Hyponatremia

Hyponatremia refers to serum sodium < 135mmol / L, which only reflects the decrease of sodium concentration in plasma and does not necessarily mean the loss of total sodium in the body. The total sodium can be normal or even slightly increased. It is very common clinically, especially in the elderly. The main symptoms were weakness and fatigue, nausea and vomiting, headache and lethargy, muscle painful spasm, neuropsychiatric symptoms and reversible ataxia.