Hypotonic dehydration is the loss of water and sodium at the same time but lack of water than sodium, serum sodium lower than the normal range of extracellular fluid was hypotonic body status to reduce the secretion of antidiuretic hormone, so that the water in the renal tubular reabsorption decrease in urine output to increase from an increase in extracellular osmotic pressure. Extracellular fluid but also to reduce the amount of anti-. Interstitial fluid into the blood plasma ring are able to compensate in part, blood volume, but the decrease in interstitial fluid more than the decrease of plasma. Faced with decreased circulating blood volume of the body will no longer be taken into account as far as possible to maintain blood volume and osmotic pressure. Renin - aldosterone system excited to emission reduction in renal Na Cl-and water re-absorption increases. Therefore, sodium chloride content in urine was decreased. Decline in blood volume will stimulate the posterior pituitary antidiuretic hormone secretion so that an increase in water re-absorption increases, resulting in oliguria such as reduced blood volume will continue to decline, the compensatory function is no longer able to maintain blood volume, the shock will occur. This shock is caused by numerous loss of sodium, also known as hyponatremia.