water. Dilution of sodium can occur with
excessive fluid intake or secondary to the
body’s ability to eliminate fluid, which is the
case with heart and renal failure. There have
also been cases of hyponatremia seen in
infants when their formula has been diluted
with water or the child has been fed tap
water. 3 This is referred to as hypervolemic
In this case, the patient developed hyponatremia secondary to the body’s inability
to eliminate fluid because of the alteration in
ADH levels. Common signs and symptoms
of hyponatremia include lethargy, apathy,
confusion, disorientation and seizures.
Other non-specific symptoms include muscle cramps, nausea and weakness. 4
Identification of hyponatremia in the prehospital setting may be difficult. A thorough history is a good start, and agencies
using bedside lab devices, such as i-STAT,
will be able to obtain a sodium value. However, treatment should be based on the
underlying cause, type of hyponatremia and
whether the onset was acute of chronic.
EMS providers should keep hyponatremia
in mind as a possible cause of patient’s
symptoms rather than attempting to fix the
patient’s electrolyte imbalance.
1. Vaidya C, Ho W, Freda BJ. Management of hyponatremia: Providing treatment and avoiding harm.
Cleve Clin J Med. 2010;77( 10):715–726.
2. Simon EE. (March 6, 2012). Hyponatremia. In
Medscape. Retrieved Oct. 12, 2012, from
3. Keating JP, Schears GJ, Dodge PR. Oral water
intoxication in infants: An American epidemic.
Am J Dis Child. 1991;145( 9):985–990.
4. Marx JM, Hockberger R, Walls R. Rosen’s emergency medicine concepts and clinical practice,
6th ed., vol. 2. Mosby: St. Louis, p. 1934, 2002.
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