Respiratory Pathology 1 (Non-Neoplastic) Flashcards
What is the radiographic appearance of a lung abscess?
Cavitating lesion
Air-fluid level
What are the risk factors for developing a lung abscess?
Aspiration Immunosuppression Bronchial obstruction Chronic lung damage Bacteraemia Staph and Gram negatives causing pneumonia
Why are lung abscesses most common in the right lower lobe?
Right main bronchus more vertical
How do infections responsible for abscesses cause necrosis?
ROS
Proteases from inflammatory cells
Proteases from bacteria
What is the natural environment of aspergillus?
Soil
What patients are particularly susceptible to aspergillus infections?
Those with pre-existing lung condition
What is secondary TB?
Reactivation of TB
Usually due to immunosuppression
What are the symptoms of secondary TB?
Cough
Fever
Weight loss
Malaise
What medication can predispose to secondary TB?
Corticosteroids
What is primary TB?
First infection
Forms Ghon complex, usually in upper half of right lower lobe
What are the symptoms of primary TB?
Usually asymptomatic and self-limiting
Why are lesions of secondary TB typically located in the apices of the lungs?
High oxygen concentration
What are the histopathological features of TB?
Granuloma
What histological changes take place with healing of TB in immunocompetent people?
Scar
What is a Ranke complex?
Calcified Ghon lesion + ipsilateral calcified hilar lymph node
What tests are available for diagnosing TB?
Mantoux Quatiferon gold Interferon gamma release assay Zeihl-Neelsen stain PCR
How should you change the management if active TB is suspected?
Isolation
Is TB a notifiable disease?
Yes
What are some non-infectious causes of granulomatous inflammation in the lung?
Sarcoidosis Hypersensitivity pneumonitis Granulomatosis with polyangiitis Churg-Strauss syndrome Aspiration pneumonia Rheumatoid nodules Bronchocentric granulomatosis Foreign body
What are some differential diagnoses for shortness of breath developing in seconds to minutes?
Anaphylaxis PE Arrhythmias Anxiety Pneumothorax Acute asthma ARDS
What are some differential diagnoses for shortness of breath developing in hours to days?
Asthma Pneumonia Heart failure Infective exacerbation of COPD Pleural effusion
What are some differential diagnoses for shortness of breath developing in weeks or longer?
Chronic anaemia COPD Heart failure Chronic bronchitis Fibrosis
In lung disease, why is it important to take an occupational history?
Exposure to irritants
What is DLCO in respiratory function tests?
Diffusing capacity of carbon monoxide
What is usual interstitial pneumonia?
Interstitial lung disease with no underlying cause
- Idiopathic pulmonary fibrosis
- Cryptogenic fibrosing alveolitis
What are the secondary causes of usual interstitial pneumonia?
Drug toxicity
Collagen vascular diseases
Environmental exposures
At what age is usual interstitial pneumonia common?
50-70 years
What are the radiographic features of usual interstitial pneumonia?
Bilateral, symmetrical, irregular linear opacities causing reticular pattern
Honeycombing sub-pleurally
What is interstitial lung disease
Inflammation +/- fibrosis
What is the presentation of interstitial lung disease?
Progressive dyspnoea
Persistent, non-productive cough
What is the pattern in lung function tests of interstitial lung disease?
Restrictive pattern
Reduction of DLCO
Variable hypoxaemia
What is the radiographic appearance of interstitial lung disease?
Reticular/nodular/mixed-patterns
What is the clinical classification of interstitial lung disease?
Drug-induced Environmental and occupational exposure Idiopathic interstitial pneumonias Diffuse alveolar damage Collagen vascular disease IBD Primary/unclassified
How is sarcoidosis diagnosed?
By exclusion
- Radiology
- Lung function test
- Biopsy
What are the causes of bilateral hilar enlargement?
Sarcoidosis
Infection
Lymphoma
Metastatic carcinoma
What is the clinical term for diffuse alveolar damage?
Acute respiratory distress syndrome (ARDS)
What is diffuse alveolar damage?
Acute injury to endothelium and/or alveolar epithelium >
- Oedema
- Cytokines
- Inflammation
What are the causes of diffuse alveolar damage?
Infection Trauma Aspiration Inhalation Injury Drugs Radiation Acute pancreatitis
What is the time course of diffuse alveolar damage?
Rapid onset - within 24-48 hours of precipitating event
What are the clinical features of diffuse alveolar damage?
Respiratory failure
Pulmonary oedema
What are the three phases of diffuse alveolar damage?
Exudative - acute
Organising
Fibrotic - chronic
What are the macroscopic features of diffuse alveolar damage?
Acute - Lungs heavy - Oedematous - Dark red cut surface Organising/chronic - Rubbery firm - Yellow-grey - Fine cysts
What are the microscopic features of diffuse alveolar damage?
Acute - Alveolar spaces show hyaline membranes - Oedema Organising - Pneumocyte hyperplasia - Inflamed interstitium - Reactive fibrosis Chronic - Denser fibrosis - Microscopic cysts
What is honeycomb lung?
Irreversible end-stage manifestation of large number of interstitial, inflammatory, and proliferative lung diseases
What are the causes of pulmonary fibrosis in the upper lobes?
Silicosis Sarcoidosis Coal workers' pneumoconiosis Langerhans' cell histiocytosis Ankylosing spondylitis Allergic bronchopulmonary aspergillosis TB
What are the causes of pulmonary fibrosis in the lower lobes?
Rheumatoid arthritis Asbestosis Scleroderma Idiopathic pulmonary fibrosis Radiation Drugs
What is the difference between transudate and exudate?
Transudate = changes in oncotic pressure > low protein Exudate = change in vascular integrity > high protein
What are the test findings in a transudate pleural effusion?
Low protein
Low specific gravity
Low LDH
Lower cellular and fibrin content
What are the test findings in an exudate pleural effussion?
High protein
High specific gravity
High LDH
High cellular content
What are some causes of transudative pleural effusion?
Increased venous pressure - Cardiac failure - Cirrhosis Hypoproteinaemia - Nephrotic syndrome - Cirrhosis
What are some causes of exudative pleural effusion?
Implies local process Infection Inflammation - Infarction - Trauma - Radiation - Connective tissue disorders - Uraemia Neoplasia
What is a large unilateral pleural effusion (more than one litre) in the elderly highly suspicious of?
Malignancy
Why should pleural effusions be re-tapped if the first tap shows no malignant cells or is inconclusive?
Numbers of neoplastic cells in recurrent effusions often increase
What is the main differential diagnosis of mesothelioma?
Primary lung adenocarcinoma
