Pneumonia Flashcards
Pneumonia definition and most important clinical point
Infection of the lung parenchyma
When you are dealing with a patient with pneumonia, the most important thing you can do is figure out what the bug is*
Defense mechs
Nasal clearance
Tracheobronchial clearance…mucociliary escalator
Alveolar clearance…alveolar macrophages phagocytize
Despite the large number of organims in the URT, the LRT is pretty sterile
Think smokers, intubated, long term steroids,
Transmission of pathogens to the lung (asp)
Most commonly - aspiration of organisms that colonize the oropharynx
Some during certain times of the year, some only during certain situations
Inhalation and other ways
Organsism are 1-10 microns…TB, influenza, histoplasmosis
Hematogenous spread
Direct penetration
Direct extension from close infection (overhwelming sepsis)
Patho of lobar
Consolidation of entire lobe of the lung
Pneumococcus causes 90-05%
Congestion
Red hepatization
Gray hepatization
Resolution
Broncho vs. lobar
Lobar - entire lobe
Broncho - alvolar spaces around the major bronchi
CXR lobar pneumonia
Lobe will appear white bc full of pus instead of air
Patho of lobar (on slide)
Will see pus in the alveolar space…means when someone coughs, something comes out
Bronchopneumonia patho
Patchy consolidation through more than 1 lobe
Bacterial
Very common at autopsy
Grossly scattered 3-4 cm ofci
PMNs in alveolar space around larger bronchi
Patho of interstitial pneumonitis
Inflammation in the interstitium but NOT alveolar space
Caused by mycoplasma pneumonia and viruses
No gross evidence of consolidation…looks kind of dirty
Micro-lymphocytes in the interstitium
Microscopic - interstitial pneumonia
Widening of all the walls of inflammation
Comps from pneumonia
Lung abscess
Empyema - pus out in the pleural space
Organization - Pt doesn’t cough inflammation out and it turns to scar
Bacteremia going to heart valves, CNS, or joints
Typical vs. atypical pneumonia
Typical - pneumococcus
Atypcial - mycoplasma
Atypical looks more normal than typical
Pneumoccocal
Etiology, patho, gross, micro
Strep pnuemoniae is biggest one
Aspiration, attachment of antiphagocytic capsule of pneumolysis
Classic stages of lobar pneunmonia
PMNs since bacterial
Looks clinically typical
Haemophilus infleunzae
Etiology, patho, gross, micro, clinical
Haemophilus type B but also other non-type B due to HiB
Colonization, aspiration, laryngotracheobronchitis can result
Bronchopneumonia or lobar
PMNs bc bacterial
Pediatric emergency
Legionnares dz
Etiology, patho, gross, micro, clinical
Legionella pneumophilia
Colonizes air conditioners…can block ofrmaiton of phagolysosome…can rupture macrophages via pore formign toxins
Bacterial so consolidation
PMNs and macropahges
Depends on health of host..if healthy, feels like flu…dx via urinary antigen testing
Anaerobic pneumonia
Etio, path, gross, micro, clinical
Bacteroides, fusobacteria, actinomyces, microaerophilic cocci
Aspiration and bad teeth
ronchopneumonia or rearely lobar can form abscesses in the lung
Bacterial so heavy PMN infiltrate
Bad teeth, high fever, productive cough
CO-MRSA
Etio, path, gross and and micro, clinical
CO-MRSA
More likely to be in skin or soft tissue infections than HA-MRSA
Similar to other bacteria
Younger healtheir with a bilateral necortizing pneumonia and abscesses…these organisms must be covered for in this setting
Mycoplasma
etiology, path, gorss, macro, clinical
Mycoplasma pneumoniae
Can interfere with cilia and cause desquamation of surface epithelium…passed by resp droplets
Very little seen grossly
Classic interstitial pneumonits
Class dry cough and CXR…PCR is gold std for diagnosis
Chlyamydial pneumonia
Etio, patho, gross, micro, clinical
Obligate intracellular parasite…LPS stimulate inflammation
Can depend on severity
Interstitial lymphs and histiocytes
Usually in young adults 1-3 weeks after a pharyngitis…PCR is gold std
Viral pneumonia
Etiology, patho, gorss, micro, clinical
Influenza, adenovirus, RSV
Spread via droplets, can vary in severity…influenza may get bacterial superinfecion
Congestion but no consolidation
Intersittial lymphs and histiocytes
Sx often not resp…dx done via nasal swab or PCR
Pseudomonas pneumonia
Etiology, path, gorss, micro, cliicial
Pseudomonas aeruginosa
over 50% of hospitals
Bronchopneumonia
Bacterial so PMNs in alveolar space
Fever, dyspnea, and CXR during hospitalization..sputum for dx
Enteric gram neg bacilli pneumonia
Etio, path, gross, micro, clinical
Serratia, enterbacter
Colonization and aspiration…klebsiella has antiphagocytic casule
Gross - broncho or rarely lobar…kelbsiella can produce abscess
Bacterial so PMN rich in alveolar space
Fever, sputum, and CXR…blood cultures important…rales may be influenced by hydration of pt
Staph - hospital
Etiology, patho, gross, micro, clinical
HA-MRSA
Colonization-aspiration or hematogenous from IV site
Broncho, lobar, or abscess
Can be multifocal if hematogenous
Can be dramatic or subtle depending on route
Cell counts of pnuemonia for HIV
And other things
Typical bacteirial can still ocur and be severe
Some infiltrates on CXR are not infection but Kapsoi sarcoma
> 200 - bacteiral
50-200 - CMV
Under 50 - pneumocystis
Pneumocystis penumonia
Etio, patho, gross, micro, clinical
Pneuocystis carinii
Ubiquitious organisms tht fills alvolear spaces with little rxn
Lung is solid and airless
ALveoli look foamy
Resistent infiltrate…may be confirmed by BAL and silver stain PCR can be done
CMV
Etio Path Gorss Micro Clinical
SImilar to mono in normal but IC are overhwelemd
Patchy or diffuse infiltrate seen
Classic intranucelar inculsions
IN HIV, common with PCP dx oftne iwth PCR on BAL or evidence of CMV cytopathic effect on cytology
Histoplasmosis pneumonia
Etio, patho, gross, micro, clinical
Histoplasma cpasulatum
Lives in soil and is inhaled…granulomas in normal pt but not in IC
Can be focal airless consolidation
Grandulomas not seen, only yeast
Can look like miliary TB with fever, night sweats and wieght loss…dx by urine antigen testing or culture…PCR is insensitive
