Pathology of Pulmonary Infection Flashcards
What are micro-organisms three pathways of pathogenicity
Primary - infectious on their own
Facultative - Need additional help to infect
Opportunistic - Hit you when your immune system is low
What does your capacity to resists infection depend on
state of the hosts defence mechanism
Age of the host (new born and elderly most at risk)
Is the Upper respiratory tract Sterile or not?
Not sterile
What are examples of URT infections
Crazy- common cold Sore throat syndrome Acute Laryngotracheobronchitis (Croup) - swelling of windpipe Laryngitis Sinusitis Acute Epiglottitis
Is the lower respiratory tract sterile or non sterile
Sterile
What are examples of LRT infections
Bronchitis
Bronchiectasis
Pneumonia
What are upper respiratory tract defence mechanisms
The nose acts as a filter
URT is moist anf lined with cilla
Allows large particle deposition
What is the lower respiratory tract defence mechanism
Macrophage-mucociliary escalator system
What are the three mechanism of the Macrophage-mucociliary escalator system
and over all function
ALVEOLAR MACROPHAGES
MUCOCILIARY ESCALATOR
COUGH REFLEX
beat in a corrdianted fashion to move the alveolar macrophages and mucous up and out of the lungs
What is the alternative pathway of the alveolar macrophages
Rather than moving up the throat they can leave the throat wall and enter the interstitial pathway via lymph tp the lymph nodes
What is the effect of viral infection e.g. influenza on the
Macrophage-mucociliary escalator system
Can destroy epithelium so no longer has cilla
What are you more likely in catching if virus infection destroys epithelium
Bacterial infection
What are the 6 different aetiologies of pneumonia
Community Acquired Pneumonia Hospital Acquired (Nosocomial) Pneumonia Pneumonia in the Immunocompromised Atypical Pneumonia Aspiration Pneumonia Recurrent Pneumonia
How does atypical pneumonia occur
the infection is caused by different bacteria than the ones that cause typical pneumonia
How does Aspiration Pneumonia occur
lung infection that develops after you aspirate (inhale) food, liquid, or vomit into your lungs
Define recurrent Pneumonia
Pneumonia that reoccurs more than twice in a year
What is the different patterns of pneumonia
Bronchopneumonia - bronchioles
Segmental - parts of the lungs
Lobar - whole lobe
What is the complications with pneumonia?
Pleurisy - inflammation of pleura
Emphysema - a condition in which the air sacs of the lungs are damaged and enlarged, causing breathlessness.
Lung abscess
Fibrous organisation resulting constrictive bronchiolitis or mass lesion
Bronchiectasis
cryptogenic organising pneumonia
What is cryptogenic organising pneumonia
is a form of non-infectious pneumonia that is an inflammation of the bronchioles (bronchiolitis) and surrounding tissue in the lungs.
What is Bronchiectasis
abnormal widening of the bronchi or their branches, causing a risk of infection
As the damaged dilated airways have thickened airway wall and increased mucus production
What is the causes of lung abscess
Obstructed Bronchus: tumour or foreign body
Pneumonia Aspiration
Particular Microorganism (Staph aureus, some pneumococci, Klebsiella)
Metastatic in Pyaemia - Pus in the blood
Necrotic Lung
What is the potential causes for Bronchiectasis
Sever or repetitive infections
Lung tissue destruction
Bronchial obstruction
Symptoms of bronchiectasis
Daily Cough Daily copious purulent sputum production (> 2 tsps/day) Occasional haemoptysis Chest Infections frequent
What are the signs for bronchiectasis
Finger clubbing, lung crackles on inspiration & expiration
What are the causes of pneumonia aspiration
Vomiting Oesophageal Lesion Obstetric Anaesthesia Neuromuscular Disorders Sedation
Where is aspiration pneumonia most likely to occur
Right bronchus (where objects are most likely to get lodged due to the angle)
What is the treatment options for bronchiectasis
Antibiotics
Surgery - possible if localised
Postural Drainage
How does empyema occur in pneumonia
In pneumonia, acollection of fluid may form between the two pleural layers occasionally, microorganisms will infect this fluid
Beyond bronchiole terminal how does air move
By diffusion
What is hypostatic pneumonia
patients has lots of accumulation of fluid in the lung
What is the cause of hypostatic pneumonia
chronic bronchitis
pulmonary odema
Is there any air in lobar pneumonia?
No
What is the normal alveolar partial pressure for pulmonary gas exchange
Normal PaO2 10.5 – 13.5 kPa
Normal PaCO2 4.8 – 6.0 kPa
What does airflow across the alveoli to the blood depend on
The blood air pressure difference
What are the four abnormal states associated with Hypoxiemia
Ventilation / Perfusion imbalance - V/Q
Diffusion impairment
Alveolar Hypoventilation
Shunt
What do all vessels do if there is arterial hypoxemia and why do they do this
Constrict
Protective mechanism not to send blood to alveoli short of oxygen
What is the two respiratory failures
Type 1 Pa Oxygen decrease below 8Kpa
Type 2 Pa CO2 increases above 6KPa
What two abnormal states causes hypoxemia in broncho/lobarpneumonia + bronchitis
bronchopneumonia + bronchitis
- Ventilation / Perfusion abnormality (mismatch)
Severe bronchopneumonia and lobar pneumonia
- Shunt
How do you decreases hypoxemia in pneumonia due to ventilation perfusion mismatch
Increase oxygen levels
What is not an issue in Ventilation / Perfusion abnormality (mismatch)
CO2 retention
In a shunt how does it respond to an increase in oxygen
poorly
Is ventilation occurring in Ventilation / Perfusion abnormality (mismatch) or shunts?
V/Q - Yes, some
Shunt - No
What causes the type 2 respiratory failure when Pa CO2 to high
alveolar hypoventilation
Why does a pulmonary shunt not respond to an increase in oxygen
as is doesn’t contact ventilated alveoli
How does alveolar hypoventilation increase ventilation drive
cant move air out of the lungs, this increase PCO2 therefore decrease PO2, resulting in an increase in ventilation drive to increase inspired oxygen
What is Chronic (Hypoxic) Cor Pulmonale
Hypertrophy of the Right Ventricle resulting from disease affecting the function and/or the structure of the lung,
What is the effect of Cor Pulmonale
Pulmonary vasoconstriction
Loss of capillary bed
Secondary polycythaemia - increase in RBC
Why does pathological large shunts respond poorly to increased oxygen
as the blood leaving the lung is already 98% saturated
a shunt only affect 2-4% of the blood
