Pneumonia Flashcards
Common cause of lobar pneumonia
Strep pneumoniae
Reason for increased risk of pneumonia post influenza
Disruption of respiratory epithelium and ciliary dysfunction
Common causes of atypical pneumonia
Mycoplasma pneumoniae
Chlamydophila pneumonia
Viral
Timeframe for chronic pneumonia
Symptoms for 3 wks or more
CXR findings in typical pneumonia
Consolidation
CXR findings in atypical pneumonia
Patchy interstitial infiltrates
CXR findings in chronic pneumonia
Coin lesions
Localized collection of neutrophils/pus and necrotic pulmonary parenchyma
Lung abscess
Gram positive diplococci with a polysaccharide capsule. Causes typical pneumonia
Strep pneumoniae
Virulence factors of strep pneumoniae
Pneumolysin
IgA protease
Teichoic acid
Polysaccharide capsule
Phosphorylcholine
Cytokines increased by pneumolysin virulence factor of Strep pneumoniae
TNF
IL-1
Virulence factor of Strep pneumoniae that inhibits alternate complement pathway
Teichoic acid
Virulence factor of Strep pneumoniae that binds to platelet activating factor receptors on endothelial cells, leukocytes, and tissue cells to facilitate entry into cells
Phosphorylcholine
Gram positive diplococci that is optochin sensitive with alpha hemolysis on blood agar. It is bile soluble and activates autolysin.
Strep pneumoniae
Treatment options for strep pneumoniae
Third gen cephalosporin
Levoflox
Gariflox
Vancomycin
Penicillin if sensitive
Vaccine types for Strep pneumoniae
23 valent pneumococcal polysaccharide vaccine
Pneumococcal conjugate vaccine –> 12, 15, or 20
What is pneumococcal conjugate vaccine conjugated to?
Diphtheria toxoid
Gram negative rods that cause atypical pneumonia. Not transmitted person to person
Legionella pneumophila
Risk factors for legionella
> 50 yo
Smokers and COPD
Alcoholics
Immunocompromised
Main target of legionella in the human host
Macrophage
Negative on gram stain. Positive silver stain and DFA. Cultured on BYCE with cysteine and iron agar. Obligate or facultative IC pathogen
Legionella
Cytokines released by triggering of macrophage by legionella
TH1
IFN-gamma
IL-2
Function of type 1 interferon release in infection with legionella
Reduce replication and reduce iron required by bacteria
Signs of severe legionella infection
Respiratory failure
Bilateral pneumonia
Rapidly worsening pulmonary infiltrates
Neurologic symptoms
Treatments for legionella
Azithromycin
Fluoroquinolones
Common viral causes of atypical pneumonia
Influenza
RSV
Parainfluenza
Bacteria with peptidoglycan bound cell membrane containing sterols that requires cholesterol –> grows on fried egg colonies. To small to show up on gram stain
Mycoplasma pneumonia
Cause of ciliostasis in M pneumonia
Respiratory epithelial damage due to hydrogen peroxide
Complications of M pneumonia
Hemolytic anemia
Stevens Johnson syndrome
Raynaud’s phenomenon
Hypersensitivity type of Stevens Johnson syndrome
Type IV hypersensitivity
Increases risk of hemolysis in M pneumonia
Sickle cell disease
Treatments for M pneumonia
Erythromycin
Tetracyclines –> doxy
Prophylaxis for M pneumonia used in households with high-risk pt
Macrolide or doxycycline
TWAR agent
Chlamydophila pneumonia
Obligate IC organism that uses host ATP. Causes atypical pneumonia. May also infect and grow in smooth muscle cells, endothelial cells, coronary A, and macrophages
Chlamydophila pneumoniae
Metabolically inert form of Chlamydophila pneumoniae
Elementary body
Metabolically active form of Chlamydophila pneumoniae
Reticulate body
Methods used to identify inclusions of Chlamydophila pneumoniae
Giemsa stain
Immunofluorescence
Foreign material will localize to this portion of the lungs if the pt is sitting or standing
Posterior-basal segment of R lower lobe
Foreign material will localize to this portion of the lungs if the pt is supine
Superior segment of R lower lobe
Most common segment affected in aspiration pneumoniae
Superior segment of R lower lobe
Foreign material will localize to this portion of the lungs if the pt is on the R lateral decubitus
R middle lobe or posterior segment of R upper lobe
Common causal organisms of lung abscess in community acquired aspiration pneumonia
Oral anaerobes
Strep pneumonia
Klebsiella pneumonia
Oral anaerobes that can cause lung abscess in aspiration pneumonia
Prevotella
Bacteroides
Peptostreptococcus
Fusobacterium
Capsulated gram negative bacteria that ferments lactose. Forms colonies on MacConkey Agar and MAC. Possible causal organism of lung abscess in aspiration pneumonia
Klebsiella pneumoniae
Common causes of lung abscess in hospital acquired aspiration pneumonia
Oral anaerobes
Hospital gram negative enterics
S aureus
Complications of aspiration pneumonia
Lung abscess
Empyema
Common causal organisms in post-influenza pneumonia
S aureus
Strep pneumonia
H influenzae
Complication of post-influenza pneumonia
Empyema
Hallmark of post-influenza pneumonia
Abscess
Treatments for post-influenza pneumonia
Vancomycin
Linezolid
Clindamycin