Ashley Fletcher

Iatrogenic Creutzfeldt–Jakob disease at the millennium

Article abstract The causes and geographic distribution of 267 cases of iatrogenic Creutzfeldt–Jakob disease (CJD) are here updated at the millennium. Small numbers of still-occurring cases result from disease onsets after longer and longer incubation periods following infection by cadaveric human growth hormone or dura mater grafts manufactured and distributed before the mid-1980s. The proportion of recipients acquiring CJD from growth hormone varies from 0.3 to 4.4% in different countries, and acquisition from dura mater varies between 0.02 and 0.05% in Japan (where most cases occurred). Incubation periods can extend up to 30 years, and cerebellar onsets predominate in both hormone and graft recipients (in whom the site of graft placement had no effect on the clinical presentation). Homozygosity at codon 129 of the PRNP gene is over-represented in both forms of disease; it has no effect on the incubation period of graft recipients, but may promote shorter incubation periods in hormone cases. Knowledge about potential high-risk sources of contamination gained during the last quarter century, and the implementation of methods to circumvent them, should minimize the potential for iatrogenic contributions to the current spectrum of CJD.

Analysis of EEG and CSF 14-3-3 proteins as aids to the diagnosis of Creutzfeldt–Jakob disease

Objective: To improve diagnostic criteria for sporadic Creutzfeldt–Jakob disease (CJD). Methods: Pooled data on initial and final diagnostic classification of suspected CJD patients were accumulated, including results of investigations derived from a coordinated multinational study of CJD. Prospective analysis for a comparison of clinical and neuropathologic diagnoses and evaluation of the sensitivity and specificity of EEG and 14-3-3 CSF immunoassay were conducted. Results: Data on 1,003 patients with suspected CJD were collected using a standard questionnaire. After follow-up was carried out, complete clinical data and neuropathologic diagnoses were available in 805 cases. In these patients, the sensitivity of the detection of periodic sharp wave complexes in the EEG was 66%, with a specificity of 74%. The detection of 14-3-3 proteins in the CSF correlated with the clinical diagnosis in 94% (sensitivity). The specificity (84%) was higher than that of EEG. A combination of both investigations further increased the sensitivity but decreased the specificity. Conclusions: Incorporation of CSF 14-3-3 analysis in the diagnostic criteria for CJD significantly increases the sensitivity of case definition. Amended diagnostic criteria for CJD are proposed.

Surgical treatment and risk of sporadic Creutzfeldt-Jakob disease: a case-control study

BACKGROUND Apart from the small number of iatrogenic and familial cases, the cause of most cases of Creutzfeldt-Jakob disease (CJD) is not known. We aimed to identify risk factors for sporadic CJD. METHODS In a case-control study, we compared the medical history and selected demographic characteristics of 241 definite (neuropathologically confirmed) and probable (clinically likely) patients with CJD, ascertained from the Australian National Creutzfeldt-Jakob Disease Registry between Jan 1, 1970, and October 31, 1997, and of 784 controls, recruited from the community by random telephone interview in August, 1997. Standard logistic regression was used for the comparisons. FINDINGS Surgical procedures were significantly associated with the development of sporadic CJD. This risk progressively increased with the number of surgical treatments to a maximum for three procedures (odds ratio 2.13 [95% Cl 1.34-3.41], p=0.002). There was also a significant association between risk of CJD and residence or employment on a farm (p<0.001) or market garden (p=0.002) for longer than 10 years. We found no significant risk associated with a history of blood transfusion, organ transplantation, major dental work, or occupation. INTERPRETATION Our findings accord with the hypothesis that a range of surgical treatments may serve as unrecognised contamination events and account for a proportion of cases of sporadic CJD. Possible biases in different methods and times for the acquisition of data on cases and controls suggest our findings need to be replicated in independent studies with community controls.

Quinacrine does not prolong survival in a murine Creutzfeldt-Jakob disease model.

Paramount among issues relating to the transmissible spongiform encephalopathies (also known as prion diseases) is the absence of any effective therapy. This need has been heightened by the substantial European and emerging global problem of bovine spongiform encephalopathy and consequent variant Creutzfeldt‐Jakob disease. Stimulated by the recent reports of a potent antiprion effect in cell culture–based clearance assays, we studied the utility of quinacrine in a well‐characterized in vivo model of mouse‐adapted transmissible spongiform encephalopathy. Our results failed to show any evidence that quinacrine is effective when using the simple but objective measure of survival prolongation.

Creutzfeldt-Jakob disease: diagnostic utility of 14–3–3 protein immunodetection in cerebrospinal fluid

With the aim of improving the pre-mortem diagnostic accuracy of sporadic Creutzfeldt-Jakob disease (CJD), there has been considerable recent interest in the merit of immunodetecting 14-3-3 proteins in the cerebrospinal fluid (CSF) using Western blotting, with cumulative support for the utility of this technique. As a corollary, during a 20 month period, CSF samples from an unselected prospective series of 124 patients in whom sporadic CJD was a differential diagnostic possibility were examined by the Australian Creutzfeldt-Jakob disease Registry (ACJDR) for the presence of 14-3-3 proteins. Follow up to achieve a final diagnosis or clinical outcome was successful in 119. For definite and probable sporadic CJD combined, a positive result was 91.4% sensitive, while the sensitivity for the pathologically verified group alone was 96.0%. A negative outcome was 92.5% specific with false positive results seen in five patients with diagnoses which included inflammatory CNS disorders, cerebral ischaemia and dementia with Lewy bodies (DLB). Immunodetectable 14-3-3 proteins were present in three of four symptomatic patients with prion protein gene (PRNP) mutations. CSF samples containing significant amounts of blood were confirmed as suboptimal, with weak or qualitatively unusual positive results found in greater than 50% of such specimens, with only one of 14 such cases ultimately classified as definite or probable CJD.

Creutzfeldt-Jakob disease in Australia 1970-1999.

Objective: To ascertain all persons who developed a transmissible spongiform encephalopathy (TSE) within Australia during the 30-year period 1970 to 1999 through a comprehensive national surveillance program and subject the group to detailed epidemiologic analysis. Methods: Cases were ascertained through reviews of morbidity separation coding data from all university-affiliated tertiary referral hospitals, as well as the centralized data bases of state and territory health departments, regular national death certificate searches, and semiannual mailout questionnaires to all neurologists and pathologists throughout Australia. Prospective monitoring commenced in September 1993. Results: A total of 387 patients were confirmed as having TSE during this epoch. The majority of cases were sporadic Creutzfeldt–Jakob disease (CJD) (90.7%), with 7.2% heredofamilial and 2.1% iatrogenic. Over this 30-year period, the national average annual sporadic CJD incidence rate per million progressively increased from 0.31 for the decade 1970 through 1979 to 0.77 for 1980 through 1989, reaching 1.03 for 1990 through 1999. Death certificates were found to have a false-positive rate of 11.5% and sensitivity of 83.0% for sporadic CJD. Conclusions: Within Australia, there has been a gradual increase in the incidence of transmissible spongiform encephalopathy over the three-decade period 1970 through 1999, peaking in 1999 at 1.4/million/year for sporadic Creutzfeldt–Jakob disease. This increase is believed secondary to improved case ascertainment. Variant Creutzfeldt–Jakob disease was not identified during this period. Age- and sex-adjusted comparisons showed a decline in incidence rates in the elderly in both sexes, usually from age 74 years. Death certificates were a useful but imperfect method of case detection.

Recent advances in the pre-mortem diagnosis of Creutzfeldt-Jakob disease

Included in the spectrum of human transmissible spongiform encephalopathies are Creutzfeldt-Jakob disease (CJD) and the new variant form (vCJD), Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia, kuru and various less distinct neuropsychiatric disorders. Progress in our understanding of this group of disorders continues at a prodigious rate, although important vexing practical issues persist. The definitive confirmation of symptomatic prion disease still requires pathological examination, most reliably performed post-mortem. However, paralleling the recent advances in the molecular biological understanding of normal prion protein (PrP(c)) function and the pathophysiology of prion diseases, there have been worthwhile developments in the pre-mortem diagnosis of CJD. Efforts to develop less invasive but very reliable ante-mortem diagnostic tests have received an additional impetus because of the potential epidemic of vCJD. Historically, the ancillary investigation of most merit has been the EEG, whereas the recent advances have encompassed a broader range of technologies, including both magnetic resonance and radioisotopic neuroimaging, and immunoassays for a range of non-specific marker proteins in both CSF, and less commonly, blood. However, given the recent refinement of sophisticated immunoassays, it is envisaged that the pathognomonic, protease-resistant, disease-associated isoforms of the prion protein (PrPres) may soon be directly detectable in the blood and tissues of patients manifesting or incubating a spongiform encephalopathy.

URBAN–RURAL DIFFERENCES IN THE MANAGEMENT OF SCREEN‐DETECTED INVASIVE BREAST CANCER AND DUCTAL CARCINOMA IN SITU IN VICTORIA

Background:  At least one‐third of primary breast cancers in Australia are discovered by population‐based mammographic screening. The aim of this study was to determine whether there were any differences in the surgical treatment of women diagnosed with breast cancer by BreastScreen Victoria between urban and rural populations and to investigate temporal changes in their pattern of care.

Topical corticosteroid allergy in an urban Australian centre

The reported prevalence of allergic contact dermatitis from topical corticosteroids in clinical populations, in the period 1993–2002, varied from 0.55 to 5.98%. This study is a retrospective analysis of 1153 individuals undergoing routine patch testing in an Occupational Dermatology Clinic in Melbourne, Australia. We report a rate of 0.52% for positive patch test reactions to 5 corticosteroids. Corticosteroids tested were betamethasone‐17‐valerate, budesonide, Diprosone® cream (betamethasone diproprionate 0.05%) (Essex‐Pharma, a division of Schering‐Plough Pty Ltd, Sydney, Australia), tixocortol‐21‐pivalate and triamcinolone acetonide. Population characteristics were described using the MOAHL (M = percentage of males tested; O = occupational; A = atopics; H = patients with hand eczema; L = patients with leg ulcers or stasis eczema) index. Prescribing patterns, rate of referral and rate of relevant positive patch test reactions were characterized for the region. These results were compared to the rates of corticosteroid allergy and patch testing methodologies from published international studies. It was noted that many high‐sensitization potential corticosteroids were not available in our region. Although a low percentage of leg ulcers and stasis dermatitis may be associated with a lower rate of corticosteroid allergy, this association may be confounded by regional factors such as prescribing habits and the local availability of corticosteroids. We conclude that the low rate of topical corticosteroid contact allergy reported by our clinic is associated with regional availability and prescribing practices and the scarcity of stasis dermatitis and leg ulcers in our clinic population.

Creutzfeldt-Jakob disease cluster in an Australian rural city

Through the Australian National Creutzfeldt‐Jakob Disease Registry, 6 pathologically confirmed sporadic cases were recognized over a 13‐year period in persons who had been long‐term residents of a moderate‐sized rural city, whereas the expected number was 0.923. An extensive investigation could not find any point‐source or case‐to‐case transmission links. This occurrence is highly statistically significant (p = 0.0027) when viewed in isolation and remains significant (p < 0.02) when only the cases that arose after the cluster was recognized were taken into account. However, a more conservative statistical analysis suggests that such a grouping could have arisen by chance in at least one population group of this size when the whole country is taken into consideration.