Alcoholic polyneuropathy
Encyclopedia
Alcoholic polyneuropathy is a neurological disorder
in which multiple peripheral nerves
throughout the body malfunction simultaneously
. It is defined by axonal
degeneration in neuron
s of both the sensory
and motor systems
and initially occurs at the distal ends of the longest axons in the body
. This nerve damage
causes an individual to experience pain and motor weakness, first in the feet and hands and then progressing centrally. Alcoholic polyneuropathy is caused primarily by chronic alcoholism
; however, vitamin deficiencies
are also known to contribute to its development. This disease
typically occurs in chronic alcoholics who have some sort of nutritional deficiency. Treatment may involve abstaining from alcohol, nutritional supplementation, and pain management.
. An early warning sign (prodrome
) of the possibility of developing alcoholic polyneuropathy, specially in a chronic alcoholic, would be weight loss because this usually signifies a nutritional deficiency that can lead to the development of the disease.
The disease typically involves sensory and motor loss, as well as painful physical perceptions (paresthesia
s), though all sensory modalities may be involved. The symptoms affecting the sensory and motor systems seem to develop in a symmetrical pattern; for example, if the right foot is affected, the left foot will be affected simultaneously or soon thereafter as well. In most cases the legs are affected first, followed by the arms. The hands usually become involved when the symptoms reach above the ankle level. This is called a stocking-and-glove pattern of sensory disturbances.
The polyneuropathy that develops spans a large range of severity. Some cases are seemingly asymptomatic
and may only be recognized upon careful examination. The most severe cases may result in profound physical disability
.
experienced by individuals depends on the severity of the polyneuropathy. It may be dull and constant in some individuals while being sharp and lancinating in others. In many subjects, tenderness is seen upon the palpitation of muscles in the feet and legs. Certain people may also feel cramp
ing sensations in the muscles affected and others say there is a burning sensation in their feet and calves.
in men, problems urinating, constipation
, and diarrhea
. Individuals also may experience muscle wasting and decreased or absent deep tendon reflexes. Some people may experience frequent falls and gait unsteadiness due to ataxia
. This ataxia may be caused by cerebellar degeneration, sensory ataxia, or distal muscle weakness. Over time, alcoholic polyneuropathy may also cause difficulty swallowing (dysphagia
), speech impairment (disarthria), muscle spasms, and muscle atrophy
.
In addition to alcoholic polyneuropathy, the individual may also show other related disorders such as Wernicke-Korsakoff syndrome
and cerebellar degeneration that result from alcoholism-related nutritional disorders.
accompanied by a nutritional deficiency. There is some debate over whether the main cause is the direct toxic
effect of alcohol itself or whether the disease is a result alcoholism-related malnutrition
.
Frequently alcoholics have disrupted social links in their lives and have an irregular lifestyle. This may cause an alcoholic to change his eating habits including more missed meals and a poor dietary balance. Alcoholism may also result in loss of appetite
, alcoholic gastritis
, and vomiting, which decrease food intake. Alcohol abuse damages the lining of the gastrointestinal system and reduces absorption of nutrients that are taken in. The combination of all of them may result in a nutritional deficiency that is linked to the development of alcoholic polyneuropathy.
There is evidence that providing individuals with adequate vitamins improves symptoms despite continued alcohol intake, indicating that vitamin deficiency may be a major factor in the development and progression of alcoholic polyneuropathy. In experimental models of alcoholic polyneuropathy utilizing rats
and monkeys has not resulted in convincing evidence that proper nutritional intake along with alcohol results in polyneuropathy.
In addition, the consumption of alcohol may lead to the build up of certain toxins in the body. For example, in the process of breaking down alcohol, the body produces acetaldehyde
, which can accumulate to toxic levels in alcoholics. This suggests that there is a possibility ethanol
(or its metabolites) may cause alcoholic polyneuropathy. There is evidence that polyneuropathy is also prevalent in well nourished alcoholics, supporting the idea that there is a direct toxic effect of alcohol.
Many of the studies conducted that observe alcoholic polyneuropathy in patients are often criticized for their criteria used to assess nutritional deficiency in the subjects because they may not have completely ruled out the possibility of a nutritional deficiency in the genesis of the polyneuropathy. Many researchers favor the nutritional origin of this disease, but the possibility of alcohol having a toxic effect on the peripheral nerves has not been completely ruled out.
The pathophysiology
of alcoholic polyneuropathy is an area of current research. Damage to the nervous system takes place before symptoms appear in individuals, beginning with segmental thinning and loss of myelin
on the peripheral ends of the longest nerves. Segmental thinning is the demyelination of axons in small sections at a time. This occurrence increases leakage of an action potential current down the axon, so it is weakest at the peripheral end. Decrease in current causes further thinning of myelin.
In most cases, individuals with alcoholic polyneuropathy have some degree of nutritional deficiency. Alcohol, a carbohydrate
, increases the metabolic demand for thiamine
(vitamin B1) because of its role in the metabolism of glucose
. Thiamine levels are usually low in alcoholics due to their decreased nutritional intake. In addition, alcohol interferes with intestinal absorption of thiamine, thereby further decreasing thiamine levels in the body. Thiamine is important in three reactions in the metabolism of glucose
: the decarboxylation
of pyruvic acid
, d-ketoglutaric acid, and transketolase
. A lack of thiamine in the cells may therefore prevent neurons from maintaining necessary adenosine triphosphate
(ATP) levels as a result of impaired glycolosis. Thiamine deficiency alone could explain the impaired nerve conduction
in those with alcoholic polyneuropathy, but other factors likely play a part.
The metabolic effects of liver damage associated with alcoholism may also contribute to the development of alcoholic polyneuropathy. Normal products of the liver, such as lipoic acid
, may be deficient in alcoholics. This deficiency would also disrupt glycolosis and alter metabolism, transport, storage, and activation of essential nutrients.
The malnutrition many alcoholics suffer deprives them of important cofactors
for the oxidative metabolism of glucose. Neural tissues depend on this process for energy, and disruption of the cycle would impair cell growth and function. Schwann cells produce myelin that wraps around the sensory and motor nerve axons to enhance action potential
conduction in the periphery. An energy deficiency in Schwann cells would account for the disappearance of myelin on peripheral nerves, which may result in damage to axons or loss of nerve function altogether. In peripheral nerves, oxidative enzyme activity is most concentrated around the nodes of Ranvier
, making these locations most vulnerable to cofactor deprivation. Lacking essential cofactors reduces myelin impedance, increases current leakage, and slows signal transmission. Disruptions in conductance first affect the peripheral ends of the longest and largest peripheral nerve fibers because they suffer most from decreased action potential propagation. Thus, neural deterioration occurs in an accelerating cycle: myelin damage reduces conductance, and reduced conductance contributes to myelin degradation. The slowed conduction of action potentials in axons causes segmental demyelination extending proximally; this is also known as retrograde degeneration
.
Acetaldehyde
has been shown to be toxic to peripheral nerves. There are increased levels of acetaldehyde produced during ethanol
metabolism. If the acetaldehyde is not metabolized quickly the nerves may be affected by the accumulation of acetaldehyde to toxic levels.
polyneuropathies and therefore can be difficult to diagnose. When alcoholics have sensorimotor polyneuropathy as well as a nutritional deficiency, a diagnosis of alcoholic polyneuropathy is often reached.
In order to confirm the diagnosis, it is necessary to rule out other causes of similar clinical syndromes. Other neuropathies can be differentiated
on the basis of typical clinical or laboratory features. Differential diagnoses to alcoholic polyneuropathy include amyotrophic lateral sclerosis
, beriberi
, Charcot-Marie-Tooth disease
, diabetic lumbosacral plexopathy
, diabetic neuropathy
, mononeuritis multiplex and post-polio syndrome
.
To clarify the diagnosis, medical workup most commonly involves laboratory tests, though, in some cases, imaging
, nerve conduction studies
, electromyography
, and vibrometer testing may also be used.
A number of tests may be used to rule out other causes of peripheral neuropathy. One of the first presenting symptoms of diabetes mellitus
may be peripheral neuropathy, and hemoglobin A1C can be used to estimate average blood glucose levels
. Elevated blood creatinine
levels may indicate renal
insufficiency and may also be a cause of peripheral neuropathy. A heavy metal toxicity screen should also be used to exclude lead toxicity as a cause of neuropathy.
Alcoholism is normally associated with nutritional deficiencies, which may contribute to the development of alcoholic polyneuropathy. Thiamine
, vitamin B-12
, and folic acid
are vitamins that play an essential role in the peripheral
and central nervous system
and should be among the first analyzed in laboratory tests. It has been difficult to assess thiamine status in individuals due to difficulties in developing a method to directly assay
thiamine in the blood and urine. A liver function test may also be ordered, as alcoholic consumption may cause an increase in liver enzyme levels.
is beneficial for strength training of weakened muscles, as well as for gait and balance training.
In order to best manage symptoms of the person with the disease, refraining from consuming alcohol is essential. Abstinence from alcohol will encourage proper consumption of nutrients and prevent progression or recurrence of the neuropathy. Once an individual stops consuming alcohol it is important to make sure they understand that substantial recovery will usually not be seen for a few months. Some subjective improvement may be seen right away, but this is usually due to the overall benefits of alcohol detoxification. If alcohol consumption continues, vitamin supplementation alone is not enough to improve the symptoms of most individuals.
Nutritional therapy with parenteral
multivitamins is beneficial to implement until the person can maintain adequate nutritional intake. Treatments also include vitamin
supplementation (especially thiamine
). In more severe cases of nutritional deficiency 320 mg/day of benfotiamine
for 4 weeks followed by 120 mg/day for 4 more weeks may be prescribed in an effort to return thiamine levels to normal.
or amitriptyline
in combination with over-the-counter pain medications, such as aspirin
, ibuprofen
, or acetaminophen. Tricyclic antidepressants such as phenytoin
, amitriptyline
, or carbamazepine
may help stabbing pains and have central and peripheral anticholinergic
and sedative effects
. These agents have central effects on pain transmission and block the active reuptake of norepinephrine and serotonin.
Anticonvulsant drugs
like gabapentin
block the active reuptake of norepinephrine
and serotonin
and have properties that relieve neuropathic pain. However, these drugs take a few weeks to become effective and are rarely used in the treatment of acute pain
.
Topical analgesics like capsaicin
may also relieve minor aches and pains of muscles and joints.
of a patient because it is hard to convince chronic alcoholics to abstain from drinking alcohol completely. It has been shown that a good prognosis may be given for mild neuropathy if the alcoholic has abstained from drinking for 3-5 years. During the early stages of the disease the damage appears to be reversible when people are given adequate amounts of vitamins, such as thiamine. If the polyneuropathy is mild, the individual will normally experience a significant improvement in the symptoms they experience and may be completely eliminated within weeks to months after proper nutrition has been maintained. When those people diagnosed with alcohol polyneuropathy experience a recovery it is presumed to be a result of regeneration and collateral sprouting of the damaged axons.
As the disease progresses, the damage may become permanent. In severe cases of thiamine deficiency, a few of the positive symptoms (including neuropathic pain) may persist indefinitely. Even after the restoration of a balanced nutritional intake, those patients with severe or chronic polyneuropathy may experience lifelong residual symptoms. Alcoholic polyneuropathy is not life threatening but may significantly affect one's quality of life. Effects of the disease range from mild discomfort to severe disability.
The rate of incidence of alcoholic polyneuropathy involving sensory and motor polyneuropathy varies from 10% to 50% of alcoholics depending on the subject selection and diagnostic criteria. If electrodiagnostic criteria is used, alcoholic polyneuropathy may be found in up to 90% of individuals being assessed. The distribution and severity the disease depends on regional dietary habits, individual drinking habits, as well as an individual’s genetics
. Large studies have been conducted and show that alcoholic polyneuropathy severity and incidence correlates best with the total lifetime consumption of alcohol. Factors such as nutritional intake, age, or other medical conditions are correlate in lesser degrees. For unknown reasons, alcoholic polyneuropathy has a high incidence in women.
Certain alcoholic beverages can also contain congeners that may also be bioactive; therefore, the consumption of varying alcoholic beverages may result in different health consequences. An individual’s nutritional intake also plays a role in the development of this disease. Depending on the specific dietary habits, they may have a deficiency of one or more of the following: thiamine (vitamin B1), pyridoxine
(vitamin B6), pantothenic acid
and biotin
, vitamin B12
, folic acid, niacin (vitamin B3)
, and vitamin A
.
; acetaldehyde is then oxidized to acetate mainly by aldehyde dehydrogenase (ALDH)
. ALDH2
is an isozyme of ALDH and ALDH2 has a polymorphism (ALDH2*2, Glu487Lys) that makes ADLH2 inactive; this allele is more prevalent among Southeast and East Asians and results in a failure to quickly metabolize acetaldehyde. The neurotoxicity resulting from the accumulation of acetaldehyde may play a role in the pathogenesis of alcoholic polyneuropathy.
The first description of symptom
s associated with alcoholic polyneuropathy were recorded by John C. Lettsome
in 1787 when he noted hyperesthesia
and paralysis
in legs more than arms of patients. Jackson has also been credited with describing polyneuropathy in chronic alcoholics in 1822. The clinical title of alcoholic polyneuropathy was widely recognized by the late nineteenth century. It was thought that the polyneuropathy was a direct result of the toxic effect alcohol had on peripheral nerves when used excessively. In 1928, George C. Shattuck argued that the polyneuropathy resulted from a vitamin B deficiency commonly found in alcoholics and he claimed that alcoholic polyneuropathy should be related to beriberi
. This debate continues today over what exactly causes this disease, some argue it is just the alcohol toxicity, others claim the vitamin deficiencies are to blame and still others say it is some combination of the two.
Further research is looking at the effect an alcoholics’ consumption and choice of alcoholic beverage on their development of alcoholic polyneuropathy. Some beverages may include more nutrients than others (such as thiamine), but the effects of this with regards to helping with a nutritional deficiency in alcoholics is yet unknown.
There is still controversy about the reasons for the development of alcoholic polyneuropathy. Some argue it is a direct result of alcohol's toxic effect on the nerves, but others say factors such as a nutritional deficiency or chronic liver disease may play a role in the development as well. This debate is ongoing and research is continuing in an effort to discover the real cause of alcoholic polyneuropathy.
Neurological disorder
A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...
in which multiple peripheral nerves
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
throughout the body malfunction simultaneously
Polyneuropathy
Polyneuropathy is a neurological disorder that occurs when many peripheral nerves throughout the body malfunction simultaneously. It may be acute and appear without warning, or chronic and develop gradually over a longer period of time. Many polyneuropathies have both motor and sensory...
. It is defined by axonal
Axon
An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....
degeneration in neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s of both the sensory
Sensory system
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...
and motor systems
Motor system
The motor system is the part of the central nervous system that is involved with movement. It consists of the pyramidal and extrapyramidal system....
and initially occurs at the distal ends of the longest axons in the body
Body
With regard to living things, a body is the physical body of an individual. "Body" often is used in connection with appearance, health issues and death...
. This nerve damage
Nerve injury
Nerve injury is injury to nervous tissue. There is no single classification system that can describe all the many variations of nerve injury. Most systems attempt to correlate the degree of injury with symptoms, pathology and prognosis...
causes an individual to experience pain and motor weakness, first in the feet and hands and then progressing centrally. Alcoholic polyneuropathy is caused primarily by chronic alcoholism
Alcoholism
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...
; however, vitamin deficiencies
Avitaminosis
Avitaminosis is any disease caused by chronic or long-term vitamin deficiency or caused by a defect in metabolic conversion, such as tryptophan to niacin...
are also known to contribute to its development. This disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
typically occurs in chronic alcoholics who have some sort of nutritional deficiency. Treatment may involve abstaining from alcohol, nutritional supplementation, and pain management.
Signs and symptoms
Alcoholic polyneuropathy usually has a gradual onset over months or even years although axonal degeneration often begins before an individual experiences any symptomsSymptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
. An early warning sign (prodrome
Prodrome
In medicine, a prodrome is an early symptom that might indicate the start of a disease before specific symptoms occur. It is derived from the Greek word prodromos or precursor...
) of the possibility of developing alcoholic polyneuropathy, specially in a chronic alcoholic, would be weight loss because this usually signifies a nutritional deficiency that can lead to the development of the disease.
The disease typically involves sensory and motor loss, as well as painful physical perceptions (paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
s), though all sensory modalities may be involved. The symptoms affecting the sensory and motor systems seem to develop in a symmetrical pattern; for example, if the right foot is affected, the left foot will be affected simultaneously or soon thereafter as well. In most cases the legs are affected first, followed by the arms. The hands usually become involved when the symptoms reach above the ankle level. This is called a stocking-and-glove pattern of sensory disturbances.
The polyneuropathy that develops spans a large range of severity. Some cases are seemingly asymptomatic
Asymptomatic
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
and may only be recognized upon careful examination. The most severe cases may result in profound physical disability
Physical disability
A physical disability is any impairment which limits the physical function of one or more limbs or fine or gross motor ability. Other physical disabilities include impairments which limit other facets of daily living, such as respiratory disorders and epilepsy....
.
Sensory
Common manifestations of sensory issues include numbness or painful sensations in the arms and legs, abnormal sensations like “pins and needles,” and heat intolerance. PainPain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
experienced by individuals depends on the severity of the polyneuropathy. It may be dull and constant in some individuals while being sharp and lancinating in others. In many subjects, tenderness is seen upon the palpitation of muscles in the feet and legs. Certain people may also feel cramp
Cramp
Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...
ing sensations in the muscles affected and others say there is a burning sensation in their feet and calves.
Motor
Sensory symptoms are gradually followed by motor symptoms. Motor symptoms may include muscle cramps and weakness, erectile dysfunctionErectile dysfunction
Erectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....
in men, problems urinating, constipation
Constipation
Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
, and diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
. Individuals also may experience muscle wasting and decreased or absent deep tendon reflexes. Some people may experience frequent falls and gait unsteadiness due to ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
. This ataxia may be caused by cerebellar degeneration, sensory ataxia, or distal muscle weakness. Over time, alcoholic polyneuropathy may also cause difficulty swallowing (dysphagia
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
), speech impairment (disarthria), muscle spasms, and muscle atrophy
Muscle atrophy
Muscle atrophy, or disuse atrophy, is defined as a decrease in the mass of the muscle; it can be a partial or complete wasting away of muscle. When a muscle atrophies, this leads to muscle weakness, since the ability to exert force is related to mass...
.
In addition to alcoholic polyneuropathy, the individual may also show other related disorders such as Wernicke-Korsakoff syndrome
Wernicke-Korsakoff syndrome
Wernicke–Korsakoff syndrome is a manifestation of thiamine deficiency, or beriberi. This is usually secondary to alcohol abuse...
and cerebellar degeneration that result from alcoholism-related nutritional disorders.
Causes
The general cause of this disease is prolonged and heavy consumption of alcoholAlcoholic beverage
An alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption...
accompanied by a nutritional deficiency. There is some debate over whether the main cause is the direct toxic
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
effect of alcohol itself or whether the disease is a result alcoholism-related malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
.
Frequently alcoholics have disrupted social links in their lives and have an irregular lifestyle. This may cause an alcoholic to change his eating habits including more missed meals and a poor dietary balance. Alcoholism may also result in loss of appetite
Appetite
The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is...
, alcoholic gastritis
Gastritis
Gastritis is an inflammation of the lining of the stomach, and has many possible causes. The main acute causes are excessive alcohol consumption or prolonged use of nonsteroidal anti-inflammatory drugs such as aspirin or ibuprofen. Sometimes gastritis develops after major surgery, traumatic...
, and vomiting, which decrease food intake. Alcohol abuse damages the lining of the gastrointestinal system and reduces absorption of nutrients that are taken in. The combination of all of them may result in a nutritional deficiency that is linked to the development of alcoholic polyneuropathy.
There is evidence that providing individuals with adequate vitamins improves symptoms despite continued alcohol intake, indicating that vitamin deficiency may be a major factor in the development and progression of alcoholic polyneuropathy. In experimental models of alcoholic polyneuropathy utilizing rats
Brown Rat
The brown rat, common rat, sewer rat, Hanover rat, Norway rat, Brown Norway rat, Norwegian rat, or wharf rat is one of the best known and most common rats....
and monkeys has not resulted in convincing evidence that proper nutritional intake along with alcohol results in polyneuropathy.
In addition, the consumption of alcohol may lead to the build up of certain toxins in the body. For example, in the process of breaking down alcohol, the body produces acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...
, which can accumulate to toxic levels in alcoholics. This suggests that there is a possibility ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
(or its metabolites) may cause alcoholic polyneuropathy. There is evidence that polyneuropathy is also prevalent in well nourished alcoholics, supporting the idea that there is a direct toxic effect of alcohol.
Many of the studies conducted that observe alcoholic polyneuropathy in patients are often criticized for their criteria used to assess nutritional deficiency in the subjects because they may not have completely ruled out the possibility of a nutritional deficiency in the genesis of the polyneuropathy. Many researchers favor the nutritional origin of this disease, but the possibility of alcohol having a toxic effect on the peripheral nerves has not been completely ruled out.
Pathophysiology
Pathophysiology
Pathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome...
of alcoholic polyneuropathy is an area of current research. Damage to the nervous system takes place before symptoms appear in individuals, beginning with segmental thinning and loss of myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
on the peripheral ends of the longest nerves. Segmental thinning is the demyelination of axons in small sections at a time. This occurrence increases leakage of an action potential current down the axon, so it is weakest at the peripheral end. Decrease in current causes further thinning of myelin.
In most cases, individuals with alcoholic polyneuropathy have some degree of nutritional deficiency. Alcohol, a carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
, increases the metabolic demand for thiamine
Thiamine
Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
(vitamin B1) because of its role in the metabolism of glucose
Carbohydrate metabolism
Carbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms....
. Thiamine levels are usually low in alcoholics due to their decreased nutritional intake. In addition, alcohol interferes with intestinal absorption of thiamine, thereby further decreasing thiamine levels in the body. Thiamine is important in three reactions in the metabolism of glucose
Carbohydrate metabolism
Carbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms....
: the decarboxylation
Decarboxylation
Decarboxylation is a chemical reaction that releases carbon dioxide . Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carbonation, the addition of CO2 to...
of pyruvic acid
Pyruvic acid
Pyruvic acid is an organic acid, a ketone, as well as the simplest of the alpha-keto acids. The carboxylate ion of pyruvic acid, CH3COCOO−, is known as pyruvate, and is a key intersection in several metabolic pathways....
, d-ketoglutaric acid, and transketolase
Transketolase
Transketolase, an enzyme of both the pentose phosphate pathway in animals and the Calvin cycle of photosynthesis, catalyzes two important reactions, which operate in opposite directions in these two pathways...
. A lack of thiamine in the cells may therefore prevent neurons from maintaining necessary adenosine triphosphate
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
(ATP) levels as a result of impaired glycolosis. Thiamine deficiency alone could explain the impaired nerve conduction
Conductance
Conductance may refer to:* Electrical conductance, the ability for electricity to flow a certain path* Fluid conductance, the ability for fluid to transmit through materials* Thermal conductivity, the ability for temperatures to transmit through materials...
in those with alcoholic polyneuropathy, but other factors likely play a part.
The metabolic effects of liver damage associated with alcoholism may also contribute to the development of alcoholic polyneuropathy. Normal products of the liver, such as lipoic acid
Lipoic acid
Lipoic acid , also known as α-lipoic acid and Alpha Lipoic Acid is an organosulfur compound derived from octanoic acid. LA contains two vicinal sulfur atoms attached via a disulfide bond and is thus considered to be oxidized...
, may be deficient in alcoholics. This deficiency would also disrupt glycolosis and alter metabolism, transport, storage, and activation of essential nutrients.
The malnutrition many alcoholics suffer deprives them of important cofactors
Cofactor (biochemistry)
A cofactor is a non-protein chemical compound that is bound to a protein and is required for the protein's biological activity. These proteins are commonly enzymes, and cofactors can be considered "helper molecules" that assist in biochemical transformations....
for the oxidative metabolism of glucose. Neural tissues depend on this process for energy, and disruption of the cycle would impair cell growth and function. Schwann cells produce myelin that wraps around the sensory and motor nerve axons to enhance action potential
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...
conduction in the periphery. An energy deficiency in Schwann cells would account for the disappearance of myelin on peripheral nerves, which may result in damage to axons or loss of nerve function altogether. In peripheral nerves, oxidative enzyme activity is most concentrated around the nodes of Ranvier
Nodes of Ranvier
Myelin sheath gaps or nodes of Ranvier are the gaps formed between the myelin sheaths generated by different cells. A myelin sheath is a many-layered coating, largely composed of a fatty substance called myelin, that wraps around the axon of a neuron and very efficiently insulates it...
, making these locations most vulnerable to cofactor deprivation. Lacking essential cofactors reduces myelin impedance, increases current leakage, and slows signal transmission. Disruptions in conductance first affect the peripheral ends of the longest and largest peripheral nerve fibers because they suffer most from decreased action potential propagation. Thus, neural deterioration occurs in an accelerating cycle: myelin damage reduces conductance, and reduced conductance contributes to myelin degradation. The slowed conduction of action potentials in axons causes segmental demyelination extending proximally; this is also known as retrograde degeneration
Degeneration (medical)
Degeneration is deterioration in the medical sense. Generally, it is the change from a higher to a lower form. More specifically, it is the change of tissue to a lower or less functionally active form....
.
Acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...
has been shown to be toxic to peripheral nerves. There are increased levels of acetaldehyde produced during ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
metabolism. If the acetaldehyde is not metabolized quickly the nerves may be affected by the accumulation of acetaldehyde to toxic levels.
Diagnosis
Alcoholic polyneuropathy is very similar to other axonal degenerativeNeurodegeneration
Neurodegeneration is the umbrella term for the progressive loss of structure or function of neurons, including death of neurons. Many neurodegenerative diseases including Parkinson’s, Alzheimer’s, and Huntington’s occur as a result of neurodegenerative processes. As research progresses, many...
polyneuropathies and therefore can be difficult to diagnose. When alcoholics have sensorimotor polyneuropathy as well as a nutritional deficiency, a diagnosis of alcoholic polyneuropathy is often reached.
In order to confirm the diagnosis, it is necessary to rule out other causes of similar clinical syndromes. Other neuropathies can be differentiated
Differential diagnosis
A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...
on the basis of typical clinical or laboratory features. Differential diagnoses to alcoholic polyneuropathy include amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...
, beriberi
Beriberi
Beriberi is a nervous system ailment caused by a thiamine deficiency in the diet. Thiamine is involved in the breakdown of energy molecules such as glucose and is also found on the membranes of neurons...
, Charcot-Marie-Tooth disease
Charcot-Marie-Tooth disease
Charcot–Marie–Tooth disease- , known also as Morbus Charcot-Marie-Tooth, Charcot-Marie-Tooth neuropathy, hereditary motor and sensory neuropathy , hereditary sensorimotor neuropathy , or peroneal muscular atrophy, is an inherited disorder of nerves that takes different forms...
, diabetic lumbosacral plexopathy
Plexopathy
Plexopathy is a disorder affecting a network of nerves, blood vessels, or lymph vessels. The region of nerves it affects are at the brachial or lumbosacral plexus. Symptoms include pain, loss of motor control, and sensory deficits....
, diabetic neuropathy
Diabetic neuropathy
Diabetic neuropathies are neuropathic disorders that are associated with diabetes mellitus. These conditions are thought to result from diabetic microvascular injury involving small blood vessels that supply nerves in addition to macrovascular conditions that can culminate in diabetic neuropathy...
, mononeuritis multiplex and post-polio syndrome
Post-polio syndrome
Post-polio syndrome is a condition that affects approximately 25–50% of people who have previously contracted poliomyelitis—a viral infection of the nervous system—after the initial infection. Typically the symptoms appear 15–30 years after recovery from the original paralytic attack, at an age of...
.
To clarify the diagnosis, medical workup most commonly involves laboratory tests, though, in some cases, imaging
Medical imaging
Medical imaging is the technique and process used to create images of the human body for clinical purposes or medical science...
, nerve conduction studies
Nerve conduction study
A nerve conduction study is a test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body.Nerve conduction velocity is a common measurement made during this test...
, electromyography
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
, and vibrometer testing may also be used.
A number of tests may be used to rule out other causes of peripheral neuropathy. One of the first presenting symptoms of diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
may be peripheral neuropathy, and hemoglobin A1C can be used to estimate average blood glucose levels
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
. Elevated blood creatinine
Creatinine
Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...
levels may indicate renal
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
insufficiency and may also be a cause of peripheral neuropathy. A heavy metal toxicity screen should also be used to exclude lead toxicity as a cause of neuropathy.
Alcoholism is normally associated with nutritional deficiencies, which may contribute to the development of alcoholic polyneuropathy. Thiamine
Thiamine
Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
, vitamin B-12
Vitamin B12
Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...
, and folic acid
Folic acid
Folic acid and folate , as well as pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are forms of the water-soluble vitamin B9...
are vitamins that play an essential role in the peripheral
Peripheral nervous system
The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...
and central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
and should be among the first analyzed in laboratory tests. It has been difficult to assess thiamine status in individuals due to difficulties in developing a method to directly assay
Assay
An assay is a procedure in molecular biology for testing or measuring the activity of a drug or biochemical in an organism or organic sample. A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized...
thiamine in the blood and urine. A liver function test may also be ordered, as alcoholic consumption may cause an increase in liver enzyme levels.
Management
Although there is no known cure for alcoholic polyneuropathy, there are a number of treatments that can control symptoms and promote independence. Physical therapyPhysical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
is beneficial for strength training of weakened muscles, as well as for gait and balance training.
Nutrition
Nutritional therapy with parenteral
Parenteral
Parenteral is a route of administration that involves piercing the skin or mucous membrane. Parenteral nutrition refers to providing nutrition via the veins.-Etymology:...
multivitamins is beneficial to implement until the person can maintain adequate nutritional intake. Treatments also include vitamin
Vitamin
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...
supplementation (especially thiamine
Thiamine
Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
). In more severe cases of nutritional deficiency 320 mg/day of benfotiamine
Benfotiamine
Benfotiamine is a synthetic S-acyl derivative of thiamine . After absorption, benfotiamine can be dephosphorylated by cells bearing an ecto-alkaline phosphatase to the lipid-soluble S-benzoylthiamine...
for 4 weeks followed by 120 mg/day for 4 more weeks may be prescribed in an effort to return thiamine levels to normal.
Pain
Painful dysesthesias caused by alcoholic polyneuropathy can be treated by using gabapentinGabapentin
Gabapentin is a pharmaceutical drug, specifically a GABA analogue. It was originally developed for the treatment of epilepsy, and currently is also used to relieve neuropathic pain...
or amitriptyline
Amitriptyline
Amitriptyline is a tricyclic antidepressant . It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs...
in combination with over-the-counter pain medications, such as aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...
, ibuprofen
Ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug used for relief of symptoms of arthritis, fever, as an analgesic , especially where there is an inflammatory component, and dysmenorrhea....
, or acetaminophen. Tricyclic antidepressants such as phenytoin
Phenytoin
Phenytoin sodium is a commonly used antiepileptic. Phenytoin acts to suppress the abnormal brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage-gated sodium channels...
, amitriptyline
Amitriptyline
Amitriptyline is a tricyclic antidepressant . It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs...
, or carbamazepine
Carbamazepine
Carbamazepine is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia...
may help stabbing pains and have central and peripheral anticholinergic
Anticholinergic
An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicycloverine, and the classic example is atropine....
and sedative effects
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
. These agents have central effects on pain transmission and block the active reuptake of norepinephrine and serotonin.
Anticonvulsant drugs
Anticonvulsant
The anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers, and in the treatment of neuropathic pain. The goal of an...
like gabapentin
Gabapentin
Gabapentin is a pharmaceutical drug, specifically a GABA analogue. It was originally developed for the treatment of epilepsy, and currently is also used to relieve neuropathic pain...
block the active reuptake of norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
and serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
and have properties that relieve neuropathic pain. However, these drugs take a few weeks to become effective and are rarely used in the treatment of acute pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
.
Topical analgesics like capsaicin
Capsaicin
Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...
may also relieve minor aches and pains of muscles and joints.
Prognosis
It is difficult to assess the prognosisPrognosis
Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
of a patient because it is hard to convince chronic alcoholics to abstain from drinking alcohol completely. It has been shown that a good prognosis may be given for mild neuropathy if the alcoholic has abstained from drinking for 3-5 years. During the early stages of the disease the damage appears to be reversible when people are given adequate amounts of vitamins, such as thiamine. If the polyneuropathy is mild, the individual will normally experience a significant improvement in the symptoms they experience and may be completely eliminated within weeks to months after proper nutrition has been maintained. When those people diagnosed with alcohol polyneuropathy experience a recovery it is presumed to be a result of regeneration and collateral sprouting of the damaged axons.
As the disease progresses, the damage may become permanent. In severe cases of thiamine deficiency, a few of the positive symptoms (including neuropathic pain) may persist indefinitely. Even after the restoration of a balanced nutritional intake, those patients with severe or chronic polyneuropathy may experience lifelong residual symptoms. Alcoholic polyneuropathy is not life threatening but may significantly affect one's quality of life. Effects of the disease range from mild discomfort to severe disability.
Epidemiology
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
. Large studies have been conducted and show that alcoholic polyneuropathy severity and incidence correlates best with the total lifetime consumption of alcohol. Factors such as nutritional intake, age, or other medical conditions are correlate in lesser degrees. For unknown reasons, alcoholic polyneuropathy has a high incidence in women.
Certain alcoholic beverages can also contain congeners that may also be bioactive; therefore, the consumption of varying alcoholic beverages may result in different health consequences. An individual’s nutritional intake also plays a role in the development of this disease. Depending on the specific dietary habits, they may have a deficiency of one or more of the following: thiamine (vitamin B1), pyridoxine
Pyridoxine
Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.-Chemistry:...
(vitamin B6), pantothenic acid
Pantothenic acid
Pantothenic acid, also called pantothenate or vitamin B5 , is a water-soluble vitamin. For many animals, pantothenic acid is an essential nutrient. Animals require pantothenic acid to synthesize coenzyme-A , as well as to synthesize and metabolize proteins, carbohydrates, and fats.Pantothenic acid...
and biotin
Biotin
Biotin, also known as Vitamin H or Coenzyme R, is a water-soluble B-complex vitamin discovered by Bateman in 1916. It is composed of a ureido ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring...
, vitamin B12
Vitamin B12
Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...
, folic acid, niacin (vitamin B3)
Niacin
"Niacin" redirects here. For the neo-fusion band, see Niacin .Niacin is an organic compound with the formula and, depending on the definition used, one of the forty to eighty essential human nutrients.Niacin is one of five vitamins associated with a pandemic deficiency disease: niacin deficiency...
, and vitamin A
Vitamin A
Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...
.
Acetaldehyde
It is also thought there is perhaps a genetic predisposition for some alcoholics that results in increased frequency of alcoholic polyneuropathy in certain ethnic groups. During the body’s processing of alcohol, ethanol is oxidized to acetaldehyde mainly by alcohol dehydrogenaseAlcohol dehydrogenase
Alcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide...
; acetaldehyde is then oxidized to acetate mainly by aldehyde dehydrogenase (ALDH)
Aldehyde dehydrogenase
Aldehyde dehydrogenases are a group of enzymes that catalyse the oxidation of aldehydes.- Function :Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, which leave the liver and are metabolized by the body’s muscle and heart...
. ALDH2
ALDH2
Aldehyde dehydrogenase 2 family , also known as ALDH2, is a human gene found on chromosome 12.-Function:The enzyme encoded by this gene belongs to the aldehyde dehydrogenase family of enzymes that catalyze the chemical transformation from acetaldehyde to acetic acid...
is an isozyme of ALDH and ALDH2 has a polymorphism (ALDH2*2, Glu487Lys) that makes ADLH2 inactive; this allele is more prevalent among Southeast and East Asians and results in a failure to quickly metabolize acetaldehyde. The neurotoxicity resulting from the accumulation of acetaldehyde may play a role in the pathogenesis of alcoholic polyneuropathy.
History
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
s associated with alcoholic polyneuropathy were recorded by John C. Lettsome
John C. Lettsome
Dr. John Coakley Lettsome was an English physician and philanthropist born on Little Jost Van Dyke in the British Virgin Islands. He was born into one of the early Quaker settlements in the territory, and grew up to be an abolitionist...
in 1787 when he noted hyperesthesia
Hyperesthesia
Hyperesthesia is a condition that involves an abnormal increase in sensitivity to stimuli of the sense. "When a non-noxious stimulus causes the sensation of pain the area will be termed hyperaesthetic". Stimuli of the senses can include sound that one hears, foods that one tastes, textures that...
and paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
in legs more than arms of patients. Jackson has also been credited with describing polyneuropathy in chronic alcoholics in 1822. The clinical title of alcoholic polyneuropathy was widely recognized by the late nineteenth century. It was thought that the polyneuropathy was a direct result of the toxic effect alcohol had on peripheral nerves when used excessively. In 1928, George C. Shattuck argued that the polyneuropathy resulted from a vitamin B deficiency commonly found in alcoholics and he claimed that alcoholic polyneuropathy should be related to beriberi
Beriberi
Beriberi is a nervous system ailment caused by a thiamine deficiency in the diet. Thiamine is involved in the breakdown of energy molecules such as glucose and is also found on the membranes of neurons...
. This debate continues today over what exactly causes this disease, some argue it is just the alcohol toxicity, others claim the vitamin deficiencies are to blame and still others say it is some combination of the two.
Research directions
The mechanism of axonal degeneration has not been clarified and is an area of continuing research on alcoholic polyneuropathy.Further research is looking at the effect an alcoholics’ consumption and choice of alcoholic beverage on their development of alcoholic polyneuropathy. Some beverages may include more nutrients than others (such as thiamine), but the effects of this with regards to helping with a nutritional deficiency in alcoholics is yet unknown.
There is still controversy about the reasons for the development of alcoholic polyneuropathy. Some argue it is a direct result of alcohol's toxic effect on the nerves, but others say factors such as a nutritional deficiency or chronic liver disease may play a role in the development as well. This debate is ongoing and research is continuing in an effort to discover the real cause of alcoholic polyneuropathy.