Prion Disease.

Prion diseases are a phenotypically diverse set of disorders characterized by protease-resistant abnormally shaped proteins known as prions. There are three main groups of prion diseases, termed sporadic (Creutzfeldt-Jakob disease [CJD], sporadic fatal insomnia, and variably protease-sensitive prionopathy), genetic (genetic CJD, fatal familial insomnia, and Gerstmann-Straussler-Scheinker syndrome), and acquired (kuru, variant CJD, and iatrogenic CJD). This article will review the pathophysiology, genetics, clinical presentations, and diagnostic challenges in patients with prion disease. Case discussions, images, and tables will be used to highlight important characteristics of prion disease and prion mimics.

Elevated cerebrospinal fluid tau in Wernicke encephalopathy.

Wernicke encephalopathy (WE) commonly presents with oculomotor abnormalities, gait ataxia and confusion. WE can mimic rapidly progressive dementia syndromes, such as Creutzfeldt-Jakob disease (CJD). Cerebrospinal fluid (CSF) tau is frequently used for diagnosis of several dementia subtypes, predominantly CJD and Alzheimer's disease. The combination of very high CSF tau (tau) and normal phosphorylated tau (p-tau) levels is almost exclusively seen in aggressive diseases, such as CJD. The authors present a case of a woman with WE, caused by chronic insufficient dietary intake, with highly elevated CSF tau and normal p-tau. The clinical symptoms and CSF findings raised the suspicion of CJD. However, shortly after immediate treatment with thiamine the patient clinically improved. At follow-up, 2.5 months later, she had made a good recovery. This case of rapidly progressive dementia illustrates that, even in the case of a highly elevated CSF tau, clinicians should be alert for treatable causes such as WE.

Elevated cerebrospinal fluid tau protein levels in Wernicke's encephalopathy.

OBJECTIVE: Limited neuronal cell loss is seen in the neuropathology of Wernicke's encephalopathy (WE), but the extent of neuronal damage has not been well studied. Moreover, there is still a debate as to whether alcohol itself causes brain damage in humans. Although, it is difficult to examine the extent of neuronal damage in living patients, recent studies have revealed that total tau protein levels in the cerebrospinal fluid (CSF) reflect the rate of neuronal degeneration. Therefore, we hypothesized that the elevated CSF total tau in patients with WE was due to neuronal damage and thus we examined CSF total tau protein in patients with WE, as well as in those with alcohol withdrawal delirium (WD) and Korsakoff syndrome (KS). We also examined CSF total tau in nonalcohol dependent patients with Alzheimer's disease (AD) as a disease control. METHODS: CSF samples were obtained from 13 acute WE patients with alcohol dependence, 9 WD patients with alcohol dependence and 16 KS patients with alcohol dependence, and from 20 nonalcohol dependent AD patients. CSF was also obtained from 10 of the WE patients after their disease had progressed to the chronic stage. CSF tau protein levels in all samples were determined by sandwich enzyme-linked immunosorbent assay. Tau phosphorylated at threonine 181 (p-tau(181)) and amyloid beta-protein ending at amino acid 42 (A beta 42) in CSF were also determined for comparison between acute WE with AD. RESULTS: Total tau was significantly elevated in acute WE and decreased on long-term follow-up, but was not elevated in WD or KS. The patterns of p-tau(181) and A beta 42 differed between acute WE and AD. CONCLUSIONS: Intense neuronal cell death occurs transiently in WE, and the mechanism differs from that in AD. Neuronal damage is generally unaccompanied in WD. These results suggest that CSF total tau is a useful biological marker for WE.

Cerebrospinal fluid tau protein levels in demented and nondemented alcoholics.

The tau protein levels in cerebrospinal fluid (CSF-tau) were examined in 27 patients with alcohol dependence (20 demented and 7 nondemented), 36 age and dementia severity-matched patients with Alzheimer's disease (AD), and 23 age-matched normal control subjects. The CSF-tau levels in the demented alcoholic group (alcohol-induced organic brain disorders, 25.4 +/- 10.2 pg/ml) was significantly lower (p < 0.0001) than that in the AD group (96.1 +/- 53.3 pg/ml), but not significantly different from that in the nondemented alcoholics (18.1 +/- 10.2 pg/ml) or the controls (19.2 +/- 12.9 pg/ml). Using a 44.9 pg/ml as a cut-off value (mean + 2 SD of the normal control group), only one patient with alcohol-induced organic brain disorders exceeded the value, whereas 3 of 36 of the AD group showed CSF-tau levels less than this level. These findings suggest that alcohol-induced organic brain disorders are a group of dementias that are characterized by normal CSF-tau levels, and that the CSF examination for tau in combination with other clinical findings may help in differentiating alcohol-induced organic brain disorders from AD.