Discussion
This is a young patient came with no significant medical history of structural lung disease who presented with persistent cough of four months duration that did not respond to multiple trials of antibiotics. While at the RUMC, she was diagnosed with HIV positive with full blown AIDS and found to have this rare disease, pulmonary MAC. MAC infection typically affects extrapulmonary sites. MAC pulmonary disease occurs in patients with known structural lung diseases such as chronic obstructive pulmonary disease and bronchiectasis.4 Otherwise isolated pulmonary MAC infection in patients without prior structural lung disease is uncommon. In patients with HIV, an isolated pulmonary MAC infection is extremely rare, even though colonization of the lungs is common and may be predictive of disseminated disease. 1 To our knowledge, reports of isolated pulmonary MAC infection began to appear in the medical literature in 1988, after zidovudine became available as an anti-retroviral agent. Including our patients, there are now 26 reported cases of isolated pulmonary MAC infection in HIV-infected individuals.3-11 However, there are no reported cases of isolated pulmonary MAC over the last 17 years, with the last case report being in 2003. This is likely due to the advent of newer and highly active antiretroviral therapies.
The diagnosis of isolated pulmonary MAC is difficult as it takes weeks for non-tuberculous mycobacterium to grow on culture. In our case, the results of sputum culture were reported after 26 days. The patient was misdiagnosed as community-acquired pneumonia and treated with multiple courses of antibiotics. The number of days it took to get culture report posed a diagnostic challenge for us. Unless physicians have high index of suspicion, especially when there is a treatment failure in high-risk patients may be misdiagnosed.
In addition, to the best of our knowledge, this case is the first case of an isolated pulmonary MAC as the initial presentation of a newly diagnosed HIV/AIDS patient.
Generally, it is recommended to delay the initiation of HAART therapy in patients with opportunistic infections like MAC in order to reduce the chances of immune reconstitution syndrome, which has been reported.3,5