This HIV+ patient with a CD4 count of 27 cells/uL is suffering from a disseminated mycobacterium avium-intracellulare complex (MAC) infection. A macrolide, such as azithromycin or clarithromycin, should be given to HIV+ patients with a CD4 count less than 50 cells/uL in order to prevent MAC infections.
If a patient is unable to tolerate or has a contraindication to the macrolides, rifabutin may be used as an alternative agent for MAC prophylaxis. If the clinical picture suggests that a patient may have an active MAC infection at the time of starting MAC antibiotic prophylaxis (when CD4 count drops below 50), blood cultures should first be obtained to rule out this possibility, as the treatment regimen of MAC differs from prophylaxis. Treatment of disseminated MAC requires the addition of either ethambutol or rifabutin to the macrolide (azithromycin or clarithromycin). In a patient with disseminated MAC infection, after effective anti-retroviral therapy is resumed, the patient's CD4 count must rise to greater than 100 cells/uL for a time period of 3 months before it is appropriate to discontinue MAC prophylaxis.
Sherin et al. review recent recommendations in the prevention and management of HIV infection. Routine HIV testing is now recommended, regardless of individual patient risk, for all persons between ages 15-65. Additionally, it is now stressed that within the first 2 weeks after the diagnosis of an opportunistic infection in an HIV+ patient, combination antiretroviral therapy should be restarted.
Henkle et al. discuss nontuberculous mycobacterial infections in immunocompromised patients. MAC is the most common causative organism; however, there are many other species that are becoming more common and important. 50% of nontuberculous mycobacterial infections are pulmonary, 25% involve skin and/or soft tissue, and the remaining 25% are disseminated. In the treatment of these infections, addressing the underlying immunodeficiency (restarting HAART) is just as, if not more, important than initiating appropriate antibiotic therapy.
Figure A is a chest radiograph of a patient with disseminated mycobacterium intracellulare infection with concomitant pulmonary involvement; note the patchy, ground-glass opacity in the left lung. Illustration A summarizes the different options for a prophylactic regimen for MAC infections. Illustration B reviews all of the opportunistic infection prophylaxis needed for HIV patients. Illustration C depicts an algorithm for the diagnosis and management of disseminated MAC infection.
Answer 1: Although isoniazid is a common agent in the treatment of M. tuberculosis infections, it does not have a role in the treatment or prevention of MAC infections in HIV+ patients.
Answer 2: All HIV patients should receive the pnemococcal vaccine; however, this patient is suffering from disseminated MAC infection, not pneumococcal pneumonia.
Answer 3: Trimethoprim-sulfamethoxazole is recommended for patients with CD4 counts less than 200 cells/uL in order to prevent pneumocystis jiroveci pneumonia. TMP-SMX is also useful to suppress and prevent reactivation of toxoplasmosis in patients with CD4 count less than 100 cells/uL and positive toxoplasmosis serologies.
Answer 5: Although all HIV patients should receive vaccination against hepatitis B, it would not have prevented the development of disseminated MAC infection in this patient.
Sherin K, Klekamp BG, Beal J, Martin N. What is new in HIV infection? Am Fam Physician. 2014 Feb 15;89(4):265-72.
PMID:24695446 (Link to Abstract)
Henkle E, Winthrop KL. Nontuberculous Mycobacteria Infections in Immunosuppressed Hosts. Clin Chest Med. 2015 Mar;36(1):91-99. doi: 10.1016/j.ccm.2014.11.002. Epub 2014 Dec 23.
PMID:25676522 (Link to Abstract)