TABLE 1.

DEFINITION OF IDIOPATHIC PNEUMONIA SYNDROME

I: Evidence of widespread alveolar injury:
a. Multilobar infiltrates on routine chest radiographs or computed tomography
b. Symptoms and signs of pneumonia (cough, dyspnea, tachypnea, rales)
c. Evidence of abnormal pulmonary physiology
1. Increased alveolar to arterial oxygen difference
2. New or increased restrictive pulmonary function test abnormality
II: Absence of active lower respiratory tract infection based upon:
a. Bronchoalveolar lavage negative for significant bacterial pathogens including acid-fast bacilli, Nocardia, and Legionella species
b. Bronchoalveolar lavage negative for pathogenic nonbacterial microorganisms:
1. Routine culture for viruses and fungi
2. Shell vial culture for CMV and respiratory RSV
3. Cytology for CMV inclusions, fungi, and Pneumocystis jirovecii (carinii)
4. Direct fluorescence staining with antibodies against CMV, RSV, HSV, VZV, influenza virus, parainfluenza virus, adenovirus, and other organisms
c. Other organisms/tests to also consider:
1. Polymerase chain reaction for human metapneumovirus, rhinovirus, coronavirus, and HHV6
2. Polymerase chain reaction for Chlamydia, Mycoplasma, and Aspergillus species
3. Serum galactomannan ELISA for Aspergillus species
d. Transbronchial biopsy if condition of the patient permits
III: Absence of cardiac dysfunction, acute renal failure, or iatrogenic fluid overload as etiology for pulmonary dysfunction

Definition of abbreviations: CMV = cytomegalovirus; HSV = herpes simplex virus; RSV = respiratory syncytial virus; VZV = varicella zoster virus.

Table updated from Reference 1.