Upper Respiratory Tract Infections Flashcards
At what point does the respiratory tract become sterile?
Below the epiglottis
Are there more aerobic or anaerobic microbiota in the upper respiratory tract?
Anaerobic
What are the most common pathogens in the upper respiratory tract?
viridans streptococci, neisseria spp., corynebacterium spp., gram negative anaerobes, H. influenzae, C. albicans, strept. pneumoniae
What does viridans streptococci cause?
Plaque by producing acid that wears away teeth - if it becomes a significant pathogen it may cause infective endocarditis
What are occasional pathogens of the upper respiratory tract?
strep. pyogenes, meningococci
What are uncommon pathogens of the upper respiratory tract?
enterobacteria, pseudomonas, C. diptheria
What pathogens are latent in the lung?
P. jirovecii and M. tuberculosis
What pathogens are latent in lymph nodes and sensory nerves?
CMV, HSV, EBV
What are the frequent aetiological agents of the common cold?
rhinovirus, parainfluenza virus, RSV, enterovirus, coronavirus, human metapneumovirus
What are the frequent aetiological agents of pharyngitis/tonsilitis?
adenovirus, enterovirus, infleunza
What are the aetiological agents of pharyngitis/tonsilitis without nasal involvement?
Either the same viruses which cause tonsillitis with nasal involvement or in about 1/5 times strept. pyogenes - requires early antibiotic treatment
What is secondary sinusitis?
Where pathogens take advantage of damaged epithelium due to viral infection and get infected by bacteria e.g. h.influenzae or strept. pneumoniae
What are the frequent aetiological agents of otitis media?
pneumococci, h. infleunzae, m. catarrhalis
What is the frequent aetiological agent of epiglottitis?
h. influenzae type b - can be immunised against
What are the frequent aetiological agents of croup?
parainfluenza virus, influenza A, RSV
What is the pathogenesis of the common cold?
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.
Why is otitis media more common in children?
Because children have a wider and shorter eustacion tube which allows organisms to go from pharynx to middle ear
When is a laboratory diagnosis done for an URTI?
For tonsillitis and epiglotitis
What kind of laboratory diagnosis is done for epiglottitis?
Blood culture
When is specific treatment of URTI done?
If the cause is bacterial - for tonsillitis, sinusitis, otitis media and definitely for epiglottitis
