Restrictive Lung Diseases Flashcards
Describe the chronic inflammatory pathways that can lead to the end stage honeycomb lung.
Usual interstitial pneumonitis - idiopathic pulmonary fibrosis/ cryptogenic alveolar fibrosis
Granulomatous - sarcoidosis and hypersensitivity pneumonitis
What is the acute inflammatory outcome from lung injury?
Diffuse alveolar damage (adult respiratory distress syndrome)
What is diffuse alveolar damage associated with?
Idiopathic Chemical injury/toxic inhalation Radiation Trauma Autoimmune disease Infection Circulatory shock Drugs
What are the histological features of diffuse alveolar damage?
Protein rich oedema (incl fibrin) Denuded basement membrane Hyaline membranes Fibroblast proliferation Epithelial proliferation Scarring in interstitial and air space
What is sarcoidosis characterised by?
Sarcoidosis is characterised by granulomas.
Granulomas are non-necrotising and therefore don’t undergo necrosis.
This sets sarcoidosis apart from some infections which contain necrotising granulomas such as TB, pneumonia etc.
Describe the histopathology of sarcoidosis.
Epithelial and giant cell granulomas
Necrosis is very unusual
Little lymphoid infiltrate
Associated fibrosis will vary
What is the clinical presentation of sarcoidosis?
The presentation depends on the age of the patient and the progression of the disease.
The most common is in young adults F>M : acute arthralgia , erythema nodosum, bilateral hilar lymphadenopathy
In a more severe case patient will present with shortness of breath, cough and abnormal CXR.
What is used in the diagnosis of sarcoidosis?
Clinical finding Image finding Elevated serum calcium Elevated ACE levels Biopsy
What is the cause of hypersensitivity pneumonitis?
Hypersensitivity pnuemonitis is caused by an antigen which the body produces an over reacted response against. The antigens are usually organic in origin such as from:
Bird/animal proteins , fungi, chemicals, thermophillic actinomycetes
What is the acute presentation of someone with hypersensitivity pnuemonitis?
Fever, myalgia, dry cough, chills 4-9 hrs post Ag exposure, crackles, wheeze, tachypnoea
What is the clinical presentation of someone with chronic hypersensitivity pneumonitis?
Shortness of breath, cough, malaise, low grade illness, crackles and wheeze
Describe the histopathology of hypersensitivity pneumonitis.
Immune complex mediated type III and type IV hypersensitivity reaction
Soft centriacinar epitheliod granulomas (softer than sarcoidosis)
Interstitial pneumonitis
Foamy histiocytes
Bronchiolites obliterans (obstruction of airways, popcorn lung)
Primarily around small airways where the Ag can easily be deposited
Upper zones of the lunng
Where might idiopathic pulmonary fibrosis be seen in?
Connective tissue disorder
Drug reaction
Post infection
Industrial exposure i.e. asbestos
Describe the histopathology of idiopathic pulmonary fibrosis.
Patchy interstitial chronic inflammation
Type II pneumocyte hyperplasia
Smooth muscle and vascular proliferation
What is the clinical presentation of someone with idiopathic pulmonary fibrosis?
Most commonly elderly > 50 & M>F
Dyspnoea, cough, basal crackles, cyanosis, clubbing
Restrictive pulmonary function tests, reduced gas transfer (KCO)
Diffuse infiltrates, cysts on CXR (usually base/posterior of lung)
