Pathology of Restrictive Lung Diseases Flashcards
Describe the clinical symptoms associated with restrictive lung diseases
- Abnormal CXR (shortened lungs)
- Dyspnoea
- Type I respiratory failure (hypoxia, normo/hypocapnia)
- Heart failure
Define the major classes of restrictive lung disease
- Occupational
- Granulomatous lung disease (sarcoidosis)
- Idiopathic pulmonary fibrosis
Identify the lung interstitium
The connective tissue around the airways and vessels and the space between the basement membranes of the alveolar walls.
Normally, all basement membranes are in direct contact.
Describe the aetiology of diffuse alveolar damage (DAD) syndrome
Acute response to lung parenchymal injury.
- Major trauma
- Chemical injury
- Circulatory shock
- Drugs
- Infection
- Autoimmune disease
- Radiation
- Can be idiopathic
Describe the aetiology and epidemiology of sarcoidosis
A multisystem granulomatous disorder of unknown origin.
- Young adults
- F/M
- More common in Afro-Caribbean
Describe the aetiology of hypersensitivity pneumonitis
- Thermophilic actinomycetes (bacteria): micropolyspora faeni, thermoactinomyces vulgaris
- Animal proteins
- Chemicals
Describe the aetiology of idiopathic pulmonary fibrosis (usual interstitial pneumonitis)
- Connective tissue disease: scleroderma, rheumatoid
- Drug reaction
- Post-infection
- Industrial exposure: asbestos
- Most are idiopathic
Recall the causes and effects of end stage lung fibrosis/honeycomb lung
Variable sized cysts upon background of scar tissue.
- Enlarged, fibrosed interstitium
- Seen in IDF, CHP, Sarcoidosis
- Dyspnoea, cough
- Haemoptysis, wheeze, chest pain
Describe the functional effects of interstitial (diffuse) lung disease
- Reduced lung compliance
- Low FVC and FEV1 but ratio remains same
- Reduced gas transfer
- V/Q mismatch when bronchioles affected
Describe the pathogenesis of diffuse alveolar damage (DAD) syndrome
- Protein-rich oedema
- Fibrin
- Hyaline membrane surrounds alveoli
- Denuded basement membranes
- Epithelium/fibroblast replication
- Scarring
Describe the pathogenesis of sarcoidosis
- Lymph nodes, lungs, spleen, liver
- Epithelioid and giant cells
- Little infiltrate/necrosis/caseation
- Variable associated fibrosis
Describe the presentation, diagnosis and treatment of sarcoidosis
Presentation;
- <40 years, F>M
- Acute arthralgia
- Erythema nodosum
- Bilateral hilar lymphodenopathy
- SOB, cough, incidental abnormal CXR
Diagnosis;
- Clinical/imaging findings
- Serum (high Ca2+) and ACE
- Biopsy
Treatment;
- Corticosteroids
Describe the pathogenesis of hypersensitivity pneumonitis
- Combined type III and IV hypersensitivity reaction
- Soft centriacinar epithelioid granulomata
- Interstitial pneumonitis
- Foamy histocytes
- Bronchiolitis obliterans
- Upper zone disease
Describe the clinical presentation of hypersensitivity pneumonitis
Acute;
- Fever, dry cough, myalgia
- Chills
- Crackles, tachypnoea, wheeze
- Precipitating antibody
Chronic;
- Malaise, SOB, cough
- Some crackles and wheeze
- Can lead to respiratory failure
- Gas transfer low
- History important
Describe the pathogenesis of idiopathic pulmonary fibrosis (usual interstitial pneumonitis)
- Patchy interstitial chronic hyperplasia
- Type II pneumocyte hyperplasia
- Smooth muscle and vascular proliferation
- Evidence of old and new injury
