Prevalence and Improvement of Caine-Positive Wernicke-Korsakoff Syndrome in Psychiatric Inpatient Admissions.

BACKGROUND: Wernicke-Korsakoff Syndrome (WKS) resulting from thiamine deficiency is classically defined as including encephalopathy, ataxia, and ophthalmoplegia. Only 16% of autopsy-confirmed patients with WKS exhibit all three signs. Caine-positive WKS criteria include two or more of the following: nutritional deficiency, delirium or mild memory impairment, cerebellar dysfunction/ataxia, and oculomotor abnormalities. OBJECTIVE: We describe Caine-positive WKS prevalence among psychiatric inpatients and compare pretreatment-versus-posttreatment neurocognitive improvement to an unaffected group. METHODS: This 6-month quality-improvement evaluation included two-stage screening for Caine-positive WKS, administering high-dose intravenous thiamine (day 1: 1200 mg; days 2-4: 200 mg) with reexamination on day 5. We used descriptive statistics and fitted random effects models to examine rate-of-change differences in pre-/posttreatment Montreal Cognitive Assessment (MoCA), delayed 5-item recall, and gait/coordination scores between treated Caine-positive patients with WKS and untreated Caine-negative patients. RESULTS: Of 262 patients, 32 (12%) had Caine-positive WKS; 17 (53%) used alcohol currently. Treated Caine-positive WKS (n = 26) versus Caine-negative comparison (n = 34) before and after treatment observed a mean change (standard deviation) in the MoCA score of 3.6 (2.5) versus 1.8 (2.5) (P < 0.01); 5-item recall: 1.8 (1.4) versus 0.5 (1.4) (P < 0.001); gait/coordination scores: -0.6 (1.2) versus -0.1 (0.6) (P < 0.001). Oculomotor abnormalities were infrequent (n = 4 in Caine-positive WKS, n = 2 in Caine-negative comparison groups). CONCLUSIONS: Caine-positive WKS prevalence among psychiatric inpatients was 12%; only half used alcohol. Patients treated with high-dose thiamine demonstrated clinically significant neurocognitive improvement.

Phenomenological characteristics of autobiographical memory in Korsakoff's syndrome.

A body of research suggests compromise of autobiographical memory in Korsakoff's syndrome (KS). The present paper extends this literature by investigating the subjective experience of autobiographical recall in the syndrome. Patients with KS and controls were asked to retrieve autobiographical memories. After memory retrieval, participants were asked to rate phenomenological characteristics of their memories (i.e., reliving, back in time, remembering, realness, visual imagery, auditory imagery, language, emotion, rehearsal, importance, spatial recall and temporal recall). Analysis showed lower "Mean Phenomenological Experience" in the Korsakoff patients than in controls. However, the Korsakoff patients attributed relatively high emotional value and importance to their memories. Although our findings suggest compromised phenomenological reliving of autobiographical memory in patients with KS, affective characteristics such as emotion and importance are likely to play a main role in the subjective experience of the past in these patients.

Sustaining high acetylcholine levels in the frontal cortex, but not retrosplenial cortex, recovers spatial memory performance in a rodent model of diencephalic amnesia.

Although the thalamus and/or mammillary bodies are the primary sites of neuropathology in cases of diencephalic amnesia such as Wernicke Korsakoff Syndrome (WKS), there is also functional deactivation of certain cortical regions that contribute to the cognitive dysfunction. Acetylcholine (ACh) is a key neurotransmitter that modulates neural processing within the cortex and between the thalamus and cortex. In the pyrithiamine-induced thiamine deficiency (PTD) rat model of WKS, there are significant reductions in cholinergic innervation and behaviorally stimulated ACh efflux in the frontal (FC) and retrosplenial (RSC) cortices. In the present study, ACh released levels were site-specifically amplified with physostigmine (0.5 µg, 1.0 µg) in the FC and the RSC, which was confirmed with in vivo microdialysis. Although physostigmine sustained high ACh levels in both cortical regions, the effects on spatial memory, assessed by spontaneous alternation, were different as a function of region (FC, RSC) and treatment (PTD, pair-fed [PF]). Higher ACh levels in the FC recovered the rate of alternation in PTD rats as well as reduced arm-reentry perseverative errors. However, higher ACh levels within the FC of PF rats exacerbated arm-reentry perseverative errors without significantly affecting alternation rates. Maintaining high ACh levels in the RSC had no procognitive effects in PTD rats, but rather impaired alternation behavior in PF rats. These results demonstrate that diverse cortical regions respond differently to intensified ACh levels-and the effects are dependent on thalamic pathology. Thus, pharmacotherapeutics aimed at enhancing cognitive functions must account for the unique features of cortical ACh stimulation and the connective circuitry with the thalamus.

The role of cholinergic and GABAergic medial septal/diagonal band cell populations in the emergence of diencephalic amnesia.

The septohippocampal pathway, which is mostly composed of cholinergic and GABAergic projections between the medial septum/diagonal band (MS/DB) and the hippocampus, has an established role in learning, memory and disorders of cognition. In Wernicke-Korsakoff's syndrome (WKS) and the animal model of the disorder, pyrithiamine-induced thiamine deficiency (PTD), there is both diencephalic damage and basal forebrain cell loss that could contribute to the amnesic state. In the current experiment, we used the PTD animal model to access both cholinergic (choline acetyltransferase [ChAT] immunopositive) and GABAergic (parvalbumin [PV]; calbindin [CaBP]) neuronal loss in the MS/DB in relationship to midline-thalamic pathology. In addition, to gain an understanding about the role of such neuropathology in behavioral dysfunction, animals were tested on a non-rewarded spontaneous alternation task and behavioral performance was correlated to neuropathology. Unbiased stereological assessment of neuronal populations revealed that ChAT-positive neurons were significantly reduced in PTD rats, relative to control pair-fed rats, and thalamic mass and behavioral performance correlated with ChAT neuronal estimates. In contrast, both the PV- and CaBP-positive neurons in the MS/DB were not affected by PTD treatment. These results support an interactive role of both thalamic pathology and cholinergic cell loss in diencephalic amnesia.

Severe dysphagia as the presenting symptom of Wernicke-Korsakoff syndrome in a non-alcoholic man.

We present the case of a non-alcoholic man, who, following severe malnutrition, presented with dysphagia that necessitated gastrostomy tube placement. The patient subsequently developed encephalopathy, at which point thiamine deficiency was suspected and thiamine supplementation initiated. The encephalopathy and the dysphagia resolved, but the patient was left with a dense amnestic deficit consistent with Korsakoff syndrome. MRI at the time of the encephalopathy revealed lesions consistent with Wernicke-Korsakoff syndrome. This case represents a remarkable example of Wernicke-Korsakoff syndrome that for a prolonged time period had as its sole manifestation severe dysphagia. To our knowledge, there is only one similar case reported in the literature. This case serves to alert neurologists that isolated dysphagia may be the presenting symptom of this classic neurological syndrome even in the absence of alcoholism.

Blunted hippocampal, but not striatal, acetylcholine efflux parallels learning impairment in diencephalic-lesioned rats.

A rodent model of diencephalic amnesia, pyrithiamine-induced thiamine deficiency (PTD), was used to investigate the dynamic role of hippocampal and striatal acetylcholine (ACh) efflux across acquisition of a nonmatching-to-position (NMTP) T-maze task. Changes in ACh efflux were measured in rats at different time points in the acquisition curve of the task (early=day 1, middle=day 5, and late=day 10). Overall, the control group had higher accuracy scores than the PTD group in the latter sessions of NMTP training. During the three microdialysis sampling points, all animals displayed significant increases in ACh efflux in both hippocampus and striatum, while performing the task. However, on day 10, the PTD group showed a significant behavioral impairment that paralleled their blunted hippocampal--but not striatal--ACh efflux during maze training. The results support selective diencephalic-hippocampal dysfunction in the PTD model. This diencephalic-hippocampal interaction appears to be critical for successful episodic and spatial learning/memory.

Development and resolution of brain lesions caused by pyrithiamine- and dietary-induced thiamine deficiency and alcohol exposure in the alcohol-preferring rat: a longitudinal magnetic resonance imaging and spectroscopy study.

Wernicke's encephalopathy (WE) is characterized by lesions in thalamus, hypothalamus (including mammillary nuclei), and inferior colliculi, results in serious disabilities, has an etiology of thiamine deficiency, is treatable with thiamine, and occurs most commonly with alcoholism. Despite decades of study, whether alcohol exposure exacerbates the neuropathology or retards its resolution remains controversial. To examine patterns of brain damage and recovery resulting from thiamine deprivation with and without alcohol exposure, we conducted in vivo magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) at 3 T in alcohol-preferring (P) rats, which had voluntarily consumed large amounts of alcohol before thiamine manipulation. A total of 18 adult male P rats (nine alcohol-exposed) received a thiamine-deficient diet for 2 weeks: 10 (five alcohol-exposed) received intraperitoneal (i.p.) pyrithiamine (PT) and eight (four alcohol-exposed) received i.p. thiamine supplementation. Neurological signs developed by day 14. Rats were scanned before thiamine depletion and 18 and 35 days after thiamine repletion. Two-dimensional J-resolved MRS single-voxel spectra with water reference were collected in a voxel subtending the thalamus; metabolite quantification was corrected for voxel tissue content. MRI identified significant enlargement of dorsal ventricles and increase in signal intensities in thalamus, inferior colliculi, and mammillary nuclei of PT compared with thiamine-treated (TT) groups from MRI 1-2, followed by significant normalization from MRI 2-3 in thalamus and colliculi, but not mammillary nuclei and lateral ventricles. Voxel-by-voxel analysis revealed additional hyperintense signal clusters in the dorsal and ventral hippocampus and enlargement of the fourth ventricle. MRS showed a significant decline and then partial recovery in thalamic N-acetylaspartate, a marker of neuronal integrity, in PT compared with TT rats, with no change detected in creatine, choline, or glutamate. PT rats with prior alcohol exposure exhibited attenuated recovery in the thalamus and arrested growth of the corpus callosum; further, two of the five alcohol-exposed PT rats died prematurely. Parenchymal and ventricular changes with thiamine manipulation concur with human radiological signs of WE. The enduring macrostructural and neurochemical abnormalities involving critical nodes of Papez circuit carry liabilities for development of amnesia and incomplete recovery from other cognitive and motor functions subserved by the affected neural systems.

A cluster of polyneuropathy and Wernicke-Korsakoff syndrome in a bariatric unit.

BACKGROUND: Wernicke-Korsakoff syndrome and peripheral neuropathy are very uncommon in bariatric surgical practice. The literature indicates that these complications tend to strike patients receiving unbalanced diets or undergoing rapid weight-loss. METHODS: In a retrospective analysis of the initial experience of a bariatric team in the city of Belem, Pará, in northern Brazil, 5 cases were diagnosed in the first year, 4 of them following gastric bypass and the last one after therapy with an intragastric balloon. RESULTS: All episodes followed periods of severe vomiting, which certainly interfered with intake of food as well as of routine vitamin supplements, resulting in severe polyneuropathy and other neurologic manifestions, mostly damaging motility of lower limbs. Therapy consisted of pharmacologic doses of vitamin B1 along with restoration of adequate diet and multivitamin prescriptions. Physical therapy was employed to prevent atrophy and accelerate normalization of muscle strength. All patients responded to this program after variable intervals without significant sequelae. CONCLUSIONS: Thiamine-related neurologic derangements were a cause for much concern and prolonged morbidity in this series, but responded to vitamin B1 replenishment. A high degree of clinical suspicion in bariatric patients and urgent therapeutic intervention whenever postoperative vomiting persists for several days, especially during the first 2-3 months after operation, are the safest approach to these uncommon episodes. It is speculated whether peculiarities in the regional diet of this area in Brazil could have influenced the high incidence of the neurologic aberrations.

Voxel-based mapping of brain hypometabolism in permanent amnesia with PET.

In this study, we used voxel-based mapping methods to compare the resting cerebral metabolic rate of glucose (CMRglc) measured with PET in five patients with permanent amnesia (three with chronic Wernicke-Korsakoff and two with postanoxia syndrome) to that of nine healthy age-matched subjects. We assessed (i) a group pattern of relative hypometabolism; and (ii) the consistency of this group pattern, if any, in individual subjects, according to etiology. The results from the group analysis documented that permanent amnesia is associated with hypometabolism in the thalamus, posterior cingulate cortex, and mesial prefrontal cortex (near the anterior cingulate gyrus), bilaterally, as well as in the left supramarginal and middle temporal gyri. The individual analysis showed that this group pattern was found in essentially each patient, regardless of the cause of amnesia. Thus, permanent amnesia is subtended by dysfunction in structures belonging to Papez/limbic circuits as well as in left-hemisphere areas typically concerned with verbal functions, probably through a mechanism of thalamo-cortical disconnection and possibly involved in retrograde amnesia. The use of a voxel-based method allowed us to map a common network of synaptic dysfunction in a neuropsychological syndrome regardless of etiology. Our results indicate that this should be a powerful method in functional neuropsychology.

Rats exposed to acute pyrithiamine-induced thiamine deficiency are more sensitive to the amnestic effects of scopolamine and MK-801: examination of working memory, response selection, and reinforcement contingencies.

Pyrithiamine-induced thiamine deficiency (PTD), which has been used as a model of Wernicke-Korsakoff syndrome (WKS), produces a range of neuropathological and behavioral abnormalities in rodents. The extent of the diencephalic damage produced by this treatment varies from moderate to extreme cell loss. The magnitude of working memory impairment tends to correlate with the degree of neuropathology. In this study a PTD protocol that produces moderate thalamic pathology was used to gain further insight into the neurobehavioral consequences of thiamine deficiency. Towards this end, two distinct manipulations were conducted. First, the differential outcomes procedure (DOP), which correlates specific reinforcers with specific to-be-remembered events, was applied to an operant version of matching-to-position (MTP). This behavioral manipulation was conducted to determine if the DOP would improve memory performance in PTD-treated rats, demonstrating some intact cognitive functions. Additionally, to assess the functional integrity of the cholinergic and glutamatergic systems, normal and PTD-treated rats were administered i.p. injections of scopolamine and MK-801. It was found that the DOP enhanced memory, but not acquisition performance, in both normal and PTD-treated rats. Furthermore, when administered scopolamine, but not MK-801, rats trained with the DOP continued to outperform rats trained with a non-differential outcomes procedure (NOP). However, PTD-treated rats, regardless of training procedure (DOP, NOP), were more disrupted by the 'amnestic' effects of both scopolamine and MK-801. The differential sensitivity of treatment groups to the amnestic effects of scopolamine and MK-801 reveals insights into the neurochemical correlates of memory processes and WKS.