Case 149: Immune Reconstitution Inflammatory Syndrome

History A 43-year-old man was admitted for new onset of bitemporal headache, bilateral lower extremity numbness, and generalized tonic-clonic seizure. Physical examination findings were remarkable for bilateral lower extremity weakness. Magnetic resonance (MR) imaging of the brain was performed. Initial analysis of cerebrospinal fluid (CSF) revealed an elevated nucleated cell count, with 92% lymphocytes (normal range, 37%–75%) and 8% monocytes and/or macrophages (normal range, 0%–15%). CSF staining, cell culture, and polymerase chain reaction results were negative for cryptococcus, histoplasmosis, Coccidioides infection, syphilis, cytomegalovirus, West Nile virus, herpes simplex virus, and Epstein-Barr virus. Enzyme immunoassay, Western blot analysis, and indirect immunofluorescence assays were positive for human immunodeficiency virus (HIV) antibodies. The plasma HIV RNA level was 32 806 copies per milliliter, and the CD4+ T-cell count was 29 cells per microliter (normal range, 500–1800 cells per microliter). The antitoxoplasmosis immunoglobulin G titer was elevated; however, the immunoglobulin M titer was normal. CSF samples from two lumbar punctures did not show signs of acid-fast bacillus growth; however, an antituberculosis regimen was initiated because of positive purified protein derivative skin test results and positive MR findings. In addition, the patient received a 2-week course of sulfadiazine and pyrimethamine to treat toxoplasmosis. Six weeks after presentation, the patient was readmitted for dehydration, mild systemic hypotension, and persistent lower extremity weakness and numbness. Additional MR images of the brain were obtained. At this time, the patient had completed a 5-week course of antituberculosis therapy. Highly active antiretroviral therapy (HAART)—which consisted of efavirenz, emtricitabine, and tenofovir administration—was started during this second hospitalization. While undergoing this treatment, the CD4+ T-cell count increased to 45 cells per microliter, and plasma HIV RNA was undetectable. Seven weeks after presentation, the patient presented with increasing lightheadedness and persistent bilateral lower extremity weakness and numbness. MR imaging of the brain was performed at admission. CSF staining and cell cultures were negative. During this admission, the CD4+ T-cell count increased to 63 cells per microliter, and plasma HIV RNA remained undetectable. After 6 weeks of corticosteroid therapy, MR imaging of the brain was performed. © RSNA, 2009