Lectures Flashcards
What is Sarcoidosis
Granulomatous disease affecting mainly the lungs, but also lymph nodes in a greater frequency
What is Kveim test
subcutaneous injection of sterile homogenised sarcoid tissue induces granulomas in affected patients
What is asbestos
Inconsumable silicate
What is asbestosis
Diffuse pulmonary fibrosis
What can result from asbestos
Diffuse pleural fibrosis, persistent pleural effusion, plaque, lung cancer, mesothelioma
What are silicates
inorganic minerals abundant in stone and sand
What is the effect of silicates on macrophages (silicosis)
2μm fibres toxic to macrophages, leading to their death with release of proteolytic enzymes
Pathophysiology of silicosis
Silicates are 2μm fibres toxic to macrophages, leading to their death with release of proteolytic enzymes
Tissue destruction and fibrosis
Nodules are formed after many years of exposure -> Interstitial fibrosis
Raised incidence of TB
What is pneumocosis
Lung disease caused by inhaled dust
Types of pneumocosis reactions/Different ways in which lung can respond to dust exposure
Inert
Fibrous
Allergic
Neoplastic
Examples of pneumocosis: Inert Fibrous Allergic Neoplastic
Inert: coal worker’s pneumoconiosis
Fibrous: progressive massive fibrosis, asbestosis and silicosis
Allergic: extrinsic allergic alveolitis
Neoplastic: mesothelioma, lung cancer
Examples of Coal Workers pneumocosis
Progressive massive fibrosis (PMF)
Emphysema
Honeycomb lung and /or cor pulmonale are the terminal conditions
Caplan’s syndrome (Rh’ Arthritis association)
What is antracosis
the presence of coal dust pigment in the lung
Describe Macular CWP (Coal Workers pneumocosis)
aggregates of dust laden macrophages with no significant scarring
Describe Nodular CWP (Coal Workers pneumocosis)
nodules >10mm in a background of extensive macular CWP, with no significant scarring
What regions of the lung are predominantly affected by fibrosing alveolitis
Subpleural regions
Describe histology of (end-stage) fibrosing alveolitis
Abnormally large irregular spaces separated by thick fibrous septa (Honeycomb Lung*)
Complications of fibrosing alveolitis
Cor pulmonale
End-stage fibrosis (honeycomb lung)
Systemic presentation of fibrosing alveolitis
Finger and toe-clubbing
Result of cytotoxic drugs on the lung
e.g. Busulphan, Bleomycin
Lead to low grade alveolitis with healing interstitial fibrosis
What is Paraquat
Potent herbicide
Acts by release of hydrogen peroxide and the superoxide free radical. It remains in high concentrations in the lungs after ingestion.
Pathophysiology of Adult Respiratory Distress Syndrome (ARDS) and result of damage to hyaline membranes
Diffuse alveolar damage with hyaline membranes
Severe injury to alveolar-capillary walls leads to acute respiratory distress with tachypnoea, dyspnoea, pulmonary oedema and arterial hypoxaemia refractory to O2 therapy
Examples of Acute Interstitial diseases
Adult respiratory distress syndrome Drug and toxin reactions Gastric aspiration Radiation pneumonitis Diffuse intrapulmonary haemorrhage
Describe pathophysiology of interstitial lung diseases and effect of FEV1 etc
Increased amount of lung tissue
Increased stiffness and decreased compliance
Restrictive lung defect of the pulmonary function
Reduced Tco, VC, FEV1
Relatively normal FEV1/FVC ratio and PEFR
What is Bronchiectasis
The permenant dilation of bronchi and bronchioles
Cause of bronchiectasis
Obstruction:
Results from bronchial obstruction with distal infection and scarring or severe infection alone -> may go on to further tissue damage and loss of lung tissue
Severe inflammation:
During acute exacerbations
What lobes of lung are usually affected by bronchiectasis
Usually the lower lobes
Symptoms of bronchiectasis
chronic cough with expectoration of large quantities of foul-smelling sputum, flecked with blood sometimes
Pathophysiology of bronchioectasis
Describe types of bronchioles that can result
Destruction of bronchial and alveolar walls, especially interstitial elastin and fibrosis of lung parenchyma (non-reversible)
Dilatation of the airways (bronchi and bronchioles) as the surrounding scarring fibrosis contracts
Inflammation during acute exacerbations
Inflammation and fibrosis extend into adjacent lung tissue
Cylindrical, saccular or fusiform bronchioles
Complications of Bronchiectasis
Pneumonia Fungal colonisation Emphysema Septicaemia Meningitis Metastatic abscesses (e.g. brain, heart) Amyloid formation
Further necrosis and destruction of lung tissue can lead to pulmonary fibrosis
Cor pulmonale
What is emphysema
Enlargement of alveolar airspaces with destruction of elastin in walls
Frequently associated with chronic bronchitis
Main cause of emphysema
Cigarette smoking
Other causes of emphysema (not cigarette smoking)
alpha-1-antitrypsin deficiency,
coal dust exposure,
cadmium toxicity
Pathophysiology of emphysema
Gas trapping effect from emphysema - prevents full exhalation of air, particularly if large bullae
Pathogenesis probably revolves around recruitment of neutrophils in response to free oxygen radicals with release of IL8, LTB4 and TNF.
Also released are destructive enzymes e.g. neutrophil elastase.
Tissue damage results
True of False:
Emphysema causes an increased risk of cancer
False (apparently)
Emphysema does cause tho:
Pulmonary hypertension
Poor oxygen delivery to tissues
What % of lung capacity is destroyed in emphysema before symptoms appear
1/3
Clinical features of emphysema
Weight loss due to metabolic demands ++
Right heart failure
Overinflated chest
Poor oxygen delivery to tissues
‘pure’ emphysema appears with reduced PaCO2 and normal PaO2 at rest due to overventillation (‘pink puffers’)
What can acute localised obstruction progress to?
(Chronic localised obstruction)
Bronchiectasis
Describe asthma
Increased irritability of bronchi causing spasm
Overdistended lungs
Mucus plugs in bronchi
Enlarged bronchial mucous glands with excess secretions
Clinical categories of asthma
Extrinsic
Intrinsic
Subtypes of extrinsic asthma
Atopic
Occupational
Allergic bronchopulmonary aspergillosis
What type of hypersensitivity is atopic asthma
Type 1 (IgE)
What type of hypersensitivity is occupational asthma
Type 3
Causes of intrinsic asthma
Aspirin Cold Infection Stress Exercise Sulfur dioxide Pollutants etc (induced)
Aetiology and risk factors of extrinsic asthma
Environmental agents like dust, pollens, foods, animal dust etc
Family history often present
Other atopic disorders except asthma
Eczema
Hay-fever
Asthma pathogenesis
Bronchial obstruction with distal overinflation or atelectasis
Mucus plugging of bronchi
Bronchial inflammation (mixed)
Seromucinous gland hypertrophy
Bronchial wall smooth muscle hypertrophy
Thickening of bronchial basement membrane
Chemicals involved in asthma pathogenesis
Leukotrienes C4, D4, E4
Prostaglandins D2, E2, F2a
PAF
Mast cell tryptase
Describe intrinsic asthma
Associated with recurrent chest infections
Chronic bronchitis
Not immune-mediated
Possibly unusually hyper-reactive airways
What type of asthma is associated with recurrent chest infections
Intrinsic asthma
Describe aetiology/pathology of aspirin-induced asthma
Unknown mechanism
Possibly increased locally leukotrienes or decreased prostaglandins
Usually associated with recurrent rhinitis with nasal polyps
Skin urticaria
Allergic bronchopulmonary aspergillosis causative organism
Aspergillus fumigatus
Describe Allergic bronchopulmonary aspergillosis
Induces both immediate type I reaction
And delayed immune complex type III hypersensitivity reaction
What type of hypersensitivity is occupational asthma
Type 1 and 3
Describe aetiology of occupational asthma
Work-associated inhaled agent
This acts either as non-specific stimulus precipitating asthma in people with hypersensitive airways or capable of inducing airway hyper-reactivity
