Restrictive lung disease Flashcards
Clincial presentation of restrictive lung disease
Cough, SOB and symptoms of the assoicated disease (if present).
Cough, clubbing (but not always) and crackles (CCC).
Restrictive lund disease
/Interstitial lung disease/diffuse parenchymal lung disease.
These disorders are characterised by diffuse and usually chronic involvement of the pulmonary CT, largerly the most peripheral and delicate interstitium in the alveolar walls. With just about all causes initially there is an inflammation within the alveolar walls and spaces. This results in the distortion of the normal alveolar structure and the inflammatory cells release mediators that can injure the parenchymal cells and stimulate fibrosis. Advanced forms may cause gross destruction of the lungs end stage lung or honeycomb lung.
The most common cause of lung restriction
Pulmonary fibrosis
‘Pneumonia’ in usual interstitial pneumonia
Used broadly to refer to predominantly interstitial inflammation (interstitial pneumonias) of the lung with restriction (but not necessarily infection).
Pneumoconioses
Lung disease due to environmental inhalants. These are often associated with other diseases such as emphysema and mesothelioma due to their common risk factors.
e.g. silicosis, anthracosis, asbestosis etc.
Classification of restrictive lung disease
- Fibrosing
- Idiopathic
- Identified cause
- Granulomatous
- Eosinophilic
- Smoking-related
- Other
Fibrosing restrictive lung diseases
Idiopathic
- Usual interstitial pneumonia (UIPP) (idiopathic pulmonary fibrosis or cryptogenic fibrosing alveolitis)
- Idiopathic non-specific interstitial pneumonia
- Crytogenic organising pneumonia (aka bronchiolitis obliterans organising pneumonia (BOOP))
Identified cause
- Associated with collagen vascular disease
- Pneumoconiosis
- Drug reactions
- Radiation pneumonitis
Aetiology of UIP
Repeated cycles of alveolitis by an unidentified agent, may be modified by genetic or environmental factors. Predominantly a Th2 response, eosinophils, mast cells, IL-4, IL-13 found in the lesions. TGF-beta1 is released from injured type I alveolar epithelial cells and favours the production of collagen scar tissue in the lung.
Microscopic features of UIP
Cycles of injury and wound healing lead to patchy interstitial fibrosis-fibroblastic foci. Variable states of inflammation and fibrosis- early and late lesions. Lower lobes predominantly show fibrosis. Secondary pulmonary hypertensive changes are often present.
Clinical presentation of UIP
Insidious onset - exertional dyspnoea and dry cough, age 40-70. hypoxia, cyanosis, variably progressive - 3 years or less, some rapid deterioration.
<20% improve with steroids. Lung transplantation required.
Microscopic features of Interstitial non-specific interstitial pneumonia
Not quite characteric features of other interstitial diseases.
Cellular (mild to mdoerate chronic interstitial inflammation, unifrom or patchy) and fibrosing patterns (diffuse or pathy interstitial fibrosis). All lesions are about the same age. Honeycomb areas are rar.e Fibroblasic foci are absent.
Clinical features of interstitial non-specific interstitial pneumonia
Dyspnoea and cough, 46-55 years old.
Those with highly cellular pattern are generally younger and better outcome (than UIP or the fibrosing pattern) - most improve with treatment with steroids.
Cryptogenic organising pneumonia
AKA Bronchiolitis Obliterans Organising Pneumonia.
Characterised by teh polypoid plugs of loose organising CT (all of the same age - known as Masson bodies) within alveolar ducts, alveoli and often bronchioles. Underlying lung architecture is normal. No interstitial fibrosis or honeycomb lung.
Clinical features of Cryptogenic organising pneumonia
Presents in the 50s-60s, men = women, with fever, fatigue, dyspnoea, cough, hypociv, inspiratory crackles, subpleural (therefore peripheral) or peribronchial patchy areas of air space consolidation are seen radiographically.
Spontaneous recovery, oral steroids 6 or so months.
Note: similar picture see in post infection, viral and bacterial pneumonia, inhaled toxins, drugs, collagn vascular disease, graft versus host disease, bone marrow transplant - prognosis same as the underlying disease).
Fibrosing RLD associated with collagen vascular disease
Includes:
- Systemic lupus erythematosus
- Rheumatoid arthritis (lung pathology seen in 30-40% of pateints)
- Progressive systemic sclerosis (scleroderma)
- Dernatomyositis-polymyositis
- Mixed CT disease
Various patterns of lung pathology.
