Splenic infarction complicated with immune reconstitution inflammatory syndrome due to disseminated Mycobacterium genavense infection in a patient infected with human immunodeficiency virus.

Mycobacterium genavense (M. genavense) is one of the most fastidious, difficult to culture Mycobacterium species. Patients infected with human immunodeficiency virus (HIV) may develop immune reconstitution inflammatory syndrome (IRIS) due to disseminated M. genavense infection as well as disseminated M. avium and intracellulare complex infection. Consensus regarding treatment of IRIS due to disseminated mycobacterium infection has not yet been obtained, although systemic steroid therapy has been recommended in recent guidelines. Here we report the case of a 48-year-old Japanese man diagnosed with HIV and disseminated M. genavense infection. His initial CD4-positive T cell count was 3/μL, and his HIV1-RNA viral load was 13,000 copies/mL. He developed IRIS due to disseminated M. genavense infection after two weeks of receiving antiretroviral agents. The patient's serum alkaline phosphatase level, as a barometer of disseminated M. genavense infection in this case, was difficult to control with several anti-mycobacterial agents, although his fever was improved by non-steroidal anti-inflammatory drugs. About five weeks after the onset of IRIS, the patient developed acute left upper quadrant pain and was diagnosed with splenic infarction by contrast-enhanced computed tomography. After the splenic infarction, the patient's serum alkaline phosphatase level decreased without systemic steroid therapy or anticoagulant agents, and his left upper quadrant pain improved naturally within a few days. This case suggests that IRIS due to disseminated M. genavense infection can complicate splenic infarction in patients with HIV, and splenic infarction could improve the IRIS due to disseminated M. genavense infection.