Respiratory pathology Flashcards
Define COPD
progressive airway obstruction which does not change markedly over several months. It is characterised by persistent airflow obstruction which is poorly reversible and usually progressive
define chronic bronchitis
cough productive of sputum for 3 consecutive months for 2 consecutive years which cannot be attributed to other cardiac or pulmonary disease
define emphysema
permanent dilatation of the airways distal to the terminal bronchioles due to the destruction of alveolar walls.
effects of smoking in the airways
bronchi: hyperplasia of mucus-producing glands in the submucosa and hyperplasia of the goblet cells on the surface epithelium causing increased sputum production
chronic inflammation, heals by fibrosis causing stenosis of airways
destruction of the walls of the respiratory bronchioles, with loss of elastic tissue but without significant fibrosis–> airway dilatation–> emphysema
what effect does the destruction of the respiratory bronchiole walls have?
loss of pulmonary surface area for gas exchange leading to hypoxia
loss of the elastic tissue of the terminal airways results in the loss of the natural recoil of the lungs –> airway obstruction
what is an acute exacerbation of COPD?
sudden, sustained worsening in a patient’s symptoms that is beyond their normal day to day variation
most common cause of acute exacerbation of COPD
infection
what are 3 complications of COPD
cor pulmonale
emphysema- loss of pulmonary arterioles and capillaries
chronic hypoxia causes pulmonary arterial vasoconstriction
chronic hypoxia also causes increased EPO leading to increased RBC production and blood viscosity
define pneumonia
inflammation of the lung parenchyma due to an infective agent
characteristics of bronchopneumonia
widespread patchy inflammation centred on the airways- often bilateral
characteristics of lobar pneumonia
diffuse inflammation affecting an entire lobe or lobes
4 types of pneumonia
hospital acquired
community acquired
aspiration
pneumonia in the immunocompromised
what is the main cause of hospital acquired pneumonia
60% gram negative bacteria e.g. E.coli and Pseudomonas
commonest cause of community acquired pneumonia
Strep pneumoniae
2 other important causes of community acquired pneumonia
Legionella
Staph aureus
what is the CURB-65 score?
severity score for community-acquired pneumonia
Confusion Urea >7mmol/L Resp rate >30 BP <90/60 65 years or older
causes of pneumonia in the immunocompromised
pneumocystis Candida Aspergillus M. tuberculosis CMV HSV
what are diffuse parenchymal lung diseases
large group of conditions characterised by inflammation centres on the interstitium of alveolar walls.
pathology of diffuse parenchymal lung disease
lung interstitium becomes expanded by an anti-inflammatory cell infiltrate which impairs gas exchange and causes breathlessness
In some instances the inflammation is followed by repair by scarring; macrophages release fibrogenic cytokines and stimulate fibroblasts in the interstitium to secrete collagen. The thickened walls of the alveoli are ineffective at gas exchange which worsens SOB.
define pneumonitis
inflammation of the lung parenchyma i.e. alveoli
5 causes of diffuse parenchymal lung disease
idiopathic inhaled inorganic/mineral dust extrinsic allergic alveolitis chest radiation drugs e.g bleomycin and amiodarone multisystem disease e.g. SLE, sjorgens
long term consequences of diffuse parenchymal lung disease
pulmonary hypertension
cor pulmonale
4 types of lung cancer
squamous cell carcinoma
adenocarcinoma
small cell carcinoma
large cell carcinoma
RFs for lung cancer
smoking asbestos radiation radon gas genetic factors e.g. EGFR gene mutations
