Pneumonia, Rheumatic Fever, Endocarditis Flashcards
What bacteria causes most pneumonia?
strep pneumoniae
What are the predisposing conditions that make pneumonia more likely in some people?
impeded drainage from lungs
HF, viral infection, immobility, foreign bodies, suppressed cough reflex, smoking, allergies
How do you diagnose strep pneumoniae?
clinical features, DIRECT EXAMINATION of SPUTUM for presence of DIPLOCOCCI, culture for abx sensitivity
step pneumoniae is _____ hemolytic, gram ______, ___cocci, lancefield group ______, ______ sensitive
alpha hemolytic gram positive doplicocci lancefield group negative bile/ optochin sensitive
Strep pneumoniae reservoir
throat 5-50% of people
strep pneumoniae toxins
leucocidins
what type of capsule does strep pneumoniae have? What functions does it serve?
polysaccharide capsule; antigen and virulence factor –> stimulates opsonizing antibody AND impedes phagocytosis
How is the strep pneumonia vaccine made? Who should get it?
polysaccharide capsule is used in the polyvalent vaccine
-elderly or susceptible patients
how do you treat strep pneumoniae?
PCN/erythromycin, drug resistance has increased so vancomycin is the alt.
*test for drug sensitivity
When is pneumonia most common? Why?
Winter–> close quarters–> viruses spread–> pneumonia predisposition
What are the other common causes of pneumonia besides strep pneumoniae?
klebsiella pneumoniae, S. aureus, Group B step, HACEK gram negative rods
What is a rheumatic fever?
post-streptococcal condition that arises ~3 wks after resolution of sore throat caused by group A stre
A 9yo patient with fever, polyarthritis, endocarditis, myocarditis presents to your clinic. Her sx started a few months ago after a strep infection. What do you think the diagnosis is?
Rheumatic fever
kids 6-15 are the at-risk group
What will you find if you culture the lesions of rheumatic fever?
NOTHING; the lesions are sterile because it is a post-strep condition
How do you diagnose rheumatic fever?
clinical features + IgM anti-streptolysin O Ab + sterile lesions + inflamed joints are sterile + Aschoff body
Although the pathogenesis of rheumatic fever has not been directly demonstrated, it is thought to be:
auto-immune
certain M-protein types (M5, M3) are more likely to be assoc. with Rheumatic Fever
certain HLA types are more common in pts
Why are rheumatic fever patients at life-long risk for endocarditis?
Rheumatic fever endocarditis can cause fibrosis or calcification of the endocardium which can distort and damage the valves permanently
What is the treatment for Rheumatic Fever?
anti-inflammatory drugs, no abx! May require valve replacement
When do you treat Rheumatic Fever patients with abx?
Pts with a hx of RF should have aggressive abx tx if they have subsequent strep infections
What are the virulence factors of endocarditis?
extracellular polysaccharides (make the bacteria “sticky” and create vegitations
splinter hemorrhages under the fingernails and conjunctiva indicate _________.
edocarditis
What are the bacteria that commonly cause endocarditis?
S. viridans, IV drug users sometimes get endocarditis from S. aureus, HACEK gram negative rods also cause endocarditis
Post-streptococcal conditions, such as RF, are assoc. with variants in which aspect of streptococcus>
The M protein
