24/25 Upper Respiratory Tract Flashcards
what URT tissues are considered sterile?
mastoid air cells middle ear sinuses trachea bronchi bronchioles (conjunctiva)
what are the normal flora of the nose?
- staph. epidermidis
- staph. aureus
- corynebacterium
staph. epidermidis gram stain and shape
gram positive cocci clusters
staph. areus gram stain and shape
gram positive cocci clusters
corynebacterium stain and shape
gram positive rod
normal nasopharynx flora
- streptococcus
- viridians group
- moraxella catarrhalis
- bacteriodes
who is in the viridans group?
- s. mutans
- s. mitis
- s. milleri
- s. salivarius
describe streptococcus
gram positive cocci in chains
describe moraxella catarrhalis
gram neg, diploid coccobacillus
aerobic
strict anaerobes in the RT?
bacteriodes
what pathogens are seen in the nasopharynx in increasing numbers in the winter?
- strep. pneumoniae
- haemophilus flu
- neisseria meningitides
- moraxella catarrhalis
what differentiates strep from staph?
strep is catalase negative
group A strep
strep. pyogenes
group B strep
strep. agalactiae
group D strep
strep. bovis and enterococcus faecalis
what is the only alpha hemolytic strep?
strep. pneumoniae
what does the rapid strep test target?
cell wall antigen
what is associated with m prtn and what is the m prtn?
strep. pyogenes
antiphagocytic component essential for virulence (80 serotypes)
does s. pyogenes have a capsule?
not in all strains
if it has one it helps to inhibit phagocytosis
what are the super antigens associated with strep. pyogenes?
nine proteins that are pyrogenic exotoxins
what is a super antigen
causes an upregulation/activation of massive immuen response which causes damage
what 3 diseases are the strep. pyogenes super antigens responsible for?
- scarlet fever
- toxic shock
- necrotizing fasciitis
what disease must be proceeded by strep throat?
scarlet fever
10 yo female presents with redness of throat, patches of adhering pus, scattered tiny hemorrhages, temperature 38.9C
strep. pyogenes
SPE release, redness of skin, desquamation of hands, and a whit coating on the tongue
scarlet fever
fever, joint pain, chest pain, rash, skin nodules, uncontrollable jerky movements, acute inflammatory process
acute rheumatic fever
skin infections, swelling, redness, destruction of tissue inside, SPE release
necrotizing fasciitis
will getting rid of strep. pyogenes stop acute rheumatic fever?
NO- caused by strong immune response to strep. pyogenes super antigens
- treat with immunosuppression
- next time pt. sees s. pyogenes will have equal or worse immune response
what diseases are directly caused by exotoxin release of strep. pyogenes?
scarlet fever and necrotizing fasciitis
- deposition of antigen-antibody complexes in the glomeruli
- 3-6 wks after strep. pharyngitis or skin infection
- edema, hypertension, hematuria, proteinuria, decreased serum complement levels
acute glomerulonephritis caused by strep. pyogenes
- mild sore throat, slight fever, high fatigue and malaise
- dramatic neck swelling
- clotted blood
- whitish gray membrane on tonsils, throat, nasal cavity
diptheria
what causes diptheria?
corynebacterium diptheriae
what does corynebacterium look like under a microscope?
gram positive rod (chinese letters)
non-spore forming
is diptheria a toxin mediated disease?
yes,
- it is controlled by a toxoid vaccine
is diptheria invasive?
not invasive
toxin is absorbed by the bloodstream
how is the diptheria toxin released?
inactive in A and B subunit
B binds to host receptor, A inactivates elongation factor 2 –> stops prtn synthesis and induces cell death
where is the B subunit receptor of diptheria toxin found within the body?
heart
kidneys
nerve cells
bacterial v. viral conjunctivitis
bacterial has more pus and discharge
what are the main two causative agents of bacterial conjunctivitis?
- haemophilus flu
- strep. pneumoniae
what are the other three causes of bac. conjunctivitis?
- moraxella lacunata
- enterobacteria
- neisseria gonorrhoeae
describe haemophilus flu.
gram negative rod
describe strep. pneumoniae
gram positive cocci
what is the treatment for bac. conjunctivitis
gentamicin or ciprofloxacin
for which causative agent of conjunctivitis do we have a vaccine?
haemophilus flu. type B
what are the 3 most common causative agents of otitis media?
strep. pneumoniae
haemophilus flu.
moraxella catarrhalis
what are the 3 most common causative agents of sinusitis?
strep. pneumoniae
haemophilus flu.
moraxella catarrhalis
what type of pneumonia is strep. pneumoniae associated with?
lobar pneumonia
what type of strep. is associated with meningitis?
strep. pneumoniae
chlamydia trach. or chlamydophila: obligate intracellular parasite
chlamydophila
elementary bodies v. reticulate bodies
EB-metabolically inactive and infectious
RB- metabolically active, noninfectious forms
trachoma, adult inclusion bodies, neonatal conjunctivitis, infant pneumonia
chlamydia trachomatis
pathogenesis of chlamydia trachoma
direct destruction of host cells during replication and the host inflammatory response
how does chlamydia trachoma. gain access to cells?
minute abrasions or lacerations and then granuloma formation
causitive agent of adult inclusion conjunctivitis/acute follicular conjunctivits
chlamydia trachomatis
diffuse inflammation, conjunctival scarring, eyelids turn inward
- same serovars associated with genital infections
- occurs in sexually active adults
- mucopurulent discharge, keratitis, corneal infiltrates and some vascularization
adult inclusion conjunctivitis caused by chlamydia trachomatis
5-12 days after birth eyelids swell
- at risk for developing c. trachomatis pneumoia
neonatal conjunctivitis caused by c. trachomatis
onset 2-3 wks after birth
- bronchitis with a dry cough, afebrile
infrant pneumonia caused by c. trachomatis
TWAR pathogen
chlamydophila pneumoniae
only one lobe affected, associated with atherosclerosis
chlamydophila pneumoniae
16 yo female with cough 3 wks. mild but chronic shortness of breath, persistent cough and noted malaise.
- pet parrots
chlamydophila psittaci
what do you use to diagnosis c. psittaci?
PCR
complement fixation
what do you use to treat c. psittaci?
macrolides (erythromycin and azithromycin), tetracyclines or levofloxacin for 10-14 days
where does c. psittaci spread after infecting the respiratory tract?
reticuloendothelial cells in liver and spleen
-multiplies at these sites producing focal necrosis
