Infectious Diseases in Critical Care Medicine

occur with HIV or TNF-aantagonists. Clinically, cavitation<72 hours occurring in a patient

with CAP is limited toS. aureusorP. aeruginosapneumonias (Table 12).

In adults, human seasonal influenza A may usually present as influenza pneumonia

alone and less commonly with superimposedS. aureuspneumonia with focal segmental/lobar

Table 10 Clinical Diagnostic Approach to Severe CAP with Bilateral Diffuse Pulmonary Infiltrates

With mild/moderate hypoxemia With severe hypoxemia
(;PO 2 /N/:A–a gradient) (;;;PO 2 /A-a gradient>35)

.Aspiration pneumonia .PCP

.Acute pulmonary edema .CMV

.Typical bacterial pneumonias .HSV-1

.Atypical bacterial pneumonias .HHV-6

.Advanced pulmonary TB .Human seasonal influenza A

.Fungal pneumonias .Avianinfluenza (H5N1)

.Rickettsial pneumonias .Swine influenza (H1N1)

.Parasitic pneumoniasa .SARS

.Radiation pneumonitis .BOOP

.Pulmonary drug reactions

.Noncardiogenic pulmonary edema

.Leukostasis

aexcluding PCP.

Abbreviations: TB, tuberculosis; Pneumocystis (carinii) jiroveci pneumonia (PCP); CAP, community-acquired
pneumonia; CMV, cytomegalovirus; HSV, herpes simplex virus; HHV, human herpes virus; BOOP, bronchiolitis
obliterans with organizing pneumonia.

Table 9 Swine Influenza (H1N1) Pneumonia: Winthrop-University Hospital Infectious Disease Division’s Clinical
Diagnostic Point Score System for Adults with Negative Rapid Influenza Diagnostic Tests (RIDTs)

Adults with an ILI with fever> 1028 F and a CXR with no focal/segmental lobar infiltrates with negative
RIDTsplusthis Diagnostic Triad{:
l Severe myalgias
l Relative lymphopenia(otherwise unexplained*)
l Elevated CPK(otherwise unexplained)

þ 5
þ 5
þ 5
Consistent butnotessential:
l Elevated serum transaminases (SGOT/SGPT)
l Thrombocytopenia (otherwise unexplained)

þ 2

þ 2

Arguesagainstthe diagnosis of Swine influenza (H1N1) Pneumonia:
l Relative bradycardia (otherwise unexplained)
l Leukopenia (otherwise unexplained)
l Atypical lymphocytes
l Highly elevated serum ferritin levels (> 2 n)
l Hypophosphatemia (otherwise unexplained)

Swine influenza Diagnostic Point Score Totals:
Probable swine influenza (H1N1)¼ > 15
Possible swine influenza (H1N1)¼10–15
Unlikely swine influenza (H1N1)¼ < 10

{Diagnostic tests negative for other viral CAP pathogens (CMV, SARS, HPS, RSV metapneumoviruses,

parainfluenza viruses, adenoviruses).
*Other causes of relative lymphopenia:Infectious causes: CMV, HHV-6, HHV-8, HIV, military TB, Legionella,
typhoid fever, Q fever, brucellosis, SARS, malaria, babesiosis, influenza A, avian influenza (H5N1), RMSF,
histoplasmosis, dengue fever, chickungunya fever, ehrlichiosis, parvovirus B19, HPS, WNE, viral hepatitis,
Noninfectious causes: cytoxic drugs, steroids, sarcoidosis, SLE, lymphoma, RA, radiation therapy, Wiskott-Aldrich
syndrome, Whipple’s disease, severe combine immunodeficiency disease (SCID), common variable immune
deficiency (CVID), Di George’s syndrome, Nezelof’s syndrome, intestinal lymphgiectasia, constrictive pericarditis,
tricuspid regurgitation, Kawasaki’s disease, idiopathic CD 4 cytopenia, Wegener’s granulomatosis, acute/chromic
renal failure, hemodialysis, myasthenia gravis, celiac disease, alcoholic cirrhosis, coronay bypass, CHF, acute
pancreatitis, carcinomas (terminal).
Source: Adapted from Ref. 10.

Severe Community-Acquired Pneumonia in Critical Care 171