Atypical vs. Typical CAP - Clinical Signs/Sx

Definition of CAP: Community Acquired Pneumonia is acquired in the community or within the first 72hrs of hospitalization

Typical

Bugs: 

S. pneumo (most common)

H. Flu

Staph aureus

Klebsiella

Clinical Symptoms:

Quick onset with fever/chills

Pleuritic chest pain

Productive (thick) cough

Signs:

Tachycardia

late inspiration crackles

CXR:

Lobar consolidation

Tx:

Doxycycline, Azithromycin, Clarithromycin, Flouroquinolones

Atypical

Bugs: 

Mycoplasma pneumoniae (most common)

Chlamydia pneumoniae

Chlamydia psittaci 

Coxiella burnetii

Legionella

Viruses

Clinical Symptoms:

Slow onset

HA, sore throat, fatigue, myalgias

Dry cough

Fever

Signs:

normal pulse with high fever

wheezing/rhonci

CXR:

Diffuse infiltrates

No/minimum consolidation

Tx:

start empiric tx with:
 erythromycin (for Mycoplasma pneumoniae and Legionella)
tetracycline (for Chlamydia pneumoniae)

Pic: http://emedicalppt.blogspot.com/2011/02/community-acquired-pneumonia-cap.html

Source: Step Up to Medicine 2nd Ed Agabegi and Agabegi