Alcohol-related peripheral neuropathy: a systematic review and meta-analysis.

The primary aim of this systematic review was to establish the prevalence, character, and risk factors of peripheral neuropathy amongst chronic alcohol abusers and to identify the most appropriate management strategies. In this review, possible pathogenetic mechanisms are also discussed. A systematic, computer-based search was conducted using the PubMed database. Data regarding the above parameters were extracted. 87 articles were included in this review, 29 case-control studies, 52 prospective/retrospective cohort studies and 2 randomised control trials, 1 cross sectional study, and 3 population-based studies. The prevalence of peripheral neuropathy amongst chronic alcohol abusers is 46.3% (CI 35.7- 57.3%) when confirmed via nerve conduction studies. Alcohol-related peripheral neuropathy generally presents as a progressive, predominantly sensory axonal length-dependent neuropathy. The most important risk factor for alcohol-related peripheral neuropathy is the total lifetime dose of ethanol, although other risk factors have been identified including genetic, male gender, and type of alcohol consumed. At present, it is unclear what the pathogenetic mechanisms for the development of neuropathy amongst those who chronically abuse alcohol are, and therefore, it is unknown whether it is attributed to the direct toxic effects of ethanol or another currently unidentified factor. There is presently sparse data to support a particular management strategy in alcohol-related peripheral neuropathy, but the limited data available appears to support the use of vitamin supplementation, particularly of B-vitamin regimens inclusive of thiamine.

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.

[Thiamine (vitamin B1) treatment in patients with alcohol dependence]. / Le traitement par thiamine (vitamine B1) dans l'alcoolodépendance.

Thiamine deficiency (vitamin B1) is common in patients with alcohol dependence. Cognitive impairments may be an early consequence of thiamine deficiency. Wernicke's encephalopathy is underdiagnosed and undertreated. In patients with established Wernicke's encephalopathy, parenteral thiamine 200-500mg three times a day should be given for 3-5 days, followed by oral thiamine 250-1000mg/day. In patients with suspected Wernicke's encephalopathy, parenteral thiamine 250-300mg should be given two times a day for 3-5 days, followed by oral thiamine 250-300mg/day. In patients at high risk of thiamine deficiency, parenteral thiamine 250-500mg/day should be given for 3-5 days, followed by oral thiamine 250-300mg/day. In patients at low risk (with uncomplicated alcohol dependence), oral thiamine 250-500mg/day should be given for 3-5 days, followed by oral thiamine 100-250mg/day.

Chronic alcoholics retain dyspeptic symptoms, pan-enteric dysmotility, and autonomic neuropathy before and after abstinence.

OBJECTIVE: To carry out a comprehensive study on gastrointestinal symptoms, motility and autonomic neuropathy in chronic alcoholics before and one year after abstinence. METHODS: Dyspeptic symptoms (questionnaires), fasting and postprandial gallbladder and gastric motility (ultrasonography), oro-cecal transit time (lactulose H2 -breath test), stool form score (indirect marker of colonic transit), and autonomic neuropathy (sweat spot test, R-R ratio) were assessed at baseline in 268 subjects (136 chronic alcoholics and 132 healthy controls). A subgroup of 39 patients was re-evaluated after 12 months of abstinence. RESULTS: Chronic alcoholics had increased dyspepsia, delayed gastric emptying and oro-cecal transit time but faster gallbladder emptying, with slightly accelerated colonic transit. Sympathetic, but not parasympathetic, autonomic dysfunction was found. Dyspeptic symptoms and functional alterations of gastric emptying and oro-cecal transit tests were still present after 12-month abstinence, whereas gallbladder motility, stool form score and sympathetic function improved. CONCLUSIONS: Chronic alcoholics exhibit combined and interdependent presence of dyspeptic symptoms, impaired motility at different levels of the gastrointestinal tract, with sympathetic dysfunction. Only a few of these abnormalities improve after one year of abstinence from alcohol.

The significance of folate deficiency in alcoholic and nutritional neuropathies: analysis of a case.

OBJECTIVE: To elucidate the significance of folate deficiency in alcoholic and nutritional neuropathies. METHODS: We preformed a comprehensive clinical screening of a patient with chronic alcoholism who manifested neuropathy, macrocytic anemia, liver dysfunction, and folate deficiency. RESULTS: A 33-y-old woman with chronic alcoholism presented with acutely progressive glove- and stocking-type sensorimotor polyneuropathy. Although an episode of neuropathy preceded the current episode by 2 y, its cause was never determined. The findings of nerve conduction studies were indicative of axonal neuropathy. Laboratory findings revealed macrocytic anemia and liver dysfunction. Her serum level of folate was reduced, whereas thiamine, riboflavin, and cobalamin levels were within normal range. The neuropathy and anemia showed gradual recovery after the initiation of folic acid supplementation. CONCLUSIONS: This case study indicates that folate deficiency should be monitored closely in patients with chronic alcoholism and associated malnutrition. Additionally, folate deficiency should be considered as a differential diagnosis of neuropathy.

Alcoholic neuropathy: possible mechanisms and future treatment possibilities.

Chronic alcohol consumption produces painful peripheral neuropathy for which there is no reliable successful therapy, mainly due to lack of understanding of its pathobiology. Alcoholic neuropathy involves coasting caused by damage to nerves that results from long term excessive drinking of alcohol and is characterized by spontaneous burning pain, hyperalgesia and allodynia. The mechanism behind alcoholic neuropathy is not well understood, but several explanations have been proposed. These include activation of spinal cord microglia after chronic alcohol consumption, oxidative stress leading to free radical damage to nerves, activation of mGlu5 receptors in the spinal cord and activation of the sympathoadrenal and hypothalamo-pituitary-adrenal (HPA) axis. Nutritional deficiency (especially thiamine deficiency) and/or the direct toxic effect of alcohol or both have also been implicated in alcohol-induced neuropathic pain. Treatment is directed towards halting further damage to the peripheral nerves and restoring their normal functioning. This can be achieved by alcohol abstinence and a nutritionally balanced diet supplemented by all B vitamins. However, in the setting of ongoing alcohol use, vitamin supplementation alone has not been convincingly shown to be sufficient for improvement in most patients. The present review is focused around the multiple pathways involved in the development of peripheral neuropathy associated with chronic alcohol intake and the different therapeutic agents which may find a place in the therapeutic armamentarium for both prevention and management of alcoholic neuropathy.

Muscle pain in models of chemotherapy-induced and alcohol-induced peripheral neuropathy.

OBJECTIVE: While inflammatory pain is well described in skeletal muscle, neuropathic muscle pain remains to be clarified. We used 3 well-established rodent models of peripheral neuropathy to evaluate for muscle pain. METHODS: In rats exposed to either of 2 neurotoxic cancer chemotherapies, paclitaxel or oxaliplatin, or to alcohol consumption, we assessed the evolution of mechanical hyperalgesia in skeletal muscle and skin, in the same animal. To explore the involvement of protein kinase C epsilon (PKCε), a second messenger implicated in some forms of neuropathic pain, antisense oligodeoxynucleotides (AS-ODNs) or mismatch ODNs (MM-ODNs) for PKCε were administered intrathecally. RESULTS: Rats submitted to models of chemotherapy-induced and alcohol-induced neuropathy developed persistent muscle hyperalgesia, which evolved in parallel in muscle and skin. The administration of PKCε AS, which has been shown to mediate cutaneous hyperalgesia in paclitaxel and ethanol models of neuropathic pain, also inhibited muscle hyperalgesia induced by these agents. Stopping AS-ODN was associated with the reappearance of hyperalgesia at both sites. The AS-ODN to PKCε treatment was devoid of effect in both muscle and skin in the oxaliplatin neuropathy model. INTERPRETATION: Our results support the suggestion that neuropathic muscle pain may be a greater clinical problem than generally appreciated.

Alcohol-related peripheral neuropathy: nutritional, toxic, or both?

Alcohol-related peripheral neuropathy (ALN) is a potentially debilitating complication of alcoholism that results in sensory, motor, and autonomic dysfunction. Unfortunately, ALN is rarely discussed as a specific disease entity in textbooks because it is widely assumed to primarily reflect consequences of nutritional deficiency. This hypothesis is largely based on observations first made over eight decades ago when it was demonstrated that thiamine deficiency (beriberi) neuropathy was clinically similar to ALN. In recent studies, failure of thiamine treatment to reverse ALN, together with new information demonstrating clinical and electrophysiological distinctions between ALN and nutritional deficiency neuropathies, suggests that alcohol itself may significantly predispose and enhance development of neuropathy in the appropriate clinical setting. We reviewed the evidence on both sides and conclude that ALN should be regarded as a toxic rather than nutritional neuropathy.

[Effectiveness of cortexin in the complex treatment of patients with chronic alcohol encephalopathy and polyneuropathy].

Investigation of therapeutic effectiveness of cortexin in chronic alcohol encephalopathy and chronic alcohol polyneuropathy was conducted in an open randomized study. The aim of the study was to compare these disorders with diabetic and professional polyneuropathy. Cortexin was prescribed in dose 10 mg/d intramuscular during 10 days, along with standard therapy. The group of patients consisted of 15 people with alcohol disorders, 15 people with diabetic polyneuropathy and 15 people with professional polyneuropathy. The control group included 15 patients with alcohol disorders who did not receive cortexin. Encephalography (EEG) and electroneuromyography (ENMG) were used in addition to the clinical examination. Cortexin had the positive effect on clinical symptoms, EEG and ENMG. The drug was well-tolerated, no side-effects were observed.

[Metabolic and nutritional neuropathy].

We assessed whether postgastrectomy polyneuropathy associated with thiamine deficiency is clinicopathologically identical to beriberi neuropathy, including a biochemical determination of thiamine status. The typical presentation for the two etiologies was as a symmetric sensorimotor polyneuropathy predominantly involving the lower limbs. In both groups, the main electrophysiologic findings were those of axonal neuropathy, most prominently in the lower limbs. Sural nerve biopsy specimens also indicated axonal degeneration in both groups. Subperineurial edema was commonly observed. Thiamine-deficiency neuropathies due to gastrectomy and dietary imbalance are identical despite variability in their clinicopathologic features and suggested that thiamine deficiency can be a major cause of postgastrectomy polyneuropathy. Characteristics of alcoholic neuropathy have been obscured by difficulty in isolating them from features of thiamine-deficiency neuropathy. We assessed 64 patients with alcoholic neuropathy including subgroups without and with coexisting thiamine deficiency. Thirty-two patients with nonalcoholic thiamine-deficiency neuropathy also were investigated for comparison. We concluded that pure-form of alcoholic neuropathy was distinct from pure-form of thiamine-deficiency neuropathy, supporting the view that alcoholic neuropathy can be caused by direct toxic effect of ethanol or its metabolites. However, features of alcoholic neuropathy is influenced by concomitant thiamine-deficiency state, having so far caused the obscure clinicopathological entity of alcoholic neuropathy.

[A man with the combination of dry and wet beriberi]. / Een man met de combinatie van droge en natte beriberi.

A 34-year-old alcoholic man had neurological and cardiac symptoms. The patient was admitted to the hospital for acute painful sensory disturbances and severe weakness of the feet. Neurological and electrophysiological investigation revealed axonal sensorimotor polyneuropathy that was most prominent in the legs. Cardiac assessment showed signs and symptoms of heart failure due to a high-output state. Blood analysis showed a low thiamine concentration of 58 nmol/l (lower reference limit: 80). Therefore, a diagnosis of combined wet beriberi with cardiomyopathy and dry beriberi with axonal polyneuropathy was made. The treatment of beriberi is simple and effective and consists of thiamine supplementation in conjunction with diuretic treatment. With this approach, the patient recovered fully. Patients with beriberi have a good prognosis, particularly when the diagnosis is made at an early stage.

Peripheral nerve conduction abnormalities in children exposed to alcohol in utero.

OBJECTIVE: We performed a longitudinal study of nerve conduction velocity to determine the effect of prenatal alcohol exposure on the peripheral nervous system. Study design We studied 17 children exposed to >2 oz of absolute alcohol/day prenatally and 13 unexposed children, identified prospectively from a cohort of pregnant women screened during prenatal care. Nerve conduction assessment was done on the median, ulnar, peroneal and tibial nerves during the newborn period and between 12 and 14 months of age. RESULTS: At both assessments the alcohol-exposed subjects had significantly slower ulnar motor nerve velocity (P=.007), smaller proximal (P=.018) and distal amplitude (P=.051). They also showed reduced tibial nerve velocity (P=.06) and a decrease in distal amplitude. CONCLUSIONS: This study demonstrates that prenatal alcohol exposure is associated with abnormalities in nerve electrical properties, and that the pattern is different from that seen in adults. Electrophysiologic abnormalities in peripheral nerves should be added to the problems found in children of alcohol abusing mothers.

[Peripheral and optical myeloneuropathy in a folic acid deficient alcoholic patient]. / Mieloneuropatía periférica y óptica en un paciente alcohólico deficiente en ácido fólico.

INTRODUCTION: In Western countries, neurological disorders secondary to toxic nutritional problems usually present as isolated cases that are generally associated to identifiable causes (alcoholism, eating disorders, absorption disorders, use of medicines) that reduce the availability of basic nutrients, especially B group vitamins, but also folic acid (FA). The optic nerves and the peripheral axons are frequent target organs in this type of pathology, but leukoencephalopathy and spinal cord involvement may also appear, often in combination. CASE REPORT: We describe the case of a 38-year-old female smoker with a heavy alcohol habit, who developed a subacute clinical pattern of, predominantly axonal, sensitive peripheral polyneuropathy, with vegetative fibre involvement. She also presented involvement of the posterior spinal cord, which gave rise to an ataxic disorder in the gait, as well as a severe bilateral retrobulbar optic neuropathy. Likewise, she presented macrocytosis (MCV: 118) due to megaloblastosis. She was also found to have a FA deficit but a normal vitamin B12 metabolism. With the help of supplementary vitamins, stopping drinking and the regularisation of her diet, the patient presented progressive clinical improvement, and was able to walk without support at 3 months and almost completely recovered her sight, which was corroborated by an improvement in the studies of both visual and somatosensorial evoked potentials. CONCLUSIONS: In our community, alcoholism is a frequent cause of nutritional deficiencies, which lead to neurological problems. FA is one of the nutrients that become deficient in alcoholics. More and more descriptions are being reported of peripheral polyneuropathy, retrobulbular optic neuropathy, myelopathy or leukoencephalopathy associated to FA deficiency, above all in patients with a history of alcoholism.

Pathogenesis of alcoholic neuropathy.

Chronic alcoholism is a medical, economical and social problem. Motility and mental function disorders are among the complications of chronic alcoholism and have been known for more than two centuries as "alcoholic paralysis", and are caused by alcoholic neuropathy. The pathogenesis of alcoholic neuropathy does not appear to be identical with central nervous system disorders which are caused by chronic alcoholism and it seems that it results from a failure of the protection barrier systems in the peripheral nervous system. To the pathogenesis of alcoholic neuropathy includes: 1. direct toxic effects of alcohol on the cellular population of the central nervous system and other tissues, especially of parenchymatous organs (in particular of the liver), 2. indirect metabolic and exotoxic changes mediated by malabsorption, maldigestion and secondary caloric and energy deprivation, 3. effects of genetic factors. (Fig. 2, Ref. 23.)

[Alcohol and the peripheral nervous system]. / Alkohol und peripheres Nervensystem.

The most frequent consequence of chronic alcohol intake is a toxic polyneuropathy. It results from inadequate nutrition, mainly deficiency of thiamine and other B vitamins. Additionally there is a direct neurotoxic effect of ethanol. Signs and symptoms are 1. distal sensory disturbances with pain, paresthesia, and numbness in a glove and stockings-pattern, 2. weakness and atrophy of distal muscles, pronounced in the lower limbs, 3. loss of tendon jerks, 4. affection of autonomic fibers. Therapy consists in absolute alcohol abstinence, high-caloric nutrition, parenteral thiamine and other vitamins. Against paresthesia and pain, carbamazepine, salicylates, amitryptiline are effective. Parenteral tioctacid may be tried. The prognosis of alcoholic polyneuropathy is favorable, with alcohol abstinence, within several months up to a few years. In chronic alcoholic patients peripheral nerves frequently are injured by compression during alcohol intoxication. Peroneal nerve lesions result from compression in the region of the neck of the fibula during a prolonged lying position, the radial nerve is injured during sitting with the upper arm placed on the backrest of a bench. Usually pressure palsies resolve spontaneously. Rhabdomyolysis is a rare but life-threatening complication of alcoholic delirium. Symptoms are severe muscle pain, swelling of extremities, pigmenturia. The major complications of rhabdomyolysis are renal and respiratory failure, and cardiac arrhythmias due to electrolyte imbalance. Intensive care is needed with control of hyperkalemia, hydration, alkalinization of urine, hemodialysis if indicated.