Hyponatremia cerebral edema

In a 12-year-old boy taking desmopressin for nocturnal enuresis, hyponatremia and cerebral edema developed after high fluid intake before a urodynamic procedure... 

In a retrospective analysis of all cases of hyponatremia associated with ecstasy (SEDA-25, 37) at the London Centre of the National Poisons Information Service from December 1993 to March 1996,17 patients were identified with a serum sodium concentration under 130 (range 107-128 mmol/1) (96). In 10, ecstasy was identified analytically, and six of them had SIADH. The clinical presentation was very consistent, with initial vomiting and delirium, and 11 had seizures. There was complete recovery in 14, but two died of cerebral edema 5 hours after ingestion. 

Hypernatremia (plasma Na >150 mmol/L) is always hyperosmolar, Symptoms of hypernatremia are primarily neurological (because of intraneuronal loss of H2O to the ECF) and include tremors, irritability, ataxia, confusion, and coma. As with hyponatremia, the rapidity of the development of hypernatremia wiU determine the plasma Na value at which symptoms occur. Acute development may cause symptoms when Na reaches 160 mmol/L, although in chronic hypernatremia, overt symptoms may not occur until Na exceeds 175 mmol/L. In chronic hypernatremia, the intracellular osmolality of CNS cells wiU increase to protect against intracellular dehydration. Because of this, rapid correction of hypernatremia can cause dangerous cerebral edema, as CNS cells will take up too much water if the ICF is hyperosmotic when normonatremia is achieved. ... 

Patients with weakened hearts, including the elderly, who often have decreased cardiac capacity to adapt to volume changes, or pediatric patients, who have smaller hearts with less capacity to handle large volumes, are at particular risk for cardiac overload. 2 Increased fluid volume also could cause a dilutional hyponatremia. Thus symptoms of low sodium concentration with fluid shifts including cerebral edema could occur. 4... 

Watch for signs of cerebral edema and neurologic disturbances, particularly if hyponatremia has been present for 48 hours or longer. 

Ghatol A, Kazory A. Ecstasy-associated acute severe hyponatremia and cerebral edema a role for osmotic diuresis J Emerg Med 2012 42(6) el37-40. 

Amiry-Moghaddam M, Xue R, Haug FM, Neely JD, Bhardwaj A, Agre P, Adams ME, Froehner SC, Mori S, Ottersen OP (2004) Alpha-syntrophin deletion removes the perivascular but not endotheUeil pool of aquaporin-4 at the blood-brain barrier and delays the development of brain edema in an experimenUil model of acute hyponatremia. FASEB J 18 542-544 Anderson CM, Nedeigaard M (2003) Astrocyte-mediated control of cerebral microcirculation. Trends Neurosci 26 340-345... 

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