[Hyponatremies: clinical, prognostic and etiological aspects. About 4 observations]

Hyponatremia is defined as a plasmatic sodium level lower than 136 mmol/l it is a relatively frequent pathology and it is often discovered incidentally. The authors report 4 cases of hyponatremia illustrating the variety of mechanisms and the need for adapted treatments. The prognosis depends mostly on the etiology