Subacute sclerosing panencephalitis

To the Editor.-Extensive postmortem studies on 4 patients autopsied after infection with West Nile virus (WNV) in Mississippi demonstrated injury to spinal and sympathetic ganglia mirrored by damage to the spinal gray matter. The disappearance of sympathetic neurons was incriminated for the autonomic instability observed in some WNV patients.1 That could well be responsible for any observed labile vital signs, hypotension, and potentially lethal cardiac arrhythmias. Fundamental information about the neurological changes linked with WNV could as well be determined with imaging techniques like magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS).

Imaging techniques have addressed some of the fundamental features of viral replication in the central nervous system. For example, MRI of the cervical spine of a 27-year-old man who developed acute flaccid paralysis 3 weeks after his 20-month-old infant was immunized with live poliovirus vaccine revealed smooth hyperintense bands. Sagittal proton-density T2-weighted images revealed involvement of the regions corresponding to the anatomic locations of ventral horns.2

Examination of a 13-year-old girl with subacute sclerosing panencephalitis during MRS to establish any in vivo pathophysiologic abnormalities was intriguing. Both inflammatory processes and glial proliferation were evident prior to neuronal loss visible in MRI-negative as well as MRI-fjpositive regions.3 Furthermore, 3 patients with Creutzfeldt-Jakob disease showed evidence of reduced N-acetylaspartate-creatine ratios on MRS. These changes implied that neuronal loss and/or dysfunction were a consistent feature of established Creutzfeldt-Jakob.4

Using imaging techniques on survivors of WNV infection and future patients with a neurological manifestation would be intriguing. West Nile virus encephalitis was also responsible for fatal encephalitis during its transmission from an organ donor to a kidney transplant recipient. There were extensive postmortem viral encephalopathic changes. Immunohistochemical studies had highlighted WNV antigens within neurons, especially in the cerebellum and brainstem.5

SUBHASH C. ARYA, PhD

NIRMALA AGARWAL, FRCOG

Sant Parmanand Hospital

Delhi 110054, India

1. Fratkin JD, Leis AA, Stokic DS, Slavinski SA, Ceiss RW. Spinal cord neuropathology in human West Nile virus infection. Arch Pathol Lab Med. 2004;128:533-537.

2. Malzberg MS, Rogg JM, Teta CA, et al. Poliomyelitis: hyperintensity of the anterior horn cells on MRI imaging of the spinal cord. Am J Roentgenol. 1993;161:563-565.

3. Kalo Z, Saito K, Yamada M, Asano T, Kondo N. Proton magnetic resonance spectroscopy in a case of subacute sclerosing panencephalitis. J Child Neurol. 2002;17:788-790.

4. Pandya HG, Coley SC, Wilkinson ID, Griffiths PD. Magnetic resonance spectroscopic abnormalities in a sporadic and variant Creutzfeldt-Jakob disease. CUn Radiol. 2003:58:148-153.

5. Cushing MM, Brat DJ, Mosunjac MI, et al. Fatal West Nile virus encephalitis in a renal transplant recipient. Am I Clin Pathol. 2004;121:26-31.

In Reply.-We appreciate the interest our manuscript has generated.1 The authors of the above letter raise important questions about the utility of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) in understanding the structural and pathophysiologic changes associated with West Nile virus (WNV) infection and other well-known viral and prion diseases. They suggest that altered spectroscopic patterns may correspond to the neuronal loss and gliosis found at post-mortem in these diseases. Although definitive MRI changes have thus far been absent in many cases of WNV poliomyelitis, clear documentation of such changes has also been reported.2-4 Neuroimaging data in persons with WNV or poliomyelitis due to wild-type poliovirus, or other neurotrophic viruses, has not been consistently gathered, and the incidence of such MRI changes is unknown. It is likely that specific MRI changes may be missed because of variations in the stage of disease at the time of imaging. This may also be true for MRS.

Questions about the utility of MRI and MRS in WNV and other viral and prion diseases may be addressed by serial MRI/MRS assessments of patients during and following acute illness. In addition, we must emphasize the importance of autopsy studies in the validation of clinical studies that hypothesize morphologic changes at the cellular level. Direct correlations ultimately improve the clinical care of patients and also create dynamic tools for the study of neurotrophic viral diseases.

JONATHAN D. FRATKIN, MD

Department of Pathology

University of Mississippi Medical Center

Jackson, MS 39216

A. ARTURO LEIS, MD

Center for Neuroscience and Neurological Recovery

Methodist Rehabilitation Center

Jackson, MS 39216

1. Fratkin JD, Leis AA, Stokic DS, Slavinski SA, Geiss RW. Spinal cord neuropathology in human West Nile virus infection. Arch Pathol Lab Med. 2004;128:533-537.

2. Li J, Loeb JA, Shy M, et al. Asymmetric flaccid paralysis: a neuromuscular presentation of West Nile virus infection. Ann Neurol. 2003;53:703-710.

3. Jeha LE, Sila CA, Lederman RJ, Prayson RA, Isada CM, Cordon SM. West Nile virus infection: a new acute paralytic illness. Neurology. 2003;61:55-59.

4. Park M, Hui JS, Bartt RE. Acute anterior radiculitis associated with West Nile virus infection. J Neurol Neurosurg Psychiatry. 2003;74:820-826.

Copyright College of American Pathologists Nov 2004
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