Hypernatremia
What is it?
Hypernatremia is a greater 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 hypernatraemia.
Who gets it?
Hypernatremia is most common in the elderly,
who may not recognize that they are thirsty or are
unable to get themselves something to drink. It is
also more likely to occur in people who take
diuretics, which cause the kidneys to excrete (rid
the body of) more water, and in those with
diabetes insipidus or diseases of the hypothalamus
or pituitary gland, which can also interfere with
normal kidney function.
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 ingested with the amount excreted (put out)
by the kidneys. Hypernatremia occurs when the body
loses too much water in relation to the amount of
sodium in the blood. Excessive water loss can
occur if the kidneys excrete too much urine
(called polyuria). Or, it can be caused by
excessive sweating during intense heat or
exercise, prolonged diarrhea or vomiting, or
simply by not drinking enough water. Hypernatremia
can also be caused by a high salt intake, either
in the diet or in intravenous treatments for other
conditions.
What are the symptoms?
Symptoms of hypernatremia depend upon the
cause. When water is lost through diarrhea or
vomiting, for example, the patient urinates very
little, with the small amounts of urine produced
having a dark yellow color. If hypernatremia is
caused by kidney dysfunction, the patient urinates
large quantities of clear urine, much like water.
When the sodium concentration in the blood is
extremely high, it affects the brain cells. As
this occurs, the patient experiences muscle
twitching, and begins to feel tired and confused.
Eventually, severe hypernatremia can lead to coma
and death, especially in young children and the
elderly.
How is it diagnosed?
Hypernatremia 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
hypernatremia will have a blood sodium level
higher than 145 mEq/L. Physicians will also look
for any underlying causes of hypernatremia, such
as diabetes insipidus or other disorders.
What is the treatment?
Hypernatremia is treated by replacing the lost
fluids. In mild cases, this can be done by
drinking electrolyte replacement fluids. In more
severe cases, fluids are given intravenously
(through a vein). The fluid is given slowly, and
the blood sodium levels are constantly monitored
so the sodium/water levels are brought to the
proper balance. Unless brain function has been
affected, most people make a full recovery from
hyernatremia.
Self-care tips
You can prevent hypernatremia by drinking
plenty of fluids, especially during extremely hot
weather and intense exercise. 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. If you have a medical condition that
affects kidney function, make sure you follow your
doctor’s treatment guidelines.
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.
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