16 - Interstitial Occupational & Environmental Lung Disease Flashcards
What is the general pathogenesis of interstitial lung disease?
- injury or antigen exposure to alveolar epithelium/capillary –> acute inflammation (alveolitis) –> chronic inflammation (granuloma) and fibrosis
- fibrosis can occur without inflammation and indicates an abnormal repair process after injury
- disease can occur from single or repeated injury
- some diseases are antibody related
Interstitial lung disease has [increased/decreased] compliance and [increased/decreased] elastic work of breathing.
Decreased compliance, increased elastic WOB
Why is hypercapnia not seen in someone with interstitial lung disease?
Because CO2 is more diffusible
What is the major cause of hypoxemia at rest in someone with interstitial lung disease? With exercise?
V/Q mismatch at rest, diffusion abnormality with exercise
Interstitial lung disease has [normal/increased] dead space.
Increased dead space, especially with rapid shallow breathing
What PFT patterns will be seen for someone with interstitial lung disease?
- restrictive pattern - decreased FEV1, FVC, TLC, RV
- decreased DLCO
- normal or increased FEV1/FVC
What are the complications of pulmonary fibrosis?
- respiratory failure
- pulmonary emboli
- lung cancer
- pneumothorax
- pulmonary hypertension
- cor pulmonale
- susceptibility to pulmonary infection
- acute exacerbations
What are the clinical findings for interstitial lung disease?
- progressive dyspnea
- non-productive cough
- rapid, shallow breathing
- velcro inspiratory crackles
- signs of cor pulmonale
- clubbing may occur
- multi-organ involvement may occur
- lower extremity edema
- tachypnea, tachycardia
What are the radiological findings that may be seen with interstitial lung disease?
- bilateral diffuse infiltrates (reticular, nodular, or reticulonodular)
- ground glass
- honeycombing
What do reticular bilateral diffuse infiltrates on chest x ray suggest?
fibrosis (interstitial lung disease)
What do nodular bilateral diffuse infiltrates on chest x ray suggest?
granulomas or infection (interstitial lung disease)
What do reticulonodular bilateral diffuse infiltrates on chest x ray suggest?
tumor (interstitial lung disease)
In general, what does a ground glass appearance on chest x ray suggest?
inflammation –> acute onset
In general, what does a honeycombing appearance on chest x ray suggest?
fibrosis
What does IPF stand for?
idiopathic pulmonary fibrosis
Pulmonary fibrosis can take [weeks/months or years] to develop.
months or years
What are some common pulmonary disease that result in end stage pulmonary fibrosis?
- hypersensitivity pneumonitis
- sarcoidosis
- asbestosis
- connective-tissue disease
Idiopathic pulmonary fibrosis (IPF) is more common in [men/women].
men
What are the clinical findings associated with idiopathic pulmonary fibrosis (IPF)?
- dyspnea
- cough
- velcro rales
DIP [is/is not] related to smoking. If related, does smoking cessation help?
Is related; yes, smoking cessation may be the best treatment
RB-ILD [is/is not] related to smoking. If related, does smoking cessation help?
Is related; yes, smoking cessation may be the best treatment
Langerhans Cell Histiocytosis [is/is not] related to smoking. If related, does smoking cessation help?
Is related; yes, smoking cessation may be the best treatment
IPF [is/is not] related to smoking. If related, does smoking cessation help?
Is related; no, there is no definite benefit from smoking cessation
Which interstitial lung diseases affect other organs?
- sarcoidosis
- connective tissue disease
What is the pathogenesis of sarcoidosis?
immunologic response to an unknown antigen –> CD4 alveolitis –> well formed, non-caseating granulomas without necrosis
What demographics more commonly have sarcoidosis?
- younger ages
- African Americans
- Ireland
- Iceland
- Scandinavia
Enlarged hilar and mediastinal notes +/- interstial infiltrates and well formed, non-caseating granulomas without necrosis suggest ___.
sarcoidosis
What organs are affected by sarcoidosis?
- lungs
- eyes
- brain
- heart
- liver
- skin
What enzyme is elevated in most sarcoidosis patients?
ACE (angiotensin converting enzyme)
How is sarcoidosis treated?
treat with steroids; may remit spontaneously
What are some medications that cause medication-related interstitial lung disease?
- amiodarone (anti-arrhythmic)
- bleomycin (chemo)
- cyclophosphamide (chemo)
- nitrofurantoin (antibiotic)
- monoclonal antibodies
What is the work up for someone with interstitial lung disease?
- occupational history
- review of systems looking for rheumatology overlap
- medications
- radiation exposure
- high resolution CT
- PFTs
- ABGs
- screenings for connective tissue disease
- often need a lung biopsy
What is the major mechanism that leads to occupational/environmental lung disease?
ineffective clearance (size of inhaled particle determines site of disease, immunological reaction determines nature of lung disease that results)
What are the four major categories of occupational/environmental lung disease?
- pneumoconiosis - fibrotic reaction to inhaled inorganic dust, often with ineffective clearance
- hypersensitivity pneumonitis - exaggerated immunologic reaction, usually to inhaled organic dust
- direct tissue injury (non-immunologic)
- occupational asthma (most common form of occupational lung disease in the US)
What occupations are at high risk for asbestos exposure?
- pipe fitters
- auto mechanics
- construction workers
What is the definition of asbestosis?
Exposure to asbestos + ILD/pulmonary fibrosis
What can result from asbestos exposure?
- asbestosis
- pleural plaques
- effusions
- mesothelioma
What occupations are at high risk for berylliosis?
- dental technicians
- computer and aerospace industry
Alveolar macrophages release cytokines that lead to fibroblast proliferation in which diseases?
- asbestosis
- silicosis
- coal workers pneumoconiosis
What are the major types of hypersensitivity pneumonitis?
- bird fancier
- humidifier
- farmer’s lung
- hot tub lung
What immune cell is predominant in hypersensitivity pneumonitis?
lymphocyte (CD8+)
What is the treatment for hypersensitivity pneumonitis?
- remove from exposure
- steroids
What is direct tissue injury?
an acute, severe disease manifested as acute lung injury and non-carcinogenic pulmonary edema (injury to alveolar-capillary membrane)
What occupations are at risk for direct tissue injury? What is the dangerous inhalant in each case?
- silo fillers (NO2)
- metal workers/welders (galvanized metals)
- cotton workers (endotoxin in unprocessed cotton)
What are the symptoms of direct tissue injury?
- cough
- fever
- flu-like
How do you differentiate between occupational asthma and work-exacerbated asthma?
occupational asthma - asthma with onset after start of exposure (usually takes a few weeks)
work-exacerbated asthma - symptoms start very soon after the exposure begins
What is reactive airways dysfunction syndrome (RADS)?
Irritant-induced asthma with airway hyperreactivity that occurs in response to a fume-induced injury to airways
How do you treat reactive airways dysfunction syndrome?
steroids
What does IIP stand for?
idiopathic interstitial pneumonia
What does DPLD stand for?
diffuse parenchymal lung disease
What does CEP stand for?
chronic eosinophilic pneumonia
What does PLCH stand for?
pulmonary Langerhans cell histiocytosis
What does DIP stand for?
desquamative interstitial pneumonia
What does RB-ILD stand for?
respiratory bronchiolitis interstitial lung disease
What does COP stand for?
cryptogenic organizing pneumonia
What does LIP stand for?
lymphocytic interstitial pneumonia
