Hyponatremia ( Low Sodium ) ACUTE : Management in primary care

Hyponatraemia, defined as a serum sodium concentration of less than 133 mmol/L, is a common yet potentially life-threatening electrolyte disturbance. Management, particularly of acute hyponatraemia, requires urgent attention due to the risk of cerebral oedema and its associated morbidity and mortality. This introduction will focus on the principles of managing acute hyponatraemia, which is characterized by a rapid fall in sodium levels (greater than 10 mmol/L within 48 hours).

The classification of hyponatraemia into mild, moderate, and severe based on serum sodium levels provides a useful framework for clinical assessment. However, it's important to emphasize that symptomatology, especially in severe hyponatraemia, can also guide classification and management decisions.

Even patients with serum sodium levels typically classified as mild or moderate may exhibit severe symptoms (e.g., seizures, coma) if the sodium concentration has decreased rapidly. Conversely, patients with severe biochemical hyponatraemia may present with only mild symptoms if the condition has developed gradually, allowing for some cerebral adaptation. The critical point that the rate of sodium decline and the presence of symptoms drive treatment...