What Is a Diabetic Seizure?

Severe low blood sugar levels (hypoglycemia) can result in seizures and unconsciousness. Diabetic seizures are rare but potentially fatal and need emergency medical treatment.

Diabetic seizures can happen to anyone with diabetes who uses insulin or certain other glucose-lowering drugs, particularly sulfonylureas. If you have diabetes, you may need to teach your family members, caregivers, friends, or coworkers how to react in an emergency.

Seizures caused by hypoglycemia go by several different names, including:

Hypoglycemic seizure
Diabetic shock
Insulin shock

People experiencing a diabetic seizure will be unable to treat their own symptoms — they will probably lack the presence of mind to understand their situation, or the body control to fix it. Therefore, it is just as important for friends and family to be familiar with these symptoms.

Seizures can cause a variety of temporary abnormal behaviors, sometimes very suddenly, including:

Muscles that twitch, jerk, or convulse
Loss of consciousness
Limbs that go limp or stiff
Drooling or staring
Clenched teeth

During a diabetic seizure, you may become unconscious, fall, or have convulsions that cause muscles to contract involuntarily, making the body move and jerk out of control. Convulsions can be mild or severe. You may also appear to be in a trance or unable to respond, with eyes blinking rapidly or staring into space, before slipping into unconsciousness.

These symptoms require immediate emergency medical care.

In some cases, a diabetic seizure may occur without warning, especially if it happens in the middle of the night or in people who experience hypoglycemia unawareness.

Sudden seizures are especially dangerous if they strike people who are engaged in activities such as driving a car or swimming.

For most people with diabetes there will be prior warning signs as blood sugar levels drop towards unsafe levels. Everyone with diabetes should be intimately familiar with the symptoms of (moderate) hypoglycemia, including the following:

Shakiness
Sweating, chills, and clamminess
Irritability or impatience
Rapid or fast heartbeat
Lightheadedness or dizziness
Hunger and nausea
Sleepiness or weakness
Blurred or impaired vision
Tingling or numbness in the lips or tongue

Diabetic seizures can be prevented by noticing some of the above symptoms and reacting appropriately. As long as the person experiencing low blood sugar can still safely eat and drink, treating the condition is often very easy. Fast-acting carbohydrates, like the sugar found in candy or soda, can bring blood sugar back up into a safe range.

Diabetic seizures are generally caused by extremely low blood sugar levels. Very low glucose concentrations affect the brain, and when the brain cannot get the sugar it needs, it leads to severe cognitive failures and motor dysfunction, such as muscle twitching or convulsions.

One of the most common causes of severe low blood sugars are accidental insulin overdoses. Many people with diabetes, including everyone with type 1 diabetes, use insulin multiple times a day, and accidents can happen:

Using the wrong insulin
Using the wrong dosage
Forgetting to eat after administering a mealtime dose

Other lifestyle variables can cause blood sugar levels to drop to severely low levels:

Intense exercise
Unanticipated physical exertion
Excessive alcohol use
Illness, particularly those that make it difficult to eat or drink

In the United States, insulin-induced hypoglycemia may be responsible for about 100,000 emergency department visits every year. Sadly, a majority of the most serious cases are a result of intentional insulin overdoses.

While insulin is the most powerful glucose-lowering medication available, and therefore the most common cause of diabetic seizures, other diabetes drugs may have the same effect, particularly sulfonylureas.

There is no precise blood sugar level below which diabetic seizure or unconsciousness is sure to occur. Measurable cognitive impairment typically begins at 50 milligrams per deciliter (mg/dL) or below. Blood sugar levels at or below that range should be considered dangerous. They require immediate attention.

Hypoglycemia becomes most dangerous below 20 mg/dL, the point at which permanent brain damage and death might occur, especially if the episode is prolonged.

But even at this especially severe level of hypoglycemia, patients receiving timely emergency medical treatment can recover fully. The vast majority of people who overdose on insulin generally experience no long-term damage if they get to a hospital in time.

Many people with diabetes will never experience a seizure. Good diabetes management — prudently using diet, medicine, and exercise to keep your blood sugar within your target range as much as possible — will reduce the risk of extremely low (and high) blood sugar levels.

Diabetes authorities recommend using the “15/15 rule” to treat hypoglycemia: Eat or drink 15 grams of fast-acting carbohydrates, wait 15 minutes, and then measure blood sugar to see if it has returned to your target range. If the level remains below 70 mg/dL, have another 15 grams of carbohydrates, and check again in 15 minutes.

People with diabetes should take special care to try to reduce the number of hypoglycemic events that they experience. The more times you have hypoglycemia, the more your body becomes accustomed to low blood sugar levels. You will begin to stop experiencing the symptoms and warning signs associated with hypoglycemia, such as shaking, hunger, or dizziness. This condition is called hypoglycemia unawareness, and it can be extremely dangerous, because it can cause you to approach very severe levels of hypoglycemia without realizing it.

Hypoglycemia is also more dangerous overnight, because sleep dulls our ability to sense the symptoms of low blood sugar. In the hours before bedtime, some people with diabetes avoid the lifestyle variables that can cause hypoglycemia during sleep, such as carbohydrate-heavy meals (and the large doses of rapid-acting insulin that they require), alcohol, and exercise.

One item of diabetes technology is especially helpful as a defense against severe hypoglycemia: A continuous glucose monitor (CGM) can alert a patient if their blood sugar falls below a certain level, sounding a loud alarm on a smartphone or dedicated receiver device. These sensors stay attached to the body and measure your blood sugar level at least as frequently as every five minutes. An alarm can wake you up before your blood sugar declines to a severe level, giving you time to consume simple carbohydrates (like candy or juice) to bring your blood sugar back up. A CGM alarm can also potentially wake up a spouse, partner, or family member, giving them extra time to help you if you are slow to respond.

Severe hypoglycemia, especially when accompanied by seizure or unconsciousness, cannot be treated by the individual suffering from low blood sugar. If you lack the mental awareness or motor skills to give yourself treatment, then you will be completely reliant on the help of the people around you. That’s why you should make sure that the people in your life — family members, friends, coworkers, neighbors — know what to do in case of an emergency.

Many people with diabetes, despite their best efforts, have found themselves in low blood sugar emergencies during which they could not treat themselves. It’s a good idea to always be prepared for that event. A couple of tools can really help:

A medical ID bracelet that specifies that you have diabetes. If you have an emergency in the company of strangers, an ID bracelet is the best way to let first responders know exactly what you are suffering from. It could make a vital difference in making sure that you get the care you need quickly.
Emergency glucagon medication is an injection or nasal spray that is designed to bring your blood sugar back up if you are unable to eat or drink. In order to make this prescription drug an effective failsafe, you need to teach the people you spend time with — including family members, roommates, coworkers, and exercise partners — where you keep it and how to use it. Some stash multiple prescriptions in important places (one at home, one at the office), or if you have a diabetes supply bag, you can carry it with you everywhere you go.

In a low blood sugar emergency — when someone with diabetes cannot swallow, passes out, or has a seizure — treatment requires emergency glucagon. If you are attempting to help but do not have access to emergency glucagon, or do not know how to use it, call 911 immediately. First responders are trained to help people experiencing emergencies related to diabetes and should carry emergency glucagon.

If you have access to emergency glucagon, you should use it yourself to treat a hypoglycemic emergency, and then immediately call a doctor. After treating an unconscious person with glucagon, roll them onto their side; the medicine can cause vomiting, and this will reduce the risk of choking. Glucagon should cause an unresponsive individual to wake up within fifteen minutes. When they are able, they should eat or drink more carbohydrates.

When people talk about diabetic seizures or insulin shock, it’s usually in the context of low blood sugar emergencies. But it is also possible for high blood sugar (hyperglycemia) to cause seizures in people with type 1 and type 2 diabetes. Two consequences in particular are associated with this severe side effect:

Diabetic ketoacidosis (DKA), which is most common in people with type 1 diabetes
Hyperosmolar hyperglycemic syndrome (HHS), which is most common in people with type 2 diabetes

Though DKA and HHS are very different, they share many similarities. Both are usually accompanied by severe high blood sugar levels. Both are often triggered by illnesses with dehydrating symptoms, such as vomiting or diarrhea, and both have similar symptoms, including:

Increased urination
Increased thirst
Vision problems
Confusion

These symptoms require emergency medical care. Eventually, both DKA and HHS will lead to acute neurological symptoms, such as delirium, seizure, and coma.

Extremely low blood sugar levels can cause unconsciousness and seizures. These symptoms require immediate emergency medical treatment.
Continuous glucose monitors (CGM) can alert individuals to dangerously low blood sugar levels, offering a critical warning ahead of potential seizures, especially overnight. Diabetes medical bracelets can also help first responders.
People with diabetes who use insulin or sulfonylureas should teach their friends, family, and coworkers how to recognize the signs of low blood sugar and how to locate and administer emergency glucagon medication.
High blood sugar levels can also cause seizures which tend to develop more slowly than severe low blood sugar emergencies. Knowing the signs of diabetic seizures and what to do in case of emergency can keep you or your loved one with diabetes safe.

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