A proposal of new diagnostic pathway for fatal familial insomnia

BACKGROUND

In absence of a positive family history, the diagnosis of fatal familial insomnia (FFI) might be difficult because of atypical clinical features and low sensitivity of diagnostic tests. FFI patients usually do not fulfil the established classification criteria for Creutzfeldt-Jakob disease (CJD); therefore, a prion disease is not always suspected.

OBJECTIVE

To propose an update of diagnostic pathway for the identification of patients for the analysis of D178-M129 mutation.

DESIGN AND METHODS

Data on 41 German FFI patients were analysed. Clinical symptoms and signs, MRI, PET, SPECT, polysomnography, EEG and cerebrospinal fluid biomarkers were studied.

RESULTS

An algorithm was developed which correctly identified at least 81% of patients with the FFI diagnosis during early disease stages. It is based on the detection of organic sleep disturbances, either verified clinically or by a polysomnography, and a combination of vegetative and focal neurological signs and symptoms. Specificity of the approach was tested on three cohorts of patients (MM1 sporadic CJD patients, non-selected sporadic CJD and other neurodegenerative diseases).

CONCLUSIONS

The proposed scheme may help to improve the clinical diagnosis of FFI. As the sensitivity of all diagnostic tests investigated but polysomnography is low in FFI, detailed clinical investigation is of special importance.

8-OHdG in cerebrospinal fluid as a marker of oxidative stress in various neurodegenerative diseases

BACKGROUND

The 8-hydroxy-2 deoxyguanosine (8-OHdG) is a product of nucleoside oxidation of DNA and a reliable marker of oxidative stress markers. Increased levels of oxidative stress have been reported in the cerebrospinal fluid (CSF) of patients with various neurodegenerative disorders.

OBJECTIVE

In search of a biochemical indicator of Parkinson's disease (PD), we analyzed the levels 8-OHdG in the CSF of 99 patients, using ELISA to assess the differences between various neurodegenerative disorders.

RESULTS

Statistically significant higher CSF levels (p = 0.022) of 8-OHdG in non-demented PD patients as compared to the control group were observed. No differences between CSF 8-OHdG levels and age at the time of lumbar puncture, presence or severity of dementia, or gender were found.

CONCLUSIONS

8-OHdG levels could be potentially useful in the neurochemically supported diagnosis of PD.

Updated clinical diagnostic criteria for sporadic Creutzfeldt-Jakob disease

Several molecular subtypes of sporadic Creutzfeldt–Jakob disease have been identified and electroencephalogram and cerebrospinal fluid biomarkers have been reported to support clinical diagnosis but with variable utility according to subtype. In recent years, a series of publications have demonstrated a potentially important role for magnetic resonance imaging in the pre-mortem diagnosis of sporadic Creutzfeldt–Jakob disease. Magnetic resonance imaging signal alterations correlate with distinct sporadic Creutzfeldt–Jakob disease molecular subtypes and thus might contribute to the earlier identification of the whole spectrum of sporadic Creutzfeldt–Jakob disease cases. This multi-centre international study aimed to provide a rationale for the amendment of the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease. Patients with sporadic Creutzfeldt–Jakob disease and fluid attenuated inversion recovery or diffusion-weight imaging were recruited from 12 countries. Patients referred as ‘suspected sporadic Creutzfeldt–Jakob disease’ but with an alternative diagnosis after thorough follow up, were analysed as controls. All magnetic resonance imaging scans were assessed for signal changes according to a standard protocol encompassing seven cortical regions, basal ganglia, thalamus and cerebellum. Magnetic resonance imaging scans were evaluated in 436 sporadic Creutzfeldt–Jakob disease patients and 141 controls. The pattern of high signal intensity with the best sensitivity and specificity in the differential diagnosis of sporadic Creutzfeldt–Jakob disease was identified. The optimum diagnostic accuracy in the differential diagnosis of rapid progressive dementia was obtained when either at least two cortical regions (temporal, parietal or occipital) or both caudate nucleus and putamen displayed a high signal in fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging. Based on our analyses, magnetic resonance imaging was positive in 83% of cases. In all definite cases, the amended criteria would cover the vast majority of suspected cases, being positive in 98%. Cerebral cortical signal increase and high signal in caudate nucleus and putamen on fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging are useful in the diagnosis of sporadic Creutzfeldt–Jakob disease. We propose an amendment to the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease to include findings from magnetic resonance imaging scans.

MRI in the classical MM1 and the atypical MV2 subtypes of sporadic CJD: an inter-observer agreement study

BACKGROUND AND PURPOSE

To establish radiological features in the atypical MV2 subtype of sCJD compared with the classical MM1 subtype, as well as region- and sequence-dependent inter-observer correlation.

METHODS

MRI hyperintensity of basal ganglia (BG), cortex and thalamus was evaluated in 31 MM1 and 32 MV2 patients. Each MR scan was analyzed independently by two neuroradiologists blinded to PRNP genotype/prion protein type.

RESULTS

Cumulative T2-sensitivity for BG hyperintensity was higher in the MV2 subtype (84% for both observers versus 61% in observer 1/42% in observer 2 in MM1 patients). Significant inter-observer agreement was found for BG and thalamus on T2, FLAIR, PD and DWI, but for cortex only on DWI. Thalamic changes were significantly more frequent in MV2 than in MM1 patients (cumulative sensitivity 86% vs. 12.5% on DWI).

DISCUSSION

The high frequency of thalamic hyperintensity in the MV2 subtype allowed differentiation from MM1 patients. Good inter-observer agreement was found for BG and thalamus in all sequences. DWI showed the highest inter-observer correlation independent of the investigated brain region and was therefore not only highly sensitive but also relatively independent of investigator bias. Since inter-observer correlation for cortical hyperintensity in T2, FLAIR and PD is relatively low, the cortical changes should not be over-interpreted with these sequences.

Isolated cortical signal increase on MR imaging as a frequent lesion pattern in sporadic Creutzfeldt-Jakob disease

BACKGROUND AND PURPOSE

Hyperintense basal ganglia on MR imaging support the diagnosis of sporadic Creutzfeldt-Jakob disease (CJD). Our aim was to study the frequency of patients with sporadic CJD presenting with and without characteristic basal ganglia lesions on MR imaging and to examine the corresponding patient characteristics.

MATERIALS AND METHODS

Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted images (DWI) of 55 patients with CJD were assessed for signal-intensity increase (FLAIR) or restricted diffusion (DWI) in 7 cortex regions and the basal ganglia, thalamus, and cerebellum. Patient characteristics as well as electroencephalography, CSF, and codon 129 genotype of the prion protein gene (PRNP) were correlated with the most frequent MR imaging lesion patterns.

RESULTS

Two major lesion patterns were identified by DWI: cortex and basal ganglia involvement (two thirds) and isolated cortex involvement (one third). In the latter patient group, the cortex involvement was widespread (at least 3 regions affected in 89% on DWI) and usually included the frontal and parietal lobes (78%). The length of the disease course was significantly prolonged (median, 12 versus 5 months). No significant differences were observed concerning electroencephalography and CSF findings and codon 129 genotype distributions. Of 4 patients with normal MR imaging findings, the CSF was positive for the 14-3-3 protein in 3.

CONCLUSION

A high number of patients with CJD present without basal ganglia lesions on MR imaging. Isolated cortex involvement on DWI and FLAIR should lead to suggestion of CJD, even if the disease course is only slowly progressive. Additional 14-3-3 protein analysis in the CSF may support the CJD diagnosis.

Creutzfeldt-Jakob disease in Germany: a prospective 12-year surveillance

Creutzfeldt-Jakob disease (CJD) is a rare and fatal neurodegenerative disorder with a worldwide incidence of 1-1.5 per million. As in other countries, a CJD surveillance unit with a clinical and neuropathological approach was established in Goettingen (Germany) in 1993. Here we report the epidemiological data from a prospective 12-year surveillance. Since 1993, there has been an increasing incidence of CJD, from 0.7 in 1993 to 1.6 in 2005 with a quite stable level since 1998. During this period, the proportion of patients with MV and VV codon 129 genotype rose, possibly because of better identification of atypical subtypes. Six percent of all patients had a PRNP mutation, mainly D178N-129M (FFI), E200K and V210I. Iatrogenic CJD was a rare phenomenon. No patient infected by cadaveric growth hormone extracts was reported. Furthermore, no variant CJD patient has yet been identified in Germany. Differential diagnoses revealed a variety of neurodegenerative diseases, with Alzheimer's disease in the lead. One-third of the non-CJD patients included in this study suffered from a potentially treatable disorder such as metabolic or inflammatory diseases. The incidence and mortality rates in Germany are similar to those in other European countries. In contrast, however, acquired forms, such as iatrogenic and variant CJD are still rare in Germany or have not yet been identified.

Sporadic Creutzfeldt-Jakob disease: clinical and diagnostic characteristics of the rare VV1 type

BACKGROUND

Recently, six molecular subtypes of sporadic CJD (sCJD) have been identified showing differences regarding the disease course, neuropathologic lesion patterns, and sensitivity to diagnostic tools. Only isolated cases of the rare VV1 type have been reported so far.

OBJECTIVE

To describe the clinical characteristics and neuropathologic lesion profiles in nine cases.

METHODS

In the years 1993 until late 2003, 571 definite neuropathologically confirmed cases of sporadic CJD were identified in Germany. Of these, nine were homozygous for valine and displayed type 1 of the pathologic PrPSc in the brain (VV1 type).

RESULTS

The authors describe eight men and one woman belonging to the VV1 type. All patients were relatively young at disease onset (median 44 years vs 65 years in all sCJD) with prolonged disease duration (median 21 months vs 6 months in all sCJD). During the initial stages, their main clinical signs were personality changes and slowly progressive dementia as well as focal neurologic deficits. None of the nine VV1 patients had periodic sharp-wave complexes (PSWCs) in the EEG. Only two out of seven displayed the typical signal increase of the basal ganglia on MRI, whereas signal increase of the cortex was seen in all patients. The 14-3-3 protein levels were elevated in CSF in all cases tested.

CONCLUSIONS

The clinical diagnosis of the VV1 type of sCJD can be best supported by the 14-3-3 test and cortical signal increase on MRI. Because of the young age at onset vCJD is sometimes suspected as a differential diagnosis. MRI plays an important role in differentiating these two disease types and should be performed early during the disease course.