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42 Cards in this Set
- Front
- Back
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What is the most common agent of URT disease?
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viruses (40%)
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What causes Rhinitis?
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common cold- viral
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What causes acute sinusitis?
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viral, often follows rhinitis
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What cause chronic sinusitis?
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anaerobic bacteria, comes from unresolved acute sinusitis
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What causes pharyngitis?
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viral AND bacterial (strep. pyogenes GABHS)
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What causes acute epiglotitis?
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can be lethal, cause by haemophilus influenzae type B
(explosively rapid, 6-12 hours till serious airway obstruction) |
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What causes laryngitis?
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parainfluenza viruses (PIV 1 usually)
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What is the morphology of steptococcus?
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Chains/Pairs, G+
Catalase negative, non motile Can be hemolytic alpha, beta, or gamma (non hemolytic) |
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What is the typical growth conditions for strep
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enriched/BAP, CO2, 35-37C
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Other than HiB, what can cause epiglottitis?
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STREP. Pneumoniae?
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What are the three terms used to describe strep pyogenes cultivation?
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Fastdious
Mesophile Capnophile |
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What is the major virulence factor for strep pyogenes? what does it do?
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M protein- inhibits complement
TWO classes Class 1- antigenic Class 2- non antigenic |
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What do protein F and LTA do?
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F binds to fibronectin
LTA attaches to the pharyngeal epithelium |
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What is the capsule of strep pyogenes made of?
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hyaluronic acid, gives it a stealth advantage- inhibits phagocytosis
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What does Streptolysin O do?
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this is Oxygen lablie, destroys RBC's and WBCs, causes hemolysis in deep cuts.
IMMUNOGENIC |
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What does Streptolysin S do?
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oxygen stable-NONIMMUNOGENIC
destroys RBCs and WBCs- surface colonies, and in serum |
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What does C5a peptidase do?
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this degrades C5a preventing recruitment and activation of phagocytic cells
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What does streptodornases do?
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these degrade deoxyribonucleaic acid DNA- (reduces viscosity of purulent exudates)
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What does Streptokinase/fibrinolysin do?
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this generates plasmin, to break down clot folding proteins.
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What does SpeA do?
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this is a superantigen, causes massive cytokine release and tissue damage.
comes from lysogenized trains of SpeA Cause TSS and Scarlet fever |
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What is the only reservior of strep pyogenes?
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human noses and skin
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What is the peak age group for strep pyogenes?
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5-15 years old
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how is strep pyogenes usually transmitted?
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RESPIRATORY DROPLETS
and...skin, crowded spaces, etc |
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What are the 3 mechanisms for strep pyogenes pathogenesis?
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pyogenic inflammation (paryngitis)
Toxin-mediated- scarlet fever Immunologic disease |
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What is pyogenic inflammation like in small children?
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subacute nasopharyngitis w/discharge
tends to lead to middle ear/ mastoid cervical lymphadenopathy persists for weeks |
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What is pyogenic inflammation like in adults?
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acute intents nasopharyngitis/ tonsilitis, with intense erythemya
purulent exudates cervical lymphadenopathy HIgh fever above 38C Self limited about 5 days |
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Who is most likely to get scarletina?
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children, with repeat strep, infected with a lysogenized strain.
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What are the signs of scarletina?
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same as scarlet fever-
sand-paper like skin Pastia's lines strawberry tounge desquamation |
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When does RF usually occur?
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this occurs 1-4 weeks after infection with GABHS PHARYNGITIS
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What are the 5 major signs of RF?
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Myocarditis
Joint Swelling Chorea Subcue nodules Rash |
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What are Aschoff bodies/
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these are granulomas in the myocaridum replaced by scar tissues, due to RF
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What is Poststreptococcal Acute Glomerulonephritis associated with?
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Type 3 hypersensitivity rxn.
Children CUTANEOUS INFECTION Nephritogenic M protein causes this |
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how does a kid with AGN present?
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puffy face (edema)
Hematuria Possible hypercolemia |
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What is the Rapid Antigen Detection Test good for?
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Very specific (low false positive)
but not as sensitive (some false negatives) negatives confirmed by culture |
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What does the Bacitracin test look for?
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almost ALL group A streps are inhibited by bacitracin
so if it grows, its probably not group A strep |
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What does the PYR test do?
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this differentiates GAS from other B-hemolytic streps
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What serum titer is used to post strep infection to confirm?
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High titers of Antistreptolysin O (ASO)
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How long is the penicillin treatment for GAS?
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10 days penicillin VK
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what is the main therapy goal in treating strep pyogenes?
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eliminate it before day 9
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If your pt has a b-lactam hypersensitivty, what do you treat it with?
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Macrolides (mycins)
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what type of hypersensitivity is RF?
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a type 2 hypersensitivty
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What have all the vaccines tried to target?
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M protein
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