Histopathology 12 - Respiratory pathology Flashcards
Main causes of pumonary oedema
- Left heart failure
- Alveolar injury i.e. in patients who have inhaled fire-smoke fumes
- Neurogenic i.e. after a brain injury, can lead to systemic effects
- High altitude
How does diffuse alveolar damage appear on CXR?
Firm and expanded lungs
Also “white out” of all lung fields
What are the acute features of the airway in asthma?
Acute bronchospasm
Acute mucosal oedema
Inflammation
What are the chronic features of the airway in asthma?
Muscular hypertrophy
Airway narrowing
Mucus plugging
What are the features of COPD?
Chronic bronchitis and emphysema
Describe the features of chronic bronchitis
- Chronic cough productive of sputum
- Most days for at least 3 months over at least 2 consecutive years
How does chronic hypoxia affect the heart?
Pulmonary hypertension —> right heart failure
COR PULMONALE
What is emphysema?
Permanent loss of the alveolar parenchyma distal to the terminal bronchiole
What is the genetic association of emphysema?
Alpha 1 anti-trypsin
Since a1 antitrypsin helps neutralise the activation of neutrophils and proteases and keep this system in balance, so deficiency increases R of emphysema due to damage from immune cells
Recall the pathophysiology of emphysema
- Smoking causes inflammation
- Neutrophil and macrophage involvement
- Proteases recruited
- Breakdown of epithelium
What does lung bullous rupture cause?
Pneumothorax
NB bullae form as complication of emphysema (bullae = large air spaces)
What is bronchiectasis?
Permanent abnormal dilatation of bronchi with inflammation and fibrosis into adjacent parenchyma
Recall the complications of bronchiectasis
- Haemoptysis
- Pulmonary HTN
- RHF
- Amyloidosis secondary to chronic inflammation
- Recurrent infections
Which condition has the strongest association with bronchiectasis?
Cystic fibrosis
What is bronchopneumonia?
Inflammation centred around airway (small bronchi and bronchioles)
Occurs in elderly pts
Where does bronchopneumonia often affect?
Lower lobes
Which type of pneumonia has become much rarer since ABx have been in use?
Lobar pneumonia
What is empyema?
Infected pleural effusion
Which type of pneumonia is most likely to cause interstitial inflammation?
Atypical pneumonias
What are the most common lung tumours?
Epithelial tumours - non small cell and small cell
What are the 3 subtypes of non-small cell lung cancer?
Adenocarcinoma (30%)
Squamous cell carcinoma (30%)
Large cell carcinoma (20%)
Which 2 types of lung cancer are most associated with smoking?
Squamous cell (type of non-small cell) Small cell carcinoma
NB 25% of lung cancers in non-smokers are attributed to passive smoking
Where is squamous cell carcinoma most likely to develop in the lung?
Centrally
Where do adenocarcinomas typically develop?
Peripherally
Which mutations are smokers most likely to develop in adenocarcinomas?
K ras
p53
Which mutations are non-smokers most likely to develop in adenocarcinomas?
EGFR
This mutation occurs in around 25% lung adenocarcinomas
Which type of lung cancer is assoiated with the most paraneoplastic syndromes?
Small cell
Which mutations are most likely to develop in squamous cell carcinomas?
They’re not - it’s the adenocarcinomas that tend to get the mutations
Complication of chronic bronchitis (independent of smoking)
Lung cancer
Primary ciliary dyskinesia increases R of which lung disease?
Bronchiectasis
XRay sign of Bronchiectasis
tram-track opacities + signet ring sign
CXR finding in chronic LV failure
iron laden macrophages
these are blue-stained cells which are full of iron pigment as there is chronic capillary leakage into the alveolar spaces
Another name for Diffuse Alveolar Damage
Acute Respiratory Distress Syndrome (shock lung)
Effect of Diffuse alveolar damage on lungs
- congested due to the exudate of fluid into alveolar spaces
- alveoli become firm
NB if condition resolved, then lung returns to normal
Complications of pneumonia
- abscess formation
- Pleuritis and pleural effusion
- Infected pleural effusion (empyema)
- scarring
Pathophysiology of granulomatous lung disease, and 2 key causes
collection of histiocytes/ macrophages +/- multinucleate giant cells within the tissue
Causes:
- Infection- often TB in urban areas (CASEATING) - MUST EXCLUDE TB FIRST
- Sarcoidosis- unusual immune reaction (NON-CASEATING)
- Foreign body- Aspiration or IVDU
- Drugs
- Occupational lung disease
Possible enzyme effect of sarcoidosis
Elevated serum Angiotensin Converting Enzyme (ACE)
Best Ix for sarcoidosis
Biopsy
Which part of lung is effected in sarcoidosis
upper zones with a tendency to be peri-lymphatic or peri-bronchial
Cause of nutmeg liver
RH failure
Invasive Squamous Cell Carcinoma closely associated with which cause?
Where in the lung do they occur?
smoking
Centrally
What is a very aggresive lung carcinoma?
Small Cell Carcinoma - terrible prognosis since it recurs as soon as you stop chemo
Mutations in small cell carcinoma (2)
p53 and RB1 mutations
Where in lung is small cell caricnoma found?
central near bronchi
Why is surgery not that useful for small cell carcinoma?
Very aggressive, so has already metastasised by the time pt presents - therefore do chemoradiotherapy
