From the Guidelines
Hyponatremia symptoms can be severe and life-threatening, and immediate medical attention is necessary if symptoms such as confusion, disorientation, seizures, or coma occur, especially in athletes with exercise-associated hyponatremia 1. Hyponatremia symptoms vary depending on severity and how quickly sodium levels drop. Early symptoms include headache, nausea, vomiting, fatigue, muscle cramps, and irritability. As sodium levels decrease further, patients may experience confusion, disorientation, seizures, and in severe cases, coma or death. Symptoms typically appear when serum sodium falls below 130 mEq/L and become more pronounced below 125 mEq/L. Some key points to consider:
- Acute hyponatremia (developing within 48 hours) tends to cause more severe neurological symptoms than chronic hyponatremia because the brain hasn't had time to adapt to the osmotic changes 1.
- The brain swells when blood sodium drops rapidly, leading to increased intracranial pressure and neurological symptoms.
- Elderly patients may present with balance problems and falls, while athletes might experience exercise-associated hyponatremia with symptoms during or after prolonged exertion.
- If you suspect hyponatremia, seek immediate medical attention, especially if neurological symptoms are present, as proper diagnosis requires blood tests and treatment depends on the underlying cause and severity. In the context of athletes, education on potential individual risks and preventative measures, such as measuring body weight before and after long events and having a hydration plan in place, is critical for good outcomes 1. Medical providers should be aware of the presenting symptoms of symptomatic hyponatremia and have a plan in place for rapid identification and treatment, including the use of oral hypertonic solutions or hypertonic saline in severe cases 1.
From the FDA Drug Label
Other symptoms of sodium chloride deficiency are nausea, vomiting and increased irritability of muscles, evidenced by cramps and, possibly, convulsions. The symptoms of hyponatremia (sodium chloride deficiency) include:
- Nausea
- Vomiting
- Increased irritability of muscles, which can cause:
- Muscle cramps
- Convulsions 2
From the Research
Hyponatremia Symptoms
- Hyponatremia is defined by a serum sodium level of less than 135 mEq/L and can cause a range of symptoms, from mild and nonspecific to severe and life-threatening 3
- Mild symptoms of hyponatremia include nausea, vomiting, weakness, headache, and mild neurocognitive deficits 4
- Severe symptoms of hyponatremia include delirium, confusion, impaired consciousness, ataxia, seizures, and, rarely, brain herniation and death 4
- Chronic hyponatremia can cause cognitive impairment, gait disturbances, and increased rates of falls and fractures 3
- The severity of symptoms depends on the rapidity of development, duration, and severity of hyponatremia 3
Classification of Hyponatremia
- Hyponatremia can be classified as mild (130-134 mEq/L), moderate (125-129 mEq/L), or severe (<125 mEq/L) 4
- Hyponatremia can also be classified based on fluid volume status, including hypovolemic, euvolemic, or hypervolemic hyponatremia 3, 4
Treatment of Hyponatremia
- Treatment of hyponatremia depends on the underlying cause and severity of symptoms 3, 4
- Mild hyponatremia can be treated with fluid restriction or salt tablets, while severe hyponatremia may require emergency infusions with 3% hypertonic saline 4
- Vaptans, such as tolvaptan, can be effective in treating hyponatremia in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) 5