lecture 28-lower respiratory tract infections Flashcards
(29 cards)
bacterial pneumonia
describe infection
sputum features
symptoms
- often a secondary infection from a viral respiratory tract infection
- inflammation of lung as result of bacterial infection
- sputum-rust colored, foul smelling, watery, purulent (pus)
- symptoms- crackles upon auscultation, fever, malaise, pleuritic chest pain, dyspnea,
common virulent factors for bacterial lung pneumonia
-virulence factors- capsid, intracellular growth, IgA protease, exotoxins, LPS endotoxin
what does the chest xray look like for a pt who has pneumonia?
- opacity
- fluid, bacteria, neutrophils and fibrin that leads to consolidation (lungs so full that they cant expand) or infiltrate that shows that opacity
bacterial pneumonia lobar vs patchy cxr patterns and the bacterias that cause this
- *-lobar- part of TYPICAL PNEUMONIA PATTERN- covers entire lobe and leads to consolidation: streptococcus pneumoniae, s. aureus, H influenzae, most gram negative bacteria = PIA
- *patchy- ATYPICAL pneumonia -patchy and not full consolidation= mycoplasma pneumonae, chlamydophila pneumonae and legionella pneumophila (mike was in the legion with chlamydia and he’s super atypical)
how do the lungs look for a lobar vs bronchopneumonia
bronchopneumonia- has pus and looks uglier and darke
symptoms of typical vs atypical
- onset- typical sudden/atypical gradual
- looks- toxic/well (walking pneumonia)
- purulent (bloody)/scant, watery
- WBC count- left shift-causes lobar pneumonia/ patchy infiltrate
most common cause of typical pneumonia
most common cause of atypical pneumonia
typical- streptococcus pneumoniae
atypical- mycoplasma pneumoniae
complications of pneumonia
- pleural effusion -effusion into pleural space
- anemia and thrombocytopenia
- decreased pO2
- muscle atrophy
- bronchiectasis- irreversible dilation of the bronchi and bronchioles caused by muscle and elastic tissue damage
aspiration pneumonia
- different from typical and atypical
- aspiration of foreign material into the bronchial tree
- carry bacteria in and dilute out things needed to clear normal crap
- typical in alcoholics (puke) coma pt, stroke pt
- secondary bacterial pneumonia
Cap vs Hap
community acquired pneumonia- pneumonia acquired anywhere else besides hospital
hospital acquired- associated with intubation that interferes with mucocilliary escalator- OFTEN CAUSED BY GRAM NEG BACTERIA
differential diagnoses of pneumonia
-CHF, lymphoma, carcinoma, lupus, drug hypersensitivity, lung vasculitis
what do the labs look like for a pneumonia pt
elevated wbc (left shift)
elevated immature neutrophils
positive blood culture
sputum >25 PMNs and <10 epithelial cells
streptococcus pneumoniae what does it cause? what kind of bacteria? alpha or beta hemolytic? catalase neg or pos? seroypes? aka- bile solubility?
-normal in upper respiratory tract
-causes; pneumococcal pneumonia
-gram positive- diplococci in chains
-alpha hemolytic (some not hemolyzed-green)
-catalase neg
serotypes >90
aka -pneumococcal
bile-positive
pneumococcal virulence factors
- capsule
- surface adhesins
- IgA protease- (cleaves IgA and prevents clearance)
- pneumolysin -pore forming toxin
- teichoic acid and peptidoglycan- inflammation
how does streptococcus (pnumococcal) pneumoniae work?
- cough, fever, dyspnea, chest pain, crackles and sputum-rust colored
-preceded by days of rhinorrhea
-abrupt spiking fever
-pleuritic chest
-poor oxygen
resolves 7-10 days
treatment and prevention of s. pneumoniae for pneumonia
treatment- PCN, azithromycin and cephalosporin
prevention- 2 vaccines
staphylococcus aureus
type:
catalase?
coagulase?
- gram pos
- catalase- positive (different from strepto pneumonae)
- coagulase-positive- in order to distinguish from other staph’s
virulence factors of s. aureus
- protein A-binds Fc portion of antibody- coats itself in antibody to make it look like antibody vs antigen
- coagulase- clotting fac
- Panton Valentine leukocidin- severe necrotizing pneumonia and pore-forming cytotoxin
MRSA
-methicillin resistant staph aureus
-resistant to all beta lactam antibiotics including cephalosporin
-Harder to treat, no necessarily more virulent
-treatment- PCN and cephalosporin (if not resistant)
if resistant- linezoloid or vancomysin
what are the two main gram negative bacterias that cause typical pneumonia-aerobic and anaerobic
anaerobic- klebsiella pneumoniae
aerobic- pseudomonas aeruginosa
(menumonic-arrogant surgeon gives you oxygen and if you get clubbed you don’t get oxygen)
= usually hospital acquired and come from aspiration pneumonia -generally pt have underlying disease
what’s the biggest prob when it comes to gram negative pneumonia
antibiotic resistance
treatment and diagnosis of gram neg pneumonia
- diagnosis- blood culture pos in 20% of pt
- > 25PMNs , 10<epithelial cells
treatment: broad spectrum antibiotics and multidrug therapy
klebsiella pneumoniae
type
what does it have that make them resistant to antibiotics
- gram neg rod that causes pneumonia
- non-motile
- mucoid colonies (capsule)
- strains contain beta-lactamases that make them resistant to beta lactam antibiotics
where are klebsiella pneumoniae found? and what virulence factors does it have?
symptoms? mortality rate?
oxidase?
- found in resp tract and in SOME peoples feces
- has capsule and LPS (b/c it’s gram neg)
- bloody sputum and necrosis, classic lobar- “currant jelly sputum”
- 50%
- oxidase neg
