Interstitial Lung Disease Flashcards
What is interstitial lung disease (ILD)?
It is defined as a group of inflammatory conditions that affect the lung interstitium
This inflammation results in fibrosis formation
What is the lung interstitium?
It is the space between an alveolus and its surrounding capillaries
What is the pathophysiological consequence of interstitial lung disease?
Due to fibrosis formation, there is increased diffusion distance for oxygen to travel from the alveoli to the surrounding capillaries
Therefore, gas exchange in the lungs is compromised
What are the five classifications of interstitial lung disease?
Idiopathic Pulmonary Fibrosis
Secondary Pulmonary Fibrosis
Drug Induced Pulmonary Fibrosis
Hypersensitivity Pneumonitis (HP)
Asbestosis Induced Pulmonary Fibrosis
What is the most common classification of interstitial lung disease?
Idiopathic pulmonary fibrosis
What is idiopathic pulmonary fibrosis?
It is defined as pulmonary fibrosis with no cause
What are the two risk factors associated with idiopathic pulmonary fibrosis?
Male Gender
50 - 70 Years Old
What is secondary pulmonary fibrosis?
It is defined as pulmonary fibrosis due to an underlying pathological condition
What are the ten conditions associated with secondary pulmonary fibrosis?
Alpha-1 Antitrypsin Deficiency
Rheumatoid Arthritis
Systemic Lupus Erythematous (SLE)
Ankylosing Spondylitis
Systemic Sclerosis
Silicosis
Sarcoidosis
Pneumonia
Tuberculosis
Histiocytosis
What is silicosis?
It is a chronic lung disease caused by inhaling large amounts of silica dust - usually related to a mining occupation
What is a CXR feature of silicosis?
Egg-shell calcification of hilar nodes
What two pneumonia organisms cause interstitial lung disease?
Mycoplasma pneumonia
Pneumocystis pneumonia
What six drugs are associated with interstitial lung disease?
Methotrexate
Amiodarone
Bleomycin
Cyclophosphamide
Nitrofurantoin
Radiation Therapy
Which two cancer radiation therapies are associated with interstitial lung disease?
Breast Cancer
Lung Cancer
When does interstital lung disease tend to present following radiation therapy course completion?
6 - 12 months
What is another term for hypersensitivity pneumonitis (HP)?
Extrinsic allergic alveolitis (EAA)
What is hypersensitivity pneumonitis?
It is a condition in which hypersensitivity induced lung damage results due to the inhalation of organic particles
What hypersensitivity reaction is associated with hypersensitivity pneumonitis?
Type III hypersensitivty
However, type IV is thought to occur in the chronic phase
What are the four allergens associated with hypersensitivity pneumonitis? What are the specific terms used to refer to these conditions?
Bird Droppings (Bird-Fanciers Lung)
Hay Mouldy Spores (Farmers Lung)
Mushrooms (Mushroom Workers Lung)
Barley Mould (Malt Workers Lung)
When does the acute phase occur in hypersensitivity pneumonitis, following exposure to an allergen? What are the three acute clinical features?
4 - 8 hours
Dyspnoea
Dry Cough
Fever
When does the chronic phase occur in hypersensitivity pneumonitis, following exposure to an allergen? What are the four chronic clinical features?
Weeks to Months
Lethargy
Dyspnoea
Productive Cough
Weight Loss
What are two specific investigations used to diagnose hypersensitivity pneumonitis?
Blood Tests
Bronchoalveolar Lavage
What two blood test results indicate hypersensitivity pneumonitis?
IgG Antibody Positive
No Eosinophilia
What bronchoalveolar lavage feature indicates hypersensitvity pneumonitis?
Lymphocytosis
What are the two management options of hypersensitivty pneumonitis?
To avoid precipitating factors
Oral glucocorticoids
What is asbestosis induced pulmonary fibrosis?
It is defined as pulmonary fibrosis due to an inhalation of asbestosis
Which eight causes of interstital lung disease lead to upper zone fibrosis?
CHARTS
Coal Worker’s Pneumoconiosis
Histiocytosis/Hypersensitivity Pneumonitis
Ankylosing Spondylitis
Radiation
Tuberculosis
Silicosis/Sarcoidosis
Which four causes of interstital lung disease lead to lower zone fibrosis?
Idiopathic Pulmonary Fibrosis
Drug Induced
SLE
Asbestosis
What are the six clinical features associated with interstitial lung disease?
Progressive Dyspnoea
Chronic Dry Cough > 3 Months
Bibasal Fine -End Inspiratory Crepitations
Percussion Dullness
Finger Clubbing
Raynaud’s Phenomenon
What are the four investigations used to diagnose interstitial lung disease?
Spirometry
Chest X-Ray (CXR)
High-Resolution CT Scan
Bronchoscopy
What is spirometry?
It involves the conduction of tests that measure the volume and flow of air during exhalation and inhalation
What three metrics are obtained from spirometry?
Forced Expiratory Volume 1 (FEV1)
Forced Vital Capacity (FVC)
FEV1 : FVC
What is FEV1?
It is defined as the volume that has been exhaled at the end of the first second of forced expiration
What is FVC?
It is is defined as the volume that has been exhaled after a maximal expiration, following a full inspiration
What two spirometry results indicates interstitial lung disease?
It is indicated by a restrictive pattern, in which both FVC and FEV1 are reduced, resulting in FEV1 : FVC > 70%
Decreased TCLO levels
What is the feature of interstitial lung disease on CXR?
Bilateral interstitial shadowing, usually small, irregular peripheral opacities
What is the gold standard investigation used to diagnose interstitial lung disease?
High resolution CT scan
What are the four features of interstitial lung disease on a high resolution CT scan?
Ground Glass Appearance
Honeycombing
Traction Bronchiectasis
Reticular Opacites
What is honeycombing?
It is defined as the cluster of cystic airspaces
What is traction bronchiectasis? Why is this a feature of interstitial lung disease?
It is defined as the dilation of airways
This is due to the airways being pulled apart by fibrosis in surrounding areas
What are reticular opacities? Why is this a feature of interstitial lung disease?
They are defined as pulmonary opacities due to reduced gas exchange
This is caused by thickening of the lung interstitium
What is bronchoscopy?
It involves the insertion of a small camera into the bronchi
How is bronchoscopy used to diagnose interstitial lung disease?
It enables direct visualisation of the parenchymal lung disease
It allows a biopsy of this tissue to be obtained for histological examination
In hypersensitivity pneumonitis, what two bronchoscopy histology results are shown?
Increased lymphocytes
Mast cells
In what five ways do we conservatively manage interstitial lung disease?
Underlying Pathology Management
Smoking Cessation
Pulmonary Rehabilitation
Annual Influenza Vaccination
One-Off Pneumococcal Vaccination
What classification of interstitial disease can be pharmacologically managed?
Idiopathic pulmonary fibrosis
What are the two pharmacological options for idiopathic pulmonary fibrosis?
Pyridones
Monoclonal Antibodies
Name a pyridone used to manage idiopathic pulmonary fibrosis
Pirfenidone
What is the mechanism of action of pirfenidone?
It is an antifibrotic and anti-inflammatory that is administered to slow down the progression of disease
Name a monoclonal antibody used to manage idiopathic pulmonary fibrosis
Nintedanib
What is the mechanism of action of nintedanib?
It inhibits the action of tyrosine kinase which are involved in the formation of fibrosis
In what other circumstance can we pharmacologically manage interstitial lung disease? What drugs can be administered?
In cases where the underlying cause is related to connective tissue diseases or sarcoidosis
Steroids and steroid sparing agents
What steroid is used to manage interstitial lung disease related to connective tissue diseases or sarcoidosis?
Prednisolone
What two steroid sparing agents are used to manage interstitial lung disease related to connective tissue diseases or sarcoidosis?
Azathioprine
Mycophenolate
What criteria is used to determine whether interstitial lung disease patients should be administered LTOT?
Resting PaO2 < 7.3kPa
OR
Resting PaO2 < 8kPa With Peripheral Oedema, Polycythaemia, Pulmonary Hypertension
What surgical management option can be used in interstitial lung disease?
Lung transplant
When is lung transplant considered to manage interstitial lung disease?
It is only considered in individuals with severely impacted quality of life, despite optimum pharmacological management
