Hyponatremia, low sodium levels in the body, may lead to disruption of normal cell functions. It is an electrolyte disturbance. When the sodium levels in the blood become lower than normal, extra waters enters the cells resulting to cell swelling. The most difficult complication may arise from swelling in the brain, where it is confined in the skull and is incapable of expanding. Normal sodium level ranges from 135 to 145 millimoles per liter (mmol/L), thus, anything lower than 135 mmol/L is considered hyponatremia. Hyponatremia is sometimes referred to as water intoxication.
Sodium is an essential mineral of the body. It regulates the body’s fluid balance. Moreover, it also helps keep normal blood pressure and assists in nerve and muscle functions. Sodium (Na) is a cation usually present in the fluid outside of cells of the body and is found in blood and lymph fluid.
Types of Hyponatremia
Water and sodium imbalance in the body can occur in three ways
- Hypervolemichyponatremia
- Increase in water and sodium content, but greater in the former
- Caused by kidney failure, heart failure or liver failure
- Hypovolemic hyponatremia
- Decrease in water and sodium content, but loss is greater in the latter
- Caused by excessive sweating or diarrhea without replenishing loss of fluid electrolytes
- Euvolemichyponatremia
- Increase in total body water level but sodium content remains the same
- Caused by chronic health conditions or certain medications
Causes of Hyponatremia
Conditions and lifestyle factors alike can lead to hyponatremia.
- Diet
- Low-sodium and high-water diet
- Diuretics or water pills
- Eliminates more sodium in the body through increased urine
- Syndrome of inappropriate anti-diuretic hormone (SIADH)
- High levels of anti-diuretic hormones leading to water retention instead of excretion
- Certain medications
- Such as antidepressants and pain medications
- Cirrhosis
- Liver disease leading to fluid accumulation in the body
- Kidney disorders
- May lead to inefficient removal of extra fluids from the body
- Congestive heart failure
- May lead to fluid retention
- Too much water intake during exercise
- Dilutes sodium content of the blood
- Chronic or severe vomiting and/ or diarrhea, which may also lead to dehydration
- Loss of bodily electrolytes and fluids
- Burns
- Illegal drugs such as ecstasy
- Alcoholism
- If in the brain, cerebral edema
Symptoms of Hyponatremia
Although there are different causes of hyponatremia, symptoms are almost similar in all situations of hyponatremia which include:
- Confusion
- Fatigue
- Headache
- Irritability
- Loss of appetite
- Muscle cramps or spasms, weakness
- Nausea and vomiting
- Seizures
Treatment for Hyponatremia
Treatment for hyponatremia depends on the underlying cause.
- Mild chronic hyponatremia may not need medical treatment.
- Diet, lifestyle and medication adjustments
- Severe, acute hyponatremia may need medical treatment.
- Intravenous (IV) fluids – to increase sodium levels in the body
- Hormone therapy – to replace deficiency of hormones
- Medications – to manage signs and symptoms
Due to the importance of sodium in the body, it is always important to 
ensure that there is enough sodium in the healthy, well-balanced diet. Understanding hyponatremia can help when taking first aid training, especially when topics are related to heat and dehydration, among others.