Interstitial Lung Disease Flashcards
What does interstitial lung disease present as early
Alveolitis, injury with inflammatory cell infiltration
Late stage interstitial lung disease characterized by
Fibrosis
What exemplifies interstitial lung disease
Adult respiratory distress syndrome
Cause of interstitial lung disease
Environmental - Minerals, drugs, radiation
Hypersensitivity - Mouldy hay, avian protein
Idiopathic
What biopsy is more reliable
Thoracoscopic biopsy > Transbronchial biopsy
What is idiopathic pulmonary fibrosis
Cryptogenic fibrosing alveolitis (CFA) or usual interstitial pneumonia (UIP). Unknown cause of progressive interstitial fibrosis of unknown cause
What is pulmonary interstitium
Alveolar lining cells - Type 1 and 2. Consists of elastin-rich thin connective tissue containing capillary blood-vessels
Histological features of interstitial pulmonary fibrosis
Honeycombing which is dilated spaces surrounded by fibrous walls
What is extrinsic allergic alveolitis
Also known as hypersensitivity pneumonitis
Causes chronic inflammation of small airways, interstitium and occasional granulomas
Allergic origin in extrinsic allergic alveolitis
Hypersensitivity pneumonitis is of type 3 and 4
Various types of extrinsic allergic alveolitis
Farmers lungs - Thermophillic bacteria
Bird fanciers lungs - Avian protein
Malt workers lungs - Fungi
What is sarcoidosis
Multisystem granulomatous disorder of unknown cause
Hypersensitivity involved in sarcoidosis
Type 4 hypersensitivity
What type of granuloma histolically is positive for recovery
Granuloma without necrosis
Nonspecific interstitial pneumonitis vs idiopathic pulmonary fibrosis
Nonspecific interstitial pneumonitis is often present with autoimmune conditions such as rheumatoid arthritis
How can rheumatoid nodules be used to differentiate from TB
Rheumatoid nodules look histologically like TB however there are no pathogens present
What is pneumoconiosis
Lung disease due to inhalation of mineral dust such as asbestos/coal/silicon. Characterized by inflammation, coughing and fibrosis
Differentiate between types of asbestos
Serpentine (curved) asbestos fibres relatively safe
Straight (amphibole) asbestos fibres highly dangerous
What can asbestos exposure lead to
Parietal pleura plaque on diaphragm or lungs, interstitial fibrosis (asbestosis), bronchial carcinoma, mesothelioma
What are interstitial disease
Any disease process affecting the lung interstitium, Presents with restrictive lung pattern often with breathlessness and dry cough
What type of hypersensitivity is sarcoidosis
Type 4 hypersensitivity
What does sarcoidosis cause
Non-caseating granuloma of unknown aetiology in lungs, lymph nodes, joints, skins, eyes, liver
What can acute sarcoidosis cause
Erythema nodosum, bilateral hilar lymphadenopathy, arthritis, uveitis, parotitis, fever
What can chronic sarcoidosis cause
Lung infiltrates (alveoli), skin infiltrates, peripheral lymphadenopathy, hypercalcaemia, organomegaly
Differential diagnosis of sarcoidosis
TB, (tuberculin test), lymphoma, carcinoma, fungal infection
Diagnosis sarcoidosis
Chest x-ray, CT scan, tissue biopsy for non-caseating granuloma, blood tests (raised calcium, increased inflammatory markers), spirometry (restrictive pattern)
Management of sarcoidosis
Acute - Self-limiting
Chronic - Oral steroids if vital organs affected, immunosuppression
What type of hypersensitivity is extrinsic allergic alveolitis
Type 3 hypersensitivity
Cause of extrinsic allergic alveolitis
Called hypersensitivity pneumonitis -
Idopathic, thermophillic actinomycetes, avian antigens, drugs
Symptoms of acute extrinsic allergic alveolitis
Cough, dyspnoea, myalgia, pyrexia
Signs are crackles (no wheeze), hypoxia and widespread pulmonary infiltrates on chest x-ray
Treatment of acute EAA
Oxygen, steroids and antigen avoidance
Symptoms of chronic extrinsic allergic alveolitis
Due to repeated exposure to low dose antigen
Progressive breathlessness, cough
May have crackles, clubbing unusual
X-ray has pulmonary fibrosis mainly in upper zone
Treatment of chronic EAA
Remove antigen exposure, oral steroids if dyspnoea or low gas transfer
Signs and symptoms of idiopathic pulmonary fibrosis
Progressive breathlessness, dry cough, finger clubbing, bilateral fine inspiratory crackles
Spirometry of idiopathic pulmonary fibrosis
Restrictive defect, low FEV1 and FVC, normal or raised FEV1/FVC ratio with reduced lung volumes and low gas transfer
CT scan observation of idiopathic pulmonary fibrosis
Reticulonodular fibrotic shadowing worse at lung base and periphery. Traction bronchiectasis with honey-combing cystic change.
What are signet ring cells
Cells with a large vacuole often seen in carcinomas
Treatment of idiopathic pulmonary fibrosis
Steroids and immunosuppressants do not change the course of the disease. Antifibrotic drugs such as Pirfenidone and Nintedanib slow down disease progression but expensive and many side effects. Also doesn’t reverse fibrosis, only slows progression
Lung transplant in younger patients, oxygen if hypoxic
Prognosis of idiopathic pulmonary fibrosis
Most progress to respiratory failure, 4 years median survival from diagnosis
Symptoms of simple coal workers pneumoconiosis
No symptoms generally are seen, chest x-ray abnormality present without impairment of lung function
Symptoms of complicated coal workers pneumoconiosis
Progressive massive fibrosis with a restrictive pattern of breathlessness.
What is Caplan’s syndrome
Rheumatoid arthritis patient exposed to coal dust, leads to the formation of pulmonary nodules - Rheumatoid pneumoconiosis
Simple vs complicated silicosis
Simple - Few symptoms, chest x-ray abnormality (eggshell calcification of hilar nodes)
Chronic - Restrictive pattern, pulmonary fibrosis
How does asbestos affect pleural lining
Benign pleural plaque - Asymptomatic
Acute asbestos pleuritis - Fever, pain, bloody pleural effusion
Pleural effusion and diffuse pleural thickening - Restrictive impairment
Malignant mesothelioma - Incurable pleural cancer
Asbestos bodies in sputum and lung biopsy
Asbestosis, due to prolonged exposure. Causes pulmonary fibrosis and restrictive defect
