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27-06-2011 | Article

Treatable conditions often misdiagnosed as CJD

MedWire News: Many treatable neurological conditions are often misdiagnosed as Creutzfeldt-Jakob disease (CJD), US research shows.

Almost one-third of brain autopsies of patients with suspected CJD were negative for the prion disease, with one in four false-negative patients having a potentially treatable neurological condition, report Numthip Chitravas (Case Western Reserve University, Cleveland, Ohio) and colleagues in the Annals of Neurology.

"Our findings indicate that heightened awareness of CJD has led to a tendency to over-diagnose this condition," comment the researchers.

The increasing awareness of transmissible spongiform encephalopathies has led to an increased diagnostic consideration of CJD in patients with rapidly progressive dementia. Referrals to the US National Prion Disease Pathology Surveillance Center at Case Western Reserve University have also increased.

However, analyses of some cases suggest that many patients do not have prion disease.

In this study, Chitravas and colleagues performed a clinical and neuropathological review of 1106 brain autopsies referred to the national surveillance center from 2006 to 2009.

In total, 32% were negative for prion disease.

Of the 352 disease-negative patients, 304 had tissue available for histopathological review. Analyses showed that 154 patients had Alzheimer's disease and 36 had vascular dementia, the two most common misdiagnoses as prion disease. Other misdiagnoses include frontotemporal lobar degeneration, mesial temporal sclerosis, and diffuse Lewy body dementia.

Overall, 71 of the prion-negative cases had potentially treatable neurological diseases, such as lymphoma, infection, or metabolic disease.

Based on their review, the researchers note that these patients had rapid cognitive decline, and sporadic CJD was listed among the differential diagnoses. Of these, 11% of patients met the World Health Organization diagnostic criteria for probable sporadic CJD and 18% for possible sporadic CJD.

In addition, 31% had dementia and 10% had delirium, plus one of pyramidal, extrapyramidal, visual, or cerebellar symptoms, akinetic mutism, or myocloma.

Approximately 30% of patients had insufficient clinical data.

The use of recently validated magnetic resonance imaging (MRI) features of prion-infected brains should help decrease the number of false positives, as will the use of revised consensus criteria, say Chitravas and colleagues.

The team adds that although clinicians should be aware of CJD, they should not overlook other potentially treatable neurological disorders before making their diagnosis. Free abstract: http://onlinelibrary.wiley.com/doi/10.1002/ana.22454/abstract

MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By MedWire Reporters