Pathology of Pulmonary Infection Flashcards
what are the 2 factors which influence lung infections?
- micro-organism pathogenicity
- capability of organism to resist infection
what different categories of micro-organism are there?
- primary
- facultative
- opportunistic
what does infection depend on ?
pathogenicity of pathogen
is the URT/LRT sterile/non sterile?
URT- non sterile
LRT- sterile
what are common URT infections and what is the main pathology of them? (6)
-Coryza (common cold)
-sore throat syndrome
-sinusitis
-laryngitis
-acute epiglottitis
-acute laryngotracheobronchitis (croup)
main pathology = inflammation
what is acute epiglottitis?
inflammation of the epiglottis & of the tissues surrounding the epiglottis- leads to swelling of the epiglottis and obstruction of airways
what micro-organisms cause acute epiglottitis?
- Group A alpha haemolytic Streptococci
- Haemophilus Influenzae
what are 3 LRTI?
- bronchitis
- bronchioitis
- pneumonia
What are the 4 main respiratory tract defence mechanisms ?
- macrophage mucociliary escalator system
- general immune system- humeral and cellular
- respiratory tract secretions
- URT as a filter (nose catches particles)
- -> failure in any of these systems increases risk of respiratory tract infection
what is the surface of the URT like?
it is moist and lined with respiratory epithelium
what are 2 factors which play an important function in the mucociliary escalator?
- humidity
- temperature of air
what is the mucociliary escalator composed of and what does it do?
- alveolar macrophages
- mucociliary escalator
- cough reflex
it clears particles from the lungs
how does the mucociliary escalator work?
cilia from ciliated cells lines the respiratory epithelium and transports layer of mucous out of the lungs - they beat in a coordinated fashion so as to move the mucous upwards and out of the lungs
We then swallow most of what is removed from lungs from mucociliary escalator
This system is used by alveolar macrophages - when they encounter foreign material they phagocytose it
What is an alternative pathway for macrophages containing phagocytosed material to use apart from the mucociliary escalator?
pass alveolar wall and get into interstitial lymphatic system where they travel into regional lymph nodes & exit lungs that way
what happens to the mucociliary escalator in viral infections?
it fails
what can happen in severe/ very severe infections cilia function ?
cilia function becomes abnormal/ cilia is stripped off completely
what is pneumonia?
It is an inflammatory condition of the lung primarily affecting the lung tissue (alveoli)
what are the 3 classifications of pneumonia?
- Anatomical: from radiology
- Microbiological: state cause of pneumonia according to a specific organism causing it
- Aetiological: predict likely circumstance that caused it
what are some aetiological categories of pneumonia?
- community acquired pneumonia
- hospital acquired pneumonia ; likely to be a lot more aggressive
- pneumonia in immunocompromised
- atypical pneumonia; unusual infectious agents
- aspiration pneumonia; result of inhalation of gastric contents /food material from vomit
- recurrent pneumonia
What are the different patters of pneumonia?
- Bronchopneumonia
- Segmental
- Lobar
- Hypostatic
- Aspiration
what ties segmental and lobar pneumonia in common?
a whole anatomical area of the lung is involved in infection
what is hypostatic pneumonia?
Where a patient has an accumulation of fluid and secretion in the lung, usually due to bronchitis / pulmonary oedema due to cardiac failure
Most often occurs to people who are confined to supine position for long periods aka elderly, due to gravity
what is aspiration pneumonia?
Inhalation of vomit into LRT- goes into right main bronchus and if lying flat, then into apical segment of right lower lobe (most common place where aspiration pneumonia is seen)
How may bronchopneumonia come about ?
If acute exacerbation of chronic bronchitis - will have bronchopneumonia
