S8 L2 Pneumonia and LRTI

Question 1

Are lungs sterile?

Answer 1

Question 2

Lung Microbiota

What can cause dysregulation? (in an infection)

Answer 2

Pathogen
Host factors
Drugs

Question 3

Host factors affecting infection…

Answer 3

Question 4

Drugs affecting infection…

Answer 4

Question 5

Defences of the Respiratory System

How can these defences become compromised?

Answer 5

The respiratory tract has many in-built defences to infection. These include:

• Muco-ciliary clearance mechanisms – nasal hairs and ciliated columnar epithelium that line the respiratory tract.
• Expulsion mechanisms – coughing and sneezing.
• Respiratory mucosal immune system.
• Alveolar microbiota

However, there are also many ways these defences can become compromised, including having a poor swallow (usually due to muscle weakness), abnormal ciliary function (seen in people who smoke, and patients with cystic fibrosis), airway dilation (seen in bronchiectasis), and defects in host immunity (patient with immunocompromising conditions or who are on immunosuppressants). All of these things help to weaken the defence mechanisms of the respiratory system and predispose to infection.

Question 6

List of Upper Respiratory Tract Infections

Answer 6

Question 7

List of Lower Respiratory Tract Infections

Answer 7

Question 8

Bronchitis

• What is this?
• What does it affect?
• Who?
• Symptoms?
• 2 types of bronchitis (and cause for each)
• CXR result?
• Treatment
• Don’t look at pic until seen answer side

Answer 8

Question 9

Bronchiolitis

• What is this?
• Which part of the lungs?
• Which group of people?
• Symptoms
• Cause?
• Treatment?

Answer 9

Question 10

Bronchiectasis

• What is this?
• What does it affect?

Answer 10

Bronchiectasis can be defined as chronic dilation of one or more bronchi.

Question 11

Lung Abscesses

• What is this?
• Type of necrosis?
• Where?
• How can they be classified?
• Symptoms?
• Investigation (how to diagnose?)
• Treatment?

Answer 11

Question 12

Pneumonitis

• What is this?
• Cause?

Answer 12

Pneumonitis refers only to the inflammation of the lung parenchyma. The term is usually only used to describe inflammation due to non-infective causes, such as physical or chemical damage, such as occurs when noxious fumes are breathed in.

Question 13

Pneumonia:

• What is this?
• Caused by?
• 2 types (anatomically)
• Types (through where got the infection…)

Answer 13

Pneumonia can be defined as inflammation of the alveoli due to infection. This acute inflammatory response causes exudation of fibrin-rich fluid into the alveolar spaces, and neutrophil and macrophage infiltration. The presence of exudate in the alveolar spaces may be localised (lobar pneumonia) or diffuse (bronchopneumonia).

• Hospital Aquired Pneumonia
• Community Acquired Pneumonia
• Aspiration Pneumonia
• Atypical Pneumonia
• Ventilation Acquired Pneumonia

Question 14

Hospital and Community Acquited Pneumonias

• Causative organisms of each type
• Definition of HAP

Answer 14

Question 15

Aspiration Pneumonia:

• Cause
• Which patients?
• When commonly seen?
• Organisms?

Answer 15

Aspiration pneumonia is caused by the aspiration of contents such as food, liquids, saliva or vomit, into the respiratory tract, which collects and leads to infection. It is most commonly seen in patients with a defective swallowing mechanism, for example people with neurological conditions like Parkinson’s disease, or patients with an altered level of consciousness, which may be seen in anaesthetic induction, after excessive alcohol intake, or due to drug abuse.

Aspiration pneumonia can be caused either by aerobic bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella species (usually seen in aspiration pneumonia in alcoholics), or by anaerobic bacteria such as fusobacterium.

Question 16

Atypical Pneumonia

• Causative organisms?
• Type of people?

Answer 16

Atypical pneumonia is pneumonia caused by atypical organisms – organisms which lack a cell wall. These include Mycoplasma pneumoniae, Chlamydia pneumonia and Legionella pneumophila (Legionnaire’s Disease).

When considering the causative organisms of pneumonia, it is also important to mention that in the immunocompromised there might be a wider range of organisms that cause the disease, such as Pneumocystis jiroveci (commonly presenting as Pneumocystis Pneumonia (PCP) in patients with AIDS) or Cytomegalovirus. Also, Aspergillus spp. If had a splenectomy, more at risk from encapsulated organisms: e.g. S.pneumoniae, H.influenzae, malaria

Question 17

Ventilation Acquired Pneumonia
- Timeframe occurs in…

Answer 17

48 hours post intubation

Question 18

Signs and Symptoms of Pneumonia

Answer 18

The most common symptoms of pneumonia are shortness of breath, fever and a productive cough, usually with rapid onset of a few days

Other symptoms include malaise, rigors, pleuritic chest pain (chest pain that is worse on inspiration), nausea and vomiting.

The sputum seen in the productive cough may be yellow, rusty (presence of blood), or frankly stained with blood due to excess coughing.

On examination, the patient will be pyrexical, tachycardic, tachypnoeic, and depending on the severity, possibly cyanosed. There will be dullness to percussion of the chest due to the exudate collections, and bronchial breathing and crackles on chest auscultation.

Question 19

Investigations for Pneumonia

Answer 19

Question 20

Accessing Severity of the Pneumonia
- When to admit a patient?

Answer 20

Question 21

Treatment of Pneumonia

• Community-Acquired
• Hospital Acquired

Answer 21

u

Question 22

Complications of Pneumonia

Answer 22

• Initial infection progression – empyema (infection breaks open into pleural space) / lung abscess / bacteraemia
• Non resolving CAP – delayed clinical response / closed space infections e.g. absess – Abx not reaching the target/ bronchial obstruction (e.g. tumour) / subacute, chronic CAP (TB/fungal) / incorrect initial diagnosis

Question 23

Pathology of Pneumonia

Answer 23

• Acute inflammatory response
• Exudation of fibrin
• Neutrophil infiltration
• Macrophage infiltration

Question 24

Differential Diagnosis to Pneumonia

Answer 24

Question 25

WB:
Most common causative organsim of community acquired pneumonia

Most common causative organism for smokers

Most common causative organism for COPD

Most common causative organisms for Atypical pneumonia

Answer 25

Most common causative organsim of community acquired pneumonia:
Streptococcus Pneumoniae

Most common causative organism for smokers:
Streptococcus Pneumoniae

Most common causative organism for COPD:
Haemophilus influenzae and Moraxella catarrhalis

Most common causative organisms for Atypical pneumonia:
- Mycoplasma pneuomoniae

Question 26

WB:
Other causative organisms for Atypical pneuomina

Causative organsism for hospital acquired pneumonia

Causative organism for hospital aspiration pneumonia

Answer 26

Other causative organisms for Atypical pneuomina

• Chlamydia pneumoniae
• Legionella pneumophila

Causative organsism for hospital acquired pneumonia

• Pseudomonas aeruginosa
• Escherichia coli
• Klebsiella pneumoniae
• Aceintobacter species

Causative organism for hospital aspiration pneumonia
Pseudomonas aeruginosa
Aspergillus spp
Cytomegalovirus

Question 27

WB:

• Coomunity acquired pneumonia new focal chest sings
• Atypical organisms and pneumonia…

Answer 27

• Crackles
• Decreased breath sounds
• Dullness to percussion
• Wheeze
• Increased vocal resonance over area consolidation

Atypical organisms and pneumonia…
Cell wall active antiobiotics, such as penicillin
Require antibiotics that act on protein synethesis such as macrolide (erythromycin, clarithromycin, azithromycin) or tetracyclines (doxycycline)