Diagnostic pitfalls and therapeutic challenges in hyponatremia in adults: A systematic review

Hyponatremia is the most common disorder of water and electrolyte balance in adult clinical practice and remains a frequent cause of diagnostic uncertainty and treatment-related harm. Although the definition of hyponatremia is straightforward, its interpretation requires assessment of tonicity, chronicity, symptoms, volume status, renal water handling, medications, endocrine disease, and the risk of overly rapid correction. This systematic review summarizes current evidence on diagnostic pitfalls and therapeutic challenges in adult hyponatremia, with particular emphasis on hypotonic hyponatremia, syndrome of inappropriate antidiursis, thiazide-associated hyponatremia and severe symptomatic presentations. PubMed/MEDLINE and PubMed Central were searched for English-language publications concerning adult hyponatremia, diagnostic pathways, correction strategies, and treatment complications. Clinical guidelines, reviews, systematic reviews, randomized trials, and observational studies were included. The literature indicates that common errors include failure to exclude pseudohyponatremia or hypertonic hyponatremia, overreliance on clinical volume assessment, delayed measurement of urine osmolality and urine sodium, under-recognition of drug-induced causes, and inadequate monitoring during therapy. Therapeutic challenges include balancing urgent treatment of cerebral edema against prevention of osmotic demyelination, managing unpredictable water diuresis, and individualizing therapy in SIAD, heart failure, cirrhosis and thiazide-associated disease. A structured, physiology-based approach can improve diagnostic accuracy and reduce avoidable harm.