Sodium Deficiency (Hyponatremia)

Sodium is an essential nutrient that helps to regulate water balance in and around the cells of the body and maintain blood pressure levels. It is also necessary for proper muscle growth and nerve function.

An insufficient amount of sodium in the body can lead to a condition known as sodium deficiency. Sodium deficiency, also known as hyponatremia, is a condition that occurs when sodium in the body is insufficient or not utilized properly.

Sodium, along with chlorine and bicarbonate, helps to maintain electrically charged particles (positive and negative ions) in tissues and bodily fluids. Sodium is obtained primarily from table salt and is capable of holding water in the body tissues.

In people with circulatory problems, excess sodium may cause the build-up of water in the tissues, a condition known as edema.

Inadequate amounts of sodium, on the other hand, may cause a disturbance in the water-retention capacity of the tissues and acid-base balance that is vital for healthy nutrition.

Sodium is absorbed by the small intestine and stored in the cartilage tissues and muscles. Aldosterone is the hormone that controls the balance of water and sodium in the body.

Sodium deficiency typically occurs during periods of excessive heat, which causes the body to sweat heavily, thus reducing sodium and body water.

This may lead to extreme dehydration that affects regular body patterns. Hyponatremia is often characterized by nausea, fatigue, apathy, and cramps in the muscles.

Normal blood sodium levels are about 135 – 145 milliequivalents per liter (mEq/L). Sodium levels below 135 mEq/L, denotes hyponatremia. Treating this condition would depend on the underlying cause. It is typically treated with normal intravenous saline.

Taking salt in the form of tablets, or increasing the amounts of table salt in the diet is a preventive measure. Sodium deficiency is the most common type of electrolyte imbalance and is associated with an increased risk of death.

Causes of Sodium Deficiency

Water Content

Sodium deficiency occurs when the body has too little sodium for the amount of fluid it contains. The body may have too little, too much, or just enough liquid and still have low sodium.

For instance, people with severe cases of diarrhea and vomiting may lose sodium or have it dilute despite taking in fluid.

Existing medical conditions

Other possible causes of hyponatremia are kidney disorders, heart failure, and cirrhosis, which can cause the body to retain more fluid than sodium, thus making sodium content to be diluted.

Polydipsia, a condition that causes people to drink too much water, can also lead to the development of hyponatremia.


Drugs like thiazide diuretics (also known as water pills) have been known to cause sodium deficiency. These drugs increase water excretion by increasing sodium excretion. Thiazide diuretics are usually well-tolerated but can cause sodium deficiency in people prone to low sodium.


Also known as antidiuretic hormone, it is a substance that is produced by the body and helps in regulating the amount of water in the body by controlling how much water is excreted by the kidneys.

The pituitary gland is responsible for producing this hormone when the amount of fluid in the blood vessels or the blood pressure drops. Vasopressin is also released when there is an excess amount of electrolyte (such as sodium) in the blood.

Sodium deficiency can occur when the pituitary gland releases inappropriate amounts of vasopressin. Furthermore, certain drugs such as ecstasy, chlorpropamide, clofibrate, and vincristine may stimulate the release of vasopressin.

Other causes of sodium deficiency include:

  • Excess water intake
  • Diarrhea
  • Heart failure
  • Pancreatitis
  • Severe burns
  • Addison disease
  • Vomiting
  • Liver disease
  • Cushing’s syndrome
  • Hyperthyroidism

Signs and Symptoms of Sodium Deficiency

Sodium Deficiency (Hyponatremia)

Low sodium levels may lead to excess water retention in the tissues, causing them to swell. This is a condition known as edema.

It is referred to as cerebral edema when this occurs in the brain. Cerebral edema is especially dangerous because the brain confined within the skull, which leaves no room to swell.

Swelling can lead to brain damage as pressure increases within the skull. This type of edema occurs only in severe cases of sodium deficiency.

Chronic hyponatremia may cause sodium levels to drop gradually over type. Symptoms of chronic hyponatremia are generally less severe than that of acute hyponatremia, which is the sudden drop in blood sodium level.

Symptoms of sodium deficiency include:

  • Confusion
  • Headache
  • Decreased state of awareness/consciousness
  • Restlessness
  • Fatigue
  • Nausea
  • Vomiting
  • Cramps
  • Seizures
  • Coma and even death


Symptoms of sodium deficiency may vary from one person to another. To diagnose the condition, your doctor may order a blood test and urine test to confirm the diagnosis.

Medical history and physical examinations may also be required.


Treatment of sodium deficiency would depend on the cause of the condition. Your doctor may recommend that you cut back on water intake if you drink too much water.

They may also make changes in your medication, especially if you take diuretics so that your sodium level can go back to normal. In cases of severe or acute hyponatremia, you will need emergency treatment to improve your sodium level.

You may also need to stay in the hospital for some time, so your progress can be monitored. In cases with headaches, seizures, and nausea, your doctor may prescribe medication to control symptoms and improve health.