Alcohol poisoning, also called alcohol overdose, occurs when there is too much alcohol in the bloodstream for the brain to adequately control the functions that support life. Some examples of functions alcohol poisoning can impair include breathing, maintaining the body’s temperature, and regulating the body’s heart rate. Alcohol overdose can result in death. Even a non-fatal alcohol overdose can cause permanent brain damage.
How Alcohol Overdose Can Cause Brain Injury
There are many ways that alcohol poisoning can harm the brain, and most of them involve the risk of anoxic brain injury. Here are some examples of how this may occur:
- The Mayo Clinic says that alcohol poisoning can cause blood sugar to drop so low that the person can have seizures. Seizures can cause injury to the brain.
- Alcohol can make your body temperature plummet, sending you into cardiac arrest.
- Alcohol poisoning can cause the victim to breathe less regularly, less deeply, or both. This can significantly reduce the oxygen coming into the body. Even if you do not stop breathing completely, your brain can sustain permanent damage from the lack of oxygen.
- A person can have an irregular heartbeat from an alcohol overdose. This situation can harm the brain from the lack of oxygen circulating in the bloodstream.
- In an alcohol overdose, the victim often loses their gag reflex because the alcohol prevents the brain from controlling automatic functions. The gag reflex protects a person from choking. If the drinker vomits, they can choke to death or suffer irreversible brain damage due to a lack of oxygen.
- Alcohol itself is a toxin that can damage the brain in high enough doses. People with alcoholism often have inadequate nutrition, which can compound the toxin’s effects and lead to thiamine deficiency. The brain and other tissues need thiamine to function correctly.
- Alcohol consumption can cause Wernicke-Korsakoff syndrome, which can lead to serious conditions like Wernicke’s encephalopathy and Korsakoff’s psychosis.
Factors That Impact Brain Damage from Alcohol Poisoning
Any amount of alcohol consumption will affect the brain, but most people only experience temporary effects. The impairment of brain function a person experiences after one or two drinks over a few hours will pass quickly, assuming that the person does not consume additional drinks. Heavier consumption of alcohol can impact the brain with increasing severity. In extreme cases, a victim will require long-term care in a residential facility to manage the complications of alcohol poisoning.
Some of the most common issues that can influence the way that alcohol can affect a person’s brain and the extent of brain injury they sustain from alcohol poisoning include:
- How much alcohol a person consumes and how frequently
- The age at which the person first started consuming alcohol
- How long the person has been drinking alcoholic beverages
- The person’s overall health
- Whether the person was exposed to alcohol before birth. Prenatal alcohol exposure puts a person at a higher risk of impact to the brain.
- The person’s genetic background and family history
- The person’s gender, age, and level of education
How Blood Alcohol Concentration (BAC) Impairs a Person by Level
Many people do not have a clear understanding of the point at which alcohol poisoning or overdose occurs. They do not know if they should let a friend “sleep it off” or get medical help.
The National Institutes of Health created a guide for people to assess the level of a person’s blood alcohol concentration (BAC) by behavior to know when a person has reached dangerous amounts of alcohol consumption and may be at risk for an overdose or poisoning. The four levels are:
This level is usually between 0.0 to 0.05 percent BAC. The person might start to feel sleepy. It is at this level that relaxation and other perceived benefits of alcohol happen. There might be some minor impact on speech, coordination, balance, memory, and attention.
This level is from 0.06 to 0.15 percent BAC. The person goes from relaxed to intoxicated. Some people become aggressive at this stage. The person is at greater risk of injury to themselves and others. They can experience increased issues with coordination, balance, attention, and speech, with even more impairment of memory. They will have a significant impairment of all driving skills.
This level is from 0.16 to 0.30 percent BAC. The person can lose consciousness. A person who has passed out from alcohol can die. Blackouts with amnesia can occur at this level. There can be significant and dangerous impairment of judgment, decision-making, all driving-related skills, balance, coordination, speech, reaction time, attention, and memory. Vomiting and other signs of alcohol poisoning are common at this level.
At a BAC of 0.31 to 0.45 or above, the drinker is at a significant risk of death from alcohol overdose and the alcohol suppressing vital life functions. The person often loses consciousness. The person can experience seizures, irregular breathing, and a slow heart rate. The skin can feel clammy. They might have a hard time staying awake or be unable to wake up. Their body temperature can plummet, causing paleness or a bluish skin color.