Interstitial lung disease Flashcards
What is ILD?
Interstitial lung disease is an umbrella term to describe conditions that affect the lungparenchyma (the lung tissue) causinginflammation andfibrosis.
What are the different types?
200 different types
- Usual Interstitial Pneumonia (UIP)
- Non-specific Interstitial Pneumonia (NSIP)
- Extrinsic Allergic Alveolitis
- Sarcoidosis
- Idiopathic pulmonary fibrosis
- Several other conditions
What happens physiologically to the lung tissue?
- alveolar capillary membrane is thickened
- Increased collagen in alveloar walls- decreased compliance and increased elastic recoil
- increased diffusion distance for O2 and CO2
- Impaired gas exchange
Causes: specific exposure
- Asbestos
- Drugs/medications
- Mouldy Hay- Farmer’s lung (EAA)
- Dust- Silicosis
- Coal- pneumoconiosis
What drugs/medication can cause ILD?
- radiation
- Chemotherapy
- Amiodarone
- Bleomycin
- Methotrexate
- Nitrofurantoin
- Penicillamine
Causes: autoimmune?
- Sarcoidosis
- Rheumatoid arthritis
- SLE
- Schleroderma
- Sjorgen’s
- Polymyositis
Causes: unknown injury?
Fibrosing alveolitis- cryptogenic fibrosing alveolitis or idiopathic pul fibrosis (CFA/IPF)
Symptoms?
- Dry cough
- Dyspnoea on exertion
- Fatigue
- Typical gradual progressive Sx
Signs?
- decreased lung expansion on palpation
- Bi-basal end inspiratory crackles- “Velcro crackles”
- Finger clubbing
- Small pleural effusions
- Cyanosis
- Hypoxaemia
General investgations?
- Detailed history important
- Clinical examination
-
Spirometry
- Typically restrictive lung diseases on PFT’s
- FEV1/FVC ratio normal >0.7
- however FVC lower than normal
- Typically restrictive lung diseases on PFT’s
- CXR
- Diagnosis: CT of the thorax
How to investigate the cause of the fibrosis?
- bronchoalveolar lavage or transbronchial biopsyand/or
- surgical lung biopsy, with the agreement of the thoracic surgeon.
ANA – connective tissue disease OR SLE
ENA – connective tissue disease
Rh F – Rheumatoid Arthritis
ANCA – Vasculitis
Anti-GBM – Pulmonary Renal disease
ACE – Sarcoidosis
Ig G to serum precipitins e.g. pigeon, budgie-Extrinsic
Allergic Alveolitis
HIV
How to manage ILD?
- Occupational exposure – remove
- Environmental exposure – remove (e.g. pet birds)
- Drug associated – avoid
- Stop smoking
- MDT approach – maybe suitable for specialist
medications such as Pirfenidone to slow progression - Treatment of infective exacerbations
- Oxygen if respiratory failure
- Palliative care
- Transplantation
Usual Interstitial pneumonia (UIP) what findings are there ?
Commonest cause of
- clubbing, reduced chest expansion
- Auscultation – fine inspiratory crepitations (like pulling Velcro slowly) – usually best heard basal / axillary areas
- Cardiovascular – may be features of pulmonary hypertension
What can cause Extrinsic Allergic Alveolitis?
- Bird-fanciers lungis a reaction to bird droppings
- Farmers lungis a reaction to mouldy spores in hay
- Mushroom workers’ lungis a reaction to specific mushroom antigens
- Malt workers lungis a reaction to mould on barley
Extrinsic Allergic Alveolitis: what is it known as and what type of reaction is it?
Also known as Hypersensitivity Pneumonitis
- type III hypersensitivity reaction
- Inhalation of organic antigen to which the individual has been sensitised
Extrinsic Allergic Alveolitis: 2 types and explain how manage ?
- ACUTE – short period from exposure, 4-8 hrs. Usually reversible: spontaneously settle 1-3 days. Can reoccur.
- CHRONIC – chronic exposure (months – years). Less reversible.
Extrinsic Allergic Alveolitis: Investigations
Same as for ILD
Bronchoalveolar lavage involves collecting cells from the airways duringbronchoscopy by washing the airways with fluid then collecting that fluid for testing. Findings in hypersensitivity pneumonitis:
- raised lymphocytes
- mast cells
Extrinsic Allergic Alveolitis: management
- removing the allergen
- oxygen where necessary
- steroids.
Sarcoidosis: What is it ?
Multisystem inflammatory condition of unknown cause
Immunological response
Sarcoidosis: on histology?
Non-caseating granulomas
Sarcoidosis: What does it commonly affect?
Commonly involves Resp system BUT can affect nearly all organs
Sarcoidosis: investigations
- PFTs: (obstructive until) fibrosis
- CXR: 4 stages
- Bloods: renal function, ACE, Calcium
- Urinary Calcium
- Cardiac involvement: ECG, 24 tape, ECHO, cardiac MRI
- CT/MRI head: headaches – Neuro sarcoid