More  common in  patients  older then  60 yo presenting with nausea  malaise , headache  confusion   gait  disturbance progressing to seizure and  eterioration of  conscious  state.

May  be associated  with  vomiting  , diarrhea kidney  disease  ,   diuretic   use/ abuse pituitary disease , medication  side effect   Inappropriate  fluid intake.

Treatment  initially is by  fluid restriction and  salt  supplementation after  review  of  medication.