Lower Resp tract infections and pneumonia

Question 1

What are 3 defences of the resp tract?

Answer 1

1. mucociliary escalator
2. cough and sneezing reflexes
3. Respiratory mucosal immune system: secretory IgA and IgG, alveolar macrophages, lymphoid follicles of pharynx and tonsils

Question 2

What defines acute vs chronic bronchitis? What is the phase between the two?

Answer 2

Acute: viruses and bacteria, may lead to pneumonia and commonly in the winter and <5 yr olds

Sub-acute (between)

Chronic: At least 2 years, a consequence of repeated infections, irritation from smoking, can form the bases of COPD and pneumonia

Question 3

What is pneumonia?

Answer 3

Infection of pulmonary parenchyma; the part of the lung tissue involved in gas exchange

Question 4

What is characteristic of the pathology of pneumonia?

Answer 4

1. Fluid-filled airspaces (more involving distal airspaces) creating a heavy, stiff lung and impairment of gas exchange
2. results in inflammatory exudation

Question 5

Name the scenarios where you could acquire pneumonia

Answer 5

1. community-acquired
2. hospital-acquired
3. Aspiration pneumonia (inhale food, stomach acid, saliva in the lungs, slow onset)
4. pneumonia in an immuno-compromised patient

Question 6

Describe the 3 lung pathologies:

a) lobar pneumonia
b) bronchopneumonia
c) interstitial pneumonia

Answer 6

a) Respects the fissures
b) infection starts in airways (bronchi/bronchioles) and spreads to alveoli (most common)
c) lungs are globally infected, virus or toxin (more rare)

Question 7

How would you classify pneumonia?

Answer 7

1. by clinical setting
2. by presentation (acute - chronic)
3. by organism (virus, bacteria, fungus)
4. by lung pathology

Question 8

What are the predisposing factors for pneumonia? INSPIRATION

Answer 8

1. immunosuppression
2. neurological impairment of cough reflex
3. secretion retention
4. pulmonary edema
5. Impaired mucociliary escalator
6. resp tract infection
7. antibiotics and cytotoxins used by CD8 cells to destroy infected cells
8. Tracheal instrumentation
9. impaired alveolar macrophages
10. other
11. neoplasia

Question 9

What might you analyze to check for pneumonia and which 3 organisms would you more commonly see in community-acquired pneumonia and what features are associated with them?

Answer 9

Sputum culture

1. streptoccocus pneumonia; elderly, co-morbidities, fever, pleuritic pain, pus
2. klebsiella pneumonia; tend to be alcoholics and IV drug users
3. hemophilis influenza; COPD

Question 10

Name 3 atypical bacteria that may cause community-acquired pneumonia? What features are associated with them?

Answer 10

1. Legionella: recent travel, smokers, exposure to aerosols, a notifiable disease
2. Mycoplasma: young, extrapulmonary involvement, may present with rashes, joint pain, malaise, can cause pulmonary fibrosis
3. Chlamydia species through contact with birds

Question 11

Name 3 kinds of organisms that commonly cause pneumonia in hospital-acquired pneumonia

Answer 11

1. Viruses: influenza, parainfluenza, resp syncytial virus
2. Mixed infections
3. Bacteria (hospital-acquired): staphyloccocus aureus, pseudomonas, Gram (-) enteric bacteria like coxiella

Question 12

Name 3 things that commonly cause pneumonia in an immunocompromised host?

Answer 12

Candida, aspergillus, viruses

Question 13

What makes you more at risk for acquiring Coxiella and klebsiella?

Answer 13

Coxiella: contact with animals
Klebsiella: thrombocytopenia, leucopenia

Question 14

Which organism commonly causes lobar bronchitis? What is the pathology? What might you see on an X-ray?

Answer 14

Streptococcus pneumonia
Typical acute inflammatory response:
1. fibrin rich exudate
2. neutrophil and macrophage infiltration

X ray: lobar consolidation

Question 15

What is hepatization?

Answer 15

When the lung tissue transforms into liver-like substance

Question 16

Name 5 characteristics of acquiring bronchopneumonia

Answer 16

1. seen with pre-existing disease
2. if you have a viral infection
3. aspiration pneumonia
4. complication of COPD
5. cardiac failure predisposes you as your interstitium is already filled with fluid

Question 17

How would bronchopneumonia appear on a chest x-ray?

Answer 17

Patchy consolidation more in the bases of the lungs

Question 18

Name 4 organisms likely to cause bronchopneumonia, what will help in deciding which one?

Answer 18

1. streptococcus pneumonia
2. staphyloccocus aureus
3. anarobes
4. coliforms
   Use clinical context to decide

Question 19

What are the complications of acute bacterial pneumonia?

Answer 19

Lung abscess, bronchiectasis, empyema (pus in the pleural cavity)

Question 20

What makes a lung abscess so difficult to resolve?

Answer 20

May form a wall around it making aspiration difficult, may need 2-3 months of antibiotics to get through the wall

Question 21

What is bronchiectasis and what is the consequence? What can you infer about the patient’s past?

Answer 21

Increased collection of mucus in permanently dilated alveoli, so the patient will always be prone to pneumonia as they have juicy cavities in their lungs

Means they either had CF or an infection when they were young

Question 22

How might atypical pneumonia look on an x-ray

Answer 22

Patchy segmental filtrates usually on the lower lobes

Question 23

How would viral pneumonia appear on an x-ray? What does severe viral pneumonia lead to?

Answer 23

Patchy or diffuse ‘ground-glass’ opacity, severe viral pneumonia leads to necrosis and hemorrhage into the lung parenchyma

Question 24

Why does influenza commonly cause pandemics and epidemics? When is it most common?

Answer 24

As the virus is constantly mutating making variations of the virus (antigenic shift), common in the winter

Question 25

What condition often predisposes you to aspiration pneumonia?

Answer 25

Neurological dysphasia; problems swallowing means more likely to aspirate exogenous material or secretions into the lungs

Question 26

Name 5 common symptoms of pneumonia

Answer 26

1. chills/fever/sweats
2. cough
3. hemoptysis
4. dyspnoea
5. anorexia and vomiting

Question 27

Name 5 common signs of pneumonia

Answer 27

1. wheeze
2. crackles
3. increased vocal resonance
4. bronchial breath sounds
5. dull percussion due to consolidation

Question 28

Name 4 investigations you might do for pneumonia

Answer 28

1. Chest x-ray
2. FBC (platelets and white count)
3. O2 saturation and blood gases
4. Urea, liver function tests and CRP

Question 29

When would you admit pneumonia?

Answer 29

More than 2 of the following:

1. confusion
2. urea >7mmol/L
3. resp rate >30
4. Low BP (systolic <90 or diastolic <60)
5. Age >65

Question 30

Name 4 methods you could attain a sample for microbiology (and 2 for bonus)

Answer 30

1. blood tests
2. sputum
3. nose and throat swabs
4. urine antigens for atypical organisms
   +endotracheal aspirates and bronch-alveolar lavage

Question 31

How would you base your decision on which antibiotic to prescribe?
Name 2 commonly used antibiotics for pneumonia and one commonly used antibiotic for legionella.

Answer 31

Based on the local guidelines:
2 commonly used: clarithromycin and penicillin
Legionella: levofloxacin

Question 32

When would you inform ITU of a pneumonia patient?

Answer 32

1. resp failure (going hypoxic)
2. rising pCO2 - worsening acidosis
3. hypotension despite fluids - the systemic inflammatory response causes vasodilation

Question 33

What are some prevention steps against pneumonia?

Answer 33

Annual influenza immunization, and immunisation for vulnerable risk patients (chemoprophylaxis)

Question 34

What is pneumocystis pneumonia and what organism commonly causes this?

Answer 34

opportunistic infection of immune-compromised patients, caused by pneumocystis jirovecii

Question 35

How does whooping cough present and which organism commonly causes this?

Answer 35

Starts like a cold and develops into a cough sounding like a ‘whoop’, Bordetella pertussis