Table 1

HIV associated pulmonary infections

*The common causes of bacterial pneumonia are shown.5,6 One third of the pneumonias are bacteraemic. Bacteraemia is more common in pneumococcal pneumonia. Pseudomonal pneumonia is associated with a lower CD4 count than with pneumococcal pneumonia.6
**Multidrug-resistant (MDR) tuberculosis (resistant to isoniazid and rifampicin) is becoming an increasing problem among HIV positive individuals in North America. Antituberculous treatment requires careful monitoring for drug interactions and toxicity, especially if the patient is on HAART. Interactions such as those between the rifamycins and protease inhibitors or non-nucleoside reverse transcriptase inhibitors can lead to lower efficacy or increased toxicity of the anti-retroviral regimen.4
***Cryptococcal infection presents either as a primary lung infection or as part of a disseminated infection with cryptococcaemia, pneumonia, meningitis, and cutaneous disease.8
Streptococcus pneumoniae*M tuberculosis** Pneumocystis carinii Toxoplasma gondii,Influenza
Haemophilus influenzae* M avium intracellulare Cryptococcus neoformans***Cryptosporidium sppParainfluenza
Staphylococcus aureus* M kansasii Candida albicans Microsporidium sppRespiratory syncytial virus
Klebsiella pneumoniae* Aspergillus sppLeishmania sppRhinovirus
Pseudomons aeruginosa* Penicillium marneffei Strongyloides stercoralis Adenovirus
Nocardia asteroides Histoplasma capsulatumCytomegalovirus
Rochalimaea henselae Coccidiodes immitisHerpes simplex virus
Blastomyces dermatitidis Herpes varicella-zoster virus
Bacterial pneumonia occurs more frequently in HIV positive patients at all CD4 counts than HIV negative controls. The risk increases as the CD4 count falls below 200 cells/mm3and in intravenous drug users5HIV positive individuals are at increased risk of infection with M tuberculosis, whatever the CD4 count, and should be offered an HIV test.7 Extrapulmonary tuberculosis tends to occur at CD4 counts <150 cells/mm3. M avium intracellulare and M kansasii both occur late in the course of HIV infection when the CD4 count falls below 50–100 cells/mm3Pulmonary infections with Candida and Aspergillus are relatively rare. Endemic mycoses caused by Histoplasma capsulatum, Coccidiodes immitis and Blastomyces dermatitidis occur in patients who live in North AmericaCommon respiratory viral infections occur comparably in HIV infected and non-infected people. CMV is frequently isolated in BAL, but its role in causing disease is not clear. The presence of CMV in BAL is associated with a worse prognosis in PCP9