ID Exam 2 Pneumonia and opportunistic infections Flashcards
Predisposing factors to opportunistic infections and bugs
Granulocytopenia (chemo/radiation): G- and staph Cellular immune dysfxn (T-cell): intracellular Humoral dysfxn (B-cell): encapsulated Foreign body (cath, implant): G- and staph Surgery: staph, e-coli, pseudo
Iron states and relation to infection
High iron states promote infection
Host response is to down regulate iron absorption during infection (fever)
Hemochromatosis can predispose to infection
Acinetobacter baumanni
Common is desert soil
Infected wounds of soliders in Iraq
Acts pseudo like
Pseudo aeruginosa: characteristics
G- rod, oxidase +, catalase + (CGD assoc), obligate aero
Thrives in aquatic environments
Encapsulated
Pseudo aeruginosa and CF infections
Higher calcium secretion (as chloride is sequestered)
Calcium creates cross-linking of alginate
Can’t cough up pseudo
Pseudo virulence
High resistance mechs (efflux pumps)
Biofilm forming
Exotoxin A: similar to diptheria, ribosylation of EF2
Pseudo associations
Burn patients Nosocomial pneumonia and UTI's Respiratory failure in CF Osteomyelitis (IV drug users, diabetics) Hot tub folliculitis Otitis externa Systemic infection: ecthyma gangrenosum
Treatment of pseudomonas
Piperacillin
Also AG’s and FQ’s
1st cause of death from infection
The PNEUMONIA
PNA most likely bugs: Acute presentation, 19 years old Acute presentation, 65 years old Subacute, Asian immigrant Subacute, HIV
Mycoplasma
Strep. pneumo
TB
PCP
Mycoplasma pneumo
No cell wall, don’t gram stain
Lots of cholesterol in membrane
Atypical, walking pneumo (CXR looks worse than clinical)
Young adults, close contact (esp. military recruits)
Cold agglutination of RBC’s by IgM (dx test)
Culture: Eaton’s agar
Tx: macs (no cell wall)
Atypical PNA bugs
Myco. pneumo
Chlam. pneumo
Legion. pneumo
Influenza, RSV, adenovirus
Atypical spelling of MILC
Typical PNA bugs
Strep pneumo
H. Flu
M. catarrhalis
S. aureus
Steamboat Springs Has Moose? (so Typical)
Complications of CAP
Effusion Respiratory failure Cavitation Pneumothorax PE CVD: CHF/MI/CVA/Afib
Strep pneumo diseases
Meningitis
Otitis media
Pneumonia
Sinusitis/bronchitis
Strep pneumo pathogenesis
Aspiration into lungs Adhere to epithelium (Cho-P on bug with platelet activating factor on epi) Epi injury (H2O2 and pneumolysin [similar to streptolysin])
Host defense agains strep pneumo
Bind IgA antibody and don’t bind epi
Bind Fc region with macrophage on other end
Bind epi and activate PMN’s via cytokines
How sick is a PNA patient?
C - confusion U - uremia R - respiratory rate >30 B - BP < 90/60 65 >65 y/o
> /=3 -> ICU
2 = ward
=1 -> outpatient
CAP treatment: 4 groups
Previously healthy outpatient: mac; doxy
Outpatient w/ comorbid: FQ; mac + augmentin
Inpatient not ICU: FQ; mac + ßlactam/3rd cef
Inpatient ICU: 3rd cef + FQ/mac (anti-pseudo ßlactam)
Encapsulated disease
Meningitis: Strep pneumo>N. men>H. flu
PNA: Strep pneumo>H. flu
Otitis media: Strep pneumo, Moraxella sp, H. flu
H. flu: characteristics
Gram- coccobaccilus Chocolate agar (Factor V and Factor X) V= nicotinamid (NAD), X= hematin Blood agar: grows close to s. aureus Aersol transmission
H. flu: disease
Epiglottitis
Otitis media
Meningitis (capsular form, type B)
Splenectomy: aseptic arthritis
Phylis’ shop is next to MOES bagels
H. flu: vaccine and treatment
Vaccine against type B capsule
Polysacchride of H. flu conjugated to diptheria toxoid
Give at 2-18 months
Treatment: ceftriaxone, rifampin for close contacts in meningitis
N. men: characteristics and pathogenesis
Respiratory spread/nasopharynx colonization
Ferments maltose
Encapsulated
LOS (version of LPS) causing SIRS, DIC (petchial rash)
Waterhouse Friderichsen syndrome (adrenals)
