The frequency of brain lesions in alcoholics. Comparison between the 5-year periods 1975-1979 and 1983-1987

Coordination and Cognition in Pure Nutritional Wernicke’s Encephalopathy with Cerebellar Degeneration after COVID-19 Infection: A Unique Case Report

Background: Alcoholic cerebellar degeneration is a restricted form of cerebellar degeneration, clinically leading to an ataxia of stance and gait and occurring in the context of alcohol misuse in combination with malnutrition and thiamine depletion. However, a similar degeneration may also develop after non-alcoholic malnutrition, but evidence for a lasting ataxia of stance and gait and lasting abnormalities in the cerebellum is lacking in the few patients described with purely nutritional cerebellar degeneration (NCD). Methods: We present a case of a 46-year-old woman who developed NCD and Wernicke’s encephalopathy (WE) due to COVID-19 and protracted vomiting, resulting in thiamine depletion. We present her clinical course over the first 6 months after the diagnosis of NCD and WE, with thorough neuropsychological and neurological examinations, standardized clinical observations, laboratory investigations, and repeated MRIs. Results: We found a persistent ataxia of stance and gait and evidence for an irreversible restricted cerebellar degeneration. However, the initial cognitive impairments resolved. Conclusions: Our study shows that NCD without involvement of alcohol neurotoxicity and with a characteristic ataxia of stance and gait exists and may be irreversible. We did not find any evidence for lasting cognitive abnormalities or a cerebellar cognitive-affective syndrome (CCAS) in this patient.

Chronic Neurologic Effects of Alcohol

Chronic alcohol use induces silent changes in the structure and function of the central and peripheral nervous systems that eventually result in irreversible, debilitating repercussions. Once identified, nutritional supplementation and cessation measures are critical in preventing further neurologic damage. The proposed mechanisms of neuronal injury in chronic alcohol abuse include direct toxic effects of alcohol and indirect effects, including those resulting from hepatic dysfunction, nutritional deficiencies, and neuroinflammation. Clinical manifestations include cerebellar ataxia, peripheral neuropathy and Wernicke-Korsakoff encephalopathy. Continued exploration of the pathophysiologic mechanisms may lead to the discovery of early interventions that can prevent permanent neurologic injury.

Neurologic complications of alcoholism

PURPOSE OF REVIEW

This review serves as an overview of neurologic conditions associated with alcohol abuse or withdrawal, including epidemiology, clinical symptoms, diagnostic approach, and treatment.

RECENT FINDINGS

Frequent alcohol abuse and frank alcoholism are very common among adults in the United States. Although rates decline with each decade, as many as 10% of the elderly drink excessively. Given the ubiquitous nature of alcoholism in society, its complications have been clinically recognized for generations, with recent advances focusing on improved understanding of ethanol's biochemical targets and the pathophysiology of its complications.

SUMMARY

The chronic effects of alcohol abuse are myriad and include neurologic complications through both direct and indirect effects on the central and peripheral nervous systems. These disorders include several encephalopathic states related to alcohol intoxication, withdrawal, and related nutritional deficiencies; acute and chronic toxic and nutritional peripheral neuropathies; and myopathy. Although prevention of alcoholism and its neurologic complications is the optimal strategy, this article reviews the specific treatment algorithms for alcohol withdrawal and its related nutritional deficiency states.

Human alcohol-related neuropathology

Alcohol-related diseases of the nervous system are caused by excessive exposures to alcohol, with or without co-existing nutritional or vitamin deficiencies. Toxic and metabolic effects of alcohol (ethanol) vary with brain region, age/developmental stage, dose, and duration of exposures. In the mature brain, heavy chronic or binge alcohol exposures can cause severe debilitating diseases of the central and peripheral nervous systems, and skeletal muscle. Most commonly, long-standing heavy alcohol abuse leads to disproportionate loss of cerebral white matter and impairments in executive function. The cerebellum (especially the vermis), cortical-limbic circuits, skeletal muscle, and peripheral nerves are also important targets of chronic alcohol-related metabolic injury and degeneration. Although all cell types within the nervous system are vulnerable to the toxic, metabolic, and degenerative effects of alcohol, astrocytes, oligodendrocytes, and synaptic terminals are major targets, accounting for the white matter atrophy, neural inflammation and toxicity, and impairments in synaptogenesis. Besides chronic degenerative neuropathology, alcoholics are predisposed to develop severe potentially life-threatening acute or subacute symmetrical hemorrhagic injury in the diencephalon and brainstem due to thiamine deficiency, which exerts toxic/metabolic effects on glia, myelin, and the microvasculature. Alcohol also has devastating neurotoxic and teratogenic effects on the developing brain in association with fetal alcohol spectrum disorder/fetal alcohol syndrome. Alcohol impairs function of neurons and glia, disrupting a broad array of functions including neuronal survival, cell migration, and glial cell (astrocytes and oligodendrocytes) differentiation. Further progress is needed to better understand the pathophysiology of this exposure-related constellation of nervous system diseases and better correlate the underlying pathology with in vivo imaging and biochemical lesions.

Human alcohol-related neuropathology

Alcohol-related diseases of the nervous system are caused by excessive exposures to alcohol, with or without co-existing nutritional or vitamin deficiencies. Toxic and metabolic effects of alcohol (ethanol) vary with brain region, age/developmental stage, dose, and duration of exposures. In the mature brain, heavy chronic or binge alcohol exposures can cause severe debilitating diseases of the central and peripheral nervous systems, and skeletal muscle. Most commonly, long-standing heavy alcohol abuse leads to disproportionate loss of cerebral white matter and impairments in executive function. The cerebellum (especially the vermis), cortical-limbic circuits, skeletal muscle, and peripheral nerves are also important targets of chronic alcohol-related metabolic injury and degeneration. Although all cell types within the nervous system are vulnerable to the toxic, metabolic, and degenerative effects of alcohol, astrocytes, oligodendrocytes, and synaptic terminals are major targets, accounting for the white matter atrophy, neural inflammation and toxicity, and impairments in synaptogenesis. Besides chronic degenerative neuropathology, alcoholics are predisposed to develop severe potentially life-threatening acute or subacute symmetrical hemorrhagic injury in the diencephalon and brainstem due to thiamine deficiency, which exerts toxic/metabolic effects on glia, myelin, and the microvasculature. Alcohol also has devastating neurotoxic and teratogenic effects on the developing brain in association with fetal alcohol spectrum disorder/fetal alcohol syndrome. Alcohol impairs function of neurons and glia, disrupting a broad array of functions including neuronal survival, cell migration, and glial cell (astrocytes and oligodendrocytes) differentiation. Further progress is needed to better understand the pathophysiology of this exposure-related constellation of nervous system diseases and better correlate the underlying pathology with in vivo imaging and biochemical lesions.

Is there more than one neuropsychological disorder commonly associated with alcohol dependence?

There are two popular neuropsychological entities commonly attributed to the effects of alcohol dependence: the well-known Wernicke-Korsakoff syndrome, and the putative alcoholic encephalopathy. Wernicke-Korsakoff syndrome is a highly variable neurological and neuropsychological disorder, which is frequently missed or misdiagnosed on clinical examination. The available prevalence figures suggest that Wernicke-Korsakoff neuropathology probably occurs with a high incidence in hospitalized alcohol-dependent people. Thus, Wernicke-Korsakoff syndrome confounds clinical descriptions of the alcoholic encephalopathy and may account for most cases presumed to suffer from the latter disorder. Even if it is assumed that there is a specific alcoholic neurotoxicity, the clinical descriptions of this condition encompass features which are all attributable to Wernicke-Korsakoff syndrome. In other words, the proponents of the alcoholic encephalopathy have failed to provide a distinctive description, thus precluding positive identification.

Nutritional cerebellar degeneration, with comments on its relationship to Wernicke disease and alcoholism

Nutritional cerebellar degeneration occurs in alcoholism and other states that predispose to malnutrition, such as gastric bypass surgery. Gait ataxia is the principal clinical manifestation. Ataxia of the lower limbs is not uncommon, but upper extremity ataxia and nystagmus are rare. Atrophy of the anterior superior vermis is the primary pathological manifestation in established disease. Typically, the onset is subacute. This cerebellar disease is part of the spectrum of the Wernicke-Korsakoff syndrome, i.e. the cerebellar manifestation of Wernicke disease. It may occur with other lesions of Wernicke disease or in isolation. Rarely, with florid disease, lesions may be hemorrhagic. Active disease should be treated with thiamine in the same way that one treats Wernicke disease. Clinicopathologic correlation in this disease has provided the best evidence that the anterior superior vermis is important in coordinating bipedal locomotion.

Alcoholic cerebellar degeneration: A clinicopathological study of six Japanese autopsy cases and proposed potential progression pattern in the cerebellar lesion

Alcoholic cerebellar degeneration (ACD) is one of the most common neurological complications in alcoholics. As far as we know, however, only four Japanese autopsy cases of ACD have been reported, and only limited clinicopathological data on this disease are now available in Japan. The aims of this study were: (i) to examine the clinicopathological correlation of six Japanese autopsy cases of ACD, including three asymptomatic cases; and (ii) to elucidate the pattern of progression of the cerebellar lesion in ACD. All six alcoholics were histopathologically diagnosed as having "pure" ACD without Wernicke's encephalopathy. The characteristics of the topographical distribution of the cerebellar lesion were as follows. Symptomatic cases (cases 1-3) showed more severe and widespread change than asymptomatic cases (cases 4-6). Even in case 6, which had the mildest lesion, the anterior vermis developed a moderate change (Purkinje cell loss and narrowing of the molecular layer). In cases 4 and 5 with more severe and widespread lesions, the superior and posterior vermis and the adjacent regions of the superior hemisphere, including the anterior lobe and simple lobule, were involved. In all symptomatic cases, the anterior superior hemisphere had severe lesions involving the granular cell layer. In contrast to asymptomatic cases, all symptomatic cases also had severe to moderate lesions in the anterior inferior hemisphere. In cases 1 and 2 with the most severe lesions, the moderate to severe changes were distributed in the posterior and inferior portions of both the vermis and hemisphere. These findings suggest that in ACD, severe lesions successively develop: (i) in the anterior superior vermis; (ii) anterior superior hemisphere; (iii) anterior inferior hemisphere; and (iv) anterior inferior vermis. In addition, cerebellar symptoms may frequently occur if the anterior superior hemisphere and anterior inferior hemisphere, in addition to the anterior superior vermis, are involved.

Frequency and clinicopathological characteristics of alcoholic cerebellar degeneration in Japan: a cross-sectional study of 1,509 postmortems

Alcoholic cerebellar degeneration (ACD) is a pivotal neurological complication in alcoholics. However, although there are a few autopsy reports and some data on its frequency, it is considered very rare in Japan. The aims of this study were (1) to estimate the frequency of the disease in Japanese autopsy cases, and (2) to examine the clinicopathological features of symptomatic and asymptomatic cases of ACD. We reviewed the records of 1,509 Japanese autopsies obtained from three autopsy series in Japan, and selected all 55 cases (3.6%) with alcoholism. On neuropathological reexamination, ACD was confirmed in six male alcoholics [0.4% of all subjects; 10.9% of all alcoholics; mean age at death 59.3+/-13.4 years (+/- SD)], including three asymptomatic cases. These frequencies were much lower than some previous Western findings, but more common than that has been expected in Japan. The frequencies of memory impairment and ataxia in ACD cases were significantly higher than those in alcoholics without any alcohol-related pathologies. In ACD cases, loss of Purkinje cells, narrowing of the width of the molecular layer, and tissue rarefaction in the granular layer were observed in the anterior and superior portions of the vermis of the cerebellum. In adjacent regions, the Purkinje cell and molecular layers were more mildly affected. The distribution of severely affected regions was more restricted in the asymptomatic cases than in the symptomatic cases. This study confirmed the frequency of asymptomatic cerebellar degeneration in alcoholics, suggesting that early intervention in alcoholism in the subclinical phase is important to prevent the development of cerebellar symptoms.

Vermal atrophy of alcoholics correlate with serum thiamine levels but not with dentate iron concentrations as estimated by MRI

Chronic alcohol consumption is frequently accompanied by cerebellar degeneration. The exact aetiology of alcoholic cerebellar degeneration is still a matter of debate. The aim of the present study was to investigate whether patients with chronic alcohol consumption exhibit a decrease in dentate nuclei intensity as measured by MRI, and if so, whether this decrease correlates with cerebellar atrophy as revealed by MR imaging or with clinical signs of cerebellar ataxia. A decrease in dentate nuclei intensity would indirectly indicate that iron accumulation, and therefore, oxidative stress may play a role in alcoholic cerebellar degeneration. MRI of 45 alcoholics and 44 age and sex-matched healthy control subjects was performed using a 3D-T1-weighted fast low angle shot (FLASH) echo sequence. Signal intensities of the dentate nuclei and cerebellar white matter were bilaterally measured. Planimetric measurements of cerebellar size were performed using a 3D-T1-weighted magnetization prepared rapid acquisition gradient echo (MPRAGE) sequence. Results demonstrated that dentate nuclei intensity was not significantly decreased in patients with chronic alcohol consumption (mean +/- SD signal intensity 65.36 +/- 13.0) if compared with control subjects (mean +/- SD signal intensity 68.95 +/- 9.4) (p = 0.15). Dentate nuclei intensity did not correlate with cerebellar size neither in control subjects nor in alcoholics. In contrast, vitamin B1 level correlated with cerebellar size in alcoholics even if the vitamin B1 concentration was within normal values (r = 0.344, p = 0.028). These results support the view that thiamine deficiency rather than direct neurotoxic effects of alcohol is the main causative factor for the development of alcoholic cerebellar degeneration.

Depletion of brain histamine produces regionally selective protection against thiamine deficiency-induced lesions in the rat

Breakdown of the blood brain barrier and the subsequent accumulation of free radicals, lactate, and glutamate appear to be the immediate causes of thiamine deficiency (TD)-induced damage to thalamus. The mechanisms triggering these events are unknown but recent evidence suggests an important role of histamine. We therefore studied the effects of histamine depletion on thalamic lesions in the pyrithiamine-induced thiamine deficient (PTD) rat. Chronic intracerebroventricular (i.c.v., 7 days) infusion of alpha-fluoromethylhistidine (FMH), combined with bilateral ibotenate destruction of the histamine-containing neurons in the tuberomammillary (TM) nucleus and bolus i.c.v. infusion of 48/80, a potent mast cell degranulating agent, was used to deplete brain histamine levels. PTD rats receiving combined FMH + 48/80 + TM lesions developed acute neurological symptoms, including spontaneous seizures, approximately 1 day earlier than PTD rats treated with i.c.v. infusion of vehicle and sham lesions of the TM. When examined 1 week after restoration of thiamine, the PTD vehicle + sham lesion animals contained severe neuronal loss and gliosis in midline, intralaminar, ventral, lateral, and posterior nuclei. PTD animals treated with FMH + 48/80 + TM lesions had little evidence of neuronal loss or microglial proliferation in thalamus except in the gelatinosus and anteroventral nuclei, in which there was complete neuronal loss. These data demonstrate a significant and regionally selective role of histamine in the development of thalamic lesions in a rat model of Wernicke's encephalopathy. Furthermore, these data suggest either a dissociation between seizures and thalamic lesions or a significant role of histamine in seizure-related damage to the thalamus.

Alcohol-thiamine interactions: an update on the pathogenesis of Wernicke encephalopathy

Wernicke encephalopathy is a neurological disorder commonly observed in chronic alcohol abuse, in patients with AIDS, and in other conditions of compromised nutritional status. The underlying cause of the disorder is thiamine deficiency. The present review highlights data focusing on alcohol-thiamine interactions and their relationship to the pathogenesis of Wernicke encephalopathy. Recent findings on the effects of alcohol on thiamine absorption and storage and on thiamine phosphorylation to the enzyme co-factor form (thiamine diphosphate) are discussed with regard to the postulated "biochemical lesion" of Wernicke encephalopathy. Also discussed are new findings on the molecular genetics of the thiamine-dependent enzyme transketolase in patients with Wernicke encephalopathy. A discussion of the hypotheses regarding the mechanisms underlying the phenomenon of selective neuronal cell death observed in this disorder including cerebral energy deficit, focal lactic acidosis, glutamate excitotoxicity, increased expression of immediate-early genes, free radicals and perturbations of the blood-brain barrier are presented. Finally, the possible role of thiamine deficiency in alcoholic peripheral neuropathy is reviewed.

Chronic ethanol consumption in rats: correlation between memory performance and hippocampal acetylcholine release in vivo

The effects of chronic alcohol consumption on memory performance and hippocampal acetylcholine release in vivo were investigated in rats. Rats were allowed to drink 25% (v/v) ethanol solution as the only source of fluid for nine consecutive months, whereas control rats received only tap water. Memory performance was tested by the acquisition of shuttle box active and passive avoidance. Chronic ethanol-consuming rats were not impaired in the acquisition of the active avoidance response task, whereas in the passive avoidance task, latency scores of treated rats were significantly lower than in controls. The basal release of acetylcholine in freely moving rats, assessed by the microdialysis technique, was significantly decreased in ethanol-treated rats. Impairment in memory performance, as assessed in the passive avoidance task, was significantly correlated with hippocampal acetylcholine release in vivo.

Delayed matching to sample and concurrent learning in nonamnesic humans with alcohol dependence

Small samples of alcohol-dependent subjects who showed no clinical signs of Wernicke-Korsakoff syndrome were compared with nonalcohol-dependent controls on two animal memory tests which are performed poorly by human amnesics. Compared to the control subjects, the alcohol-dependent subjects' performance was impaired on a version of the delayed matching to sample task. On concurrent discrimination learning the overall group difference just failed to reach significance. The results are interpreted as suggesting that behavioural impairment may occur in alcohol-dependent subjects who are not clinically amnesic, and that the impairment is similar in type to that observed in cases of severe Wernicke-Korsakoff syndrome.

Wernicke's encephalopathy in an autopsy material obtained over a one-year period

In a material comprising 279 consecutive autopsies obtained over a one-year period there were four cases of Wernicke's encephalopathy (WE), of which three were inactive (chronic) and one was active (acute). The latter was not related to chronic alcoholism. Our findings show that WE may be regularly present in a routine autopsy series. In only one case was WE suspected clinically and none of the cases revealed macroscopic brain changes indicative of WE. We therefore suggest that sections of the mammillary bodies should be taken routinely to detect all possible cases of WE.

Cerebral lesions and causes of death in male alcoholics. A forensic autopsy study

Autopsies on 195 male alcoholics aged 30-64 years who died outside hospitals and nursing homes in Oslo from 1984 to 1988, were carried out at the Institute of Forensic Medicine, Rikshospitalet. In 127 cases brain tissue was examined neuropathologically, 86 (67.7%) showed abnormalities and 28 contained lesions of more than one type. Lesions associated with alcoholism were found in 61 cases (48%), 18 (14.2%) showed Wernicke's encephalopathy, 47 (37%) cerebellar atrophy, 2 central pontine myelinolysis and 1 hepatic encephalopathy. Subdural haematoma and/or cortical contusions were found in 30 cases (23.6%) and cerebrovascular lesions in 19 (15%). Of the 195 cases, 22 had a history of recurrent convulsive attacks of which 19 were examined neuropathologically and 13 had focal damage that could have caused epileptic fits. Although cerebral damage was more frequent among vagrants and other persons dependent on social support, 50% of the alcoholics living in their own homes were also affected. Alcohol-related disease was considered the cause of death in 15 of 127 cases examined neuropathologically and 9 of these died from acute Wernicke's encephalopathy all of whom were sober at death. Although the post mortem analyses included neuropathological examination of the brain, the cause of death remained unknown in 27 (21%) of the 127 cases.

Delayed growth and maturation of astrocytic cultures following exposure to ethanol: electron microscopic observations

This investigation examined the effects of ethanol on the morphologic features of cultured rat astrocytes using a treatment paradigm that provided consistent exposure to ethanol at concentrations of 0.2%, 0.5%, or 1.0% (w/v). Cultures were assessed between 4 and 8 days in vitro during the logarithmic phase of growth; differences in culture growth, cell profile area and ultrastructural configuration were found. A dose-dependent inhibition of culture growth was observed after 48 and 96 h of ethanol exposure. In control cultures, the consequences of culture growth included the progressive crowding of cells, a concomitant reduction in the cell profile area, and increased cell-cell contact. On culture day 8, electron microscopic examination of control cultures demonstrated a complex stratified cellular layer, the junction of cells by puncta adhaerentia and the acquisition of intermediate filament bundles. In contrast, the impaired growth in ethanol-exposed cultures was associated with the retention of an extensive cell profile area suggesting restrained morphologic development. At the electron microscopic level, ethanol-exposed cultures showed a dose-dependent attenuation in both the depth and complexity of the cell layer. These findings indicated that the growth kinetics and morphologic development of astrocytic cultures are vulnerable to ethanol exposure at moderate and high levels. These findings were attributed to both ethanol cytotoxicity and a deprivation of cellular interaction resulting from the restricted population size.

Wernicke's encephalopathy in non-alcoholics. An autopsy study

In a 5-year autopsy material constituting 6,964 autopsies, there were 52 cases of Wernicke's encephalopathy of which 12 (23%) occurred in non-alcoholics. Among 18 cases with active (acute) disease, 7 cases (39%) were found in non-alcoholics. Only 4 cases of active Wernicke's disease were diagnosed clinically, all of them in alcoholics. The predominant clinical symptoms were disorientation and depressed levels of consciousness, whereas eye symptoms were recorded in only 3 cases. None of the non-alcoholics were given specific thiamine therapy, whereas some alcoholics received large doses of the vitamin as a routine procedure. However, the thiamine therapy was often instituted too late. It is concluded that active Wernicke's encephalopathy should be considered in all patients with prolonged malnutrition and that disorientation and depressed levels of consciousness may be the predominating symptoms of the disease. Even the slightest suspicion of Wernicke's encephalopathy should prompt immediate administration of large doses of thiamine parenterally.