Hyponatremia
What is it?
Hyponatremia is a lower than normal
concentration of sodium in the blood. Sodium is an
electrolyte that helps with nerve and muscle
function, and also helps to maintain blood
pressure. May also be spelled hyponatraemia.
Who gets it?
Hyponatremia is more likely to occur in people
whose kidneys do not function properly, as well as
in those with heart failure, cirrhosis of the
liver, and Addison’s disease, in which underactive
adrenal glands excrete too much sodium.
What causes it?
Sodium must be maintained at a specific
concentration in the blood and the fluid
surrounding the body’s cells for the body to
function properly. The body maintains a balance of
sodium in the blood by matching the amount of
sodium we take in with the amount excreted (put
out) by the kidneys. Hyponatremia occurs when the
level of sodium in the blood becomes diluted by
too much water intake. This can be caused by
kidney disorders in which the kidneys have
difficulty eliminating fluids. It can also be
caused by diuretic drugs used to treat high blood
pressure. These drugs make the kidneys produce
more urine, which can wash away too much sodium,
especially when the patient is following a low
sodium diet. Some psychiatric disorders cause
people to drink extremely large quantities of
water, which can result in hyonatremia. Other
causes include receiving too much fluid
intravenously, prolonged diarrhea or vomiting,
marathon running, hypothalamus and pituitary
disorders, certain types of cancer, and a
combination of poor diet and excessive consumption
of beer.
What are the symptoms?
Because the brain is very sensitive to sodium
levels, low sodium causes symptoms including
confusion and lethargy. The patient may feel
nauseated, and experience muscle twitching, which
can progress to seizures. Eventually, severe
hyponatremia can lead to coma and death.
How is it diagnosed?
Hyponatremia is diagnosed by measuring the
sodium levels in a blood sample. Normal blood
sodium levels are 136 to 145 milliequivalents per
liter (mEq/L) of blood. A patient with
hyponatremia will have a blood sodium level lower
than 136 mEq/L. Your doctor will also perform
tests and study your medical history to look for
the underlying cause of your condition.
What is the treatment?
Mild hyponatremia is treated by reducing your
intake of water and monitoring the use of
diuretics. When hyponatremia is severe, it is
considered a medical emergency that is treated in
a hospital. The doctor will slowly increase the
blood sodium levels with intravenous (IV) fluids.
Additional treatment depends upon the underlying
cause of hyponatremia.
Self-care tips
If you take diuretics, make sure you have your
blood sodium levels checked on a regular basis. If
you are sick and symptoms include vomiting or
diarrhea, follow your doctor’s recommendations for
replacing lost fluids with clear liquids or
electrolyte replacement fluids. People who run
marathons and train intensely should drink
electrolyte replacement fluids to keep sodium
levels balanced.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
|
