Cerebral toxoplasmosis in childhood and adult HIV infection treated with 1-4 hydroxynaphthoquinone and rapid desensitization with pyrimethamine

Background: We describe a child and an adult infected with the human immunodeficiency virus (HIV) who developed cerebral lesions consistent with toxoplasmosis. A biopsy in the child and IgG ELISA in both patients confirmed the diagnosis of Toxoplasma gondii. The patients were initially treated with pyrimethamine, however, computerized tomography studies (CT scan) revealed progression of a left frontal and temperoparietal lesion. Therapy in the child was changed to pyrimethamine, clindamycin, and azithromycin. Repeat CT scan showed further disease progression and therapy was changed to high-dose pyrimethamine (3 mg/kg/d) and azithromycin. A subsequent CT scan disclosed further radiologic progression with increasing edema. The adult patient developed a maculopapular rash during attempted treatment with pyrimethamine. Methods: Introduction of 2 (trans-4-[4 chlorophenol] cyclohexy[3-hydroxy-1, 4 naphthoquinone] (HNPQ) an experimental antiparasitic compound previously used only in adult HIV clinical trials, was instituted in the child and rapid oral desensitization to pyrimethamine was initiated in the adult patient. Results: HNPQ resulted in resolution of the cerebral lesion in the child and rapid oral desensitization to pyrimethamine produced an excellent clinical response in the adult. To our knowledge, these are the first cases of childhood and adult cerebral toxoplasmosis treated successfully with HNPQ and rapid oral desensitization to pyrimethamine. Conclusion: HNPQ and pyrimethamine desensitization should be considered as alternate modes of therapy in patients who become intolerant or fail to respond to traditional therapy for toxoplasmosis.