To Drown A Baby in A Water Bottle. Case of A Severe Hyponatremia Caused by Fluid Oversupply in A 2-Year-Old Child

Introduction Sodium concentration in the body is controlled by osmoregulatory system, which regulate water intake and excretion. If this system fails and plasma sodium level stray outside its normal range (135-145mmol/L), the cells are exposed to hypotonic or hypertonic stress. Hyponatremia is one of the most common electrolyte imbalances, occurring in up to 20% of hospitalized patients. It is defined as a plasma sodium concentration lower than 135mmol/L, with severe hyponatremia being below 120mmol/L. The symptoms of hyponatremia vary, depending not only on the concentration of sodium, but also on the rate of lowering of natremia. Mild symptoms may include headaches, cognitive impairment, lethargy, nausea, and vomiting; however, the signs may be subtle, or it may be asymptomatic whatsoever. In severe hyponatremia consciousness disturbances, seizures, and coma are common. The most common cause of hyponatremia include vomiting and diarrhea, adrenal insufficiency, heart, liver and renal failure, syndrome of inappropriate antidiuretic hormone secretion (SIADH), cerebral salt wasting syndrome, osmotic diuresis, and hyperglycemia. One should not forget about overhydration as a potential reason of hyponatremia. Here we present a case of a child with severe hyponatremia due to fluid oversupply. A two-year-old boy was admitted to the Emergency Department after an episode of seizures lasting several minutes, with breathing disorders and loss of consciousness. Past medical history was not relevant, the psychomotor and physical development was normal (body mass 14kg = 72pc, height 91,5cm = 63pc, BMI 16,7kg/m 2 =75pc). Laboratory examination revealed a decreased natremia of 120mmol/L, which was gradually corrected with 3% sodium chloride,