Physical Examination
Fever will be present in the majority of patients with active pulmonary disease but is nonspecific. Unilateral, localized signs of consolidation suggest a bacterial process rather than a viral process or PCP.

Laboratory Testing
Relative leukocytosis is usually seen in patients with HIV infection who have bacterial infections. Neutropenia will identify most patients at risk for aspergillosis.

Chest x-ray
Although there are suggestive patterns, there are no pathognomonic x-ray findings for specific diagnosis.

Localized infiltrates in patients with HIV infection are most commonly associated with bacterial pneumonia. Mass lesions, including nodules, have been seen associated with fungal infections, lymphoma and Kaposi’s sarcoma. Cavitation is seen with tuberculosis, primarily in patients with CD4+ counts above 400 cells/mm3. Cavitation has also been described in association with PCP, bacterial pneumonia and Kaposi’s sarcoma. Collapse with volume loss usually implies endobronchial obstruction or extrinsic compression, which may be due to malignancy or lymphadenopathy. Mediastinal adenopathy has been described in tuberculosis and PCP and may be associated with lymphoma, histoplasmosis or Kaposi’s sarcoma.

The presence of pleural disease is most commonly associated with bacterial pneumonia. Effusions are seen with tuberculosis, fungal infections, and non-Hodgkin’s lymphoma. Rarely, effusion accompanies PCP.

It is also important to recognize that a normal chest x-ray does not rule out active pulmonary disease. Normal chest x-rays have been reported in active cases of PCP, tuberculosis, and fungal pneumonias.

Computed Tomography
Computed tomography (CT) scanning can be useful in identifying patterns that suggest specific pulmonary pathologies. For instance, a ground-glass appearance and cysts suggest PCP. CT scanning, especially high-resolution techniques, may also be useful by revealing infiltrates not appreciated on routine x-ray.

Sputum Examination
Gram’s stain and culture of expectorated sputum remains the standard for diagnosing community-acquired bacterial pneumonia. Examination of sputum for acid-fast bacilli (AFB) is important for diagnosis of tuberculosis.

Fiberoptic Bronchoscopy
Flexible fiberoptic bronchoscopy has a central role in the evaluation of respiratory symptoms in the HIV-infected patient. It is useful for obtaining pulmonary secretions, examining the airway, and obtaining tissue from the bronchus, the lung parenchyma, or adjacent tissue.

Because of the risk for pneumothorax, transbronchial biopsy is usually reserved for patients who have a nondiagnostic initial bronchoscopy or patients likely to have a process that requires tissue for diagnosis, such as CMV.

Blood Culture and Serologic Studies
The increased frequency with which the etiologic agents of pneumonia invade the bloodstream in persons with HIV infection indicates that blood cultures for bacteria, mycobacteria, and fungi are more likely to be positive than in HIV-uninfected individuals. Thus, when bacterial, mycobacterial, or fungal processes are suspected, blood cultures should be obtained.