Infectious Diseases in Critical Care Medicine

superimposed Staphylococcus aureus pneumonia, or unrelated systemic disorder causing
hypotension/shock, i.e., acute MI, pulmonary embolus, etc. Virulent viral/zoonotic pathogens
aside, normal hosts do not present with severe CAP with hypotension/shock (1,8–10,26–30)
(Tables 5 to 7).

Table 5 Epidemiologic Clues to the Etiology of Severe CAP

Epidemiologic cluesa CAP pathogen associations

.Air travel Legionnaire’s disease

Human influenza A

Avian influenza (H5N1)

Swine influenza (H1N1)

.Rodent exposure SARS

HPS

Plague

.Deer/rabbit/ticks Tularemia

.Birds/poultry Avian influenza (H5N1)

.Closed populations/crowded exposures Adenovirus

.Cats Q fever

Tularemia

Plague

.Pigs Swine influenza (H1N1)

.Construction/water/air conditioning Legionnaire’s disease

.HIV/organ transplants/immunosuppressive

drugs/steroids

PCP

Legionnaire’s disease

aRecent close contact history.

Abbreviations: SARS, severe acute respiratory syndrome; CAP, community-acquired
pneumonia; HPS, hantavirus pulmonary syndrome; PCP,Pneumocystis (carinii) jiroveci
pneumonia.

Table 6 Clinical Clues to the Causes of Severe CAP

Clinical clues CAP pathogen associations

.Hyperacute onset Human influenza A

Avian influenza (H5N1)

Swine influenza (H1N1)

SARS

Tularemia

.Afebrile Plague

.Relative bradycardia Legionnaire’s disease

Q fever

.Severe myalgias Human influenza A

Avian influenza (H5N1)

Swine influenza (H1N1)

.Mental confusion Legionnaire’s disease

.Prominent headache Tularemia

Q fever

.Conjunctival suffusion Adenovirus

Human influenza A

.Sore throat Avian influenza (H5N1)

Swine influenza (H1N1)

SARS

.H. labialis S. pneumoniae

.Chest pain

Substernal HPS

Pleuritic Human influenza A

.Watery diarrhea/abdominal pain Legionnaire’s disease

Swine influenza (H1N1)

.Splenomegaly Q fever

CMV

Abbreviations: SARS, severe acute respiratory syndrome; CAP, community-
acquired pneumonia; CMV, cytolomegalovirus; HPS, hantavirus pulmonary
syndrome.

168 Cunha