Histopathology - Lung Pathology Flashcards
What are some obstructive lung diseases?
- Chronic bronchitis
- Bronchiectasis
- Asthma
- Emphysema
- Small airway disease/bronchiolitis
What is the pathology, aetiology + histological features of bronchitis?
- P = Dilation of the airways + excess mucus production
- A = tobacco smoke, air pollution
- H = Dilation of airways, goblet cell hyperplasia, hypertrophy of mucous glands
What is the pathology, aetiology + histological features of bronchiectasis?
- P = Airway dilatation + scarring
- A = Recurrent infections (e.g. CF, primary ciliary dyskinesia)
- H = Permanent fibrotic dilatation of the bronchi with mucous plugging
What is the pathology, aetiology + histological features of asthma?
- P = Widespread airway constriction due to mast cell degranulation
- A = Immunologic, allergens, drugs, cold air, exercise
- H = SM cell hypertrophy, goblet cell hyperplasia, eosinophilia, Curschmann spirals, Charcot-Leyden crystals
What is the pathology, aetiology + histological features of emphysema?
- P = airspace enlargement, wall destruction
- A = tobacco smoke, α1-AT deficiency
- H = Loss of alveolar parenchyma distal to terminal bronchiole
What is the pathology, aetiology + clinical features of bronchiolitis?
- P = inflammatory scarring/obliteration
- A = tobacco smoke, air pollutants
- C = dyspnoea, cough
What is the pathophysiology of cystic fibrosis?
- AR mutation in CTFR gene affects Cl ion transport, leading to abnormally thick secretions
- Secretions allow growth of bacteria, causing frequent lung infections, resulting in bronchiectasis
- Multisystem disease as secretions affect other organs (e.g. pancreatic insufficency = malabsorption)
What pathogen is commonly seen in patients with lung infections in cystic fibrosis?
Pseudomonas Aeruginosa
What is interstitial lung disease?
Group of >200 disease characterised by inflammation + fibrosis of pulmonary connective tissue, accounting for 15% of resp disease burden
What typical features are seen in interstitial lung disease
- Restrictive picture (spirometry)
- Chronic SOB
- Fine-end inspiratory crackles
- cyanosis
- pulmonary HTN
- Cor pulmonale
In advanced interstitial lung idease, what is seen on a CT CAP?
Ground glass/honeycomb appearance
What are the different types + categories of interstitial lung disease?
Fibrosing:
- Idiopathic pulmonary fibrosis
- Pneumoconiosis
- A/w connective tissue disease
- Drug-induced
- Radiation pneumonitis
Granulomatous:
- Sarcoid
- Extrinsic allergic alveolitis
- A/w vasculitides
Eoisinophilic
Smoking-related
What is the clinical picture of patient with idiopathic pulmonary fibrosis?
- Male
- 40-70y
- Exertional dyspnoea
- Non-productive cough
- Clubbing
How is idiopathic pulmonary fibrosis diagnosed and managed?
- D: high resolution CT +/- niopsy
- T: Steroids, cyclophosphamide, azathioprine, pirfenidone
What is pneumoconiosis + its typical presentation?
- Occupational lung disease causes by inhalation of minerla dusts or inorganic particles
- Coal miners
- Predilection for upper lobes
What is asbestosis + its typical presentation?
- Fibrosis resulting from asbestos exposure
- Affects lower lobes
What is a granuloma?
A collection of histiocytes, macrophages +/- multinucleate giant cells
What is extrinsic allergic alveolitis/pneumonitis etc. examples of?
Group of immune-mediated lung disorders caused by intense/prolonged exposure to inhaled organic antigens causing widespread alveolar inflammation
What is seen on histology for extrinsic allergic alveolitis?
- Presence of polypoid plugs of loose connective tissue within alveoli/bronchioles
- Granuloma formation + organising pneumonia
What are some typical features of bronchopneumonia?
- Patchy bronchial/peri-bronchial distribution
- Low virulence organisms
- Elderly + frail people
What are some typical features of lobar pneumonia?
- Fibrosuppurative consolidations
- High virulence organisms (e.g. Strep. pneumoniae = rust-coloured sputum)
What stages are seen in lobar pneumonia?
- Consolidation
- Red hepatisation (neutrophilia)
- Grey hepatisation (fibrosis)
- Reolution
What are some typical features of atypical pneumonia?
- Interstital pneumonitis
- No intra-alveolar inflammation
- Chronic + progressing fibrosing disease of lung
What are some tumours of the lung + their prevalence?
- Squamous cell carcinoma (30-50%)
- Adenocarcinoma (20-30%)
- Small cell carcinoma (20-25%)
- Large cell carcinoma (10-15%)
What are the risk factors, mutations, location and histological findings of Squamous Cell Carcinoma?
- RFs: Male, SMOKING
- M: p53/c-myc
- L: Proximal bronchi, local spread with late metastases
- H: sQaumous = hyperQualcaemia (of malignancy), Qeratin pearls (keratinisation), cell Qonnections (intercellular prickles)
What is adenocarcinoma of the lung, its risk factors, location and histological findings?
Malignant epithelial tumour with glandular differentiation of mucin-production
- RFs: Women + non-smokers
- L: Peripherally (type 2 pneumocytes in alveoli) + metastasizes early
- H: glandular differentiation (gland formation + mucin production)
What are the risk factors, mutations, location and histological findings of Small Cell Carcinoma + its associations?
- RFs: Smoking
- M: p53 + RB1
- L: Centrally, proximal bronchi + rapid metastases
- H: Small, poorly differentiated “oat cells” (kulchitsky cell)
- A: SIADH, Cushing’s Lambert-Eaton
What is large cell carcinoma and it’s histological findings?
- Poorly differentiated malignant epithelial tumour
- H: No evidence of glandular or squamous differentiation
What are some paraneoplastic syndromes?
- ADH –> SIADH (small cell)
- ACTH –> Cushing’s syndrome (Small cell)
- PTH/PTHrP –> primary hyperparathyroidism, hypercalcaemia + bone pain (squamous cell)
- Calcitonin –> hypocalcaemia
- Serotonin –> Carcinoid syndrome (flushing, diarrhoea, bronchoconstriction)
- Bradykinin –> cough
How is lung cancer staged?
- Tumour (T1-4): based on size, invasion of pleura, pericardium
- LN metastasis (N0-2): N0 = no involvement, N1/2 = involvement, dependant on extent
- Distant Mets (M0/1): Tumour spread to distant sites
Where does mesothelioma originate, where does it spread and what is its typical presentation?
- Arises from parietal/visceral pleura
- Spreads in pleural space
- Presentation: extensive pleural effusion, chest pain, dyspnoea
What is a pulmonary embolus?
The embolisation of a peripheral thrombus to the lung
What are some RFs for developing a PE?
- Female
- Immobility
- Cardiac disease
- Cancer
- Primary + Secondary hypercoagulable states
What are the different types of emboli and how do they differ?
- Large Emboli: Impact in main pulmonary arteries leads to acute cor pulmonale, cardiogenic shock + death if >60% pulmonary bed occluded
- Small Emboli: Silent or cause peripheral wedge infarctions. Repeated infarctions = pulmonary HTN
- Non-thrombotic emboli: Bone marrow, amniotic fluid, tumour, air, foreign body
What is the term used to describe a large emboli occluding the pulmonary trunk?
Saddle embolus
What is pulmonary hypertension?
Mean pulmonary arterial pressure >25mmHg at rest
What are the different classes of pulmonary hypertension and how do they differ?
- Class 1: Pulmonary arterial hypertension - most common in women 20-40yrs (Causes: idiopathic, hereditary, congenital HD)
- Class 2: Due to left heart disease (e.g. valve disease)
- Class 3: Due to lung disease (e.g. ILD)
- Class 4: Chronic thromboembolic pulmonary hypertension (e.g. due to many clots over time which causes fibrosis)
- Class 5: With unclear multifactorial mechanisms (e.g. metabolic/systemic/haematological disorders)
What is the pathophysiology of pulmonary hypertension?
- Pre-capillary: chronic hypoxia/embolus
- Capillary: Pulmonary fibrosis
- Post-capillary: Left heart disease/veno-occlusive disease
- Pulmonary vasoconstriction of arterioles: intimal fibrosis, thickened walls
What are some complications of pulmonary hypertension?
RHF - venous congestion of organs (nutmeg liver), peripheral oedema
What is pulmonary oedema, its aetiology + histology?
Intra-alveolar fluid accumulation leads to poor gas exchange
Aetiology:
- LHF
Histology:
- Intra-alveolar fluid
- Iron laden macrophages
What is diffuse alveolar damage, its complications + histology?
Acute damage to alveoli (alveolar epithelium) leading to exudative inflammatory reaction, rapid onoset of respiratory failure + requiring ventilation in ITU
Cx:
- ARDS
- Hyaline Membrane Disease (HMD) in neonates
Histology:
- Lung expanded, firm, plum-coloured, airless
What is seen on the CXR of diffuse alveolar damage?
White out of all lung fields
What is COPD, it’s symptoms, causes + histological findings?
Chronic bronchitis + emphysema
Sx:
- Frequent coughing
- Wheezing
- Excessive sputum
- SOB
Causes:
- Smoking
- α-1 antitrypsin deficiency (SOB + liver Sx)
Histo:
- Neutrophilic infiltration into airways
- Loss of alveoli, elastic fibres + lung parenchyma
What is cystic fibrosis, its inheritance, complications + histological findings?
AR mutation in CFTR gene on Chr 7
Cx:
- Recurrent lung infections
- Pancreatic insufficiency
- Malabsorption
Histo:
- Mucous clogged airways
- Inflammatory cell infiltration
What is the mechanism of action of cystic fibrosis?
- Mutation on CFTR gene (Chr 7) leads to defective ion transport
- Excessive resorption of water from secretions of exocrine glands
- Abnormally thick mucous secretions
- Affects all organ systems
