Respiratory Tract Infections Flashcards
portals of entry for invading microorganisms in order of importance
- Respiratory Tract [Upper (URT): Head and Neck and Lower (LRT): Thorax]
- Gastrointestinal Tract
- Urogenital Tract
- Skin [Wounds, Inapparent breaks and cracks, Unbroken Skin]
can you die from a respiratory tract infection
no you cannot but you can die from its complications
at risk groups for respiratory tract infections
immunocompromised population – very young and very old
can you distinguish between etiological agents on basis of clinical manifestation
no you cannot
what is infectious pharyngitis
sore throat
for a single syndrome, can you have multiple etiologies
yes you can and vise vera
you can have one etiology causing multiple syndromes depending on strain, where in the body, and other factors
what are some features of respiratory tract
temperature differential (lower temp in the RT) significant air exchange (breathing) antimicrobial barriers
in the respiratory tract, establishment of infection requires?
by-pass barrier defenses & filtering systems
contact with suitable receptor surfaces
evasion of immune response
can a majority of microorganism gets passed our natural defenses
no
size a particle must be to get passed lower RT
less than 5 microns
differences between upper and lower RT
upper (nose to bronchioles): lower temp (33-35oC), normal flora, respiratory epithelium, secretory IgA
lower (bronchioles down): 37oC, sterile, particles less than 5 microns can’t pass, nonciliated epithelium, IgA and IgG
effects if microorganisms makes it to the lower RT
more severe symptoms
purpose of cilia
moves mucus down to the glottis to be discarded
what is mucus made up of
mostly water, ions, proteins, glycoproteins, lipid
they all have antimicrobial effects
defense of the respiratory system are defeated by
Smoking Endotracheal intubation Pollution Suppression of the Cough Reflex Predisposing infection Disruption of homeostasis (Age, malnutrition, immunosuppression)
what are group of agents for infections
- professional or frank invaders - primary infectors
2. secondary or opportunistic invaders (part of our normal flora)
when do secondary invaders act
after professional invaders have created damage, the secondary come in and create further damage
primary respiratory infections
influenza and rotavirus
how does one get exogenous infections
- inhalation of infectious droplets (talking, sneezing, coughing)
- inhalation of dust, fungal spores
- self-inoculation of eyes, nose, or mouth via droplets on hands
what types of droplets remain suspended longer
small droplets dried droplet nuclei = even longer
how can one avoid infections
wearing a p100 mask
most common cause of work force absenteeism in north america
respiratory infections
can bacteria survive drying
most bacteria can’t survive drying – they need wet surfaces
what kills most bacteria and virus
sunlight
survival time of the following viruses in dry inanimate surfaces:
coronavirus, RSV, rhinovirus, adenovirus
coronavirus - 3 hours
RSV - 6 hours
rhinovirus - 2 hours to 7 days
adenovirus - 7 days to 3 months
viral persistence on dry inanimate surfaces is significant to?
fomite mediated transmission and survival in droplets
endogenous infections are due to what
members of the normal flora
how does normal flora become endogenous infections
they move to unusual locations (like they don’t belong in the RT)
why does normal flora relocate to abnormal location
age, preceding infections, smokers
things used to diagnose RTIs
age, season, symptoms, in office tests, lab diagnosis
virus that is common year round
adenovirus
