5th April 2024

Hyponatraemia

Causes of hyponatraemia can be divided based on fluid status:

• Hypovolaemic hyponatraemia due to renal and extra renal losses
• Euvolaemic hyponatraemia includes SIADH; hypothyroidism, glucocorticoid deficiency, primary polydipsia and drugs including antipsychotics and thiazide like diuretics. 
• Hypervolaemic hypernatraemia occurs with congestive cardiac failure; cirrhosis, nephrotic syndrome, acute and chronic kidney disease. 

Psuedohyponatraemia may occur in hypertriglyceridaemia or hyperproteinemia, giving a falsely low sodium when the actual serum sodium concentration is normal.