Imaging features of bacterial respiratory infections in AIDS

Although an emphasis has historically been placed on nonbacterial, opportunistic respiratory infections in HIV-infected individuals, it is increasingly important for clinicians to be familiar with the spectrum of bacterial respiratory infections that may occur in this population.

Bacterial pneumonia and acute bronchitis are currently the most common causes of respiratory disease in HIV-infected individuals in developed countries. Moreover, these infections are frequently the first clinical manifestation of HIV infection. Among patients with sustained CD4 cell count >200 cells/microL, the discontinuation of Pneumocystis carinii pneumonia prophylaxis is not associated with an increased risk of bacterial pneumonia. The most common radiographic pattern of bacterial pneumonia is focal consolidation, which typically presents in either a segmental or lobar distribution. In cases in which the chest radiograph is inconclusive, high-resolution chest CT has a very high accuracy for detecting pyogenic small airways disease and for distinguishing between P. carinii pneumonia and other lung infections including bacterial infection.

Knowledge of the characteristic imaging and clinical features of bacterial respiratory infections can enhance their timely diagnosis and treatment.