CXR Abnormality	Non-infectious Etiologies	Infectious Etiologies	Empiric Therapy
Focal Consolidation	Pulmonary embolism Pulmonary hemorrhage Tumor Less likely:      Drug-induced      Radiation-induced	Bacterial · Consider S. pneumoniae, H. influenzae,  Legionella pneumophila, and Mycoplasma pneumoniae if acquired in community · Consider S. aureus and GNRs if acquired nosocomially Typical and atypical mycobacteria Fungal:   Aspergillus species, Histoplasma    capsulatum, Cryptococcus neoformans,    Coccidiodes immitis Nocardia asteroides Less likely: Pneumocystis carinii, viral	Community acquired: · Macrolide + 2nd gen ceph, non-pseudomonal 3rd gen ceph, Amp/Sulb, or “new” quinolone Nosocomial: · Non-pseudomonal 3rd generation cephalosporin, Pip/Tazo, Ticar/Clav, Imipenem, Meropenem, or combination of Clinda plus either Aztreonam, Gati, Levo, Cipro, Ceftazadine or Cefepime · Add Vanco if high incidence of MRSA · Add AG if severely ill · Add Ampho B if acutely ill and prolonged immunosupression and broad spectrum antibiotic use
Nodular Infiltrates	Tumor BOOP	Fungal: Aspergillus species, Histoplasma    capsulatum, Cryptococcus neoformans,    Coccidiodes immitis Nocardia asteroides Bacterial (especially septic emboli secondary to a central intravenous catheter) Typical and atypical mycobacteria Less likely: Pneumocystis carinii, Legionella micdadei, Rhodococcus equi	Ampho B Add Vanco + Gent if central venous catheter in place Consider TMP/S if severely ill while awaiting diagnostic evaluation
Diffuse Infiltrates	· Pulmonary edema · Drug-induced · Leukoagglutination reaction (Consider when syndrome occurs acutely following transfusion) · Radiation-induced · Tumor · Kaposis sarcoma (Consider in AIDS patient with skin or mucous membrane lesions) · Pulmonary hemorrhage · BOOP	· Pneumocystis carinii · Viral     -Consider influenza if community acquired and appropriate season     -Consider CMV in transplant population. CMV only rarely a true pulmonary pathogen in AIDS     -Less common: VZV, HSV · Fungal: Histoplasma capsulatum,      Cryptococcus neoformans · Toxoplasma gondii · Typical and atypical mycobacteria MTb commonly presents with diffuse infiltrates in advanced immunodeficiency · Bacterial: Legionella pneumphila, Mycoplasma pneumoniae, Chlamydia pneumonia	TMP/S + Macrolide Add Ganciclovir in transplant patients if appropriate risk factors are present