Clinical features of HIV-Associated Disorders of the Respiratory Tract

Disorders Not Necessarily Associated with Severe Immune Suppression

Bronchitis

Acute bronchitis in the PCHIS was defined by the presence of cough with sputum production for at least 48 hours and a chest film that showed either no or stable parenchymal infiltrations occurring in a study subject who did not develop an identified pulmonary infection. Evaluations to attempt to determine the microbial cause of the bronchitis were not performed in the PCHIS. It was the general impression of the investigators that the illness tended to be self-limited but recurrent. Not surprisingly, bronchitis was more common among cigarette smokers.

Airways disease may be recognized on plain chest films by the presence of peribronchial thickening and is more clearly seen on computed tomographic (CT) scans, especially thin-section scans. In addition, bronchiectasis may also occur without a recognized antecedent lung infection. Bronchiectasis may also be a sequela of bacterial lung infection or, occasionally, PCP.

Although in the PCHIS cohort the episodes of acute bronchitis were neither associated with nor portended any other significant pulmonary diseases, the disorder may be problematic in that the symptoms may be mistaken as an indication for further, often invasive, evaluations. In general, however, bronchitis is recognizable by the absence of parenchymal infiltrations on chest films and, thus, when the constellation of symptoms and findings described previously is noted, one should, generally, simply observe the patient, with or without antimicrobial therapy, and not undertake further evaluations.

Bacterial Pneumonia

As shown in Table 412-1 , bacterial pneumonia occurred at a rate of 5.63 episodes per 100 person-years of observation in the PCHIS cohort. Bacterial pneumonia was defined as the presence of cough that was productive of purulent sputum, an area of parenchymal infiltration on chest film, and a response to antimicrobial therapy. A specific causative agent was identified in 35% of cases, a proportion that is consistent with the results of studies of the etiology of community-acquired pneumonia in persons without HIV infection.

Of the episodes for which the cause was established, Streptococcus pneumoniae accounted for 67% and Haemophilus influenzae 15%. These two agents have been generally ranked first and second in most reports of bacterial pneumonia in persons with HIV infection. In most reports, Staphylococcus aureus has been the third most common agent and seems to be especially common among persons with pulmonary KS. A long list of other bacterial pathogens has also been described as causing pneumonia in the setting of HIV infection (Table 412-2).