Hyponatremia

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Small cell carcinoma

Hyponatremia

Alternative Names:

Dilutional hyponatremia; Euvolemic hyponatremia; Hypervolemic hyponatremia; Hypovolemic hyponatremia

Symptoms:

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When sodium levels drop in the fluids outside the cells, water will seep into the cells in an attempt to balance the concentration of salt outside the cells. The cells will swell as a result of the excess water. While most cells can accommodate this swelling, brain cells cannot, because the skull confines them. Therefore, most symptoms of hyponatremia will result from brain swelling.

Common symptoms include:

Loss of appetite
Nausea
Vomiting
Headache
Restlessness
Fatigue
Irritability
Abnormal mental status
- Possible coma
- Hallucinations
- Consciousness, decreased
- Confusion
Convulsions
Muscle weakness
Muscle spasms or cramps

Signs and tests:
Hyponatremia is confirmed through the following laboratory studies:

In addition to laboratory studies, a complete physical examination will be done to find the underlying cause of this condition. During this examination, your doctor may order additional tests.

References:

Craig S. Hyponatremia. Available at: http://www.emedicine.com/EMERG/topic275.htm. Accessed 10/27/2005.

Braunwald E, Fauci AS, Kasper DL, et al., eds.Hyponatremia. In Harrison's Principles of Internal Medicine. 15th ed. New York, NY: McGraw-Hill; 2001:274-76.