Understanding Coma: What Happens When Someone Loses Consciousness and How Doctors Help

Have you ever heard someone say that a person has slipped into a coma? Or perhaps you have seen a character in a movie lying completely still with their eyes closed.

A coma is a very serious medical condition. It can pose a direct threat to a person life. Let us talk about what a coma really means, why it happens, and what doctors can do to help.

What Is a Coma?

Simply put, being in a coma means you are completely unconscious. You are not aware of what is happening around you, and you do not respond to any outside signals.

Your body and its basic needs do not get normal attention from your conscious mind. Another way to say it is that your brain is not working properly.

Think of your brain as the control center for your whole body. When it stops working correctly, these serious states can happen. Severe illnesses that damage or pressure the brain can lead to a coma.

Not every coma is the same. Some comas are much deeper than others. This the disruption to brain activity is much more severe.

How Common Are Comas?

Data from public health studies show that in places like the United States and the United Kingdom, about 250 out of every 100,000 people experience a coma each year.

However, exact numbers are hard to pin down with absolute certainty. One major reason is that many conditions that cause a coma can be treated quickly.

Sometimes, first responders or emergency room doctors treat the issue before it fully develops into a long coma. Another reason is that other medical states can sometimes look like a coma.

Anyone who has a health condition affecting normal brain function can potentially slip into a coma. Age, gender, race, and background do not stop this condition from happening to someone.

Symptoms of a Coma.

There are three main signs that point to a coma:

• Unconsciousness: This feels like a very deep sleep. You cannot be woken up by any normal method or stimulation.
• Lack of eye response: Your eyes remain closed. Even if someone tries to open your eyes, you do not react or look around.
• Lack of motor response: You do not make any purposeful movements with your arms, legs, or body.

While these are the classic signs, some people may show minor reflex movements depending on how deep the coma is. If the coma is very deep, even basic reflexes might disappear entirely.

Glasgow Coma Scale (GCS).

Doctors around the world use the Glasgow Coma Scale, or GCS, to measure how severe a coma is. The GCS looks at three main areas, giving points for each one.

The highest possible score is 15. A score of 15 means you are fully awake, alert, aware of your surroundings, and able to follow commands.

A score of 8 or lower usually means the person is in a coma. The lower the score, the deeper the coma. The absolute lowest possible score is 3.

The three categories measured in the GCS are:

• Eye opening response (scored 1 to 4) .
• Motor response or body movement (scored 1 to 6) .
• Verbal or speech response (scored 1 to 5) .

Causes of a Coma.

Many different health issues can cause or contribute to a coma. Let us look at the most common causes:

• Abnormal blood sugar levels: Diabetes complications can trigger this. Both extremely low blood sugar, known as hypoglycemia, and extremely high blood sugar, known as hyperglycemia, are dangerous.
• medicines and medical treatments: Anesthesia used during surgeries or medically induced comas managed by doctors can cause temporary unconsciousness.
• Drug and substance use: Misuse of prescription drugs or illicit substances can overwhelm the brain.
• Alcohol poisoning: Drinking dangerous amounts of alcohol in a short time can shut down normal brain functions.
• Head injuries: Accidents can cause mild concussions or much more severe traumatic brain injuries, known as TBIs.
• Brain bleeds: Blood vessels bursting inside the skull can put heavy pressure on brain tissue.
• Reduced blood flow to the brain: Any form of stroke, especially an ischemic stroke, can cut off vital blood supply.
• Lack of oxygen: A condition called cerebral hypoxia happens when the brain is starved of oxygen.
• Toxic substances: Poisoning from carbon monoxide, heavy metals, or certain strong pesticides can trigger a coma.
• Severe infections: Brain infections like encephalitis and meningitis, or body-wide infections like sepsis, can severely impact consciousness.
• Organ failure: Advanced kidney failure or liver failure allows toxins to build up in the blood and affect the brain.
• Autoimmune and inflammatory diseases: Conditions like multiple sclerosis can sometimes lead to severe neurological crises.
• Electrolyte imbalances: Having too little sodium, known as hyponatremia, or too much calcium, known as hypercalcemia, can disrupt brain cell signaling.
• Extreme body temperature: Severe hypothermia from extreme cold or hyperthermia from extreme heat can shut down brain activity.
• Increased pressure inside the skull: Conditions like hydrocephalus can compress delicate brain structures.
• Seizures: A continuous seizure state known as status epilepticus can exhaust the brain and cause a coma.

Who Is at Higher Risk for a Coma?

Certain medical conditions and daily lifestyle habits can increase your chances of having a coma:

• Metabolic conditions: Having poorly managed diabetes, such as type 1 diabetes or diabetic ketoacidosis, raises your risk greatly.
• Chronic health issues: High blood pressure, also known as hypertension, and high cholesterol can lead to strokes and brain bleeds.
• Substance and alcohol misuse: Relying on unprescribed drugs, opioids, or heavy alcohol use puts heavy stress on the nervous system.
• Not using safety gear: Failing to wear helmets while riding bikes or seatbelts in cars increases the risk of severe traumatic brain injuries.
• Heart conditions: Having irregular heart rhythms can sometimes reduce blood flow to the brain unexpectedly.
• Epilepsy and thyroid disorders: Unmanaged seizure disorders or severe hypothyroidism can also raise your overall risk.

Potential Complications of a Coma.

When someone is in a coma, they cannot care for themselves. They cannot move around, eat, or drink on their own, meaning they require round-the-clock medical care.

A person in a coma often needs a urinary catheter to help empty their bladder. They may also need mechanical ventilation, which is a machine that helps them breathe.

Other common complications that can arise during a coma include:

• Hospital-acquired infections: Ventilator-associated pneumonia or catheter-associated urinary tract infections are common risks.
• Bedsores or pressure injuries: Staying in the same position for too long can damage the skin and tissue.
• Tube feeding: Nutrition must be provided through a feeding tube to keep the body nourished.
• Muscle wasting: Muscles can shrink and weaken rapidly due to lack of movement.
• Blood clots: Deep vein thrombosis can form in the legs. Doctors use blood thinners and intermittent pneumatic compression devices to prevent clots from traveling to the lungs.
• Delirium: Confusion can occur as the person slowly wakes up.
• Tracheostomy: If a coma lasts longer than two weeks, doctors may place a breathing tube directly into a surgical opening in the windpipe.

How Doctors Diagnose a Coma.

Finding the underlying cause of a coma must happen as quickly as possible. The first step is usually a thorough neurological exam.

The doctor tests reflexes and uses scales like the Glasgow Coma Scale to see how severe the lack of response is. If the patient had a recent accident, the cause might be obvious, but tests are still needed to check for hidden damage.

When the cause is unknown, doctors must investigate multiple possibilities at the same time to save valuable time.

Common Diagnostic Tests.

Several medical tests help doctors figure out why a coma happened and how severe it is:

• Lab tests: Blood, urine, and cerebrospinal fluid tests check for sugar levels, salt balances, organ failure, poisons, and infection markers.
• Diagnostic imaging: Scans like CT scans and MRI scans create detailed pictures of the inside of your head to check for bleeding, swelling, or structural damage.
• Electroencephalogram (EEG): This test measures and records the electrical activity of your brain to check for seizure activity or coma depth.
• Electrocardiogram (ECG or EKG): This test checks your heart rhythm to see if a heart issue caused the sudden loss of consciousness.

Your medical team will decide which tests are necessary based on your unique health history and current symptoms.

Coma Treatment and Recovery.

Treatment for a coma depends almost entirely on the underlying cause. Because there are many different causes, treatments vary widely.

What helps one condition might make another condition worse. Therefore, your medical team will tailor every treatment step to your specific situation.

Immediate Emergency Treatments.

Even before the exact cause is fully known, doctors and nurses often start certain emergency treatments based on available clues and symptoms.

These treatments aim to stabilize the patient, stop the coma from getting worse, or even reverse it entirely. Common examples include:

• Glucose or insulin: These medicines quickly fix dangerous blood sugar highs or lows. Giving glucose in time can sometimes wake a person up almost right away.
• Naloxone: This medicine reverses the effects of an opioid overdose within minutes, restoring normal breathing and consciousness if opioids caused the coma.

Like any medical treatment, emergency therapies can carry side effects or risks. Your doctor can explain what risks apply to your specific care plan.

What Does It Feel Like to Be in a Coma?

Because a person in a coma is completely unconscious, they do not know they are in a coma. They show no awareness of the world around them.

They do not intentionally react to their environment, their care team, or their own bodily needs. Depending on the depth of the coma, some reflex movements might happen, but these vary from person to person.

Can You Hear or Remember Things in a Coma?

Sometimes a person can hear sounds around them, but this depends entirely on the type and depth of the coma. There is some evidence that people in certain states can process nearby voices.

Some people who recover from a coma report remembering snippets of conversations or sounds from their hospital room. However, this is not true for everyone.

It is also important to know that diagnosing a coma can be challenging. Doctors rely on training and judgment, but every patient is different.

This means a coma can sometimes be misjudged, or a person might begin to regain awareness before the medical team notices. If you have questions about your own experience or a loved one's care, your doctor is the best person to talk to.

How Long Does a Coma Last?

A coma can be very short, lasting only a few minutes, or it can last for several weeks. Sadly, death can also occur if the injury or illness is too severe or if medical help does not arrive in time.

It is rare for a coma to last longer than a few weeks. Usually, a person either wakes up from the coma or transitions into a different state of reduced consciousness.

These related states include:

• Vegetative state: In this state, the person is awake and can open their eyes, but they have no awareness of their surroundings and show no purposeful behavior. If this state lasts for a long time, doctors call it a persistent vegetative state.
• Minimally conscious state: In this state, the person shows clear, though inconsistent, signs of awareness. They might follow simple commands or speak short words, but they cannot maintain these actions consistently.

Recovery from a vegetative state varies greatly. Some people regain full or partial consciousness. This others do not. People can remain in these states for months or years, requiring constant medical support.

What Are the Chances of Recovery?

The chances of recovering from a coma vary widely depending on many factors. Your treating doctor can provide the most accurate assessment based on your loved one's specific medical situation.

Planning Ahead: Advance Directives.

Imagine if you were in a coma and could not make decisions about your medical care or tell anyone what you want. In most cases, your family or close friends must make those choices for you.

Even if you do not have a health condition that puts you at risk right now, talking to your loved ones about your wishes ahead of time is a smart step.

Having these conversations can feel difficult and uncomfortable. However, talking about them early ensures your family knows what you would want if you cannot speak for yourself.

Can Comas Be Prevented?

Many of the medical conditions that lead to a coma can be prevented, or their risks can be greatly lowered. Here are the most important steps you can take:

• Manage chronic health conditions: Follow your doctor's advice to keep diabetes, epilepsy, and high blood pressure under control.
• Wear safety gear: Use helmets when riding bikes or motorcycles and always wear seatbelts in cars to protect against traumatic brain injuries.
• Eat a balanced diet: Proper nutrition prevents salt imbalances and nutritional deficiencies that affect brain health.
• Maintain a healthy weight and stay active: Regular exercise and a healthy lifestyle protect your blood vessels and reduce the risk of strokes.
• Avoid illicit drugs and use alcohol wisely: Staying away from drug abuse lowers your risk of overdose. Use prescription medicines strictly as directed by your doctor.

Take-Home Message.

We hope this guide has given you a clear understanding of what a coma is. Remember these key points:

• A coma is a medical emergency. If you see someone who is unconscious and unresponsive, seek medical help right away.
• Comas have many different causes, and many of them can be prevented.
• Protecting your head with helmets and seatbelts, managing chronic illnesses like diabetes, and staying away from harmful drugs reduce your risk.
• Discussing your medical wishes with your family and putting them in writing with advance directives ensures your voice is heard if the unexpected happens.
• Recovery chances vary for every person, and your healthcare team is your best resource for specific guidance.

Sources & References.

• Mayo Clinic. (2025). Coma: Symptoms and Causes. Retrieved from Mayo Clinic patient care guidelines.
• National Health Service (NHS). (2024). Coma Overview and Treatment. Retrieved from NHS health information portal.
• Cleveland Clinic. (2024). Glasgow Coma Scale and Unconsciousness Management. Retrieved from Cleveland Clinic medical library.
• Centers for Disease Control and Prevention (CDC). (2024). Traumatic Brain Injury and Concussion Guidelines.
• National Institutes of Health (NIH) / PubMed. (2023). how it happens and Long-term Outcomes of Persistent Vegetative and Minimally Conscious States. DOI: 10.1016/j.neurol.2023.05.012.