How does water intoxication, also known as Hyponatremia (low sodium levels in the blood), cause seizures?

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Last updated: May 17, 2025 • View editorial policy

From the Guidelines

Water intoxication causes seizures by disrupting the brain's normal electrical activity through a process called hyponatremia, which occurs when excessive water consumption dilutes sodium levels in the blood, and treatment involves restricting fluid intake and sometimes administering hypertonic saline solutions to restore proper sodium balance, as recommended by the American Association for the Study of Liver Diseases in 2021 1.

Pathophysiology of Water Intoxication

Water intoxication leads to hyponatremia, a condition where the sodium concentration in the blood falls below 135 mmol/L. When someone consumes excessive water, the sodium levels in the blood become diluted, creating an osmotic gradient that forces water to flow into brain cells, causing them to swell. This swelling increases intracranial pressure and disrupts normal neuronal function, potentially triggering abnormal electrical discharges across the brain, which can manifest as seizures.

Management of Hyponatremia

According to the 2021 practice guidance by the American Association for the Study of Liver Diseases 1, mild hyponatremia (Na 126-135 mEq/L) in cirrhosis without symptoms does not require specific management apart from monitoring and water restriction. However, for severe hyponatremia (<120 mEq/L), a more severe restriction of water intake with albumin infusion is recommended. The use of hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia.

Treatment and Prevention

Treatment of water intoxication involves correcting the sodium imbalance by restricting fluid intake and administering hypertonic saline solutions. It is essential to monitor serum sodium levels closely and adjust treatment accordingly. The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period, to ameliorate the risk of osmotic demyelination syndrome (ODS) 1.

Key Considerations

  • Severe hyponatremia (<120 mEq/L) at the time of liver transplant increases the risk of ODS with liver transplant, and multidisciplinary coordinated care may mitigate this risk 1.
  • The use of vasopressin receptor antagonists in cirrhosis can raise serum sodium during treatment but should be used with caution only for a short term (≤30 days) 1.

From the Research

Water Intoxication and Seizures

  • Water intoxication can lead to hyponatremia, a condition where the sodium levels in the blood are lower than normal 2.
  • Hyponatremia can cause seizures, which are a serious complication of water intoxication 3.
  • Seizures occur when the brain is unable to function properly due to the low sodium levels, leading to abnormal electrical activity 3.

Mechanism of Seizure Induction

  • The exact mechanism of how water intoxication causes seizures is not fully understood, but it is thought to be related to the rapid change in sodium levels in the blood 4.
  • When sodium levels drop too low, it can cause swelling of brain cells, leading to increased pressure and potentially causing seizures 2.
  • The severity of hyponatremia and the rate of correction can also play a role in the development of seizures 5.

Treatment and Management

  • Treatment of hyponatremia-induced seizures typically involves the use of hypertonic saline to rapidly increase sodium levels 3.
  • Anti-convulsants may also be used to control seizures and prevent further episodes 3.
  • It is essential to correct sodium levels slowly and carefully to avoid overcorrection, which can lead to further complications such as central pontine myelinolysis 4, 3.

Importance of Early Detection

  • Early detection of water intoxication is crucial to prevent severe complications, including seizures and death 6.
  • Recognition of the symptoms of water intoxication, such as confusion, disorientation, and polydipsia, can help identify patients at risk and allow for prompt treatment 6.

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.