WHEN SODIAM LEVLE IS BELOW 120 THEN IT IS CONSIDERD AS HYPONATRIMIA  IT ISDUE TO ABSOLUTE DEFFICIANCY OR RELATIVE DEFICIENCY TO WATER  CAUSE MAY BE DUE TO 1. EXCESSIVE WATER INTAKE  2. SODIAM LOSS FROM BODY DUE TO KIDNEY DISEASE  3. MEDICINE LIKE LOOP  AND THIZIDE DIURETICS IN WHICH SODIAM LOSS FROM BODY 4.DEHYDRATION DUE TO VARIOUS CAUSE LIKE VOMITING SWEATING SEVER BURN 5. HORMONAL IMBLANCE LIKE SIADH SYMPTOM MAY BE IRRITRABILTY  LOSS OF CONSCIOUSNESS  AND HEADACHE  NAUSEA VOMITING  LETHARGY