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Older Age May Complicate Diagnosis of Sporadic Creutzfeld-Jakob Disease: Presented at ANA

By Jacquelyn Beals

WASHINGTON, DC -- October 11, 2007 -- Diagnosis of an 80-year-old man with sporadic Creutzfeld-Jakob disease (sCJD), subtype VV1, has extended the age of onset previously recorded for this subtype, and highlights the diagnostic challenges posed by age-related variations in phenotype and clinical expectations.

Sporadic CJD is a prion disease causing neurological problems that can include dementia, aphasia, ataxia, personality changes, myoclonus, and visual loss. Six sCJD subtypes have been described. These can be differentiated in laboratory tests by a genetic polymorphism (methionine or valine) at codon 129 of the prion protein gene, and by the isoform (type 1 or type 2) detected by electrophoresis after proteinase digestion.

Patients with subtype VV1, the rarest subtype (1%-2% of sCJD cases), have a valine (V) at position 129 on both chromosomes (homozygous: VV). Previously, VV1 was considered the subtype with the earliest average age of onset (median age 44-47; range 19-72 years), prominent psychiatric symptoms compared with other subtypes, and a long, slow disease course.

Rebecca H. Reiser, MD, Neurology Resident, University of Utah School of Medicine, Salt Lake City, Utah, United States, was first author of the poster on the case study presented here at the 132nd Annual Meeting of the American Neurological Association (ANA).

The case involves an 80-year-old man who ran his own business until developing problems with memory, gait, and word-finding. Within a month he was confined to a wheelchair. Within 2 months he displayed gaze palsy, gait ataxia and apraxia, and fragmented speech. Strength and sensation were normal, and no myoclonus was present. Death occurred 4 months after initial symptoms.

Diagnosis was delayed because the magnetic resonance imaging (MRI) was misinterpreted as stroke. Several MRI patterns common to both stroke and sCJD were noted. However, MRI patterns also identify two features that distinguish CJD, according to Dr. Reiser. "In CJD, abnormalities follow the cortical ribbon. In stroke a vascular distribution [is followed]." In addition, basal ganglia often are involved in CJD, she said.

Another challenge to reaching the correct diagnosis was the atypical course of the disease -- starting at a greater age than previously reported for subtype VV1, and progressing rapidly to death within 4 months. The authors suggest that the usual clinical features of subtype VV1 may be altered in older patients.

The report noted that sCJDVV1 symptoms may be misinterpreted in older patients, due to the much higher prevalence of other coexisting neurodegenerative diseases. As a result, the prevalence of this subtype may well be under-recognised in older patients.

For public health reasons, and for appropriate treatment, the authors recommend that older patients should receive the full clinical evaluation when sCJD is suspected, including immunohistochemical analysis and histopathology with molecular subtyping.


[Presentation title: Clinical Features in a Patient With Late-Onset Sporadic VV1 Subtype Creutzfeld-Jakob Disease. Abstract M-44]

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