Respiratory pathology Flashcards
How can non-neoplastic lung diseases be split?
- Airway disease
- asthma
- COPD
- bronchiectasis
- Parenchymal disease
- Pulmonary vascular disease
How would you define asthma?
Chronic inflammatory airway disorder with recurrent episodes of widespread narrowing of the airways which change in severity over short periods of time
What are causes and associations of asthma?
- Allergens
- Pollution
- Drugs - NSAIDs
- Occupational (gases/fumes)
What are the phases of asthma?
- Sensitisation
- > The allergen binds to the surface of the bronchial epithelial dendritic cells which present the antigen to the underlying T Cell. This triggers a cytokine reaction - Immediate phase
- > Mast Cells degranulate on contact leading to vascular permeability, eosinophil and mast cell recruitment and bronchospasm - Late phase
Chronic antigenic stimulation results in
- Tissue damage
- Increased mucus production
- Muscle Hypertrophy
What are the clinical features of a patient with asthma?
- > SOB
- > Wheeze
- > Severe - Status Asthmaticus
Define COPD
Chronic cough productive of sputum
-> Most days for at least 3 months over 2 consecutive years
What are causes of COPD?
- > Smoking (80%)
- > Air Pollution
- > Occupational Exposure
chronic injury elicits local inflammation and reactive changes which predispose to further damage
What are the complications of COPD?
- > Repeated Infections
- > Chronic Respiratory Failure
- > Pulmonary Hypertension and RHF (as a result of chronic hypoxia)
- > Increased risk of lung cancer
Define bronchiectasis
Permanent abnormal dilatation of bronchi with inflammation and fibrosis extending into the adjacent parenchyma
What are causes of bronchiectasis?
- > Post Infectious (i.e. CF*)
- > Ciliary Dyskinesia
- > Obstruction
- > Post-Inflammatory (i.e. Foreign Body)
- > Systemic Disorders
- > Asthma
What are complications of bronchiectasis?
- > Recurrent Infections
- > Haemoptysis
- > Pulmonary Hypertension
- > RHF
- > Amyloidosis
What is cystic fibrosis?
- > Abnormality which leads to defective ion transport and therefore excessive resorption of water from secretions.
- > This leads to abnormally thick mucous secretions.
What are complications of CF?
Lung = airway bstruction, resp failure, infections
GI tract = meconium ileus, malabsorption
Pancreas = pancreatitis, secondary malabsorption
Liver = cirrhosis
Male reproductive system = Infertility
What is pulmonary oedema?
Accumulation of fluid in alveolar spaces as consequence of leaky capillaries / back pressure from failing LH.
What are causes of pulmonary oedema?
- > LHF
- > Alveolar Injury
- > Neurogenic
- > High altitude
What is Diffuse Alveolar Damage?
- > A pattern of diffuse lung injury in which patients present with raid onset of respiratory failure, requiring ITU Ventilation.
- > CXR shows “white out” of all lung fields
What causes Diffuse Alveolar Damage?
-> Acute damage to endothelium and/or alveolar epithelium leading to exudative inflammatory reaction
Adults = ARDS
Neonates = Hyaline Membrane Disease of the Newborn
What are common causes of lung infections?
- > Bacterial* i.e. mycobacteria
- > Viral
- > Mycoplasma
- > Fungal&PArasitic
What is bronchopneumonia vs lobar pneumonia?
- broncho = Centered around bronchi and bronchioles, spotty pattern
- Lobar = alveolar spaces diffusely, massive consolidation
What are the stages of lobar penumonia?
- Congestion
- Red hepatization
- Grey hepatization
- Resolution
What are complications of pneumonia?
- > Abscess formation
- > Pleuritis and pleural effusion
- > Infected pleural effusion o.e. EMPYEMA
- > Fibrous scarring
- > Septicaemia
What is emphysema?
-> Emphysema is the permanent loss of alveolar parenchyma distal to the terminal bronchiole
What are causes of emphysema?
- > Smoking
- > Alpha 1 Anti Trypsin
- > Rare i.e. IVDU, Connective Tissue Disease
How does smoking cause emphysema?
- Smoke activates neutrophils and macrophages
- They release proteases that cause tissue damage.
- Alpha 1 Antitrypsin (responsible for neutralising proteases) are also inhibited by smoke
What are complications of emphysema?
- > Formation of bullae
- > Respiratory Failure (loss of area for gas exchange)
- > Pulmonary Hypertension and thus RHF
What are Granulomatous Diseases?
- > Collection of histiocytes/macrophaes +/- multinucleate giants cells
- > Can be both necrotising/non-necrotising.
What are causes of granulomatous diseases?
Infectious
- > TB
- > Fungi
- > Parasites
Non-Infectious
- > Sarcoidosis
- > Foreign Body (Aspiration/IVDU)
- > Drugs
- > Occupational
What is Fibrosing ILD?
Chronic and progressive fibrosing diseases of lung
What are causes of Fibrosing ILD?
i) Idiopathic Pulmonary Fibrosis
ii) Asbestosis
What is Pulmonary Thromboembolism?
Embolization of peripheral thrombi to the lung, 95% of which form in the deep veins of the leg
What are risk factors for Pulmonary Thromboembolism?
- > Advanced age
- > Female sex
- > Obesity
- > Immobility
- > Cardiac Failure
- > Malignancy
- > Trauma
- > Surgery
- > Childbirth
- > Haemoconcentration
- > Polycythaemia
- > DIC
- > Contraceptive Pill
- > Cannulation
- > Antiphospholipid Syndrome
What does the severity of the Pulmonary Thromboembolism depend on?
The size on the emboli
Small = pleuretic pain, SOB
Large = sudden death, RHF
What are non thrombotic causes of Pulmonary embolism?
- > Bone Marrow i.e. post fracture
- > Amniotic Fluid
- > Trophoblast
- > Tumour
- > Foreign Body
- > Air
Define pulmonary hypertension
Mean pulmonary arterial pressure >25mmHg at rest.
What is the commonest cause of malignant lung tumours?
Non small cell Adenocarcinoma
What is the main risk factor for epithelial lung cancers?
SMOKING
How are Squamous Cell Carcinomas caused?
- Repeated injury from cigarette smoke changes normal epithelium to tougher squamous type.
- Continued smoking causes mutations in these squamous cells
What is the commonest cause of cancer in non smokers?
adenocarcinoma
Where are adenocarcinomas commonly found?
In the peripheries
Define Large Cell Carcinoma
These are poorly differentiated tumours that show no histological evidence of glandular or squamous differentiation i.e. Adenocarcinoma or Squamous Cell Carcinoma.
-> Poor Prognosis
Which type of lung cancer has the worst prognosis?
Small cell carcinoma
Which hormone is associated with small cell carcinoma?
ASSOCIATED WITH ECTOPIC ACTH RELEASE
Why is it important to sub type lung cancers?
Enables you to use targeted therapies depending on the mutations present
How are lung cancers classified?
- Non small cell
- Squamous cell
- Adenocarcinoma
- Large cell carcinoma - Small cell carcinoma
