How Does Alcohol Affect the Nervous System?
Nerve damage is the lay term for a medical condition called neuropathy. People with neuropathy have some degree of degraded function in nerve cells (neurons). Neurons provide sensation throughout the body and control a wide variety of voluntary and involuntary actions and processes. Alcohol can damage nerve function when it accumulates inside the body. Heavy alcohol intake for extended periods of time can lead to alcoholic neuropathy, a serious form of nerve damage.
The Human Nervous System 101
Nerves play a key role in virtually all daily functions. To fully comprehend how alcohol negatively impacts the nervous system, it helps to have a basic understanding of its underlying functions.
Central nervous system (CNS): This includes the brain and spinal cord. The brain plays a central role in the control of most bodily functions, such as awareness, movements, sensations, thoughts, speech and memory. The spinal cord is connected to the brainstem and runs through the spinal canal. Cranial nerves exit the brainstem and nerve roots exit the spinal cord on both sides of the body. The spinal cord carries messages back and forth between the brain and the peripheral nerves.1
Peripheral nervous system: This is a network of 43 pairs of motor and sensory nerves that connect the CNS to the entire human body. These nerves control functions of sensation, movement and motor coordination.2
Autonomic nervous system: Consisting of the sympathetic and parasympathetic division, these nerves regulate body processes such as blood pressure and the rate of breathing. This part of the nervous system impacts the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, sweat, salivary and digestive glands. This system works automatically without conscious effort.3
Motor nerves: There are three types of bundles of nerve cells that control muscles. They originate in the spinal column and end at the muscles that they control. Somatic motor nerves control skeletal muscles and movement. Special visceral motor nerves control muscles in the face and neck. General visceral motor nerves control smooth muscles that lack voluntary control, such as the heart.4
Sensory nerves: These nerves carry signals from organs that respond to stimuli to the spinal cord and brain. The nerve cells that make up these nerves are commonly known as sensory neurons.5
The Detrimental Physical Effects of Alcoholism
Excessive alcohol intake can negatively impact the entire body including the liver, heart, immune system and nervous system. Up to 35% of heavy drinkers develop alcoholic hepatitis and of these, 55% already have cirrhosis.6 Excessive drinking can lead to high blood pressure, heart failure, an increased risk of diabetes, stroke, fetal alcohol syndrome, cardiomyopathy, cardiac arrhythmia and sudden cardiac death. Chronic drinkers are at greater risk of diseases such as pneumonia and tuberculosis due to a comprised immune system. Excessive drinking can also increase the risk of oral, esophageal, throat, liver and breast cancer. The effects of alcohol on the nervous system are not as well publicized as the above conditions.7
Alcoholic neuropathy (also called alcohol peripheral neuropathy) is a potentially incapacitating complication of long-term excessive consumption of alcohol. Although the exact incidence is unknown, clinical research studies have estimated that 25% to 66% of clinically diagnosable chronic alcoholics experience this type of nerve damage. The majority of people diagnosed with this condition are between the ages of 40 and 60. The condition is characterized by pain and dysesthesias (abnormal sensations), primarily in the lower extremities, that are typically treatment-resistant. Experts believe that malnutrition, thiamine deficiency, direct toxicity of alcohol and a family history of alcoholism increase one’s risk, although the exact role these factors play in development of the condition is unknown.8,9
The Role of Thiamine
Thiamine, also known as the “antiberiberi factor” or “antineuritic factor,” is an essential metabolic vitamin that plays a role in the health of the peripheral nervous system. Thiamine deficiency is closely related to chronic alcoholism and can induce neuropathy in alcoholics. Ethanol diminishes thiamine absorption in the intestine, reduces hepatic stores of thiamine and impairs the process that converts thiamine to its active form. As such, thiamine deficiency is commonly found in people who abuse alcohol.8,9
Alcoholic Neuropathy Symptoms
Clinical symptoms typically develop slowly, extending over several months, although some cases have been associated with acute, rapidly progressive onset. Symptoms include sensory, motor, autonomic and gait function abnormalities. Painful sensations with or without burning are typically the initial and major complaint in people with alcoholic neuropathy.8,9 Sensory nerve symptoms typically affect the upper and/or lower extremities (arms, legs, hands or feet). The following symptoms are classified based on the impacted nerves.10
Motor nerve damage
- Muscle spasms and cramps
- Muscle weakness and atrophy
- Loss of muscle functioning
- Movement disorders
Sensory nerve damage
- Pins and needles sensations
Autonomic nerve damage
- Urinary incontinence
- Incomplete bladder emptying
- Impotence in men
- Abnormal intolerance to heat
- Nausea or vomiting
Treatment and Long-Term Prognosis
The nerve damage caused by alcoholic neuropathy is permanent in most cases. The goal of treatment is to stop further damage to the peripheral nerves. This can be achieved through alcohol abstinence, a nutritionally balanced diet, supplementation of all B vitamins and rehabilitation. Painful dysesthesias associated with this disorder are often treated with gabapentin or amitriptyline, as well as over-the-counter pain medications such as aspirin or acetaminophen. While these drugs can alleviate a degree of associated acute pain, they do not address the basic pathological pathways inherent to this disorder. Studies have also analyzed several other vitamins in treating non-alcohol-related peripheral neuropathy. Among these are alpha-lipoic acid, acetyl-L-carnitine, vitamin E, myo-inositol and topical capsaicin cream. Tricyclic antidepressants (TCAs) affect pain transmission and block the active reuptake of norepinephrine and serotonin. They have been shown to relieve various neuropathic pain conditions in clinical trials and may have potential for alcoholic neuropathy.8
Potential long-term consequences of the condition include chronic pain and moderate to severe physical disabilities. Older adults are prone to the natural reduction of postural reflexes and the nerve cell degeneration that occurs with advanced age. Therefore, they may be more at risk for clinical problems associated with neuropathy, such as frequent falls and loss of balance.9
This debilitating and painful consequence of chronic alcoholism is yet another reason people should stop drinking alcohol excessively. If you feel that you are at risk for neuropathy or one of the many other potentially dangerous conditions associated with alcohol, we are here to help. Call Promises today at 1-888-545-4618.
- Anatomy of the Central Nervous System. eMedicineHealth website. http://www.emedicinehealth.com/anatomy_of_the_central_nervous_system/article_em.htm#central_nervous_system_facts Updated April 4, 2016. Accessed July 26, 2016.
- Peripheral Nerve System. John Hopkins Medicine website. http://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/peripheral_nerve_surgery/conditions/peripheral_nerve_system.html Accessed July 26, 2016.
- Overview of the Autonomic Nervous System. Merck Manual website. https://www.merckmanuals.com/home/brain,-spinal-cord,-and-nerve-disorders/autonomic-nervous-system-disorders/overview-of-the-autonomic-nervous-system Accessed July 26, 2016.
- What is the function of the motor nerves? Reference website. https://www.reference.com/science/function-motor-nerves-70fe4fb77d5b8553# Accessed July 26, 2016.
- What is the function of the sensory nerves? Reference website. https://www.reference.com/science/function-sensory-nerves-89e40166d195270e Accessed July 26, 2016.
- Alcohol-Related Liver Disease. American Liver Foundation website. http://www.liverfoundation.org/abouttheliver/info/alcohol/ Updated January 20, 2015. Accessed July 26, 2016.
- Alcohol’s Effects on the Body. National Institute on Alcohol Abuse and Alcoholism website. http://www.niaaa.nih.gov/alcohol-health/alcohols-effects-body Accessed July 26, 2016.
- Chopra K, Tiwari V. Alcoholic neuropathy: possible mechanisms and future treatment possibilities. Br J Clin Pharmacol. 2012 Mar; 73(3): 348–362. Published online 2011 Oct 11. doi: 10.1111/j.1365-2125.2011.04111.x.
- Alcoholic Neuropathy. Medscape website. http://emedicine.medscape.com/article/315159-overview Updated April 21, 2015. Accessed July 26, 2016.
- Alcohol. The Foundation for Peripheral Neuropathy website. https://www.foundationforpn.org/what-is-peripheral-neuropathy/causes/alcohol/ Accessed July 26, 2016.