From the Guidelines
Hyponatremia symptoms typically appear when serum sodium falls below 130 mEq/L and become more pronounced below 125 mEq/L, with early symptoms including headache, nausea, vomiting, muscle cramps, fatigue, and confusion, and worsening to irritability, disorientation, seizures, and in severe cases, coma or death 1.
Symptoms of Hyponatremia
The symptoms of hyponatremia vary based on the severity and how quickly sodium levels drop.
- Early symptoms include:
- Headache
- Nausea
- Vomiting
- Muscle cramps
- Fatigue
- Confusion
- As the condition worsens, patients may experience:
- Irritability
- Disorientation
- Seizures
- In severe cases, coma or death
Severity and Onset of Hyponatremia
Acute hyponatremia (developing in less than 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.
Pathophysiology
The symptoms occur because low sodium causes water to move into cells, including brain cells, causing them to swell, leading to cerebral edema, which is responsible for the neurological manifestations 1.
Risk Factors
Risk factors include certain medications (diuretics, antidepressants, antipsychotics), excessive water intake, heart failure, kidney disease, liver disease, and endocrine disorders like SIADH or adrenal insufficiency 1.
Diagnosis and Management
Elderly patients may present with more subtle symptoms like balance problems or falls, making diagnosis challenging, and management should be guided by the severity of hyponatremia and the presence of symptoms, with the goal of correcting serum sodium levels while minimizing the risk of osmotic demyelination syndrome 1.
From the Research
Symptoms of Hyponatremia
The symptoms of hyponatremia can range from mild to severe and life-threatening. Some of the common symptoms include:
- Nausea and vomiting 2, 3
- Weakness and fatigue 2, 3
- Headache 3
- Mild neurocognitive deficits 3
- Cognitive impairment, gait disturbances, and increased rates of falls and fractures in cases of mild chronic hyponatremia 2
- Severe symptoms such as delirium, confusion, impaired consciousness, ataxia, seizures, and brain herniation can occur in cases of severe hyponatremia 3, 4
- Somnolence, obtundation, coma, seizures, or cardiorespiratory distress in severely symptomatic cases 2
Severity of Symptoms
The severity of symptoms depends on the rapidity of development, duration, and severity of hyponatremia 2. Mild hyponatremia may not exhibit noticeable symptoms, while severe hyponatremia can be life-threatening 3, 4.
Association with Other Conditions
Hyponatremia is often associated with other conditions such as heart failure, cirrhosis, and syndrome of inappropriate antidiuresis 2, 4, 5. In patients with heart failure, hyponatremia is associated with increased morbidity and mortality 4, 5.