Thus, in a seemingly normovolemic patient with hyponatremia associated with “intracranial disease”, fluid restriction, loop diuretics, and vaptans (ADH antagonists) used for the treatment of SIADH should be avoided, as they may deteriorate both hypovolemia and hyponatremia, leading to cerebral edema and even seizures in case of CSWS [183]. The gene discussed is AVP; the disease is Hyponatremia.