Bacterial Infections of the Respiratory Tract proximal to the Alveoli

Question 1

Haemophilus influenza requires which medium in order to grown in the laboratory?

Answer 1

-Requires special nutrients found in blood for growth in
laboratory
-Frequently grown on ‘chocolate agar’ or boiled blood
agar

Question 2

What colour does H. influenzae stain? Why?

Answer 2

It stains pink because it is a Gram negative bacteria

Question 3

What is the shape of Haemophilus influenza?

Answer 3

It is shaped either as small cocco-bacilli, or as bacilli. Shape depends on site of infection and the conditions under which the organisms are growing.

Question 4

How does Haemophilus influenza avoid phagocytosis?

Answer 4

It has a polysaccharide capsule which is important for avoiding phagocytosis and effect of the complement

Question 5

How many types of antigenic capsule of H. influenzae? Which type is most virulent?

Answer 5

There are 6 different antigenic types of capsule. Type B is most virulent

Question 6

Where do unencapsulated strains of H. influenzae commonly colonize?

Answer 6

Unencapsulated strains of H. influenzae commonly colonise upper respiratory tract within first few months of
life

Question 7

Give examples of diseases caused by encapulated H. influenzae strains

Answer 7

Encapsulated strains, primarily type B, cause serious invasive disease such as meningitis, arthritis, epiglottitis

Question 8

Give examples of medical conditions caused by non-encapsulated strains of H. influenzae.

Answer 8

Non-encapsulated strains cause local disease of the respiratory tract e.g. otitis media, sinusitis, pneumonia

Question 9

Which age group is more at risk of infection by non-encapsulated strains of H. influenzae?

Answer 9

Generally, it affects children more than adults.

Question 10

Which type of H. influenzae strains are considered to be secondary invaders?

Answer 10

Non-encapsulated strains

Question 11

Which bacteria cause acute otitis media? (4)

Answer 11

S. pneumonia, H. influenzae, S. pyogenes, S. aureus

Question 12

List 5 symptoms of Acute otitis media

Answer 12

Pain, fever, irritability, vomiting, diarrhoea

Question 13

What are the clinical findings indicative of acute otitis media?

Answer 13

Redness of the tympanic membrane
Fluid accumulation in the middle ear causing bulging and occasionally perforation and discharge

Question 14

The accumulation of fluid in the ear causes what?

Answer 14

It causes temporary deafness until resorbed after a few weeks.

Question 15

In children, if the fluid doesn’t resolve, what would be the consequence?

Answer 15

Can be detrimental to language development in young children if doesn’t resolve.

Question 16

Diagnosis of acute otitis media is based on what?

Answer 16

It is based on clinical history and examination

Question 17

What it the name of the medical procedure in which fluid is aspirated form the middle ear through the tympanic membrane?

Answer 17

Tympanocentesis

Question 18

In what case would you have to use ear swabs?

Answer 18

Ear swabs only useful if there is new onset of discharge, which might occur if the tympanic membrane
perforates (rare).

Question 19

What is chronic suppurative otitis media?

Answer 19

This is a pre-existing perforation of the eardrum with chronic recurrent discharge.

Question 20

How is chronic suppurative otitis media managed?

Answer 20

generally focuses on cleaning and drying out of ear canal ‘aural toilette’

Question 21

What are the considerations for the treatment of otitis media? (3)

Answer 21

-Most of otitis media is viral - so paradigm shift away from always giving antibiotics
-Decision to give antibiotics is based on age and duration of infection (<2 years is more likely to be a secondary bacterial infection)
-Sometimes give delayed presciption.

Question 22

What causes acute sinusitis?

Answer 22

It is caused by viruses, and sometimes secondary bacterial infections.

Question 23

Which bacteria are responsible for causing secondary infections of the sinuses? (4)

Answer 23

S. pneumonia, H. influenzae, S. pyogenes, S. aureus
(same organisms as otitis media)

Question 24

What are the symptoms of acute sinusitis?

Answer 24

Pain, fever, blockage or pressure

Question 25

When are antibiotics indicated for acute sinusitis?

Answer 25

Only if symptoms persist > 10 days or get worse or are very severe or patient looks toxic

Question 26

What does bronchitis usually affects?

Answer 26

It affects the laryngo-bronchial tree

Question 27

What is the cause of acute bronchitis?

Answer 27

It is usually viral and self-limiting

Question 28

What are the signs and symptoms of acute bronchitis?

Answer 28

Cough, sputum production, fever, but doesn’t affect breathing

Question 29

What causes chronic bronchitis?

Answer 29

It is caused by irritations of smoking and pollution.

Question 30

Describe acute exacerbations of chronic bronchitis and or chronic obstructive pulmonary disease

Answer 30

Symptoms get worse for period of week or so
May be due to infection, but mostly probably due to viruses