An Overview of Hyponatremia

Symptoms, Causes, Diagnosis, Treatment, and Coping

In This Article

Table of Contents

Hyponatremia is a serious condition that results when the sodium levels in your blood fall below the normal range. Our bodies contain several electrolytes, including the mineral sodium. Sodium is necessary to help your body maintain a sufficient balance of fluids, regulate blood pressure, and facilitate the function of nerves and muscles.

Our bodies acquire sodium in the foods we eat and the beverages we drink. We tend to lose the mineral in our sweat and urine. Additionally, certain conditions, diseases, and medications can affect the rate at which sodium is excreted from the body. 

Hyponatremia can occur when your sodium level is less than 135 milliequivalents/liter (mEq/L). The normal range is between 135 and 145 mEq/L. On a cellular level, if insufficient sodium is present outside the cells, water moves to the inside of cells, causing them to swell. This swelling can result in life-threatening symptoms, particularly when it affects brain cells.

Symptoms of Hyponatremia
Illustration by Nusha Ashjaee, Verywell  

Symptoms

If a person has a mild case of hyponatremia, there may not be any significant signs or symptoms associated with it, or the symptoms may initially be subtle. If sodium loss progresses or drops rapidly, several symptoms can occur including:

  • changes in personality like confusion, irritability, restlessness, or a short temper
  • fatigue, lethargy, and drowsiness
  • headache
  • convulsions and seizures
  • feeling nauseous or vomiting
  • low blood pressure
  • decreased appetite
  • feeling weak
  • muscle spasms and cramps
  • loss of consciousness or coma

Causes

A shift in sodium levels can occur in three primary ways:

  1. Euvolemic hyponatremia: This term refers to a condition where the overall water in the body increases, but the amount of sodium doesn’t change.
  2. Hypervolemic hyponatremia: With this condition, both the body’s water and sodium levels rise, but the water levels increase to a greater degree than the sodium.
  3. Hypovolemic hyponatremia: This describes the loss of both water and sodium from the body. However, more sodium is excreted than water.

There are a variety of factors that can contribute to the conditions that alter the water-sodium balance in the body. They include:

  • diarrhea
  • burns that cover a large portion on the body 
  • sweating
  • excessive vomiting
  • drinking too much water, especially during intense activities like marathons
  • certain medications, particularity diuretics (also known as water pills)
  • diseases that affect the kidneys and impaired kidney function
  • Addison’s disease, an autoimmune disease that affects the body’s ability to make the hormones that sustain sodium levels
  • liver problems like cirrhosis
  • congestive heart failure (CHF)
  • syndrome of inappropriate antidiuretic hormone secretion (SIADH), a syndrome where too much antidiuretic hormone (ADH) is produced leading to water retention and a decrease in the body’s ability to excrete it
  • recreational drug use

Diagnosis

Your doctor will need to take your medical history, ask you questions about your symptoms, and perform a physical exam. Additional tests are usually required to confirm a diagnosis of hyponatremia because many of the symptoms overlap with other health conditions. To establish that low sodium levels are the cause of your symptoms, your healthcare provider will likely order both blood and urine tests.

Treatment

The good news is that there are several treatment options available for hyponatremia—the choice of which treatment is most appropriate for you will be decided by identifying the cause and severity of the condition. If symptoms progress or become severe, you should seek treatment as soon as possible to receive the care you need. 

Mild to Moderate Hyponatremia

If your sodium levels are in the mild or moderate range, your doctor may suggest that you restrict your water intake so that your body can begin to rebalance the fluid levels. This approach might be used if the reason for low sodium is diet-related, you’re consuming too much water, or you’re taking a diuretic. Since diuretics can cause you to lose too much sodium, your medication may need to be fine-tuned to raise sodium levels.

Severe Hyponatremia

If you’re experiencing a severe incidence of low sodium, you need to be treated more aggressively. Some of the options that can help restore your sodium to optimal ranges include:

  • Intravenous (IV) Fluids: This therapy typically occurs in a hospital setting. Sodium-rich fluids are gradually administered through an IV into your vein until the ideal sodium levels are reached. You may be asked to remain in the hospital for a few days to ensure that hyponatremia has resolved and your blood levels are stable.
  • Medications: Prescription drugs may be useful to correct hyponatremia by helping your body retain sodium while excreting the excess fluid. Other medications, like anti-nausea or pain-relieving ones, can help control the symptoms of low sodium.  
  • Dialysis: In cases of impaired kidney function, dialysis may be a necessary step to assist your kidneys with the removal of waste and excess water.

Coping

Coping with any medical condition can be a bit overwhelming, but you can take steps to help yourself or a loved one in this situation.

You can help facilitate a prompt diagnosis by keeping a list of any symptoms that are out of the ordinary that you may be experiencing, and note how long you’ve had them.

Log any medications, both prescription and over-the-counter, and any herbs and supplements you might be taking—the information you give your healthcare provider could help them understand what’s going on and why it’s happening. Whenever possible, bring a trusted friend or family member with you so that you have someone who can remember or write down any information or instructions your doctor may communicate to you.

Finally, make sure you and your friends or family members understand your condition, the treatment options available to you, and what may have caused you to experience hyponatremia. Ultimately, you’ll want to know as many details as possible so that you can avoid a recurrence of the condition.

A Word From Verywell

You may not always know when to contact your doctor, especially if the initial signs that arise are headaches and nausea. However, it’s always better to err on the side of safety. Sodium plays a vital role in your body, so talk with your healthcare provider if you’re experiencing discomfort or symptoms that interfere with your daily activities.

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Article Sources

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  • Merck Manual Professional Version. Hyponatremia.

  • National Kidney Foundation. Hyponatremia.

  • Sahay M, Sahay R. Hyponatremia: A practical approach. Indian Journal of Endocrinology and Metabolism. 2014 Nov-Dec; 18(6): 760–771. doi: 10.4103/2230-8210.141320