hiponatriemica

Hyponatremia, or hiponatriemica in some languages, is a medical condition defined by a serum sodium concentration below 135 mmol/L. It reflects an excess of body water relative to sodium and can cause brain swelling, leading to symptoms ranging from nausea and confusion to seizures or coma, especially with rapid onset.

Causes include increased water retention (for example, syndrome of inappropriate antidiuretic hormone secretion, heart failure, liver disease, kidney failure), excessive hypotonic fluid intake, and medications such as thiazide diuretics, SSRIs, and certain antiepileptics. Acute hyponatremia develops within 48 hours and tends to be more dangerous than chronic hyponatremia, but brain adaptation reduces symptoms over time.

Diagnosis relies on laboratory and clinical assessment. Hyponatremia is categorized by serum osmolality into hypotonic hyponatremia (the most common), isotonic pseudohyponatremia, and hypertonic hyponatremia caused by hyperglycemia or other osmoles. Investigations include serum osmolality, urine osmolality, urine sodium, and evaluation of volume status and medications.

Treatment depends on severity and the underlying cause. Severe, symptomatic hyponatremia warrants prompt but controlled correction with hypertonic saline (3% NaCl) under monitoring. In stable patients, fluid restriction and treating the cause are common approaches. The correction rate should be gradual to avoid osmotic demyelination syndrome, typically not exceeding about 4-6 mmol/L in 24 hours.

Prognosis varies with cause and speed of onset. Prevention focuses on cautious fluid management and careful use of hyponatremia-promoting drugs in at-risk individuals.