Hyponatremia seizure overview - why does it happen?

  • March 21, 2024
  • 3
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A man adding salt onto his food

Our bodies depend on certain minerals to perform vital functions. Take sodium, for example. We use sodium (salt) to send electric pulses throughout our nervous systems, to manage blood flow, and to regulate how much water is inside and outside our cells. So, if you don’t have enough sodium in your body, it can cause serious health problems. 

The scientific word for having low sodium levels is hyponatremia. There are many symptoms of hyponatremia, and one of the most serious is hyponatremia seizure. Let’s learn about low sodium seizures, why they happen, and how they’re treated. 

Related: Can low potassium cause seizures?

What is hyponatremia?

Hyponatremia is when sodium levels in your blood are very low. A normal sodium level is between 135 and 145 milliequivalents per liter (mEq/L) of blood. When someone has less than 135 mEq/L sodium in their blood, they have hyponatremia. If you have recently had a blood test, this information may appear on the results. 

There are many different hyponatremia symptoms, going from mild to severe, including:

  • Headaches
  • Low energy or feeling tired
  • Feeling irritable
  • Muscles feeling weak
  • Feeling or being sick
  • Hyponatremia seizure
  • Coma

Hyponatremia symptoms may be most serious when sodium blood levels fall very quickly. 

Hyponatremia can affect people of any age, although it is most common among children and women who have not yet had the menopause. 

Hyponatremia is a common disorder, and can happen for several different reasons:

  • Drinking lots of water, which dilutes salt levels 
  • Taking diuretics, which are medications and drugs which make you pee regularly
  • Diarrhea
  • Drinking too much alcohol (which makes you pee more than usual)
  • Underlying kidney, heart or liver problems

Certain medications (including epilepsy medications like carbamazepine, oxcarbazepine, and eslicarbazepine) may also cause low sodium levels. If you are taking these epilepsy medications and have low sodium levels, speak to your doctor for advice about how to take them safely. 

Related: Metabolic causes of epilepsy

Can low sodium cause seizures?

Yes, low sodium seizures are one of the most severe symptoms of hyponatremia. People who have hyponatremia and seizures usually experience tonic clonic seizures (which is when they lose consciousness and their muscles jerk uncontrollably). Focal seizures and other kinds may also happen. Hyponatremia seizures are most likely to happen if sodium levels in the blood drop rapidly to below 115 mEg/L. 

Sodium helps to control the amount of water that enters the brain. When there isn’t enough sodium in the blood, then water flows into the brain and this causes the brain to swell. The extra water inside the brain means neurons aren’t able to send electrical signals like normal, and that can make a seizure happen. 

Low sodium seizures are usually treated by giving the person a saline drip, which increases sodium levels. That quickly draws excess water out of the brain and stops the swelling. 

Does a hyponatremia seizure mean you have epilepsy?

No, if your seizures were caused by low sodium levels, then this is known as a ‘provoked’ seizure. Epilepsy is when seizures are caused by a problem in the brain itself. Because low sodium seizures are caused by something outside the brain, it isn’t technically epilepsy. 

That said, because hyponatremia can make the brain swell, this can cause permanent damage. Brain trauma is a leading cause of epilepsy - so having a hyponatremia seizure could then cause some people to develop epilepsy. 

Also read: What are dissociative seizures?

Avoiding low sodium seizures

Experiencing a hyponatremia seizure can be a very scary experience. If you have low sodium levels, then it’s vital to speak with your doctor about how to manage this - and to treat any underlying causes. Often, the treatments are simple, and just require some basic lifestyle changes. Your physician can talk you through methods to better manage your sodium levels, and avoid hyponatremia and seizures and other issues.

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