Neurology -- Correspondence for Honarmand et al., 63 (8) 1489-1493

Correspondence published:

Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis: Bénédicte Dubois, R. Lemmens, W. Laffut, M. Van Ranst (16 April 2005)

Reply to Dubois et al: Somayeh Honarmand, M.S., William J. Bellini (16 April 2005)

Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis 16 April 2005

Bénédicte Dubois,
Department of Neurology, University of Leuven, Belgium and National MS Center
Department of Neurology, University Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium,
R. Lemmens, W. Laffut, M. Van Ranst
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Re: Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis

Benedicte.Dubois{at}uz.kuleuven.ac.be Bénédicte Dubois, et al.

We read Honarmand et al’s article with interest. [1] The authors point out that SSPE is rare in the US so many clinicians do not consider this diagnosis in some cases of acute encephalopathy in children. We agree but would like to add that the diagnosis of SSPE may even be more difficult in adults, particularly if they present with a chronic progressive disease course. [2,3]
A 42-year-old woman was seen at our clinic in 2003, four years after her initial symptoms began. Before this, she had been working as a secretary without any neurological or cognitive problems. According to family members, she developed depression in 1999 and later that year was hospitalized due to frontal epileptic seizures. She became neurologically impaired with prominent cognitive deficits over the next several years. Based on radiological findings and cerebrospinal fluid (CSF) analysis, she was diagnosed with multiple sclerosis (MS). Three-and-a-half years after disease onset she was admitted to our ward. We found severe neuropsychological deficits in all cognitive domains, spasticity and ataxia in four limbs. She was unable to walk, had a neurogenic bladder and sensory deficits on the left side.
MRI showed multiple confluent periventricular as well as subcortical FLAIR hyperintense lesions and manifest corticosubcortical atrophy. The EEG patterns were abnormal with diffuse slowing. A lumbar puncture showed a normal white cell count and a normal total protein concentration, but intrathecal IgG synthesis with an IgG index of 5.07. PCR on CSF for HSV 1/2, VZV, EBV and CMV was negative. Whereas HSV 1/2, VZV and measles IgG were found in the serum, only measles IgG was elevated in the CSF. Based on these findings, the diagnosis of SSPE was established.
This case highlights that SSPE, although rare and mostly presenting as an acute encephalopathy in children, may also occur as a chronic progressive disease in adults. It should be considered in the differential diagnosis of white matter pathologies including MS.
References
1. Honarmand S, Glaser CA, Chow E, Sejvar JJ, Preas CP, Cosentino GC, et al. Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis. Neurology 2004;63:1489-1493.
2. Singer C, Lang AE, Suchowersky O. Adult-onset subacute sclerosing panencephalitis: case reports and review of the literature. Mov Disord 1997;12:342-353.
3. Gagnon A, Bouchard RW. Fulminating adult-onset subacute sclerosing panencephalitis in a 49-year-old man. Arch Neurol 2003;60:1160-1161.

Reply to Dubois et al 16 April 2005

Somayeh Honarmand, M.S.,
California Department of Health Services
Viral & Rickettsial Disease Laboratory , Richmond, CA 94804,
William J. Bellini
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Re: Reply to Dubois et al

Shonarma{at}dhs.ca.gov Somayeh Honarmand, M.S., et al.

We appreciate the comments by Dubois et al regarding our report on five cases of subacute sclerosing panencephalitis (SSPE). [1] We agree that, when appropriate, SSPE should be considered in adults.
In the California Encephalitis Project (CEP), serum and CSF from all patients (including adults) are tested for measles antibodies. [2] At the time of publication, the CEP had not identified a patient with adult-onset SSPE. However, since that time, we are investigating a case of an adult with possible SSPE.
Adult-onset SSPE is not a well-recognized entity because patients may present with atypical features; Singer et al reported that adult-onset patients were more likely to have visual disturbances as their first symptom rather than behavioral change, which is usually the first stage of the disease for pediatric patients diagnosed with SSPE. [3]
Although the MRI can be normal during the early phase of the illness, with disease progression, increased T2 signals in the cerebral white matter and brainstem may be observed. [4] Additionally, Chu et al reported that oligoclonal bands are detected in the CSF of 90% of patients with SSPE. [5] Because patients with adult-onset SSPE may initially present with visual dysfunction, have the presence of oligoclonal bands on CSF, and occasionally have white matter involvement on MRI, an erroneous diagnosis of MS could be made especially if SSPE is not considered in the differential.
Physicians should be encouraged to consider SSPE in adult as well as pediatric patients and order testing in appropriate cases.
References
1. Honarmand S, Glaser CA, Chow E et al. Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis. Neurology 2004;63:1489-1493.
2. Glaser CA, Gilliam S, Schnurr D, et al. In search of encephalitis etiologies: diagnostic challenges in the California Encephalitis Project, 1998-2000. Clin Infect Dis 2003;36:731-742.
3. Singer C, Lang AE, Suchowersky O. Adult-onset SSPE: case reports and review of the literature. Mov Disord 197;12:342-353.
4. Weissbrich B. Schneider-Schaulies J, Ter Meulen V. Clinical neurovirology. Measles and its neurological complications. In: Nath A. Berger JR, eds. Clinical Neurovirology. New York: Marcel Dekker, 203:401 -430.
5. Chu AB, Sever JL, Madden DL. Oligoclonal IgG bands in cerebrospinal fluid in various neurological diseases. Ann Neurol 1983;13:434-439.