Low sodium level
Hyponatremia; Dilutional hyponatremia; Euvolemic hyponatremia; Hypervolemic hyponatremia; Hypovolemic hyponatremia
Low sodium level is a condition in which the amount of sodium (salt) in the blood is lower than normal. The medical name of this condition is hyponatremia.
Causes
Sodium is found mostly in the body fluids outside the cells. It is very important for maintaining blood pressure. Sodium is also needed for nerves, muscles, and other body tissues to work properly.
When the amount of sodium in fluids outside cells drops below normal, water moves into the cells to balance the levels. This causes the cells to swell with too much water. Brain cells are especially sensitive to swelling, and this causes many of the symptoms of low sodium.
With low sodium level (hyponatremia), the imbalance of water to salt is caused by one of three conditions:
The imbalance of water to salt
Every part of your body needs water to function. When you are healthy, your body is able to balance the amount of water that enters or leaves your b...
- Euvolemic hyponatremia -- total body water increases, but the body's sodium content stays the same
- Hypervolemic hyponatremia -- both sodium and water content in the body increase, but the water gain is greater
- Hypovolemic hyponatremia -- water and sodium are both lost from the body, but the sodium loss is greater
Low sodium can be caused by:
-
Burns
that affect a large area of the body
Burns
Burns commonly occur by direct or indirect contact with heat, electric current, radiation, or chemical agents. Burns can lead to cell death....
- Diarrhea
- Diuretic medicines, which increase urine output
-
Heart failure
Heart failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
- Kidney diseases
-
Liver
cirrhosis
Cirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
-
Syndrome of inappropriate antidiuretic hormone secretion
(SIADH)
Syndrome of inappropriate antidiuretic ...
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition in which the body makes too much antidiuretic hormone (ADH). This ho...
- Sweating
-
Vomiting
Vomiting
Nausea is feeling an urge to vomit. It is often called "being sick to your stomach. "Vomiting or throwing-up is forcing the contents of the stomach ...
Symptoms
Common symptoms include:
-
Confusion
Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
-
Convulsions
Convulsions
A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain. The term "seizure...
-
Fatigue
Fatigue
Fatigue is a feeling of weariness, tiredness, or lack of energy.
- Headache
- Irritability
-
Loss of appetite
Loss of appetite
A decreased appetite is when your desire to eat is reduced. The medical term for a loss of appetite is anorexia.
-
Muscle spasms
or cramps
Muscle spasms
Muscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...
-
Muscle weakness
Muscle weakness
Weakness is reduced strength in one or more muscles.
- Nausea
-
Restlessness
Restlessness
Agitation is an unpleasant state of extreme arousal. An agitated person may feel stirred up, excited, tense, confused, or irritable.
- Vomiting
Exams and Tests
The health care provider will perform a complete physical examination to help determine the cause of your symptoms. Blood and urine tests will be done.
Physical examination
During a physical examination, a health care provider studies your body to determine if you do or do not have a physical problem. A physical examinat...
Lab tests that can confirm and help diagnose low sodium include:
-
Comprehensive metabolic panel
(includes blood sodium)
Comprehensive metabolic panel
A comprehensive metabolic panel is a group of blood tests. They provide an overall picture of your body's chemical balance and metabolism. Metaboli...
-
Osmolality
blood test
Osmolality
Osmolality is a test that measures the concentration of all chemical particles found in the fluid part of blood. Osmolality can also be measured with...
-
Urine osmolality
Urine osmolality
The osmolality urine test measures the concentration of particles in urine. Osmolality can also be measured using a blood test.
-
Urine sodium
Urine sodium
The sodium urine test measures the amount of sodium in a certain amount of urine. Sodium can also be measured in a blood sample.
Treatment
The cause of low sodium must be diagnosed and treated. If cancer is the cause of the condition, then radiation, chemotherapy , or surgery to remove the tumor may correct the sodium imbalance.
Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
Other treatments depend on the specific type of hyponatremia.
Treatments may include:
- Fluids through a vein (IV)
- Medication to relieve symptoms
- Water restriction
Outlook (Prognosis)
Outcome depends on the condition that is causing the problem. Low sodium that occurs in less than 48 hours (acute hyponatremia), is more dangerous than low sodium that develops slowly over time. When sodium level falls slowly over days or weeks (chronic hyponatremia), the brain cells have time to adjust and swelling may be minimal.
Possible Complications
In severe cases, low sodium can lead to:
- Decreased consciousness, hallucinations or coma
-
Brain herniation
Brain herniation
A brain herniation is when brain tissue, cerebrospinal fluid, and blood vessels are moved or pressed away from their usual position inside the skull....
- Death
When to Contact a Medical Professional
When your body’s sodium level drops too much, it can be a life-threatening emergency. Call your provider right away if you have symptoms of this condition.
Prevention
Treating the condition that is causing low sodium can help.
If you play sports or do other vigorous activity, drink fluids such as sports drinks that contain electrolytes to keep your body's sodium level in a healthy range.
Electrolytes
Electrolytes are minerals in your blood and other body fluids that carry an electric charge. Electrolytes affect how your body functions in many ways...
References
Pfennig CL, Slovis CM. Electrolyte disorders. In: Marx JA, Hockberger RS, Walls RM, et al., eds.
Rosen's Emergency Medicine: Concepts and Clinical Practice
. 8th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap 125.
Review Date: 4/30/2015
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.