Pulmonary Infections (Path) Flashcards
Classification of Pneumonias
(1) Community Acquired Pneumonias - bacterial, viral, etc
(a) Typical - Gm+/– bacteria
- -> lobar or broncho-pneumonia
(b) Atypical - viruses, other bacteria, fungi
- -> interstitial pneumonia
(2) Aspiration Pneumonias - anaerobic bacteria
(3) Nosocomial Pneumonias - various
impaired defenses leading to pneumonia
(1) ↓ cough reflex -> aspiration
(2) injury to mucociliary escalator (smoking, viral infection, genetic defects)
(3) secretions (cystic fibrosis, chronic bronchitis)
(4) edema/congestion (CHF)
(5) ↓ macrophage function (smoking, O2 toxicity)
community-acquired acute pneumonias
“Typical”
bacterial or viral; increased risk in v. young, elderly, chronic disease (COPD), immune deficiencies, lack of splenic function
morphology of lobar pneumonia
alveolar sacs fill w/ neutrophils, pink exudate
- congestion
- red hepatization - neuts + RBCs
- grey hepatization - RBC death
- resolution - Type II = stem cells
morphology of bronchopneumonia
acute neutrophilic suppurative exudation filling bronchi, bronchioles, alveoli that eventally resolves; involvement of pleura (pleuritis) can result in fibrous thickening or adhesions
causes of lobar pneumonia
Streptococcus pneumoniae
Klebsiella pnemoniae
causes of bronchopneumonia
Staphylococcus aureus Haemophilus influenzae type b Pseudomonas aeruginosa Legionella pneumophila Moraxella catarrhalis
Gm+ causes of pneumonia
diplococci, catalase negative - Streptococcus pneumoniae
cocci clusters, catalase pos - Staphylococcus aureus
most common cause of community acquired pneumonia
Streptococcus pneumoniae
diabetics, alcoholics
Klebsiella pneumoniae (aspirated Gm– enteric flora)
most common secondary to viral infection or chronic lung disease
Staphylococcus aureus
IV drug users
Staphylococcus aureus
common in children and adults w/ COPD
Haemophilus influenzae (type b) causes meningitis, epiglottitis in kids
common nosocomial, immunocompromised, cystic fibrosis
Pseudomonas aeruginosa
more severe in immunocompromised
transmitted via water source and aerosolization
Legionella pneumophila
common in elderly and patients w/ COPD
pediatric otitis media
Moraxella catarrhalis
Community-Acquired Atypical/”Walking” Pneumonias
viral or non-viral organisms (mycoplasma, chlamydia)
ranges from mild URIs to severe LRIs
morphology of atypical/interstitial pneumonia
diffuse interstitial infiltrates WITHOUT CONSOLIDATION
Streptococcus pneumoniae
(community-acquired typical pneumonia, lobar)
Gm+ diplococci
most common cause (adults, elderly)
-> empyema
Klebsiella pneumoniae
(community-acquired typical pneumonia, lobar)
Gm– rod
diabetic and alcoholics
aspirated Gm– enteric flora
mucoid capsule; gelatinous red-current jelly sputum
-> abscess
Staphylococcus aureus
(community-acquired typical pneumonia, broncho-)
Gm+ cocci clusters
most common 2ary (influenza, viral pneumonias)
IV drug users are at risk (+ endocarditis)
also elderly, hospitalized, chronic lung disease
-> abcess or empyema; hematogenous spread - endocarditis, brain and kidney abscesses
Haemophilus influenzae (type b)
(community-acquired typical pneumonia, broncho-)
Gm– coccobacillus; culture hematin/NAD+
common in children (causes meningitis, epiglottitis)
adults w/ COPD
Pseudomonas aeruginosa
(community-acquired typical pneumonia, broncho-)
Gm– rod; culture blue/green
nosocomial, immunocompromised, cystic fibrosis
focal hemorrhage and necrosis
Legionella pneumophila
(community-acquired typical pneumonia, broncho-)
Gm– coccobacillus; charcoal yeast + iron; stains poorly
immunocompromised
transmitted via water soure and aerosolization
*can also be categorized as an atypical pneumonia
