Occupational lung disease Flashcards
Cause of silicosis
Free silica toxic to lungs generates O2 radicals
Risk factors for silicosis
Mining
Gold, oil, gas, coal, shale, soft sedimentary rock
Miners, drillers, crushing machine operator
Abrasive blasting with sand
What see on CT scan in silicosis
Bilateral pulmonary calcified nodules- egg shell calcification
Upper and post zones
pleural thickening
Centrilobular and sub pleural distribution
Nodules have sharp margins
What is subpleural on CT
<1cm from pleura
What does IGRA test test for
Latent TB
What is simple silicosis
Asymptomatic
Exertional dyspnoea
Patient -» SOB -> cough and sputum
Risk progression w cumulative exposure - younger present and lower initial lung function
What is complicated/progressive silicosis
Nodules merge -> mass>1cm
Mostly upper lobes
Nodules united by fibrosis, destroy alveoli -> secondary emphysema and extensive pleural thickening
Worsening SOB and hypoxia
Pulmonary HPTN, cor pulmonale, resp failure
What is acute silicosis
Vhigh exposure to inhaled silica
Prevents macrophages clearing surfactant, accumulates in aveoli
SOB + cough
CT acute silicosis
Ground glass
Crazy paving patterns
What is Accelerated silicosis
Between chronic and acute
Rapid progression
Presence of PMF wihin 10 years exposure
Softer less defined nodules
Investigations for silicosis
FVC/FEV1, TLCO
Bronchoscopy
PET scan
What is best amrker for prognosis in silicosis
Reduced TLCO
What find on bronchoscopy in chronic silicosis vs acute
Lymphocytes with reduced macrophage count
BAL WCC differnetial normal
Acute - >70% increased macrophages, visible silica particles
PET scan in silicosis
Biospy hilar and mediastinal lymphadenopathy - high negative value exclude malignancy
Diseases ass w silica
COPD without siliosis - dose reponse
Silica ass TB - increases risk of T ad HIV
High risk of non TB mycobacterium and fungal infections
Carcingoen and lung cancer risk
Treatment for silicosis
Lung transplant only treatment - no drugs work
CXR of coal workers pneumocosis
Large irregular shadowing in both upper zones
R upper lobe mass is more defined
Hyer-lucency
Smaller distinct nodules <5mm all zones bilaterally
History questions for CWP
Any repiratory symptoms prior
Any systemic symptoms
Exact smoking history
Other co-morbidities
Duties and exposure to coal dust
PPE/controls
Causes of obstructive AW disease
COPD
Asthma
Bronchiectasis
CF
bronchiolitis
Grading of FEV1/FVC
Mild - FEV1 - 80%
Mod - FEV1 - 50-80% Sev 30-50%
V severe FEV1 <30%
What is coal mine dust lung idsease
Mixed dust pneumoconiosis - coal macules -> nodules as disease progresses
What do coal macules cuase
Centrilobular focal emphysema can surround macules
When does all exposure diseases develop
CWP - 10 years of exposure
Silicosis - 15-30 years
COPD and coal dust
Dose repsonse relationship
Bullous emphysema
Caplans syndrome
CWP+ Rheumatoid arthritis
Round or oval opacities
Managemnet of CMDLD
- Many patients asymptomatic
- Gradual dyspnoea may be attributed to ageing
- Symptoms severity doesnt correlate w radiological featires
- Symptomatic management - bronchodilators, O2 for hypoxia
- Smoking cessation
- Antifibrotics
- Lung transplantation
CXR in ILD
Bilateral reticular opacities worse in bases
Reduced lung volumes bilaterally
L sided calcified pleural plaques
No focal consolidation or pleural effisons
CT scan of ILD findings
Reticular opacities throughout lung
Ass honeycombing w distortion architecture
Traditional bronchial dilatation seen
No ground glass or pleural effusions
ILD history questions
Sympoms review + red flags
PMH - IBD, connective tissue diseases, malignancy, immunosupression
Medication history incl chemo or raido
Smoking
Occupational
Social - pets etc
FH resp disease
Qs about asbestos exposure
Comprehensive list of positions and roles
Location
Dates
Tasks being performed
PPE or ventialtion
Exposure to other hazardous materials
Colleagues known to have occupational lung disease?
Quantifying asbestos exposure
Fibre years = inhaled fibres/ml x years of exposure
Exposure to disease presentation asbestosis
10-20 years
BAL fluid fibre conc what used for
Reliable marker for prev exposure
BAL fluid what is it
bronchoalveolar lavage, washing of upper resp tract in bronchoscopy to reflect what lungs are secreting
Lung spirometry ILD
Restrictive spirometry - reduced FEV1+FVC, maintained ration
Reduced diffusion capcity - low TLCO and KCO
Trnasfer of gas impaired
What are TLCO, KCO
TLCO = total diffusing cpacity
KCO = total alveolar volume
How to differntiate extra vs inratpulmonary causes restrictive spirometry
Low TLCO + restrictive spirometry
What does Low TLCO + restrictive spirometry suggest
ILD or pneumonitis
OR
HF - alveoli fluid filled decreasing diffusion capacity
How o extrapulmonary casues of ILD cahnge TLCO, KCO
Normal TLCO
Raised KCO
What diseases cause a pulmonary restricitve spirometry
Intersitial lung diseases
Occupational lung diseases
Pulmonary oedema
Lobectoy
Radiation therapy
What are non pulmonary causes of restrictive spirometry
- Kyphoscoliosis
- NM diseases eg MND
- Pleural diseases eg effusions, chronic empyema
- Connective tissue diseases
- Obesity or ascites
Lights criteria for pleural fluid exudate are
Serum protein ratio >0.5
Serum LDH ratio >0.6
LDH >2/3 upper limit of normal serum LDH
If large pleural effusion ass w plaques seen on X ray what is next step
Pleural aspiration under US guidance
Pleural aspiration tests how much need
40ml cytology
5ml for microbiology + biochemistry (glucose, protein/albumin,LD,pH)
Causes of exudate
infection
Malginncy
CTD
PR
Chylothorac
ARDS
Pancreatitis
What do if pleural fluid analysis no diagnosis given
Request contrast CT thorax
Consider LA thorascopy or surgical VATs
Consider radiologically guided pleural biopsy + chest tube draingage if symptomatic
What can cause pleural effusion
PE
TB
Chronic HF
Lymphoma
CT ofmalignant mesothelioma
Diffuse soft tissue pleural thickening throughout left side of chest - best in mediastinal margins
Calcified pleural plaqus and large unilateralpleural effusionsn
What is pleurodesis
sticking lung wall to chest to prevent re accumulation of pleural fluid
CT silicosis
Egg shell calcification of lymph nodes
Enlarged lymph nodes + silicosis on CT
