Restictive lung disease - sarcoidosis, idiopathic pulmonary fibrosis, diffuse alveolar damage syndrome, hypersensitivity pneumonitis Flashcards
What part of the lung is affected by restrictive lung disease
the interstitium - connective tissue space around airways and vessels and space between basement membranes of alveolar walls
Characteristics typical of restrictive interstitial lung disease
Reduced lung compliance - stiff lungs
Low spirometry
Reduced gas transfer
Ventilation/perfusion imbalance
Complications of restrictive lung disease
hypoxic cor pulmonale, heart failure, type 1 respiratory failure
Restrictive lung disease is interstitial inflammation. What, in very general terms, causes the inflammatory response?
Parenchymal (interstitial) lung injury
What is the name of the syndrome relating to an acute inflammatory response
Diffuse alveolar damage syndrome
Aetiology of diffuse alveolar damage syndrome?
IDIOPATHIC Major trauma Chemical injury/toxic inhalation Circulatory shock Drugs Infection Auto(immune) disease Radiation
What happens in the exudative stage of diffuse alveolar damage syndrome
Oedema
Hyaline membrane formation
What happens in the proliferative stage of diffuse alveolar damage syndrome
Interstitial inflammation
Interstitial fibrosis
Histological features of DADS
protein rich oedema fibrin hyaline membranes denuded basement membranes epithelial proliferation fibroblast proliferation scarring
Granulomatous responses are a sub type of chronic response to lung injury. What 2 diseases do you need to know for it?
Sarcoidosis
Hypersensitivity pneumonitis
What is sarcoidosis?
A multisystem granulomatous disorder of unknown aetiology
Is sarcoidosis caesating?
No (but TB is)
Histopathology of sarcoidosis
epithelioid and giant cell granulomas
little lymphoid infiltrate
variable associated fibrosis
Who does sarcoidosis normally affect?
Young adults
Female more than male
Presentation of sarcoidosis
acute arthralgia (knee pain) erythema nodosum (rash) bilateral hilar lymphadenopathy incidental abnormal CXR dyspnoea cough
Prognosis of sarcoidosis
Most resolve
Prognosis of DADS
fatal
Investigations with sarcoidosis
CXR
Blood test - serum calcium and ACE
Biopsy
Antigens of hypersensitivity pneumonitis
Thermophilic actinomycetes
Bird/animal proteins
Fungi
Chemicals
Acute presentation of hypersensivity pneumonitis
Fever, dry cough, myalgia
Chills 4-9 hours after exposure
Crackles, tachypnoea, wheeze
Precipitating antibody
Chronic presentation of hypersensitivity pneumonitis
Insidious
Malaise, SOB, cough
Low grade illness
Crackles and some wheeze
Where in the lung is hypersensitivity pneumonitis common?
Upper zone
What type of hypersensitivity reaction is in hypersensitivity pneumonitis?
Type 3 and 4
Aetiology of interstitial pneumonitis (v bad one)
IDIOPATHIC or cryptogenic
Connective tissue diseases
Drug reaction
Post infection
Industrial exposure
3 things making up the histopathology of interstitial pneumonitis
Patchy interstitial chronic inflammation
Type II pneumocyte hyperplasia
Smooth muscle and vascular proliferation
Typical patient having idiopathic pulmonary fibrosis
elderly
male
progressive disease
What do all three chronic responses go to if they do not resolve (or haven’t died already)
Fibrosis and end stage honeycomb lung
Definition of restriction
FVC <80% predicted
What are the lung causes of restriction (3 to remember)
sarcoidosis
idiopathic pulmonary fibrosis
hypersensitivity pneumonitis
Pleural causes for restriction
pleural effusion
pneumothorax
pleural thickening
Skeletal causes for restriction
kyphoscoliosis
ankylosing spondylitis
thoracoplasaty
rib fractures
Muscle causes for restriction
amyotrophic lateral sclerosis
sub-diaphragmatic causes for restriction
obesity
pregnancy
Investigations for sarcoidosis
CXR Pumonary function test Bloods Urinalysis ECG TB skin test eye exam HR CT Surgical biopsy
Treatment of sarcoidosis
None if mild
NSAIDS
Topical steroids
Systemic steroids
Treatment for idiopathic pulmonary fibrosis
Oral antifibrotic
Palliative treatment
Transplant
