What Is Acute Hyponatremia?

Sodium is an important electrolyte that regulates the water balance inside the body. Normal serum sodium measures 135-145 mEq/L. If there is a drop in serum sodium levels in the body, extracellular fluid goes inside the cell causing it to swell. A sudden drop of serum sodium levels is called acute hyponatremia. If acute hyponatremia does not show any signs and symptoms, it resolves on its own. If symptoms are present, it is important that corrective measures are given to prevent onset of neurologic damage.

Acute hyponatremia can be caused by several conditions. These include:

- Burns

- Diarrhea

- Vomiting

- Congestive heart failure

- Kidney disease

- Liver cirrhosis

- Use of medications such as diuretics, anti-depressants, and pain relievers that cause excessive urination and sweating

- Excessive sweating due to intensive physical training and workout

- SIADH (syndrome of inappropriate antidiuretic hormone)

Common symptoms of acute hyponatremia are:

- Loss of appetite

- Muscle weakness

- Muscular spasms or cramps

- Nausea

- Vomiting

- Restlessness

- Irritability

- Fatigue

- Headache

- Convulsions or seizures

- Coma

Alteration in mental status indicates that brain cells are already starting to swell. This will pose a great problem for improper correction of severe acute hyponatremia can lead to several brain complications including brain herniation. Brain herniation is the abrupt descent of the brain inside the skull. This is a life-threatening condition for the weight of the brain depress on the brain stem, causing problems in breathing.

Treatment of acute hyponatremia is usually addressed towards the cause of hyponatremia and relief of presenting symptoms. Oxygen administration and anti-seizure medications are given to help prevent seizures and address difficulty of breathing. IV line is established as a route for immediate correction of hyponatremia, especially if hyponatremia presents severe conditions. 0.9% or 3% saline solution is given, depending on the fluid status and how low obtained serum sodium level readings were upon admission. Correction of 4-5 mEq/L within 12 hours is done, with 10-12 mEq/L correction within 24 hours. Serum sodium levels should be at 120-125 mEq/L in 48 hours. Normal serum sodium levels are targeted 3 days after induction of therapy to prevent osmotic demyelination syndrome.