Flashcards in Interstitial Lung Disease Deck (72):
What is interstitial space?
- A potential space between alveolar cells and the capillary basement membrane which is only apparent in disease states, where it may contain fibrous tissue, cells or fluid
What is interstitial lung disease?
- Group of diseases with a variety of cuases that have similar pathophysiological effects and clinical features
What is the pathophysiology of interstitial lung disease?
- Fibrous tissue develops in the interstitium, making lungs less compliant (restrictive defect)
- Diffusion path between alveolar air and blood impairs gas exchange. O2 uptake affected selectively
What are the clinical features of interstitial lung disease?
Shortness of breath
Reduced exercise tolerance
Give four signs of Interstitial Lung Disease
- Reduced chest movement
- Coarse crackles
Give five causes of interstitial lung disease?
- Treatment related
- Connective tissue disease • Immunological • Idiopathic
Give three occupational causes of interstitial lung disease
Give three treatment related causes of Interstitial Lung Disease
Give three connective tissue disease
• Rh. Arthritis • Polymyositis • Scleroderma
Give two immunological causes of Interstitial Lung Disease
• Sarcoidosis • Hypersensitivity pneumonitis
What is fibrosing alveolitis?
- Progressive inflammatory condition of unknown cause
- Increased activated alveolar macrophages
- Attract neutrophils and eosinophils
- Local lung damage due to ROS and proteases
- Tissue destruction and fibrosis
What do patients present with when they have fibrosing alveolitis?
- Progressive shortness of breath on exercise, often combined with a productive cough
- Finger clubbing
What does the chest x ray of someone with fibrosing alveolitis show?
Small lungs with micro-nodular shadowing predominating in the lower lobes, with ragged heart borders
How is fibrosing alveolitis treated, and what are the limitations of this treatment?
Treated with high dose oral steroids in the early stages
Less effective once fibrosis has developed
How is treatment of fibrosing alveolitis monitored?
• By repeated lung function tests
What is extrinsic allergic alveolitis?
• Inhalation of organic material which triggers an allergic reaction in alveoli and bronchioles
What are two states of the condition?
• Can be acute or chronic
Outline acute extrinsic allergic alveolits
- Thermophilic actinomycetes found in mouldy hay
- Inhalation causes influenza like illness 4-9 hours later with a dry cough and dyspnoea on exertion.
- Fine mid and late inspiratory crackles
Outline chronic extrinsic allergic alveolitis
- Long term antigen exposure = Faeces of pidgeons/budgies
- Insidious malaise
- Dry cough and breathlessness over months and years
- Inspiratory crackles
What sign does not occur in any types of allergic alveolitis?
• Finger clubbing
What does the x-ray show in acute extrinsic allergic alveolitis?
Diffuse micro-nodular infiltrate denser towards the hila
What does the x-ray show in chronis extrinsic allergic alveolitis?
Normal, may progress to fibrosis
What will a lung function test show in extrinsic allergic alveolitis?
Lung function test will show reduced compliance and reduced gas transfer
What is asbestosis?
- Inhalation of asbestos fibres causes a disease to develop long after exposure
Give three different types of disease as a result of asbestos inhalation
- Benign pleural plaques
What do asbestos fibres do in the lungs?
- Penetrate to the alveoli, causing alveolitis
- Causes an influx of macrophages which produce distinctive asbestos bodies
- Alveolitis progresses to fibrosis
What are the symptoms of asbestos related disease?
- Patient breathless on exertion and a dry cough
- Inspiratory crackles at the lung base, which rise as the disease advance
What do lung function tests of someone with asbestos related lung disease show?
• Small lungs, reduced compliance and impaired gas transfer
What is sarcoidosis characterised by?
• Non-caseating granulomas in multiple organs and body sitesMost commonly found in the lungs
What occurs in the airways in sarcoidosis?
• Fluid is collected by lavage of the airways and alveoli contain lots of cells, including macrophages and lymphocytes
In what ethnicities is sarcoidosis the most common?
• Afro-Carribean and Asians than in CaucasiansGenetic predisposition
When is the highest incidence of sarcoidosis?
• 30's and 40's with more female cases
What are the two main symptoms of sarcoidosis?
• Cough • Dyspnoea
How is sarcoidosis graded?
On a scale of severity of 1-4
What does X-ray show in sarcoidosis?
Miliary and nodular shadowing and diffuse fibrosis
How can sarocidosis be treated?
What does the lung function test in sarcoidosis show?
- Small lungs
- Reduced compliance
- Impaired gas transfer
May be evidence of air flow obstruction
Give four diseases associated with the work place
- Diffuse fibrosis
- Nodular fibrosis
In what occupation and after what exposure does one get Asthma
In what occupation and after what exposure does one get diffuse fibrosis
Railway/Construction - Asbestos
In what occupations (3) and after what exposure does one get nodular fibrosis (pneumoconiosis)
Coal miner, miner, demolition Coal dust, silica, asbestos
In what occupation and after what exposure does one get alveolitis
Farmer - fungal spores from hay
Pigeon fancier - Avian antigens
Name five types of intersitial lung disease
• Fibrosing alveolitis • Extrtinsic allergic alveolitis (acute) • Extrinsic allergic alveolitis (chronic) • Sarcoidosis • Asbestosis
Give the plain film x-ray found in fibrosing alveolitis
• Small lungs • Micro-nodular shadowing (lower lobes) • Ragged heart border
Give the x-ray appearance of sarcoidosis
Miliary and nodular shadowing
Give the x-ray appearance of asbestosis
What is the pleura?
A serous membrane consisting of a single layer of mesothelial cells with a thin layer of underlying connective tissue
Made up of parietal and visceral pleura
What does the parietal pleura line?
The inside of each hemithorax
What does the visceral pleura line?
The outside of the lung
Where are the visceral and parietal pleura continous?
At the hilum of the lung
What is the pleural cavity?
A potential space between two layers of pleura
What does the surface tension of the pleural fluid provide?
The cohesion that keeps the lung surface in contact with the thoracic wall
As a result, when the thorax expands, the lungs expand with it and fill with air
What is the normal turnover of pleural fluid per day
15ml turnover per day
What are the two methods by which pleural fluid is modified?
Added by capillary filtration at the parietal pleura
Absorbed via lymphatic drainage
What four factors affect the rate at which fluid is added to the pleural fluid?
1. Increase in lung interstitial fluid
2. Increase in hydrostatic pressure (heart failure)
3. Increase in permeability (Inflammation, sepsis or malignancy)
4. Increased by decreased oncotic pressure (liver failure)
What two facts factors affect the rate at which fluid is removed from the pleural cavity?
Decreased by lymphatic blockage
Decreased by systemic venous pressure
What is a transudate?
Low protein content
What is an exudate?
High protein content
Give three causes of increased transudate in the pleural space
- Increased hydrostatic pressure
- Decreased capillary oncotic pressure
Give four causes of an exudate pleural effusion
- Cancer involving pleural surface
- Secondary mets from breast, lung, ovarian, GI and lymphoma
- Primary tumour of the pleura
3. Immune disease
- Connective tissue disease
- Subphrenic abscess
What is pleurisy?
Inflammation of the pleura
- Causes sharp pain on inspiration
What is a characteristic sign of pleurisy?
Pleural rub, a creaking noise heard through a stethoscope with respiratory movements
Why do patients with pleurisy get shoulder pain?
Irritation of diaphragmatic pleura
Give five causes of pleurisy
What are the two types of infection which cause pleurisy?
What are the two types of autoimmune disease which cause pleurisy?
- Systemic Lupus Erytematosus
- Rheumatoid arthritis
What is pleural fibrosis?
- Unabsorbed pleural effusion may lead to fibrosis of the pleura
- A small degree of thickening has no effect, but widespread fibrosis restricts expansion with a measurable reduction in lung volumes and compliance
What is the most common type of pleural tumour?
- Early symptoms are loss of pleural effusion, but with a duller pain
- Signs are the of a large pleural effusion
Name two chest wall abnormalities which cause significant functional impairment of the thoracic cage
Scoliosis and kyphosis may produce significant functional impairment of the thoracic cage
Give an acquired chest wall abnormality which can cause breathing abnormalities
Give a muscular defect and two nervous defects which can cause trouble breathing
1. Muscular dystrophy
2. Motor neurone disease