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The usual mechanisms of spread are inhaling droplets small
enough to reach the
alveoli and aspirating secretions from the upper airways. Other
means include
hematogenous or lymphatic dissemination and direct spread from
contiguous
infections. Predisposing factors include upper respiratory viral
infections,
alcoholism, institutionalization, cigarette smoking, heart
failure, chronic
obstructive airway disease, age extremes, debility,
immunocompromise (as in
diabetes mellitus and chronic renal failure), compromised
consciousness,
dysphagia, and exposure to transmissible agents.
Typical symptoms include cough, fever, and sputum production,
usually
developing over days and sometimes accompanied by pleurisy.
Physical
examination may detect tachypnea and signs of consolidation,
such as crackles
with bronchial breath sounds. This syndrome is commonly caused
by bacteria,
such as S. pneumoniae and H. influenzae.
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Pathogen multiplies in the alveoli
inflammation Irritation of airway
Exudates comes from bacteria erode
the lung
Increase goblet cel
Dead space happened
Occluded the airway Increase mucus
roduction
Decrease CO2 phagocytosis
cough crakles
hyperventilatio
consolidation Impaired O2 and CO2
exchange
