CJD Dementia Diagnosis Often Delayed (from Med Page Today)
By Michael Smith, North American Correspondent, MedPage Today
Published: September 25, 2012
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Action Points
Sporadic Creutzfeldt-Jakob disease (sCJD) is often confused with other forms of dementia, even when neurologists are making the diagnosis.
Point out that the most common individual misdiagnoses included viral encephalitis, paraneoplastic disorder, depression, vertigo, Alzheimer disease, stroke, and unspecified dementia.
Sporadic Creutzfeldt-Jakob disease (sCJD) is often confused with other forms of dementia, even when neurologists are making the diagnosis, researchers reported.
In a retrospective analysis of 97 patients with pathologically-proven sCJD, it took an average of 7.9 months to arrive at the correct diagnosis, according to Michael Geschwind, MD, PhD, of the University of California San Francisco, and colleagues.
On average, the physicians involved -- mainly neurologists and internists -- made 3.8 incorrect diagnoses before arriving at sCJD, the authors reported online in Archives of Neurology.
"CJD is rarely the first diagnosis made and it is usually confused with a wide range of other conditions," the authors noted.
On the other hand, they reported, in 17 patients the first diagnosis was correct -- and in those cases 16 of the diagnoses were made by neurologists and one by a specialist in rehabilitation medicine.
Sporadic CJD is caused by prion proteins that undergo conformational changes, resulting in an invariably fatal transmissible spongiform encephalopathy. Other animals also suffer spongiform encephalopathies, including the famous bovine form -- dubbed mad cow disease -- that can be transmitted to humans as new variant Creutzfeldt-Jakob, or nvCJD.
It is difficult to distinguish sCJD from other dementias, including some that may be reversible, Geschwind and colleagues noted. Their report comes just days after the American Academy of Neurology issued a diagnostic guideline aimed at reducing the difficulty of a diagnosis of sCJD.
To investigate the issue, Geschwind and colleagues looked at all the cases referred to the UCSF Memory and Aging Center rapidly progressive dementia and CJD clinical research program between August 2001 and February 2007.
Patients were eligible for the analysis if they had pathologically-proven sCJD and medical records sufficiently detailed to allow examination of the diagnostic course.
All told, the researchers had good records for 97 patients, who received a combined total of 373 diagnoses before their physicians settled on sCJD. On average, the disease course last 12 months and it took 7.9 months before the records said sCJD was "likely" or the patients was referred to the center (whichever came first).
Primary care physicians (40%) or neurologists (36%) were the first to assess 75% of patients, and most patients were first seen by a family doctor and then referred to a neurologist.
Most of the misdiagnoses fell into a few categories -- neurodegenerative, autoimmune/paraneoplastic, infectious, and toxic/metabolic disorders, Geschwind and colleagues found. The most common individual misdiagnoses included viral encephalitis, paraneoplastic disorder, depression, vertigo, Alzheimer disease, stroke, and unspecified dementia.
With regard to viral encephalitis as the most common individual diagnosis, the authors suggested that "the multifocality, acuity, and rapidity of symptoms seen in sCJD" was a possible reason for the miscall.
Of the 222 doctors who made a diagnostic error, 95 were neurologists and 51 were internists, the researchers reported.
The diagnosis of sCJD has become more difficult, rather than easier, in recent years because of the increasing awareness of other forms of rapidly progressing dementia, commented Richard Caselli, MD, of the Mayo Clinic in Scottsdale, Ariz.
The long "diagnostic journey" faced by patients is complicated by the non-specific nature of the early symptoms, which often suggest a "more common and less lethal" disease, Caselli noted in an accompanying editorial.
Even neurologists, he argued, can be forgiven for missing the diagnosis in the hope that a reversible cause of the dementia can be found.
The study had support from the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, the Michael J. Homer Family Fund, the National Center for Research Resources University of California, San Francisco Clinical and Translational Science Institute, and the John Douglas French Alzheimer's Foundation.
The journal said Geschwind and Caselli reported no financial conflicts of interest.
