Comments on the Letter on Hyponatremia Associated with Diuretic Use and Urinary Retention in an Older Man

The document discussed a case of an 80-year-old man with hyponatremia, highlighting the potential role of urinary tract obstruction (UTO) and postobstructive diuresis (POD) in salt and water excretion. The patient, who was on medications like lisinopril and hydrochlorothiazide, reported excessive water intake and no salt consumption, leading to a serum sodium concentration of 120 mEq/L. The authors noted that UTO can be silent and insidious, affecting renal function and potentially causing resistant hypertension. The case emphasized the need for careful evaluation of urinary tract issues and cautious interpretation of urinary values, especially in older adults on medications that can cause hyponatremia.