From the Guidelines
Correction of CBI induced hyponatremia should prioritize discontinuation of diuretics and expansion of plasma volume with normal saline for hypovolaemic hyponatraemia, as recommended by the guidelines on the management of ascites in cirrhosis 1. When managing CBI induced hyponatremia, it is crucial to evaluate the severity of hyponatremia and patient symptoms.
- For hypovolaemic hyponatraemia, discontinuation of diuretics and expansion of plasma volume with normal saline is the recommended approach 1.
- Fluid restriction to 1–1.5 L/day should be reserved for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/day) 1.
- Hypertonic sodium chloride (3%) administration should be reserved for those who are severely symptomatic with acute hyponatraemia, with a focus on slow correction of serum sodium 1. The guidelines emphasize the importance of monitoring for adverse events in patients initiating diuretics, with almost half of those with adverse events requiring diuretic discontinuation or dose reduction 1. In the context of CBI induced hyponatremia, it is essential to consider the underlying mechanism and patient safety, ensuring that the correction approach prioritizes morbidity, mortality, and quality of life.
- Regular monitoring of fluid balance, mental status, and electrolytes is essential throughout the correction process.
- The use of isotonic solutions rather than hypotonic fluids, maintaining the irrigation bag at the lowest effective height, and ensuring adequate outflow can help minimize the risk of hyponatremia when resuming CBI.
From the Research
CBI Induced Hyponatremia Correction
- The approach to managing hyponatremia should consist of treating the underlying cause 2.
- For severely symptomatic hyponatremia, US and European guidelines recommend treating with bolus hypertonic saline 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.
- 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, 3.
- Fluid restriction and hypertonic saline are commonly used therapeutic modalities for SIADH 3.
- Vasopressin receptor antagonists, called vaptans, have been introduced as specific and direct therapy of SIADH, and appear advantageous to patients because there is no need for fluid restriction and the correction of hyponatremia can be achieved comfortably and within a short time 3.
- It is essential to limit the daily increase of serum sodium to less than 8-10 mmol/liter to prevent osmotic demyelination 3, 4.
Treatment Considerations
- The treatment approach should be based on the patient's fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 2.
- Demeclocycline, a tetracycline type antibiotic, can be effective in the treatment of SIADH by inhibiting the renal action of antidiuretic hormone 5.
- Strict fluid restriction and concomitant excessive free water excretion from prolonged outpatient demeclocycline therapy can lead to severe hypernatremia 6.
- Current guidance documents on the assessment and treatment of hyponatremia vary in methodological rigor, and recommendations are not always consistent 4.