Occupational lung disease Flashcards
How are causes of occupational asthma divided?
High molecular weight (proteins): flour, improvers (enzymes), small mammals
Low molecular weight (chemicals): things used in manufacture
‘Allergic’ - HMW and some LMW
‘Irritant’ - LMW
Nb. HMW cause a specific IgE response. Also affects other exposed areas therefore get nasal symptoms and conjunctivitis. Ppl who have atopy or smoke are at higher risk.
Nb2. LMW may have specific IgE and therefore nasal symptoms, but not necessarily
How is occupational asthma diagnosed?
- History - but can’t be this alone.
–> Tend to get latency period, then asthma symptoms - PEFR 4/day (best of 3) over 3 weeks. Need variability >15%
–> Nb. if variability of PEFR at work and on days off, thinking more towards work-exacerbated asthma - Total IgE, skin prick/specific IgE
- IgG not widely available
- Workplace and inhalational challenges less common
What are the risk factors for occupational asthma?
Atopic hx, smoking, at-risk job
How is occupational asthma managed?
Cessation/avoidance best (approx 1/3 full recovery)
Standard asthma therapy
Mr X has started a new job 3 weeks ago. He had asthma as a child and has now had a return of symptoms. You measure his PEFR over 3 weeks, which shows a variability of >15% each day. What is the most likely diagnosis?
Work-exacerbated asthma
- tends to not have latency period like occupational
- variability on days at work and on days off
- not eligible for compensation
Mr X started a new job 6 months ago in a bakery. He has been getting more SOB and complaining of being wheezy. He used to have eczema as a child. What would you advise him?
Sounds like occupational asthma (latency period (highest risk in first year), hx of atopy, high risk job). Would recommend cessation/avoidance (approx 1/3 recovery), or standard asthma therapy. Would be eligible for compensation.
Work-exacerbated asthma
- tends to not have latency period like occupational
- variability on days at work and on days off
- not eligible for compensation
What criteria are required on PEFR to make diagnosis of occupational asthma?
Variability of 15% over the day. Minimum 4 readings/day (best of 3) over 3 weeks. Better on days off/holidays.
Latency period usual on hx - highest risk in 1st year. May have hx of atopy or smoking.
Make have sensitisation (IgE or skin prick) if High Molecular Weight exposure (flour, ‘improver’, small mammals). If so, may also get nasal symptoms and conjunctivitis.
Mr X is a stonemason. He is getting progressively SOB. CT shows widespread nodules and fibrosis. EBUS is attempted but unsuccessful. What is most likely diagnosis?
Silicosis
- mimics sarcoidosis although tends not to cause extra-pulmonary disease
- EBUS hard as nodes full of sand
- biopsy will show silicated nodes
- CT: nodules and fibrosis
At-risk jobs: stonemason, kitchen fitters, quarry i.e. engineered stone, sandstone, concrete/mortar
Associations: TB, renal disease, RA, lung ca, systemic sclerosis
Treatment: remove exposure (no effective treatment)
What are at risk jobs for silicosis? What conditions is it associated with?
Stone mason, kitchen fitters, quarry i.e. engineered stone, sandstone, concrete/mortar
- mimics sarcoidosis although tends not to cause extra-pulmonary disease
- EBUS hard as nodes full of sand
- biopsy will show silicated nodes
- CT: nodules and fibrosis
Associations: TB, renal disease, RA, lung ca, systemic sclerosis
Treatment: remove exposure (no effective treatment)
What diseases are associated with silicosis?
Associations: TB, renal disease, RA, lung ca, systemic sclerosis
What is treatment for silicosis?
Remove exposure (no effective treatment)
What kind of diseases can asbestos exposure cause?
- Plaques (Occur on parietal pleura. Don’t need monitoring. Not eligible for compensation. Can get even with low exposure)
- Widespread pleural thickening (can get restrictive lung disease, can get with or without effusion, eligible for compensation)
- Asbestosis (looks like IPF, eligible)
- Lung cancer (most common cancer in asbestos exposure)
- Mesothelioma (can get even with low exposure)
What is the most common occupations associated with hypersensitivity pneumonitis?
Contaminated metal work
- tend to get ‘outbreaks’
- smoking is protective
Eligible for compensation even if exposure unknown
IgG tests not widely available
Does smoking increase or decrease risk of hypersensitivity pneumonitis?
Decrease in occupational exposure (not sure about others)
What are common causes of work-aggravated asthmas?
temperature, humidity, exertion, stress, dusts, pollution
Work-exacerbated asthma
- tends to not have latency period like occupational
- variability on days at work and on days off
- not eligible for compensation
- responds well to conventional asthma treatment
