Upper Respiratory Tract Infections

Question 1

At what point does the respiratory tract become sterile?

Answer 1

Below the epiglottis

Question 2

Are there more aerobic or anaerobic microbiota in the upper respiratory tract?

Answer 2

Anaerobic

Question 3

What are the most common pathogens in the upper respiratory tract?

Answer 3

viridans streptococci, neisseria spp., corynebacterium spp., gram negative anaerobes, H. influenzae, C. albicans, strept. pneumoniae

Question 4

What does viridans streptococci cause?

Answer 4

Plaque by producing acid that wears away teeth - if it becomes a significant pathogen it may cause infective endocarditis

Question 5

What are occasional pathogens of the upper respiratory tract?

Answer 5

strep. pyogenes, meningococci

Question 6

What are uncommon pathogens of the upper respiratory tract?

Answer 6

enterobacteria, pseudomonas, C. diptheria

Question 7

What pathogens are latent in the lung?

Answer 7

P. jirovecii and M. tuberculosis

Question 8

What pathogens are latent in lymph nodes and sensory nerves?

Answer 8

CMV, HSV, EBV

Question 9

What are the frequent aetiological agents of the common cold?

Answer 9

rhinovirus, parainfluenza virus, RSV, enterovirus, coronavirus, human metapneumovirus

Question 10

What are the frequent aetiological agents of pharyngitis/tonsilitis?

Answer 10

adenovirus, enterovirus, infleunza

Question 11

What are the aetiological agents of pharyngitis/tonsilitis without nasal involvement?

Answer 11

Either the same viruses which cause tonsillitis with nasal involvement or in about 1/5 times strept. pyogenes - requires early antibiotic treatment

Question 12

What is secondary sinusitis?

Answer 12

Where pathogens take advantage of damaged epithelium due to viral infection and get infected by bacteria e.g. h.influenzae or strept. pneumoniae

Question 13

What are the frequent aetiological agents of otitis media?

Answer 13

pneumococci, h. infleunzae, m. catarrhalis

Question 14

What is the frequent aetiological agent of epiglottitis?

Answer 14

h. influenzae type b - can be immunised against

Question 15

What are the frequent aetiological agents of croup?

Answer 15

parainfluenza virus, influenza A, RSV

Question 16

What is the pathogenesis of the common cold?

Answer 16

Viruses have an affinity for respiratory epithelium, gets in and damages epithelial cells which causes the early symptoms of a runny nose with clear fluid, this is followed by an inflammatory response. Bacterial commensals then take advantage of damaged epithelium and infect - this si when fluid becomes more purulent.

Question 17

Why is otitis media more common in children?

Answer 17

Because children have a wider and shorter eustacion tube which allows organisms to go from pharynx to middle ear

Question 18

When is a laboratory diagnosis done for an URTI?

Answer 18

For tonsillitis and epiglotitis

Question 19

What kind of laboratory diagnosis is done for epiglottitis?

Answer 19

Blood culture

Question 20

When is specific treatment of URTI done?

Answer 20

If the cause is bacterial - for tonsillitis, sinusitis, otitis media and definitely for epiglottitis