L22. Pathology of Lung Infection (Pneumonia) Flashcards
What is pneumonia?
Inflammation of the lung parenchyma (lower respiratory lung inflammation) which is most often due to infectious means
What is acute inflammation? What are the three key events?
A vascular reaction to some form of injury
- Dilation
- Increased vascular permeability
- Infiltration
What is acute inflammation? What are the three key events?
A vascular reaction to some form of injury
- Dilation
- Increased vascular permeability
- Infiltration
What are the major symptoms of pneumonia?
Shortness of breath
Pleuritic chest pain (depending on the type of pneumonia)
Often purulent sputum
If infective: then there is often fever
What are the major symptoms of pneumonia?
Shortness of breath
Pleuritic chest pain (depending on the type of pneumonia)
Often purulent sputum
If infective: then there is often fever
What are the causative organisms and the characteristics of the ‘classic’ pattern of acute inflammation in the lung?
The traditional bacteria (typical)
- aerobic and easy to grow
- S. pneumonia, Klebsiella, P. aeruoginosa, Legionella
What are some atypical organisms that cause an atypical pattern of acute inflammation?
Mycoplasma and some viruses
What are the two patterns of acute bacterial pneumonia?
Acute Bronchopneumonia
Acute Lobar pneumonia
Which pattern of acute pneumonia is most common? Why?
Bronchopneumonia is far more common (causative organisms of the lobar pneumonia have been less effective in the antibiotic era)
Which pattern of acute pneumonia is most common? Why?
Bronchopneumonia is far more common (causative organisms of the lobar pneumonia have been less effective in the antibiotic era)
What is the difference between community acquired pathogens and hospital acquired?
Community acquired tend to be gram positives and normal flora and more susceptible to antibiotics
Hospital acquired tend to be gram negative and resistant to antimicrobials because they are equipped to replicating under the stress of high antibiotic use environments
How is aspiration a cause of pneumonia?
Aspiration of gut contents and secretions and of upper respiratory tract secretions into the throat and into the respiratory tract can occur and cause pneumonia.
- a normal physiological process but more often and problematic for people with altered conscious levels
- important because anaerobic bacteria may be the cause
What is the most important defence against lung infection (especially pnuemonia)?
A fully functional immune system
What are some other compromised lung defense mechanisms? [5]
- loss of a cough reflex ( anaesthesia, NM diseases, etc)
- impairment of mucocilary action
- Accumulation of secretions (CF, bronchial obstruction)
- Interference with phagocytic or bactericidal actoin of alveolar macrophages (alcohol, smoking)
- Pulmonary congestion and oedema
What are some other compromised lung defense mechanisms? [5]
- loss of a cough reflex ( anaesthesia, NM diseases, etc)
- impairment of mucocilary action
- Accumulation of secretions (CF, bronchial obstruction)
- Interference with phagocytic or bactericidal actoin of alveolar macrophages (alcohol, smoking)
- Pulmonary congestion and oedema
What are some predisposing factors to bacterial pneumonia?
Smoking Reduced cough Debility and malnutrition Bronchial obstruction Immune Suppression Hospitalisation Surgery/anesthesia Alcoholism Viral infections (leads to secondary infections)
What are some predisposing factors to bacterial pneumonia?
Smoking Reduced cough Debility and malnutrition Bronchial obstruction Immune Suppression Hospitalisation Surgery/anesthesia Alcoholism Viral infections (leads to secondary infections)
What determines what type of acute bacterial pneumonia is labelled what? (lobar vs. bronco)
The distribution of inflammation
What determines what type of acute bacterial pneumonia is labelled what? (lobar vs. bronco)
The distribution of inflammation
What is the localisation of inflammation of lobar pneumonia? What does this imply about the organism?
Affects the entirety of the lob with NO area spared
- implies the pathogen is highly virulent and the inflammation and oedema is thus spread very rapidly through the whole lobe
What are the most common causes of lobar pneumonia?
Streptococcus pneumonia followed by Haemophilus influenzae
What are the most common causes of lobar pneumonia?
Streptococcus pneumonia followed by Haemophilus influenzae
What are the distinguishing features/symptoms of lobar pneumonia?
The patient is more likely to experience pleuritis (as the inflammation spreads to the pleura) and you hear ‘bronchial breath sounds’ over the area
What is the localisation of inflammation of lobar pneumonia? What does this imply about the organism?
Affects the entirety of the lob with NO area spared
- implies the pathogen is highly virulent and the inflammation and oedema is thus spread very rapidly through the whole lobe
What are the distinguishing features/symptoms of lobar pneumonia?
The patient is more likely to experience pleuritis (as the inflammation spreads to the pleura) and you hear ‘bronchial breath sounds’ over the area