Suppurative lung diseases Flashcards
What are the similarities between all suppurative lung conditions? (8)
All suppurative ie pus forming
* All essentially complications of lung infections
* All due to bacteria including some unusual ones
* All chronic problems
* All require antibiotics often for prolonged periods
* Therefore, important to try to get representative samples for culture and susceptibility testing
before starting treatment
* Often require physiotherapy to encourage drainage of excess or thick sputum (bronchiectasis
and lung abscess)
* May require surgery to drain pus (lung abscess and empyema)
What is the morphology of bronchiectasis?
Abnormal bronchi and bronchioles - permanently dilated
What is the pathogenesis of bronchiectasis?
due to previous inflammation in surrounding lung tissue resultant scarring or fibrosis
causes dilatation of bronchi. Then ongoing inflammatory changes lead to further damage to airways
What are the symptoms of bronchiectasis?
Chronic cough with copious amounts of sputum production
What are the complications of bronchiectasis?
-Recurrent pneumonia and lung abscess
* Distant spread via blood stream causing abscesses in remote parts of body ‘metastatic abscess’ e.g. brain
* Pulmonary fibrosis
* Cor pulmonale ( right heart failure secondary to lung disease)
* Amyloidosis
Which infections can lead to the development of bronchiectasis?
Severe infections such as TB, measles, pertussis, adenovirus
2. Underlying genetic abnormalities that predispose to severe infections: cystic fibrosis with abnormally thick
secretions that can’t be cleared, immotile cilia, hypogammaglobulinaemia, others
Which genetic condition can predispose to severe infection
cystic fibrosis with abnormally thick secretions that can’t be cleared, immotile cilia, hypogammaglobulinaemia, others
Which microbe is associated with bronchiectasis?
Pseudomonas aeruginosa
What type of bacteria is Pseudomonas aeruginosa?
Gram negative bacilli
Can Pseudomonas aeruginosa infect healthy tissues under normal circumstances?
No, it is an opportunistic pathogen that rarely infects healthy tissues.
If defenses are compromised, it can infect virtually all
tissues in the body leading to a wide variety of infections
How does Pseudomonas aeruginosa affect patients with bronchiectasis and chronic lung damage?
Can cause pneumonia in patients with bronchiectasis
and chronic lung damage
Whar is another term for lung abscess?
Necrotising pneumonia
What happens in lung abscess/necrotising pneumonia?
There is a focal breakdown of lung tissue
What are the symptoms of lung abscess?
Lots of sputum, often smelling bad due to anaerobes
How is a lung abscess diagnosed?
CXR: air-fluid level classic finding
Explain different ways in which a lung abscess can develop. (4)
- As a result of severe lung infection - S. aureus is notorious for causing breakdown of lung tissue
- As a consequence of a blockage of a local area of lung (e.g by a tumor or foreign body) leading to unresolving infection.
- Occasionally from haematogenous/blood borne spread
- Most commonly as a complication of aspiration pneumonia ( Aspiration of fluid or food into lung causing inflammation, sometimes termed ‘macro
aspiration’)
Which patients are at risk of developing aspiration pneumonia?
Patients at risk : sedated or with reduced level of consciousness or swallowing problems
Which organisms cause lung abscess?
Anaerobes
S. aureus
Typical respiratory bacteria
-Often polymicrobial – more than one microorganism present
How do anaerobes cause lung abscess? How do they end up in the lung?
Anaerobes are commonly associated with aspiration pneumonia- come from the mouth. They enter the lung through aspiration
How does S. aureus cause lung abscess? How does it end up in the lung?
-Staphylococcus aureus can be acquired via respiratory tract, especially after preceding viral
infection
* Can also be result of haematogenous spread when there can be multiple
lung abscesses
What is Haemothorax? what causes it?
It is a collection of blood in the pleural cavity, caused by trauma or raptured aortic aneurysm
What is transudate hydrothorax? What causes it?
It is a collection of low protein fluid in the pleural cavity. Caused by Liver failure; cardiac failure; renal failure
What is exudate hydrothorax? What causes it?
It is a collection of low protein fluid in the pleural cavity. Caused by Tumours; infection; inflammation
What is Chylothorax? what causes it?
Collection of lymph in the pleural cavity, caused by Neoplastic obstruction of thoracic lymphatics
What is a pneumothorax, what causes it?
It is a collection of air in the pleural cavity. It can be Spontaneous, following rupture of alveolus or bulla in emphysema or tuberculosis. Or it can be traumatic, e.g. following penetrating
injuries of the chest
What is pyothorax? what causes it?
It is a collection of pus in the pleural cavity. Caused by infection.
What is pleural effusion? What is its common cause?
Pleural effusion:
* fluid in pleural space
* Common in bacterial pneumonia if infection involves pleura
* Often fairly small and resolve spontaneously
What is pleural empyema? What causes it?
Pleural empyema:
* Pus in pleural space
* Occurs if pleural effusion becomes more purulent, e.g. S. aureus infection can cause pus
* Or if get secondary infection of other fluid, e.g. Infected haemothorax
How is pleural empyema treated?
Need some form of drainage to remove pus plus antibiotics
What happens if the pleural empyema is left untreated?
Untreated - ongoing infection, lung unable to expand and gets stuck down permanently by
scar tissue/fibrosis.
