What to Know About Hyponatremia and Hypernatremia

Sodium often gets a bad rap because too much salt can cause high blood pressure and heart disease. But sodium is an essential electrolyte mineral, so you do need some in your diet. Electrolytes help balance your body’s fluid volume, and they regulate blood pressure and also nerve and muscle function, among other things.

As with other electrolytes like potassium and magnesium, your body closely regulates the sodium levels in your body. But sometimes, due to certain health conditions or medicines you take, sodium levels can get too low or high. Hyponatremia means you have low sodium and hypernatremia means you have a high sodium level.

Learn what might cause either of these disorders and why it’s essential to treat them.

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Hyponatremia Causes and Symptoms

Hyponatremia happens when blood levels of sodium fall below 135 mEq/L. The problem isn’t usually a lack of sodium in your diet.

Instead, the problem is drinking excess water or having too much water in your body. This dilutes the amount of sodium in your blood.

Hyponatremia can also happen because of certain health conditions or medicines you take. Health conditions that can cause your body to hold on to too much water and trigger hyponatremia include:

  • Severe diarrhea or vomiting (if you replace fluids with plain water).
  • Cirrhosis.
  • Heart failure.
  • Kidney disease.
  • Addison’s disease (a disease that affects your adrenal glands).
  • Uncontrolled diabetes with very high blood sugar levels.

Common medicines that can increase your risk of hyponatremia include:

  • Thiazide diuretics and some antidiuretics.
  • SSRIs and some antipsychotic medicines.
  • Tegretol (seizure medication).
  • The drug Ecstasy can also cause hyponatremia.

The symptoms of hyponatremia depend on how severe it is and how fast it develops. With mild or moderate hyponatremia, you might feel nothing or feel tired, nauseous, or have a headache. If it’s more severe (less than 120 mEq/L), you can have seizures, lose consciousness, or go into a coma. In addition, acute hyponatremia which develops rapidly (within 48 hours) tends to cause more symptoms that chronic hyponatremia (over 48 hours) which allows your body to adapt and have very little or no symptoms, even when it is severe.

Hypernatremia Causes and Symptoms

With hypernatremia, your sodium levels are too high — over 145 mEq/L. As with hyponatremia, it’s an electrolyte disorder related to water balance, not a high salt intake issue. Having too little water compared to the amount of sodium in your body leads to hypernatremia.

Your body’s thirst mechanism regulates water — you feel thirsty when your fluid level gets low, and sodium is high.

Hypernatremia is most common in older adults or those who are mentally or physically impaired. These groups often don’t drink enough fluids, so sodium becomes too concentrated in their body. Severe vomiting, diarrhea, or sweating can also cause dehydration and lead to hypernatremia if fluid isn’t replaced.

One of the first symptoms of mild hypernatremia is feeling very thirsty. You might also feel tired, weak, or dizzy when you stand up. Severe hypernatremia causes symptoms like confusion, twitching or muscle spasms, seizures, or coma.

How to Treat and Prevent Hyponatremia
and Hypernatremia

Both disorders threaten your life, so it’s crucial to identify and treat them. If your doctor diagnoses you with hyponatremia or hypernatremia, they’ll work to correct your sodium levels. The exact treatment will depend on how severe it is and the nature of the underlying problem.

They might treat mild hyponatremia by having you restrict your fluids for a while. More severe cases will require IV fluids with sodium. Sometimes the doctor may use medicines that help you excrete more water.

For mild hypernatremia, drinking more water and fluids will help. If your sodium level is very high, or you can’t keep fluids down, you’ll need IV fluids.

To prevent hyponatremia and hypernatremia, make sure you’re drinking only when you are thirsty. In general, excessive water intake has no demonstrated health benefits except in specific circumstances (e.g., kidney stones).

If you’re not able to eat or drink, and you’re losing lots of fluid, call your doctor.

Sources

Merck Manual. Hyponatremia. LINK

Merck Manual. Hypernatremia. LINK

Department of Health and Human Services. Dietary Guidelines for Americans. LINK

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