Restrictive lung diseases Flashcards
What are some lung causes of restrictive lung disease?
Interstitial lung diseases
- idiopathic pulmonary fibrosis
- sarcoidosis
- hypersensitivity pneumonitis
What are some pleural causes of restrictive lung disease?
Pleural effusion
Pneumothorax
Pleural thickening
What are some skeletal causes of restrictive lung disease?
Kyphoscoliosis
Ankylosing spondylitis
Thoracoplasty (old TB treatment)
Rib fractures
What is a muscular cause of restrictive lung disease?
Amyptrophic lateral sclerosis
What are some sub diaphragmatic causes of restrictive lung disease?
Obesity
Pregnancy
What are interstitial lung diseases?
Diseases that cause a thickening of the interstitial and can result in pulmonary fibrosis
What are the main 3 types if interstitial lung disease?
Sarcoidosis
Idiopathic pulmonary fibrosis
Hypersensitivity pneumonitis
What is sarcoidosis?
Multisystem granulomatous disease of unknown cause
What does sarcoidosis cause?
Non-caseating granulomas, often around pre-existing scars or tattoos
Who is sarcoidosis most common in?
Adults under 40
Women>men
Many asymptomatic
How is sarcoidosis diagnosed?
History and examination
Chest xray
What are the 4 stages of pulmonary involvement of sarcoidosis?
Stage 1- bilateral hilar lymphadenopathy
Stage 2- bilateral hilar lymphadenopathy with pulmonary infiltrates
State 3- pulmonary infiltrates
Stage 4- fibrosis
What investigations are done for sarcoidosis?
Pulmonary function tests
Bloods, urinalysis, ECG, TB skin test, eye exam
Bronchoscopy and surgical biopsy
How is bronchoscopy useful for the diagnosis of sarcoidosis?
Can include trans bronchial biopsies and endobronchial ultrasound
White patches visible on mucous membranes- granulomas
What surgical biopsies can be carried out for sarcoidosis?
Mediastinoscopy
Video assisted thoracoscopic lung biopsy
What are the remission rates for sarcoidosis?
Stage 1- 55-90%
Stage 2- 40-70%
State 3- 10-20%
Stage 4- 0% (impossible to reverse fibrosis)
What is the treatment of mild sarcoidosis?
Mild disease with no vital organ involvement, normal lung function and few symptoms
-No treatment
What is erythema nodosum and the treatment in sarcoidosis?
Inflammation of fat cells under skin
Non steroidal anti inflammatory drugs
What is arthralgia and the treatment in sarcoidosis?
Joint pain
Non steroidal anti inflammatory drugs
What is the treatment for skin lesions, anterior uveitis and a cough in sarcoidosis?
Topical steroids
What is the treatment for cardiac, neurological or eye disease not responding to topical steroids in sarcoidosis?
Systemic steroids
What is the treatment for hypercalcaemia in sarcoidosis?
Systemic steroids
What is the prognosis for sarcoidosis?
Good, few Caucasians die
10-20% sustain permanent pulmonary or extra pulmonary complications
What are the main signs and symptoms of idiopathic pulmonary fibrosis?
Chronic breathlessness and cough
Clubbed fingers
Crackles
Who is idiopathic pulmonary fibrosis common in?
60-70 years olds
Men>women
What is the treatment for idiopathic pulmonary fibrosis?
Historically only palliative care
Oral anti-fibrotic
Transplant
What is the median survival for idiopathic pulmonary fibrosis?
3 years
What is hypersensitivity pneumonitis?
Inflammation of the alveoli
What is the interstitial of the lung?
Connective tissue space between the alveoli and capillaries
What does interstitial inflammation cause?
Lungs to become stiff
What does interstitial lung disease cause?
Reduced lung compliance
Low FEV1 and FVC ratio but FEV1/FVC ratio normal
Reduced gas transfer
V/Q mismatch
What is the usual presentation in interstitial lung disease?
Dyspnoea
What are the progressive symptoms of interstitial lung disease?
Respiratory failure
Heart failure
What is acute inflammation of the lungs associated with?
Major trauma Toxic inhalation/chemical injury Circulatory shock Drugs Infection Autoimmune disease Radiation
What does acute inflammation of the lungs cause?
ARDS
What is the evolution of acute inflammation of the lung?
Damage and destruction of endothelial cells causes them to become leaky, causing oedema
Causes outport of macromolecules that precipitate and form a hyaline membrane over the endothelium
What are the histological features of acute inflammation?
Protein rich oedema in alveolar spaces Protein precipitates creating hyaline membranes Fibrin Denuded membranes Epithelial proliferation Fibroblast proliferation Scarring
What does a granulomatous response to hypersensitivity pneumonitis cause?
Sarcoidosis
Hypersensitivity pneumonitis
What is the acute presentation of hypersensitivity pneumonitis?
Fever, dry cough, myalgia
Chills 4-9 hours after exposure
Crackles, tachypnoea, wheeze
Precipitating antibody
What is the chronic presentation of hypersensitivity pneumonitis?
Malaise, dyspnoea, cough
Crackles and some wheeze
What is the histopathology of hypersensitivity pneumonitis?
Immune complex mediated by type 3 and 4 hypersensitivity reaction Soft centriacinar epithelia granulomata Interstitial pneumonitis Foamy histocytes Bronchiolotis obliterans
When might usual; interstitial pneumonitis be seen?
Connective tissue diseases
Drug reactions
Post infection
Industrial exposure
What is the histopathology of usual interstitial pneumonitis?
Patchy interstitial chronic inflammation
Type 2 pneumocyte hyperplasia
Smooth muscle and vascular proliferation
Proliferating fibroblastic foci
What are the clinical signs of usual interstitial pneumonitis?
Dyspnoea, cough
Basal crackles, cyanosis, clubbing
Who is usual interstitial pneumonitis common in?
Men>women
Over 50s
What investigations are done for usual interstitial pneumonitis?
Chest xray
Pulmonary function test and gas transfer- reduced
What is the outcome of usual interstitial pneumonitis?
Increased risk of lung cancer
Almost all end in fibrosis
Life expectancy= 5 years
What are some causes of abnormal pulmonary gas exchange?
Alveolar hypoventilation
V/Q imbalance
Diffusion impairment
Shunt
How does alveolar hypoventilation affect pulmonary gas exchange?
Increase PACO2 causes increased PaCO2 and decreased PaO2
What is the commonest cause of hypoxaemia clinically?
Low V/Q
What are the effects of diffusion impairment on blood gases?
PaCO2 usually not affected
PaO2 maintained at rest but falls significantly on exertion
Why does shunt hypoxaemia respond poorly to oxygen?
Oxygenated is already 98% saturated, it is blood not contacting ventilated alveoli causing the problem
