Low blood sodium (hyponatremia) occurs when the sodium level in the blood falls below the normal range, typically below about 135 mEq/L. It can arise from a variety of causes, including fluid imbalances, medical conditions, and certain medications. Here’s a concise breakdown to help you understand common causes and related risk factors. Causes
- Excessive water intake or impaired water excretion
- Drinking large amounts of water quickly can dilute blood sodium, especially during strenuous endurance activities or in individuals with impaired kidney function.
- Syndrome of inappropriate antidiuretic hormone secretion (SIADH) causes the body to retain water, diluting sodium.
- Fluid losses with inadequate sodium replacement
- Severe diarrhea, vomiting, sweating, or burns can lead to loss of both water and sodium, and if fluids are not appropriately replaced, hyponatremia can develop.
- Heart, liver, and kidney diseases
- Conditions such as congestive heart failure, cirrhosis, or advanced kidney disease can cause fluid overload and reduced sodium concentration.
- Hormonal or endocrine issues
- Adrenal insufficiency (Addison disease), hypothyroidism, and other hormonal disorders can disrupt sodium balance.
- Medications
- Diuretics (water pills), certain antidepressants, antiepileptics, and pain medications can predispose to hyponatremia, often by promoting sodium loss or altering water balance.
- Other medical conditions
- Liver cirrhosis, kidney failure, pneumonia or other infections, and certain cancers can contribute to hyponatremia through various mechanisms.
Risk factors
- Older age
- Chronic illnesses such as heart, kidney, or liver disease
- Use of medications that affect fluid balance or sodium handling
- Conditions causing persistent diarrhea or vomiting
- Endurance sports with excessive fluid intake and sweat loss
Symptoms (vary with severity)
- Mild: nausea, headache, fatigue, confusion
- Moderate: disorientation, trouble concentrating, lethargy, muscle cramps
- Severe: seizures, stupor, coma, respiratory arrest in extreme cases
When to seek care
- If you notice confusion, seizures, severe headaches, or any signs of rapid worsening, seek urgent medical attention.
- If you have persistent or worsening symptoms or are at risk due to a known condition or medication, contact a healthcare provider.
Diagnosis and treatment (high-level)
- Diagnosis is made via a blood test measuring sodium levels and often includes assessing fluid status and underlying causes.
- Treatment depends on the cause and severity:
- In cases of mild, asymptomatic hyponatremia, careful fluid management and addressing the underlying condition may suffice.
- For moderate to severe cases, controlled correction with careful monitoring, sometimes using IV fluids with adjusted sodium concentrations or medications to limit water retention, is necessary.
- Rapid correction can be dangerous, so medical supervision is essential to avoid complications such as osmotic demyelination syndrome.
Note on safety and context
- Since hyponatremia has many potential causes, an individualized assessment by a healthcare professional is important, especially if there are underlying illnesses or ongoing symptoms.
- If the query relates to a specific scenario (athlete, postoperative patient, elderly individual on certain medications, etc.), providing those details can help tailor guidance.
If you’d like, share any symptoms, recent activities (like endurance exercise), medications, or known health conditions, and this can help narrow down likely causes and suggest immediate steps or questions to discuss with a clinician.
