Dyshoric capillary cerebral amyloid angiopathy mimicking Creutzfeldt-Jakob disease

Background: Subjects fulfilling the World Health Organisation clinical diagnostic criteria for Creutzfeldt-Jakob disease (CJD) often have a different diagnosis at autopsy, including Alzheimer's disease. Cerebral amyloid angiopathy (CAA) is a common finding in Alzheimer's disease, and in rare cases this is particularly capillary CAA with dyshoric changes.

Methods: Six subjects with extensive capillary CAA with dyshoric changes, in addition to neurofibrillary tangles and in the absence of CJD pathology were found in a consecutive series of 225 clinically suspected CJD cases fulfilling criteria for possible or probable CJD clinical data and results of neuroimaging, electroencephalography and cerebrospinal fluid analysis were collected to assess what has led to the erroneous clinical diagnosis of CJD.

Results: All six patients had rapidly progressive dementia (mean 8.2 months, range 3-24). Four fulfilled criteria for 'probable' and one for 'possible CJD'. 14-3-3 Protein in CSF and/or EEG-findings supported the suspicion of CJD in five patients.

Discussion: Patients with a clinical suspicion of CJD, supported by EEG and/or CSF abnormalities can have severe capillary CAA with dyshoric changes in addition to the presence of neurofibrillary tangles. Possibly dyshoric capillary CAA can contribute to rapid clinical progression in dementia.