Hyponatremia: What Illness Is Due to Lack of Salt?

October 23, 2025 •

2 min read

Hyponatremia, or low blood sodium, is the most common electrolyte imbalance found in clinical practice, affecting up to 20% of hospitalized patients. This condition is the primary illness that can be caused by a lack of salt, or more commonly, an imbalance of fluids and sodium in the body.

Quick Summary

Hyponatremia is the medical term for low blood sodium levels, causing symptoms like confusion and muscle cramps due to cellular swelling. It stems from an imbalance of water and sodium, often from overhydration or underlying diseases. Severe cases can be life-threatening.

Key Points

Hyponatremia Defined: The illness is hyponatremia, a condition characterized by abnormally low sodium levels in the blood, often caused by fluid imbalance rather than just insufficient salt intake.
Dangerous Brain Swelling: Severe or rapidly developing hyponatremia can cause brain cells to swell (cerebral edema), leading to confusion, seizures, coma, or death.
Underlying Causes: Common causes include fluid retention from heart or kidney disease, prolonged vomiting or diarrhea, excessive water intake, certain medications (diuretics), and hormonal imbalances.
Risk of ODS: Correcting chronic hyponatremia too quickly can result in a severe neurological disorder called osmotic demyelination syndrome (ODS), causing permanent brain damage.
Treatment is Causal: Effective treatment requires diagnosing the root cause. This may involve fluid restriction, medication adjustments, or supervised IV sodium replacement in severe cases.
Prevention Focus: Prevention involves managing underlying health conditions, monitoring fluid intake, and replenishing electrolytes appropriately during intense activities.

What is Hyponatremia?

Hyponatremia is a condition where the serum sodium concentration falls below 135 milliequivalents per liter (mEq/L). Sodium is essential for nerve and muscle function and fluid balance, but low levels can be hazardous. This leads to water moving into cells and causing them to swell, particularly affecting brain cells and potentially causing severe neurological issues. Hyponatremia can develop quickly (acute) or gradually (chronic).

Causes of Hyponatremia

Hyponatremia is often not simply due to a lack of dietary salt, but rather an imbalance of sodium and water in the body. This can result from excessive water diluting sodium or a net sodium loss. Causes include excessive water intake (common in endurance athletes), certain medical conditions like heart, liver, or kidney disease, SIADH, vomiting, diarrhea, excessive sweating, Addison's disease, medications, hormonal changes, and MDMA use. More details on these causes can be found at {Link: verywellhealth.com https://www.verywellhealth.com/hyponatremia-low-sodium-2488674}.

Symptoms and Dangers of Hyponatremia

The symptoms of hyponatremia depend on how rapidly sodium levels decrease. A severe or rapid drop is a critical medical situation. Common symptoms include nausea, headache, fatigue, muscle weakness, confusion, and loss of balance. Serious dangers include cerebral edema (brain swelling) in acute, severe cases, which can lead to seizures and coma. Chronic hyponatremia is linked to neurological problems and increased fall risk. Osmotic Demyelination Syndrome (ODS) can occur if chronic hyponatremia is corrected too quickly. For further information on symptoms and dangers, visit {Link: verywellhealth.com https://www.verywellhealth.com/hyponatremia-low-sodium-2488674}.

Treatment Approaches

Treatment is tailored to the cause and severity. Medical professionals must manage treatment carefully, especially for chronic cases, to ensure a gradual rise in sodium levels.

Comparison of Treatment for Mild vs. Severe Cases


Feature	Mild to Moderate Hyponatremia	Severe or Acute Hyponatremia
Symptom Severity	Mild or asymptomatic	Moderate to severe (e.g., seizures, confusion)
Initial Treatment	Address underlying cause (e.g., adjust medication, treat illness)	Emergency care to prevent brain damage
Fluid Management	Fluid restriction is often recommended	May require intravenous (IV) sodium solution to raise levels slowly
Correction Rate	Gradual increase in sodium levels over days to avoid complications like ODS	Careful, monitored increase in hospital setting

General Treatment Strategies

Treating the root cause is essential. Fluid restriction or adjusting medications may be necessary. In some cases, oral salt tablets or IV solutions might be used. Further treatment information can be found at {Link: verywellhealth.com https://www.verywellhealth.com/hyponatremia-low-sodium-2488674}.

Conclusion

Hyponatremia is the illness resulting from a sodium and fluid imbalance, rather than typically a simple lack of dietary salt. Risks are linked to brain function. Treatment involves identifying the cause and carefully correcting sodium levels under medical supervision. Prevention includes managing health issues, monitoring fluid intake, and appropriate electrolyte replenishment during activity. For further information, resources like the National Kidney Foundation's guide to hyponatremia are available.

Frequently Asked Questions

The primary illness is hyponatremia, a condition in which the concentration of sodium in your blood is too low. It often results from an imbalance of water and sodium rather than simply a low-salt diet.

Initial symptoms can include nausea, vomiting, headache, and fatigue. As the condition worsens, more severe neurological symptoms like confusion, irritability, and muscle cramps may appear.

Yes, excessive water intake is a common cause of hyponatremia. It dilutes the sodium in the blood, especially in endurance athletes who sweat profusely but only replace fluids with plain water.

Severe or acute hyponatremia, where sodium levels drop rapidly, is a medical emergency due to the risk of dangerous brain swelling. Milder cases may be managed less aggressively.

Treatment varies depending on the cause and severity. Options include fluid restriction, adjusting medications, treating the underlying condition, or administering intravenous sodium in a controlled hospital setting.

Correcting blood sodium levels too rapidly, especially in chronic cases, can cause severe and potentially irreversible brain damage known as osmotic demyelination syndrome (ODS).

People at higher risk include older adults, individuals with heart, kidney, or liver disease, those on diuretics or certain antidepressants, and endurance athletes.

Chronic hyponatremia can lead to subtle neurological deficits that affect gait, balance, and cognitive function, increasing the risk of falls and fractures. It has also been linked to osteoporosis.