How to manage a patient with severe hyponatremia and vomiting?

From the Guidelines

Management of a patient with severe hyponatremia (Na 117 mEq/L) and vomiting requires immediate attention to correct sodium levels and address the underlying cause, with the goal of improving morbidity, mortality, and quality of life. To manage this patient, begin with a thorough assessment including serum sodium, osmolality, urine sodium, and volume status.

• For severe symptomatic hyponatremia (sodium <120 mEq/L with neurological symptoms), administer 3% hypertonic saline as a 100-150 mL bolus over 10-20 minutes, which can be repeated up to 2-3 times if symptoms persist, as recommended by the American Association for the Study of Liver Diseases 1.
• Aim for a sodium correction rate of 4-6 mEq/L in the first 24 hours and no more than 8-10 mEq/L to avoid osmotic demyelination syndrome, as supported by the 2021 practice guidance by the American Association for the Study of Liver Diseases 1.
• For vomiting, administer antiemetics such as ondansetron 4-8 mg IV/PO every 8 hours or metoclopramide 10 mg IV/PO every 6 hours.
• Address fluid losses with isotonic fluids like 0.9% normal saline if the patient is hypovolemic.
• Frequent monitoring of serum sodium (every 2-4 hours initially) is essential to guide therapy, as emphasized in the kasl clinical practice guidelines for liver cirrhosis 1.
• Identify and treat underlying causes such as medications, SIADH, adrenal insufficiency, or gastrointestinal losses.
• Fluid restriction to 800-1000 mL/day may be necessary for euvolemic or hypervolemic hyponatremia, as recommended by the American Association for the Study of Liver Diseases 1. This approach balances the risks of untreated severe hyponatremia (seizures, cerebral edema) against too-rapid correction, which can cause permanent neurological damage, ultimately prioritizing the patient's morbidity, mortality, and quality of life.

From the Research

Managing Severe Hyponatremia and Vomiting

• Severe hyponatremia is a medical emergency that requires immediate attention 2, 3, 4, 5, 6.
• The management of severe hyponatremia involves treating the underlying cause and correcting the serum sodium level 2, 3, 4, 5, 6.
• For patients with severely symptomatic hyponatremia, bolus hypertonic saline is recommended to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours, but by no more than 10 mEq/L within the first 24 hours 2, 3.
• It is essential to monitor the patient's sodium levels closely to avoid overly rapid correction, which can cause osmotic demyelination, a rare but severe neurological condition 2, 3, 5.
• The approach to managing hyponatremia should consist of treating the underlying cause, and patients should be categorized according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 2, 3, 4, 5, 6.

Treatment Options

• Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 2, 4.
• Hypovolemic hyponatremia is managed by rehydration with isotonic saline 3.
• Hypervolemic hyponatremia is managed by addressing the underlying cause 3.
• Euvolemic hyponatremia is managed by restricting free water intake, addressing the underlying cause, and occasionally with drugs (eg, vasopressin receptor antagonists) 3, 4.

Considerations

• The treatment of hyponatremia should be individualized based on the patient's clinical status, serum sodium level, and underlying cause 2, 3, 4, 5, 6.
• Patients with severe or acutely symptomatic hyponatremia require urgent treatment, and their sodium levels should be monitored closely to avoid overly rapid correction 2, 3, 5.