manifestation
- generally represents exposure 20 years earlier
- not precancerous
- bilateral & symmetric
- occurs along path of ribs
- tends to progress & calcify
- pleural/diaphragmatic calcification
- thickened pleura (hyalinosis complicata)
- uncommon complication
- progressive calcification involves both visceral pleura & parietal pleura, lung apices & pericardium
- recurrent acute inflammatory phase associated withfever & exudative pleural effusion
- pleural effusion (earliest complication)
- always exudative
- bloody in 70&
- unilateral or bilateral
- malignant mesothelioma must be excluded as a cause
- mesothelioma
- pleural & peritoneal
- constant gnawing chest pain
- prolonged exposure is necessary
- interval between exposure & mesothelioma is 30-40 years
- no correlation with smoking
- pleural plaques/fibrosis (hyalinosis simplex)
- lung disease
- pulmonary fibrosis (long-term heavy exposure)
- fibrosis of visceral pleura also occurs
- progressive fibrosis & honeycombing may lead to cor pulmonale
- clinically similar to idiopathic pulmonary fibrosis
- affects primarily lower lobes of lung
- rounded atelectasis
- lung cancer
- generally bronchial adenocarcinoma
- interval between exposure & cancer is 15-35 years
- accounts for most asbestos-related deaths
- lower lobes affected twice as frequently as upper lobes
- tumors are generally peripheral & frequently involve the pleura
- also small cell carcinoma in smokers[3]
- smoking & asbestos exposure synergistically increase risk of lung cancer to 60 fold relative to non-smokers without asbestos exposure[3]
- pulmonary fibrosis (long-term heavy exposure)
- other
- pericardial tumor
- peritoneal tumors
- vocal cord polyps
- increased incidence of lymphoma
- laryngeal cancer
- gastrointestinal cancer
Clinical manifestations
- latent period of 10-15 years (20-30 years[3])
- symptoms
- gnawing chest pain or dull ache (43%)
- dyspnea (27%)
- cough (19%)
- weight loss (13)
- fever (7%)
- pleuritic chest pain is rare
- signs
- pleural effusion may be present
- clubbing of the fingers (< 5%)
- bibasilar crackles
- pleuropericardial rub
- see pathology
Laboratory
- rheumatoid factor may be positive
- anti-nuclear antibody (ANA) may be positive
- pleural biopsy for mesothelioma
- asbestois in specimen
Radiology
- chest X-ray
- predominantly lower lobe infiltrates
- bilateral basilar reticulonodular infiltrates, 'shaggy heart sign'
- high-resolution computed tomography (HRCT)
- pleural plaques or thickening (90%)
- bilateral
- latency of 10-20 years
- thickened intralobular & interlobular line (confirmation on prone image needed)
- parenchymal bands, often contiguous with pleura
- interstitial fibrosis with basilar predominance
- honeycombing (advanced disease)
- subpleural densities
- curvilinear subpleural lines of variable length
- often parallel to pleura
- confirmation on prone image needed
- nodular pleural thickening suggests mesothelioma
- pleural plaques or thickening (90%)
Complications
- cigarette smoking & asbestos have a synergistic effect on risk of lung cancer
Differential diagnosis
Management
- preventive medicine
- Pneumovax at diagnosis & 5 years later
- annual influenza vaccine
More general terms
Additional terms
References
- ↑ Contribution from Peter Baylor, VA Medical Center, UCSF Fresno
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 757-58
- ↑ 3.0 3.1 3.2 3.3 3.4 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18, American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018.
- ↑ Paris C, Thierry S, Brochard P et al Pleural plaques and asbestosis: dose- and time-response relationships based on HRCT data. Eur Respir J. 2009 Jul;34(1):72-9 PMID: https://www.ncbi.nlm.nih.gov/pubmed/19129281
- ↑ Markowitz SB, Levin SM, Miller A, Morabia A. Asbestos, asbestosis, smoking, and lung cancer. New findings from the North American insulator cohort. Am J Respir Crit Care Med. 2013 Jul 1;188(1):90-6. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23590275
- ↑ Stayner L, Welch LS, Lemen R. The worldwide pandemic of asbestos-related diseases. Annu Rev Public Health. 2013;34:205-16. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23297667
- ↑ Fishwick D, Barber CM. Non-malignant asbestos-related diseases: a clinical view. Clin Med (Lond). 2014 Feb;14(1):68-71. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24532750 Free PMC Article
- ↑ National Heart, Lung, and Blood Institute (NHLBI) Asbestos-Related Lung Diseases https://www.nhlbi.nih.gov/health-topics/asbestos-related-lung-diseases