pathology of lung disease Flashcards
which cells in the lungs make mucus
goblet cells
what epithelium is found in the lungs
pseudostratified ciliated columnar epithelium
whats the difference between type 1 and 2 pneumocytes
type 1 are flattened and make up 95% of the alveolar surface. type 2 are rounded and make surfactant.
define FEV1
- Forced expiratory volume in 1 sec. the volume that can be forcibly exhaled in the first second of forced expiration.
define FVC
forced vital capacity. the maximum volume of air that can be forcibly exhaled out of the lung until no more can be expired.
whats the lung TLC
total lung capacity.
whats the lung PEFR
peak expiratory flow rate. max flow achieved during forced expiration.
6 causes of obstructive lung disease
acute - foreign bodies, bronchiolitis
recurrent acute - asthma
chronic - chronic brochitis, emphysema, bronchiectasis.
define chronic bronchitis
chronic sputum production usually accompanied by chronic cough, occuring on most days for three months of the year, for 2 or more consecutive years.
pathogenesis of chronic bronchitis
1 - chronic irritation eg cigarrette smoke or air pollution
2 - mucus hypersecretion to protect, submucosal gland hypertrophy and hyperplasia in the larger airways, increased numbers of goblet cells in small airways.
3 -damage and death of ciliated cells (reduced mucociliary action), secondary infection, inflammation and fibrosis.
- partially reversible on stopping smoking.
what is cor pulmonale
Pulmonary heart disease (New Latin pulmōnāle, of the lungs), also known as Cor pulmonale (Latin cor, heart + of the lungs) is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance or high blood pressure in the lungs (pulmonary hypertension).
what is emphysema
Definition is Pathological:
An abnormal permanent increase in the size of air spaces beyond the terminal bronchioles with destruction of their walls but without fibrosis
In a highly compliant lung, as in emphysema, the elastic tissue is damaged by enzymes. These enzymes are secreted by leukocytes (white blood cells) in response to a variety of inhaled irritants, such as cigarette smoke. Patients with emphysema have a very high lung compliance due to the poor elastic recoil, they have no problem inflating the lungs but have extreme difficulty exhaling air. In this condition extra work is required to get air out of the lungs. Compliance also increases with increasing age.
what are the subclassificatiojns of emphysema
---Centriacinar (centrilobular) > common -cigarette smoking -chronic bronchitis -upper zones of lung -secondary to airway inflammation (increased protease activity)
—-Panacinar (panlobular)
-α1 – antitrypsin deficiency
(decreased anti-protease activity)
-lower zones of lung
-Homozygotes (PiZZ) onset <40 yrs
-Heterozygotes must smoke
histopath appearance of end stage empysema
End-stage
emphysema has
cystic alveolar spaces
visible macroscopically
- alevoli are dilated and their boundaries broken.
Lung Function Tests n empysema
Reduced FEV1 to <0.7)
Reduced PEF
Increased TLC
Also reduced diffusion capacity
loss of the elastic recoil causes premature closure of the small airways (decreased radial traction causes collapse).
what is COPD
Chronic obstructive pulmonary disease
Defined by lung function tests
Combination of bronchitis & emphysema
Secondary to smoking
Most have mixture of symptoms
‘Pure’ disease at each end of spectrum
COPD Treatment and Prognosis
Prevention & supportive therapy
Stop smoking
Oxygen therapy if hypoxic Pulmonary rehabilitation (exercise & education programme for patients to increase mobility, understand their disease, cope with their breathlessness by pacing their activities, improve anxiety and depression)
5-10% of all deaths in UK
COPD complications
Pneumonia
Respiratory failure
Pulmonary hypertension
Cor pulmonale
Polycythaemia
Pneumothorax
asthma definition, hallmarks and incidence.
Definition is largely clinical:
Paroxysmal wheezing and shortness of breath caused by acute, reversible narrowing of airways
Hallmarks:
hyper-reactive airways
inflammation (bronchial walls)
increased mucus secretion
Affects 8% of the population and incidence increasing
subclassification of asthma
Extrinsic (Immune) Atopic (allergic) asthma Occupational asthma Drug-induced asthma Allergic bronchopulmonary aspergillosis Non-atopic asthma
Intrinsic (Non-immune)
what is atopic asthma
Most common type of asthma Type I hypersensitivity reaction Environmental antigens Dust, Pollen, Animal dander, Food M >F, childhood onset Family history of atopy Gene as yet unknown Skin test positive - ‘Wheal & flare’
what is intrinsic asthma
2nd most common type of asthma Hyper-irritability of airways Triggered by diverse, non-immune mechanisms pollution, viral infection etc F>M, adult-onset No family history or other atopy IgE levels normal Skin test negative
WHAT IS Occupational asthma
Type I & III hypersensitivity
Various inhaled agents:
Formalin, Plastics, Wood, Platinum
what is Drug-induced asthma
Aspirin
Also have nasal polyps & skin urticaria
what is Allergic bronchopulmonary aspergillosis
Type I & III hypersensitivity
Inhalation of aspergillus spores
3 stages of asthma
Priming or Sensitization (1st exposure) Th2 response IgE production Eosinophil recruitment
Re-exposure
Immediate Mast cell degranulation Bronchospasm vascular permeability Oedema
Late
Eosinophils & Inflammation
Epithelial damage
Airway constriction
how is the airway obstructed in asthma
Acute response - immediate
Smooth muscle spasm
Mucosal oedema
Late phase reaction – 12-24 hours
Epithelial damage and inflammation
Mucous exudation
Chronic Phase – with repetition
Mucous gland hyperplasia
Smooth muscle hypertrophy
Bronchial BM thickening
generic treatment of asthma
Inhaled steroids (mainstay of treatment)
Bronchodilators (symptom relief)
Avoidance of allergen
+ systemic steroids for acute exacerbations
complications of asthma
Status asthmaticus
Pneumonia
Bronchiectasis
Cor pulmonale
define bronchiectasis
Permanent dilation of bronchi and bronchioles caused by destruction of the muscle and elastic tissue, resulting from or associated with chronic necrotizing infections.
3 causes of bronchiectasis
Congenital or hereditary conditions
Postinfection
Bronchial obstruction
morphology of the lungs with bronchiectasis
Usually affects the lower lobes bilaterally
Bronchial dilatation
Most severe in distal bronchi and bronchioles
Spectrum of histological changes varies with the activity and chronicity of the disease Inflammation Ulceration Necrosis Fibrosis (bronchiolitis obliterans)
Superimposed infection
complications of bronchiectasis
Respiratory insufficiency
Cor pulmonale
Brain abscess
Amyloidosis
what are interstitial lung diseases?
A heterogenous group of diseases
Mostly immune mediated
Share interstitial inflammation & fibrosis
CXR shows an bilateral infiltrative pattern
small nodules, irregular lines or ground-glass shadows
Restrictive pattern on lung function tests
reduced lung compliancy and gas exchange
8 causes/associations of interstitial lung diseases
Pneumoconioses Systemic CT (auto-immune) diseases Sarcoidosis Post radiation or chemotherapy Post ARDS Idiopathic pulmonary fibrosis Wegener’s granulomatosus Goodpasture’s Syndrome
what is pneumoconosis
Term originally for inorganic particles only
Now also includes organic particles & chemical fumes
Inorganic particles cause direct interstitial fibrosis
Organic particles cause inflammation then fibrosis
Fumes cause ARDS then fibrosis
Organic particles & fumes can also cause asthma
what is inorganic pneumoconiosis
Coal dust: Anthracosis
Silica: Silicosis
Asbestos: Asbestosis
Often clinically insignificant
Progressive massive fibrosis when significant respiratory compromise
Most common with coal & silica
Caplan’s syndrome if associated RA
Nodules of fibrosis and chronic inflammation in interstitium
what is organic pneumoconiosis
Farmer’s lung: Actinomycetes in mouldy hay
Bird fancier’s lung: Animal proteins from faeces
aka extrinsic allergic alveolitis aka hypersensitivity pneumonitis Sensitisation to organic inhaled antigen Initial type III hypersensitivity reaction Later type IV hypersensitivity reaction
Interstitial inflammation by lymphocytes & often also
granulomas, then later fibrosis
what is sarcoidosis
Systemic disease of unknown aetiology F>M, Black>>White>>Asian Probable response to antigen Activated T-cells & macrophages Hilar LN or lung involvement in 90% Skin, LN & kidney involvement common Raised serum ACE & often high calcium
Non-necrotising granulomatous inflammation
what is idiopathic pulmonary fibrosis
aka cryptogenic fibrosing alveolitis aka usual interstitial pneumonitis aka Hamman-Rich syndrome when rapidly progressive M>F, 60+ years Interstitial pneumonitis & fibrosis Cause unknown
Extensive interstitial fibrosis with alveolar distortion and interstitial expansion
what happens in the end stage of interstitial fibrosis?
End stage ‘honeycomb’ lung:
Interstitial fibrosis leading to cystic air-spaces
cystic air spaces are smaller than those seen in bronchiectasis but far far more frequent. literally like a honeycomb.
complications of pulmonary fibrosis
Respiratory failure
Pulmonary hypertension
Cor pulmonale
treatment of interstitial lung diseases
Pneumoconiosis:
Stop exposure to stop progression
Any damage irreversible
Other interstitial lung diseases:
Steroid or further immunosuppression
Response variable
Often progress to significant fibrosis
