Interstitial lung disease Flashcards
What is interstitial lung disease?
umberella term to describe conditions that affect the lung parenchyma (lung tissue) causing inflammation and fibrosis
what is fibrosis?
replacement of the normal elastic and functional lung tissue with scar tissue. it is stiff and does not function as effectively
how is interstitial lung disease diagnosed?
high resolution CT scan of thorax= HRCT shows ‘ground glass’ appearance
lung biopsy= histology
how is interstitial lung disease managed?
Remove or treat the underlying cause
Home oxygen where they are hypoxic at rest
Stop smoking
Physiotherapy and pulmonary rehabilitation
Pneumococcal and flu vaccine
Advanced care planning and palliative care where appropriate
Lung transplant is an option but the risks and benefits need careful consideration
types of interstitial lung disease
- idiopathic pulmonary fibrosis
- drug induced pulmonary fibrosis
- secondary pulmonary fibrosis
- hypersensitivity pneumonitis
- cryptogenic organising pneumonia
- asbestosis
idiopathic pulmonary fibrosis
this is a condition where you have progressive pulmonary fibrosis but there is no clear cause.
symptoms: insidious onset of shortnesss of breath and dry cough >3 months.
affects adults >50 y/o (life exp 2-5 years)
O/E
bibasal fine inspiratory crackles
finger clubbing
idiopathic pulmonary fibrosis management
to slow progression:
Pirfenidone is an antifibrotic and anti-inflammatory
Nintedanib is a monoclonal antibody targeting tyrosine kinase
drug induced pulmonary fibrosis
which drugs?
Amiodarone
Cyclophosphamide
Methotrexate
Nitrofurantoin
*there are several
secondary pulmonary fibrosis
pulmonary fibrosis occurring secondary to other conditions
RA, SLE, progressive systemic sclerosis, IBD, primary biliary cholangitis
these include: Alpha-1 antitripsin deficiency Rheumatoid arthritis Systemic lupus erythematosus (SLE) Systemic sclerosis
what is hypersensitivity pneumonitis
aka extrinsic allergic alevolitis
type III hypersensitivity reaction to an environmental allergen.
causes the parenchymal inflammation and destruction I people that are sensitiv to that allergen
diagnosis:
PCR, blood culture, urinary antigens
bronchoalveolar lavage. collect cells from arrays during bronchoscopy (wash airways with fluid). when tested, shows raised lymphocyte and mast cells
O/E wheeze, crackles, squeeks
mx: remove allergen, O2, steroids
example of specific causes of hypersensitivity pneumonitis
Bird-fanciers lung is a reaction to bird droppings
Farmers lung is a reaction to mouldy spores in hay
Mushroom workers’ lung is a reaction to specific mushroom antigens
Malt workers lung is a reaction to mould on barley
farmers sauna/ventilation birds/poultry grain/flour wood vets/animal handlers textile plastics
cryptogenic organising pneumonia
previously known as bronchiolitis obliterans organising pneumonia
this is a focal area of inflammation in the lung tissue. can be idiopathic or triggered by infection, inflammation, meds, radiation or environmental toxins/allergens
symptoms: SOB, cough, fever, lethargy
CXR: focal consolidation
lung biopsy
tx: systemic corticosteroids
asbestosis
mined mineral
lung fibrosis related to inhalation of asbestos. ‘fibrogenic’ (causes the lungs to fibres) and oncogenic (causes cancer)
asbestosis inhalation causes: 1. Lung fibrosis 2. Pleural thickening and pleural plaques (holly leaves) 3. Adenocarcinoma 4. Mesothelioma (low exposure to asbestos toxins) prognosis 12-18 months not very responsive to chemotherapy) adenocarcinoma (high exp) 5. bronchogenic carcinoma
large pleural plaques (holly leaves)
acute asbestosis pleurisy
diffuse plural fibrosis (thickening of pleura on the viscera of lung)
bronchial carcinoma
budgie lungs (not the same as bird fancier lungs)
chlamydia psittaci
atypical pneumonia’s
won’t necessarily have any crackles/ signs
they do not have a standard wall so penicillins do not work
use non penicillins- doxycycline, clarithromycin, quinolones
worsening asthma
occupational smoking mould pet dander (cat= saliva, dog=fur) NSAID use catameniol asthma (worse before periods as there is less progesterone- which is usually a smooth muscle relaxant) (progesterone= pro gestation)
silicosis
fine particles.
takes time for them to settle out
air flow is lower at the top of lungs so this is where the the silicosis particles sits.
burkholderia pseudomallei
gram negative
community acquired pneumonia in thailiand
multi-resistant
causes a necrotising severe pneumonia
most common cause of CAP in UK is streptococcus pneumonia
asbestosis (2)
development of fibrosis interstitially. insidious 40 years after exposure. microfibre that was used as instillation. high exposure (Dock Worker) (teachers) (break mechanic)
XRAY- plaques
investigate:
CT honeycombing, sub pleural lines
asbestosis histopathology
microphages ingest fibers- collagen deposition
brown IRON blobs
irreversible dilation of bronchioles- signet ring sign
infolding of the ring
idiopathic pulmonary fibrosis
a specific form of chronic progressive lung fibrosis of uknown origin
pathophysiology: fibrosis occurs in response to damage in the lung from acid reflux, viruses (EBV, HSV, hep C) environmental factors (dust, wood, textiles, metal, stone, cattle,
farming, genetic)
progressive exertion dyspnoea, non productive cough, clubbing, fine end inspiratory crepitations at lung bases.
idiopathic pulmonary fibrosis symptoms
SOB on exertion or at rest cough +/- sputum fatigue cyanosis finger clubbing fine end inspiratory crackles
IPF investigations
blood tests
environmental and occupational exposure
PEFR- restrictive lung defect
ABG type I resp failure wiht hypoxaemia and normal or low co2
ANA RF anit CCP myositosis CXR- small lung volumes, interstitial shadowing most marked at the bases and peripheries (lower zone fibrosis)
xray of reticular pattern
lun markings worse on base
CT of thorax (confirms distribution of fibrosis)
Lung function test (restrictive)
surgical bipsy
bronchoalveolar lavage
*histopathology: honeycombing, minimal cellular inflammation and regoins of proliferating myofirboblasts.
IPF management
non pharmacoogical- pulmonary rehabilitation (Exercise/educational)
pharmacological antifibrotic drugs- pirfenidone, nintedanib slow rate of scaring O2 therapy PPI NAC oral n aetyl L cysteine
surgical- lung transplantation
various new regimes- high dose steroids, immunosuppressants, azathioprine, cyclophosphamide, cyclosporin
hypersensitive pneumonitis chronic
chronic
no hx of acute eps
long onset of symptoms, lower lung tissue, resp crackles, emphysema, honeycombing, clubbing, pneumoconiosis
siliac, coal, iron, inorganic
restrictive fibrosis
long time 10+
acute attack of bird fanciers lung
4-6 hrs after exposure fever, inflammation response, cough, rash ground glass opacities poorly formed granulomatous resolves in a few days
subacute attack gradual onset severe, lasts longer no fever/chills weight loss and loss of appetite pleuritic pain pain on inspiration opacities in lower ones
cell type and associated disease
haemosiderine laden macrophage= alveolar bleeding
high CD4= sarcoidosis
eosinophils= allergic bronchopulmonary aspergillosis
neutrophils= pneumonia, interstitial lung disease
marked lymphocytes= hypersensitivity pneumontis
histological triad of….
hypersensitivity pneumonitis (farmers lung) mouldy hay or other materials. interstitial inflammation, chronic bronchitis, two foci of non-necrotising granuloma
aspergillosis
lung biopsy may show hyphae with vascular invasion surrounding tissue necrosis
sarcoidosis: schumann bodies, calcified rounded laminated concentration inside the non-caseating granuloma. formed of body giant cells (star shaped inclusions ‘asteroid bodies’)
histiocytosis X - langerhan cells
TB- caveating granulomas in the lung parenchyma. fibrosis in later stages. Ziehl Neelsen staining reveals acid-fast bacill.
pleural plaques (caused by asbestosis)
asymptomatic
asbestos exposure
irregular well defined calcified lesions that may appear as dense lines in the pleura when seen from lateral views or like ‘holly leaves’ from anterior views
mesothelioma (from asbestos exposure)
development of malignant mesothelioma is strongly associated with inhalation of asbestos fibres.
breathlessness, weight loss, lung is appeared to be ‘strangled’. but he tutor, chest pain
bronchogenic exposure (from asbestos exposure)
asbestos exposure and cigarette smoking
weight loss
anorexia
haemoptysis
small tumor
