An Overview of Low Sodium Levels

Why your sodium may be low and what to do about it

Salt Shaker on table

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It is not common to have a low sodium level. That is because sodium is a mineral that we consume in salt—and the vast majority of people consume far more sodium than they need. And even as your sodium intake fluctuates from day to day, your body does a pretty good job of maintaining the right concentration of sodium.

Sodium levels can be altered due to serious medical conditions. Major health consequences such as seizures and altered consciousness can result when your sodium is too low. But sometimes, low sodium levels can result from an extreme diet, in which a person drastically decreases salt intake. This can have some effects on your physical health, including blood pressure changes, headaches, and irritability.

Symptoms

Sodium is an essential mineral—your body needs it and can't make it—so the only way to get it is through your food or by intravenous (IV) infusion in an emergency situation. Generally, low sodium is asymptomatic (does not produce symptoms), when it is mild or related to your diet.

Symptoms of low sodium may include:

  • Thirst
  • Decreased or increased urination
  • Dehydration
  • Headaches
  • Fatigue
  • Irritability
  • Dry skin
  • Muscle cramps
  • High blood pressure or blood pressure fluctuations
  • Trouble concentrating
  • Difficulty walking and maintaining balance
  • An increased risk of falling
  • Seizures
  • Loss of consciousness

It can take weeks or months for you to experience the effects of low salt in your diet—and these effects can be corrected by just one day of normal salt intake. However, when sodium levels rapidly decline, which can happen due to certain medical issues, you may experience serious health effects that can worsen rapidly.

Associated Symptoms

The most common effects of severe dietary salt restriction involve your thyroid function. Most of the salt we eat is iodized salt. Your body needs dietary iodine to make thyroid hormones. When you have low sodium due to dietary restriction, you are likely to have symptoms of hypothyroidism too.

When your thyroid hormones are low, you can develop a number of symptoms, including:

Causes

Low sodium can result from lifestyle factors and medical conditions. There are several hormonal issues that can cause low sodium. Lifestyle issues, related to sodium or fluid intake or to excessive sweating can affect sodium levels as well.

Lifestyle Issues

Habits and lifestyle issues rarely affect sodium levels. This is due to the body's efficient ability to balance fluid and sodium. Rapid fluid intake (especially water), however, can make it hard for the body to catch up to the sudden imbalance of sodium.

In some situations, excessive sweating can cause you to lose sodium and water from your body. Sweat and other body fluids are high in sodium. If you are unable to properly replenish your sodium in time, you can develop low sodium.

Low salt intake through the diet is the least common cause of low sodium.

Medical Problems

There are a few medical illnesses that can result in low sodium levels, including hormonal issues and brain injuries. Typically, hormonal issues develop slowly, and the sodium level can be corrected gradually before it causes any serious problems. However, when brain injuries are the cause of low sodium, the problem can develop rapidly, requiring immediate attention.

Syndrome of Inappropriate Antidiuretic Hormone Hypersecretion (SIADH): Antidiuretic hormone (ADH) is a hormone that prevents your body from losing too much water in the urine—especially when you are getting dehydrated. In SIADH, ADH causes the body to hold on to too much water, which makes the sodium concentration too low.

Lung problems like cancer may cause SIADH, as can many drugs like Tegretol (carbamazepine) and Elavil (amitriptyline).

Medications: Several medications alter the concentration of fluid and sodium in the body. For example, diuretics, angiotensin-converting enzyme (ACE) inhibitors, antidepressants, and antipsychotics can cause low sodium.

Adrenal insufficiency: The adrenal glands produce aldosterone, which balances sodium and potassium. Adrenal gland disease, such as cancer or adrenal insufficiency, can cause low sodium levels.

Cerebral Salt Wasting Syndrome (CSWS): This syndrome, caused by brain damage and head trauma, causes sodium loss. This may result in brain swelling, resulting in seizures and loss of consciousness. As the name suggests, cerebral salt wasting is actually caused by the body ridding itself of salt.

Cerebral salt wasting usually starts about a week after a brain injury and resolves after two to four weeks. However, it can occasionally last for a longer time period, even lasting for several years.

Diagnosis

Low sodium levels can cause changes in your blood pressure, urine volume, urine concentration, and neurological condition. Your doctor will routinely check your neurological abilities and blood pressure on any medical visit. It is not typically standard to check urine, but if you have signs of low sodium, you may have this checked as well.

Electrolytes

Checking daily electrolytes like sodium, potassium, calcium, and bicarbonate is common practice in the hospital. So low sodium is generally detected relatively quickly in the hospital setting.

If you have slowly progressing low sodium, or if you develop low sodium at home, it may not be obvious in the early stages. Often, however, if you complain of symptoms of dehydration, fatigue, or muscle cramps, your doctor will likely check your electrolyte levels.

There can be some subtle issues when it comes to low sodium. For example, SIADH and CSWS are both associated with severe medical illness. While SIADH can cause the body’s overall fluid level to increase or at least stay the same, CSWS leads to low fluid and sodium. Your doctor may measure your blood pressure and your urine volume to determine which of these similar conditions you may have.

Imaging Tests

Depending on your sodium level and your other symptoms (such as hormonal changes or neurological symptoms), your doctor may also order imaging tests. For example, if you have weakness of one side of your body or changes in your level of consciousness, you may need a brain computerized tomography (CT) or magnetic resonance imaging (MRI) test.

If you seem to have a disease of the adrenal gland, you may need an abdominal imaging test.

A severe form of low sodium, hyponatremia, may cause the more serious symptoms of low sodium. This condition requires urgent medical treatment.

Treatment Options

The treatment of low sodium can be simple at times, and it can be very challenging in some situations. The treatment is often based in slow, careful sodium replacement, as well as management of the cause of low sodium.

Dietary Intake

If a very low salt diet is the cause of your low sodium, your doctor will recommend slowly increasing your salt intake. The recommended sodium intake is satisfied by about one teaspoon of salt per day for adults and about 1/2 teaspoon of salt per day for children. Keep in mind that the salt in processed foods, bread, pasta, sauces, and even desserts, counts towards that recommended amount.

Intravenous (IV) Sodium Replacement

If you have severely low sodium, you may need replacement with IV fluid. The IV fluid will contain water, sodium, and other electrolytes.

Your medical team would attempt to restore your proper sodium level over the course of several days, frequently checking your levels. A sudden change of your sodium concentration—either up or down—can have serious consequences.

Medical Care

If you have very low sodium, you may experience seizures, necessitating treatment with anti-epilepsy drugs (AEDs). Treatment of the medical cause of your low sodium, whether it is adrenal disease or another illness, is necessary as well.

A Word From Verywell

Low sodium is extremely rare. While lifestyle habits and diet can cause your sodium levels to be lower than they should be, medical issues are usually at the root of the problem. The consequences of very low sodium can be serious and the problem needs to be addressed urgently with medical care.

Once your sodium level is corrected, management of the underlying cause is important as well.

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Article Sources

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  1. Babaliche P, Madnani S, Kamat S. Clinical Profile of Patients Admitted with Hyponatremia in the Medical Intensive Care Unit. Indian J Crit Care Med. 2017;21(12):819-824. doi:10.4103/ijccm.IJCCM_257_17

  2. Filippatos TD, Makri A, Elisaf MS, Liamis G. Hyponatremia in the elderly: challenges and solutions. Clin Interv Aging. 2017;12:1957-1965. doi:10.2147/CIA.S138535

  3. National Institute of Diabetes and Digestive and Kidney Diseases. Hypothyroidism (Underactive Thyroid). Published August 2016.

  4. Godek SF, Peduzzi C, Burkholder R, Condon S, Dorshimer G, Bartolozzi AR. Sweat rates, sweat sodium concentrations, and sodium losses in 3 groups of professional football players. J Athl Train. 2010;45(4):364-71. doi:10.4085/1062-6050-45.4.364

  5. Gankam Kengne F, Decaux G. Hyponatremia and the Brain. Kidney Int Rep. 2018;3(1):24-35. doi:10.1016/j.ekir.2017.08.015

  6. Yasir M, Mechanic OJ. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Updated April 2, 2019.

  7. Liamis G, Milionis H, Elisaf M. A review of drug-induced hyponatremia. Am J Kidney Dis. 2008;52(1):144-53. doi:10.1053/j.ajkd.2008.03.004

  8. Yee AH, Burns JD, Wijdicks EF. Cerebral salt wasting: pathophysiology, diagnosis, and treatment. Neurosurg Clin N Am. 2010;21(2):339-52. doi:10.1016/j.nec.2009.10.011

  9. U.S. Food & Drug Administration. Use the Nutrition Facts Label to Reduce Your Intake of Sodium in Your Diet. Updated June 8, 2018.

  10. Rondon H, Badireddy M. Hyponatremia. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Updated December 13, 2018.

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