Acanthamebic Meningoencephalitis Presenting as Personality Change

Abstract

To the Editors: Central nervous system infections can have myriad presentations in immunosuppressed patients.1 A 14-year-old boy with acute lymphoblastic leukemia achieved complete remission post induction chemotherapy. During the consolidation phase of chemotherapy, he presented with irrelevant talking and bizarre behavior of 1-week duration without any fever. He had sudden mood swings and had become abusive. Neurologic examination did not reveal any abnormalities apart from the change in his personality. Computed tomographic scan, magnetic resonance imaging, and electroencephalogram of the brain were normal. Biochemical and hematologic test results were normal. He was considered to have a psychiatric illness. Lumbar puncture showed an acellular cerebrospinal fluid (CSF) with normal protein and sugar; Gram stain and culture were negative; no organisms were identified on India ink preparation and the acid fast bacilli staining was negative. The wet mount of CSF showed Acanthameba trophozoites, which was confirmed on culture. Therapy was started with oral ketoconazole 5 mg/kg/d and trimethoprim/sulfamethoxazole (15 mg/kg/d of the trimethoprim component) for the Acanthameba meningoencephalitis. He showed improvement in his symptoms within 2 weeks of starting his treatment with repeat CSF analysis showing absence of Acanthameba. The patient continued the antiamebic treatment regularly, but signs of altered behavior recurred 1 month later and he had neurologic progression to coma and death. Repeat CSF examination after recurrence of symptoms showed positive Acanthameba on wet mount and culture on 2 occasions. Similar to presentation other radiologic and laboratory tests were normal. Acanthameba meningoencephalitis is a subacute meningoencephalitis of insidious onset. Patients generally tend to present with altered sensorium, seizures, fever, visual disturbances, ataxia, and focal neurologic deficits.1 CSF examination reveals elevated white blood cells (up to 800/μL, primarily lymphocytes), elevated protein, and low glucose.2 Computed tomographic scan shows multiple non enhancing lesions in the cerebral cortex. There have been case reports of amoebic encephalitis in immunosuppressed patients undergoing autologous transplant for lymphoma, during treatment of essential cryoglobulinemia with anti-CD20 monoclonal antibody, chronic steroid administration, and post stem cell transplantation for leukemia.3–5 Those patients presented with classic features of amebic meningoencephalitis as described above and had abnormal findings in their CSF associated with positive neuroimaging findings. In contrast to the above patients, our patient presented with personality change alone along with normal laboratory and imaging examination apart from the positive Acanthameba wet mount and culture. Even preterminaly he had normal neuroimaging and CSF analysis apart from the positive Acanthameba wet mount and culture. Various drugs such as ketoconazole, trimethoprim/sulfamethoxazole, fluconazole, sulfadiazine, pentamidine, amphotericin B, flucytosine, rifampicin, and itraconazole have been used either singly or in combination for treatment of Acanthameba; however, none of these medications have proved to be uniformly effective in this condition. Thus, this case highlights that Acanthameba is a potential cause for central nervous system symptoms in immunocompromised patients even in the absence of fever, abnormal imaging, or CSF findings. Venkatraman Radhakrishnan, MD Department of Medical Oncology Dr. B. R. A. Institute Rotary cancer Hospital All India Institute of Medical Sciences New Delhi Rohit Bhatia, DM Department of Neurology All India Institute of Medical Sciences New Delhi Gita Satpathy Panda, MD Department of Microbiology All India Institute of Medical Sciences New Delhi Sameer Bakhshi, MD Department of Medical Oncology Dr. B. R. A. Institute Rotary Cancer Hospital All India Institute of Medical Sciences New Delhi