Hyponatremia means low sodium levels in the blood. Sodium is one of the body's most important electrolytes because it helps regulate fluid balance, nerve function, and muscle activity.
Low sodium can affect mental status, neurologic function, hydration balance, and overall patient stability.
The word can be broken into parts:
Hyponatremia literally means low sodium in the blood.
Sodium is the major extracellular electrolyte and plays a huge role in:
Because sodium affects water movement and brain function, severe hyponatremia can become dangerous.
| Cause | Explanation |
|---|---|
| Excess fluid intake | Too much water can dilute sodium levels. |
| Heart failure | Fluid balance changes may lower sodium concentration. |
| Kidney problems | The kidneys help regulate sodium and water balance. |
| Vomiting or diarrhea | Loss of fluids and electrolytes. |
| Diuretics | Some medications increase sodium loss. |
Sodium and water balance are closely connected. When sodium levels drop, water shifts can affect cells throughout the body, especially brain cells.
This is why sodium imbalances are often associated with neurologic symptoms and mental status changes.
| Condition | Meaning |
|---|---|
| Hyponatremia | Low sodium |
| Hypernatremia | High sodium |
Students commonly confuse these terms at first. Remember:
Sodium is monitored closely because changes can affect:
Sodium values are often reviewed alongside vital signs, lab values, kidney function, and fluid intake/output.
Severe hyponatremia can become dangerous because it may affect brain function and neurologic stability.
A common normal sodium range is 135–145 mEq/L.
Yes. Fluid balance changes can affect sodium concentration in the blood.
Sodium helps regulate fluid balance, nerve signaling, muscle function, and blood pressure.