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41 Cards in this Set

  • Front
  • Back
what % of deaths are caused by respiratory infections
25%, the # increases with low income afrcian and asian countries
what are the defense mechanisms against respiratory diseases
nasal cavity has mucociliary lining, filters the microbe out, also hair filter out microbes
2. adenoids and tonsils located on the back of the throat is lymphoid tissue and helps in killing cells
3. mucociliary lining in the lower airways traps the pathogens and the cilia allows for them to be driven upward to the back of the throat where lymph organs are
why is respiratory tract most common site of infections
because it is exposed to a lot of things like smoke, soot and normal breathing
what must an invader be able to evade to be an effective pathogen of the airways
it must be able to avoid getting trapped by the mucociliary layers and transported to the back of the throat
2) it it manages to get into the lower respiratory ways, it must be able to avoid phagocytosis or multiply in a phagosome
what are the mechanisms that the bacteria uses to initiate the disease?
bacteria must
-adhere via adherence factors
-avoid host's defense mechanisms
-extracellular toxins
-intracellular growth
what are the upper respiratory infections
-common cold
-pharyngitis and tonsilitis
-sinusitis and otitis media
what are airway problems
-diptheria, whooping cough
-laryngo-tracheo bronchitis
what are lower respiratory infections
-pneumonia and bronchopneumonia
-pulmonary TB
what are the pathogens responsible for these diseases
mainly viral but bacterial are more dangerous b/c they can be life threatening
90% viruses but bacteria pyogenes diptheriae is very serious
what is pharyngitis
is the inflammation of the pharynx, it results in 40 million MD visits
what is the majority of Pharyngitis caused by
viral infection from adenovirus, rhino and coxace viruses
what is the most common bacterial infection
pharyngitis called GAS or GABHS, called group a beta hemolytic streptococcus
what are the pharyngitis signs and syndromes
-sore throat
-pain when swallowing
-swollen lymph nodes
-runny nose and post nasal drip
-rarely difficulty breathing severe
why is it important to diagnose b/t viral and bacterial disease when it comes to pharyngitis
b/c bacterial infections are severe and the viral infections are self limiting
what are the viruses involved in causing acute pharyngitis
adeno, coxake, rhino, HSV,
what are the bacteria that cause acute pharyngitis
-it happens in 40% of the cases
-main one group a beta hemolytic streptococci called streptococcus pyogenes
streptococcus pyogenes
-causes acute pharyngitis
-facultative anaerobe
-normal habitat is the upper respiratory tract
what is the difference b/t comlication and sequelae
comp> while u have the disease u get something else like w/pharyngitis picking up scarlet fever
seq>person has recovered form the disease but has residual damage
what are some of the complication associated with Group a Strep Pharyngitis
-scarlet fever
-bacetremia and strep induced toxic shock syndrome
what are the sequelae associated with Group a Strep Pharyngitis
-rheumatic fever
where does Group a Strep Pharyngitis
upper respiratory airways
what happen Group a Strep Pharyngitis gets into lower airways
it will cause penumonia
what does beta hemolysis refers to
it refers to total lysis of RBC
as far as the epidemiology is concerned:
1)how many ppl are asymptomatic carriers
2)acute disease is seen in what % of adults and children
3)how is pharyngitis spread
2)15% in adults and 30% children
3)spread through respiratry droplets,
-crowded conditions
-fever and rheumatic fever
what are virulence factors associated with Group a Strep Pharyngitis
M protein and lipotechoic acid attachment, this helps with lancefield serotyping
-goup a carbs
-capsule hylouronic acid
enzyme- hylouronidase
pyrogenic exotoxin
what do we serotype Group a Strep Pharyngitis
-M protein
-lancefield serotype
how does Group a Strep Pharyngitis avoid phagocytosis and what are the conditions that allow phag to take place?
hylouronic acid inhibts phag
but in the presence of m protein it can proceed but it take a long time and can cause complication, also it exhibits lime basement membrabe of most of most of our tissues so an immune response is not reallu launched against it
what is the serious cause of pharyngitis
strep throat
Group a Strep Pharyngitis s&s presents as
-tonsillar exudate in 50% of patients
-tender anterior cervical lymhadenopathy
-abrupt onset
-erythmatous pharynx
-can be confused w/viral
scarlet fever
-complciation of Group a Strep Pharyngitis
due to lysogenized streptococcal spp
-has pyrogenic and erythrogenic exotoxin
-symptoms w/in 1-2 days of disease and lst upto 5-7 days
-diffused erythromatous rash on the upper chest that spreads to lower extremities and blanches with pressure, pastial lines or sand paper feel
-strwberry tongue whote and red
-high fever, nausea, and vomitting in most cases
rheumatic fever
-autoimmune sequela of Group a Strep Pharyngitis
-2-3 weeks after phrngts
inflamatory changes in the heart, joint, blood vessels, and subcutaneous tissues
-end, peri, and myocaditis
when is rheumatic fever treatable
w/in 10 days of start of phrngts
how does our immune response cause the lesion in the heart
our APC cell pick up the Strp antigen and present it to the B and CD4 t cell, this leads to the production of the antibodies than can cross rect and inflitrate the heart's proteins and cause an immune response to the heart tissue due to molcular mimicry
what is jones criteria
it a diagnostic tool for rheumatic fever that must be met before it can be diagnosed
what is the diagnostic criteria for R. Fever
-1 requried and 2 major criteria
-1 req, 1 major and 1 minor
required> antecednt strp/strep antibodies/strep a throat culture/recent scarlet fever/anti-deoxyribonuclease/anti-hylouronidase
-sydenham's chorea (uncotrollabel movements)
-erythma marginatum
-subcutaneous nodules
-previous rehumatic fever
-long PR interval
sequesla associated with Group a Strep Pharyngitis
-acute inflammation of the renalglom
-loss of renal function
-no evidence that treating tpharyngitis will imped the sequela
lab diagnostics of Group a Strep Pharyngitis
'microscopy- common in normal flora so the presence of leukocytes in association with streo is necessary
'antigen detection-must differentiate b/t viral and bacterial
-high spec and low sens
-confirmed w.culture beta hemolysis
-catalase -
-bacitracin sensitive
-PYR test +, baetria PYR enz that breaks PYR down and that yields a color, done on filter paper
-lansfiel designation
-Rapid antigen test:
2 phases
A)extraction> enz or acid extraction
B)identification> immunoassay and latex agglutination, technique dependent accuracy
-throat culture is not recommended b/c it takes a long time to Id
what is a Rapid Strep test
basically we see if BBL antibodies will bind to the strep antigen
who should be tested with RST
ppl w/2 or more S&S of GABHS but treat only if +
only treat based on S & S if 3 or 4 are present
what is the treatment for Group a Strep Pharyngitis
antibiotics but only limit ot + GANHS patients
-non responsive cases will req a 2nd course
-immediate treatment will prevent rheumatic fever