Restrictive Airways Disease Flashcards
What is happening in restrictive lung disease?
People find it hard to fully expand their lungs with air on inhalation
What area is affected by restrictive disease?
Lungs
What is restrictive lung disease?
A category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation.
What are causes of thoracic restriction out-with the lungs?
-Vertebrae, e.g. kyposcoliosis - Ribs e.g. traumatic multiple ribs - Muscle weakness e.g. intercostal or diaphragmatic - Abdominal obesity or ascites
What occurs with lung restriction?
Chronic alveolar under-ventilation with low PaO2 and raised PaCo2 and reduced lung volumes
What is Diffuse Parenchymal Lung Disease (DPLD)?
Disease of alveolar structures, specifically affecting the interstitium (the tissue and space around the air sacs of the lungs). Also known as interstitial lung disease - umbrella term.
What is the spectrum for Diffuse Parenchymal Lung Disease according to BTS classification?
1.Acute DPLD 2.Episodic DPLD, all of which may present acutely 3.Chronic DPLD due to occupational or environmental agents or drugs. 4.Chronic DPLD with evidence of systemic disease 5.Chronic DPLD with no evidence of systemic disease
What is the aetiology of DPLD?
1) Fluid in alveolar air spaces 2) Consolidation of alveolar air spaces e.g. infection or infarct 3) Inflammatory infiltrate of alveolar walls e.g. EAA, sarcoidosis etc 4) Dust disease (pneumoconiosis) e.g. fibrogenic and non-fibrogenic 5) Carcinomatosis
What are various causes of alveolitisi (i.e. inflammatory infiltrate of alveolar walls)?
- Granulomatous alveoli’s - Extrinsic allergic alveoli’s e.g. farmers lung and avian - Sarcoidosis - Drug induced alveoli’s e.g. amiodarone or bleomycin - Fibrosisng alveolitis e.g. rheumatoid or cryptogenic (IPF) - Toxic gas/fumes e.g. chlorine - Autoimmune e.g. churg strauss
What are the various dust-diseases related to DPLD?
- Fibrogenic: asbestosis and silicosis - Non -fibrogenic: sideriosis (iron), stenosis (tin) and baritones (barium)
What is the clinical syndrome of DPLD?
-Breathless on exertion -Cough but no wheeze -Finger clubbing -Inspiratory Lung crackles -Central cyanosis (if hypoxaemic) -Pulmonary fibrosis occurs as end stage response to chronic inflammation
What are the diagnostic factors in spirometry for DLPD?
-Reduced lung volumes •↓FEV1 ↓FVC normal ratio > 75% •Peak flow normal
Which serum factors are raised in sarcoidosis?
ACE and Ca2+
What antibodies may be seen in DPLD?
Avian, Fungal, Auto-antibodies (Rheumatoid, Anti-nuclear)
What tests would you do to diagnose DPLD?
-Reduced lung volumes on spirometry -Reduced gas diffusion -Arterial oxygen desaturation -Antibodies: Avian, Fungal, Auto-antibodies -Serum ACE and Ca2+ raised in Sarcoidosis -Bilateral diffuse alveolar infiltrates on chest X-ray -High resolution CT scan-Inflammatory ground glass vs Fibrotic nodular component of alveolar infiltrates -Bronchoalveolar lavage or induced sputum-to exclude Pneumocystis, TB or other infection
What is the management for DLPD?
- Remove any trigger - Treat inflammation with corticosteroids e.g. oral prednisoline (not inhaled) -O2 if hyperaemic - Lung transplant as last resort
Pulmonary interstitium
Basically the gas exchange areas of the lungs
Alveolar Type I cells
Form the blood air barrier (squamous epithelium)
Alveolar Type II cells
Produce surfactant (cuboidal)
What is the early stage of interstitial lung disease?
Alveolitis
What is the late stage of interstitial lung disease?
Fibrosis
How do you diagnose interstitial lung disease?
Transbronchial biopsy – special forceps used at bronchoscopy Thoracoscopic biopsy – more invasive but more reliable and generates far more tissue
What are the main forms of chronic interstitial disease?
- Fibrosing alveolitis (aka idiopathic pulmonary fibrosis)
- Sarcoidosis
- Extrinsic allergic alveolitis (hypersensitivity pneumonitis)
- Pneumoconiosis (caused by inhalation of mineral dust)
- Connective tissue diseases
What is fibrosing alveolitis also known as?
Idiopathic pulmonary fibrosis
What is the characteristic sign of fibrosing alveolitis/IPF?
Clubbing
Where is IPF/fibrosing alveoli’s localised to?
Subpleural and basal fibrosis (not an apical disease)
Honeycomb lung
Chronic IPF/fibrosing alveolitis where lung structure replaced by dilated spaces surrounded by fibrous walls
What is extrinsic alveolitis also known as?
Hypersensitivity pneumonitis
What kind of reactions are EAA/hypersensitivity pneumonitis?
Type III and IV hypersensitivity
What are some of the causes of EAA/hypersensitivity pneumonitis?
- Thermophilic bacteria – Farmers lung
- Avian proteins – Bird fanciers lung
- Fungi – Malt workers lung
Sarcoidosis
Multisystem granulomatous (type 4 hypersensitivity) disease of unknown cause
What are some of the extra-pulmonary manifestations of sarcoidosis?
- Uveitis (inflammation of iris)
- Erythema nodosum
- Bilateral hilar lymphadenopathy
- Hypercalcaemia
What is pneumoconiosis and what diseases does it entail?
- Lung disease caused by mineral dust exposure • Asbestosis • Coal workers lung • Silicosis
What is asbestos?
A fibrous silicate
What are the 2 basic types of occupational lung disease?
1) Pneumoconiosis
2) Hypersensitivity pneumonitis (Extrinsic Allergic Alveolitis)
What are the main types of hypersensitivity pneumonitis?
.
Chronic hypersensitivity pneumonitis
Extensive fibrosis with honeycombing and air-trapping
Asbestosis
Fibrotic lung disese caused by inhalation of asbestos fibres
How soon after exposure does mesothelioma occur?
Develops 20 years (usually 30-40)
True and False: Asbestos and smoking has a synergistic effect in terms of risk for lung cancer
True
Interstitual lung disease
Any disease process affecting lung interstitium (ie alveoli, terminal bronchi). Interferes with gas transfer and creates restrictive patterns
Pulmonary interstitium
A collection of support tissues within the lung that includes the alveolar epithelium, pulmonary capillary endothelium, basement membrane, perivascular and perilymphatic tissues.
What are the characteristic symptoms of interstitial lung disease?
SOB and dry cough
What kind of granulomas are associated with sarcoidosis: caseating or non-caseating?
Non-caseating
In which group of people is sarcoidosis more common?
Afro-carribeans
What are the investigations for sarcoidosis?
- Chest X-ray (BHL), CT scan of lungs (peripheral nodular infiltrate)
- Tissue biopsy (eg transbronchial, skin, lymph node) > non-caseating granuloma.
- Pulmonary function: Restrictive defect due to lung infiltrates.
- Blood test:
- Angiotensin Converting Enzyme (ACE) levels as activity marker (NOT diagnostic test).
- Sometimes elevated in sarcoidosis, but is very non-specific
- Raised calcium
- Increased inflammatory markers
- Angiotensin Converting Enzyme (ACE) levels as activity marker (NOT diagnostic test).
What is the treatment for acute sarcoidosis?
Usually self-limiting condition, but steroids if vital organ affected (eg impaired lung function, heart, eyes, brain, kidneys)
What are the symptoms of acute EAA?
Cough, breathless, fever, myalgia (usually several hours after exposure)
Signs: +/- pyrexia, crackles (no wheeze!), hypoxia
What is the treatment for acute EAA?
oxygen, steroids and antigen avoidance
What drugs can cause pulmonary fibrosis?
amiodarone, busulphan, bleomycin, penicillamine, nitrofurantoin, methotrexate
What are the signs and symptoms of IPF?
- Progressive breathlessness (several years), dry cough
- On examination: clubbing, bilateral fine inspiratory crackles
- Ix: restrictive defect on PFT’s
Pirfenidone
A new antifibrotic drug
Caplan’s syndrome
rheumatoid pneumoconiosis (pulmonary nodules)
What causes silicosis?
15-20 years exposure to quartz (eg mining, foundry workers, glass workers, boiler workers).
Asbestosis
Fibrosis due to asbestos exposure
What are the 4 main types of pleural disease in asbestosis?
- Benign pleural plaques - asymptomatic
- Acute asbestos pleuritis - fever, pain, bloody pleural effusion
- Pleural Effusion and Diffuse pleural thickening- Restrictive impairment
- Malignant Mesothelioma - incurable pleural cancer.
