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