A2- Interstitial Lung Disease Flashcards
(36 cards)
What is intersitial space?
It is the liquid space between the alveolar cell wall and capillaries
It is a small space
What is IDL?
Interstitial Lung disease
A ‘potential space’ that is
‘widened’ in interstitial disease by influx of inflammatory and
fibrotic cells/tissue
• Its disruption leads to type 1 Respiratory Failure- hypoxia
• Some forms of ILD’s can involve
not only the interstitial space but
also alveoli and bronchioles.
How are IDLS classified?
How can you further classify
Idiopathic interstitial pneumonias?
What is the Suspected ILD diagnostic approach?
What do you need to ask in a detailed history?
- breathlessness
is it coming and going,
getting worse,
stable
how is it impacting life (can they get dressed) - cough
dry
sputum - exposure
occupation
instruments
damp environment
so hobbies/interests - smoking
- drug history
- family history
- Pmhx
WHat to expect o physical examination?
Crackles (velcro being pulling apart)
Hands
eyes
skin- rashes
Heart disease
Swelling fingers
What are asbestos fibres?
Naturally occurring fibrous mineral silicates - good fire retardant and insulating properties. Tiny fibres that are inhaled.
Occupation wise who would be exposed to asbestos?
Occupational exposure: pipe fitters, plumbers, dockers, miners
What is Absbestosis?
A form of ILD characterised by slowly progressive pulmonary fibrosis caused by inhalation of asbestos fibres. Lungs cannot break down fibres
Immune system keeps attacking/cells release inflammatory chemicals to try and destroy fibres- fails - asbestos is a tough material
Eventually this can lead to fibrosis but often 20- 40 years after exposure - lag phase
Diagnoses for Asbestosis?
history of enough asbestos exposure need occupational history + latency period, ILD on scan, plus exclusion of other causes of that pattern of ILD on scan (i.e. right ILD patterns need to be seen). No easy ‘test’.
Diagnoses for Asbestosis?
history of enough asbestos exposure need occupational history + latency period, ILD on scan, plus exclusion of other causes of that pattern of ILD on scan (i.e. right ILD patterns need to be seen). No easy ‘test’.
Tx for asbestosis?
was no specific treatment for asbestosis.
o Now evidence that anti fibrotic drugs may have a role (await NICE assessment).
o Avoidance of any further asbestos exposure.
o Supportive care.
There is increased risk of Lung Cancer in smokers with asbestos exposure
TRUE OR FALSE
TRUE
What Hypersensitivity Pneumonitis (previously aka EAA)?
A form of ILD that is caused by an immunologic reaction to an inhaled agent/organic antigen. E.g. bird fanciers lung
How do you classify EAA
• Traditional Classification: according to onset of presentation of respiratory symptoms and amount of repeated exposure. Acute (hrs-wks), Subacute (1-4 months), chronic (>6 mths). Now probably out of date….
- Use terms acute or inflammatory HP (may be reversible if remove exposure lungs can be ok) Vs. Chronic or Fibrotic HP (fibrosis has occurred and lungs never back to normal). Findings on CT scans permit these labels to be applied. Outcomes very different.
Pathogenesis Hypersensitivity Pneumonitis?
- Host response to exposure is not predictable. Not fully understood
- Complex interaction: genetic predisposition, antigen, frequency/duration of exposure, co exposure with viruses?
- Antigen exposure → specific IgG antibodies.
- Subsequent exposure to that antigen causes immune reaction → lung inflammation
- Some patients stay at ‘inflammation’ stage despite continued exposure other progress to fibrosis and permanent lung damage
- Lymphocyte driven process- can see increases in blood and lung fluid after exposures Pathogenesis Hypersensitivity Pneumonitis CT image showing air trapping Lung tissue sample HP airway centred fibrosis loo
Hypersensitivity Pneumonitis Diagnosis
- Antigen exposure (history, IgG-specific antibodies)
- Clinical (symptoms, crackles & squawks on examination)
- Radiological (CXR, HRCT)
- PFTs: restrictive, obstructive, or mixed pattern, reduced DLCO
- Bronchoscopy/ Bronchoalveolar Lavage: lymphocytosis (>20%)
- Lung Biopsy: poorly formed, non-caseating granulomas
Hypersensitivity Pneumonitis Management:
- Antigen avoidance
- Steroids
- Immunosuppressive therapy
- Best Supportive care
Causes of Hypersensitivity Pneumonitis (HP)
..microbes, organic material and chemical sensitisers
- Bird Fanciers Lung (pigeons/budgies)
- Duck Fever/Chicken lung
- Hot tub lung (mycobacterium avium)
Occupational causes: But stays in granulomata box
- Millers (flour)Lung
- Mummy handlers lung (fungal spores as unwrap)
- Wine makers lung (mould on grapes)
What is sarcoidosis?
A multisystem disease of unknown cause characterised by tissue infiltration with non-caseating granulomas. In some leads to end organ damage if left untreated. Many organs can be affected
Who are sarcoidosis most prevalent in?
: high in Ireland/Scandinavia,
F>M,
70+% aged
20-40 yrs at presentation
Diagnosis of Sarcoidosis
: 3 Key Elements:
- Clinical + Radiological Compatibility
- Exclusion of other diseases
- Non-Caseating Granulomas (NCG) from tissue biopsy
Pathogenesis of sarcoidosis?
- Need genetic susceptibility/environmental exposures/?infectious agents probably inhaled
- Unknown trigger switches on an inflammatory process which can cause damage to organs
- Lesions seen are Sarcoid granulomatas = are non-necrotizing
- Circular swirl of inflammatory cells
