PARTICULARITIES OF THE ETIOLOGY OF HYPONATEREMIA IN THE FRAIL ELDERLY PATIENT

Hyponatremia is the most common electrolyte disorder in medical practice, and its prevalence is increasing in frail elderly patients. There are many reasons behind this phenomenon: the changes induced by aging itself, the presence of comorbidities and polypharmacy, the increased risk of dehydration, increased frequency of iatrogenesis and therapeutic noncompliance. Of the iatrogenic causes, we will refer to hyponatremia induced by thiazide-type and thiazide-like diuretics (1) due to 4-fold increase in prevalence in the frail elderly patients. Hyponatremia is a disease that benefits from prompt and appropriate treatment with excellent results, but the key to therapeutic success is the determination of its cause which can be difficult in the elderly, and of patient's volume status for a correct classification of the disease. Hyponatremia in frail elderly patients may be asymptomatic or mimic other diseases. These are due to the almost constant association of varying degrees of geriatric syndromes, the most often responsible for symptom mystification being the cognitive impairment, the presence of comorbidities that have similar symptoms, the overlapping of acute events fractures resulting from same-level falls that distort the diagnosis. We report 3 cases of hyponatremia characterized by atypical symptoms that was induced by indapamide treatment. Hospitalization for thiazide-induced hyponatremia is frequent, suggesting suboptimal monitoring, especially during the treatment initiation phase. Literature data suggest that the ionogram should be obtained 7 to 14 days after treatment initiation to detect the early onset of hyponatremia. There are reports of hyponatremia occurring after years of treatment, suggesting the need for constant monitoring of a patient treated with long-acting thiazide diuretics. Considering an iatrogenic cause (most commonly induced by thiazide-type or thiazide-like diuretics) should be in the forefront of physician's mind, but it requires a thorough medical history, assessment of patient compliance and cognitive status as well as support from patient's family. Identification of the cause of hyponatremia should prevent recurrences and provide adequate patient education to prevent secondary complications.