Flashcards in *Restrictive Airway Disease Deck (35)
What is restrictive lung disease?
Patient find it difficult to fully inflate their lungs due to the lungs being restricted from fully expanding
What are some examples of thoracic restriction due to causes out with the lungs (extrinsic causes)?
Skeletal: (thoracic kyphoscoliosis, ankylosing spondylitis, rib trauma)
Muscle weakness: (intercostal or diaphragmatic due to myopathy, neuropathy, ir myelopathy) e.g. Guillan barre, Motor neurone disease)
Abdominal obesity/ ascites
In terms of alveolar ventilation, PaO2, PaCO2, and lung volumes, what effect does thoracic restriction due to causes out with the lungs have (extrinsic causes)?
-chronic alveolar under ventilation
-reduced lung volumes
What does DPLD stand for?
Other name for this?
Diffuse Parenchymal Lung Diseases
Interstitial lung diseases
What are interstitial lung diseases?
A group of conditions that primarily affect the lung parenchyma in a diffuse manner
They are characterised by chronic inflammation +/- progressive interstitial fibrosis
They have a restrictive pulmonary spirometry with reduced carbon monoxide diffusing capacity (DLCO)
Clinical features of Diffuse parenchymal lung diseases? (5)
Dyspnoea on exertion
Non-productive paroxysmal cough (with no wheeze)
Abnormal breath sounds (inspiraotry lung crackles)
Abnormal chest x-ray or high resolution CT
Restrictive pulmonary spirometry with decreased DLCO
What 3 general groups can interstitial lung diseases be grouped into?
Those with a known cause e.g. drugs, occupation, infection, etc.
Those associated with systemic disorders e.g. sarcoidosis, rheumatoid arthritis, etc.
Idiopathic e.g. lymphocytic interstitial pneumonia, idiopathic pulmonary fibrosis
Spectrum of DPLD - BTS classification?
1) acute DPLD (e.g. infections, allergy, toxins, etc.)
2) episodic DPLD, all of which may present acutely (e.g. extrinsic allergic alveolitis, eosinophilic pneumonia)
3) Chronic DPLD due to occupational or environmental agents or drugs (e.g. aspestosis, silicosis, etc.)
4) Chronic DPLD with evidence of systemic disease (e.g. rheumatoid arthritis)
5) Chronic DPLD with no evidence of systemic disease e.g. idiopathic pulmonary fibrosis
What are the 2 very broad classifications of restrictive lung disease?
Intrinsic (interstitial lung disease)
Extrinsic (due to causes outwith the lungs)
Alveolar gas exchange in restrictive thoracic disease due to disease within he lungs? (PaO2 and PaCO2)
PaO2 = decreased
PaCO2 = normal as CO2 exchange unimpaired as alveolar perfusion normal
Aetiology of DPLD? (6)
Fluid in the alveolar air spaces
Consolidation of alveolar air spaces
Inflammatory infiltrate of alveolar walls
What causes fluid in the alveolar spaces?
Cardiac pulmonary oedema (due to raised venous pressure i.e. LVF)
Non-cardiac pulmonary oedema due to leaky capillaries (caused by sepsis or trauma - ARDS aka shock lung) - also due to altitude sickness
What causes consolidation of alveolar air spaces?
Infarction e.g. PE/ vasculitis
Other causes i.e. BOOP, rheumatoid disease, drugs
What is BOOP?
Bronchiolitis obliterans with organizing pneumonia (BOOP) is a rare lung condition in which the small airways (bronchioles) and air exchange sac (alveoli) become inflamed with connective tissue
Cryptogenic organising pneumonia
What causes an inflammatory infiltrate of alveolar walls? (5)
Granulomatous alveolitis (extrinsic allergic alveolitis, sarcoidosis)
Drug induced alveolitis
Toxic gas/ fumes
Fibrosing alveolitis (rheumatoid arthritis, idiopathic pulmonary fibrosis)
Autoimmune (Wegeners, Churg-Strauss, etc.)
Other name for dust diseases of the lungs?
Types of dust diseases?
Fibrogenic (asbestosis, silicosis)
Non fibrogenic (Siderosis (iron), stances (tin), baritosis (barium))
What type of reaction is extrinsic allergic alveolitis?
Hypersensitivity pneumonitis - type 3 reaction
What is carcinomatosis?
The widespread dissemination of carcinoma in the body
What are 4 examples of eosinophilic lung diseases?
Drugs e.g. nitrofurantin (antibiotic used to treat bladder infections)
Fungal e.g. aspergillosis
Parisites e.g. toxocara, ascaris, fiaria
Autoimmune e.g. Churg strauss
What occurs as the end stage response to chronic inflammation of the lung parenchyma?
How is DPLD diagnosed?
History e.g. occupation, drugs, pets, arthritis
Reduced lung volumes e.g. decreased FEV1 and FVC with normal ration (>75%)
Reduced gas diffusion (DLCO)
Arterial oxygen desaturation (decreased PaO2 and SaO2)
What can be measured in the blood that would indicate some interstitial lung diseases?
antibodies e.g. avian, fungal, auto-antibodies
What serum levels are raised in sarcoidosis?
Serum ACE and Ca
What could be seen on a chest x-ray of a patient with interstitial lung disease?
Alveolar infiltrates on chest x-ray
Why should an ECG be performed on patients with suspected DPLD?
To exclude LVF
What might be seen on a high resolution CT scan of a patient with DPLD?
Inflammatory ground glass appearance vs fibrotic nodular component of alveolar infiltrates
Why should bronchoalveolar lavage or induced sputum be carried out on a patient with suspected DPLD?
To exclude pneumocystis, TB or another infection
Are a transbronchial or thoracoscopic lung biopsy indicated in patients with DPLD?
Treatment of DPLD? (8)
-Remove any trigger factor (e.g. dust, drug, allergen)
-Treat any inflammation i.e. ground glass on HRCT with immunosuppressives (NB - danger of secondary super-infection due to immune suppression)
-Give systemic corticosteroids ie. oral prednisolone (inhaled corticosteroids are not effective)
-2nd line to corticosteroids = oral azathioprine (steroid sparing)
-Anti-fibrotic agents for IPF e.g. pirfenidone, nintendanib
-anti-oxidant agent can be given for IPF - acetylceysteine
-O2 if hyoxaemic
-lung tranplant is a last resort for end stage disease
What is the steroid sparing agent that is used second line to systemic corticosteroids?
What 2 anti-fibrotic agents are available for the treatment of IPF?
What anti-oxidant agent can be given for IPF?
What lung disease is erythema nodosum a sign of?
What causes bilateral hillier lymphadenopathy and lung infiltrates?