Although seizures can be linked to epilepsy, they can also happen when blood sugar drops too low. In fact, symptoms of low blood sugar can sometimes look so much like epileptic seizures that the two may be confused or even misdiagnosed.

In this article, we’ll look at what causes low blood sugar, who is most at risk, and what researchers know about why low blood sugar can sometimes lead to seizures.

Low blood sugar, also called low blood glucose or hypoglycemia, is most common in people with diabetes, but it can happen to people without diabetes, too.

Low blood sugar happens when the glucose level in the bloodstream falls below a healthy range. Low blood sugar is generally defined as a blood glucose level below 70 milligrams per deciliter (70 mg/dL). If blood sugar falls below this level, it may be dangerous.

Seizures can happen when blood sugar drops significantly, often below 50 mg/dL and sometimes as low as 40 mg/dL, especially if the decrease happens quickly.

The body's main source of energy is glucose. It’s especially important for the brain, which depends on a steady supply of glucose to function properly. When blood sugar drops too low, the brain may not be able to work as it normally does.

Can Low Blood Sugar Be Mistaken for Epilepsy?

When blood sugar levels are extremely low, seizures can occur. Low blood sugar can also cause symptoms that are often associated with epilepsy, such as:

• Confusion
• Loss of consciousness
• Shakiness
• Anxiety
• Dizziness

These symptoms may resemble epilepsy and could lead to a misdiagnosis if the cause of low blood sugar is missed.

Researchers have reported cases in which recurring episodes of low blood sugar were initially mistaken for epilepsy. In some situations, the actual cause was not discovered until blood sugar levels were closely monitored.

The Link Between Low Blood Sugar and Seizures

Scientists don’t fully understand why low blood sugar causes seizures. But researchers do have some ideas about what might be happening in the brain during a low blood sugar seizure.

Your Brain Needs Glucose To Function

Researchers know the brain relies almost entirely on glucose for energy. When blood sugar drops too low, brain cells may not have enough energy to work properly. This may disrupt the balance of signals in the brain and make a seizure more likely.

A lack of fuel in the brain can cause a range of neurological, or brain-related, symptoms, including:

• Seizures
• Confusion
• Behavior changes
• Loss of consciousness
• Coma

Electrical activity in the brain can also be disrupted by low blood sugar. These electrical disturbances may also trigger a seizure in some people.

Low Energy Disrupts Brain Signals

Some scientists believe that seizures during low blood sugar may occur because energy-deprived brain cells cannot regulate chemical signals normally.

One review noted that while the exact mechanism isn’t fully understood yet, it may have something to do with energy depletion. Energy depletion might cause an imbalance in neurotransmitters, the chemical messengers brain cells use to communicate.

When there’s an imbalance in neurotransmitters, it could increase the release of excitatory neurotransmitters, which make brain cells more active and potentially more likely to produce seizure activity.

In other words, when the brain doesn’t have enough fuel, its normal balance of signals may become disrupted.

Protecting Your Brain From Low Blood Sugar

Low blood sugar and seizures are closely connected, but scientists are still learning exactly how and why.

If you have diabetes or another condition that puts you at risk for low blood sugar, checking your levels regularly and knowing the warning signs can help you stay safe.

If you or someone you know has had a seizure linked to low blood sugar, talk to a doctor to figure out the best way to prevent it from happening again.

Join the Conversation

On MyEpilepsyTeam, people share their experiences with epilepsy, get advice, and find support from others who understand.

Have you ever had symptoms of low blood sugar that felt like something else? Let others know in the comments below.