membranes affects the concentration of sodium in the blood. sodium acts as a force that pulls water across membranes, and water moves from places with lower sodium concentration to places with higher sodium concentration. this happens through a process called osmosis. when evaluating sodium imbalances, both total body water and total body sodium must be considered. hypernatremia main article: hypernatremia hypernatremia means that the concentration of sodium in the blood is too high. an individual is considered to be having high sodium at levels above 145 meq/l of sodium. hypernatremia is not common in individuals with no other health concerns. most individuals with this disorder have either experienced loss of water from diarrhea, altered sense of thirst, inability to consume water, inability of kidneys to make concentrated urine, or increased salt intake. causes there are three types of hypernatremia each with different causes. the first is dehydration along with low total body sodium. this is most commonly caused by heatstroke, burns, extreme sweating, vomiting, and diarrhea. the second is low total body water with normal body sodium. this can be caused by diabetes insipidus, renal disease, hypothalamic dysfunction, sickle cell disease, and certain drugs. the third is increased total body sodium which is caused by increased ingestion, conn's syndrome, or cushing's syndrome. symptoms symptoms of hypernatremia may vary depending on type and how quickly the electrolyte disturbance developed. common symptoms are dehydration, nausea, vomiting, fatigue, weakness, increased thirst, excess urination. patients may be on medications that caused the imbalance such as diuretics or nonsteroidal anti-inflammatory drugs. some patients may have no obvious symptoms at all. treatment it is crucial to first assess the stability of the patient. if there are any signs of shock such as tachycardia or hypotension, these must be treated immediately with iv saline infusion. once the patient is stable, it is important to identify the underlying cause of hypernatremia as that may affect the treatment plan. the final step in treatment is to calculate the patients free water deficit, and to replace it at a steady rate using a combination of oral or iv fluids. the rate of replacement of fluids varies depending on how long the patient has been hypernatremic. lowering the sodium level too quickly can cause cerebral edema. hyponatremia main article: hyponatremia hyponatremia means that the concentration of sodium in the blood is too low. it is generally defined as a concentration lower than 135 meq/l. this relatively common electrolyte disorder can indicate the presence of a disease process, but in the hospital setting is more often due to administration of hypotonic fluids. the majority of hospitalized patients only experience mild hyponatremia, with levels above 130 meq/l. only 1-4% of patients experience levels lower than 130 meq/l. causes hyponatremia has many causes including heart failure, chronic kidney disease, liver disease, treatment with thiazide diuretics, psychogenic polydipsia, syndrome of inappropriate antidiuretic hormone secretion. it can also be found in the postoperative state, and in the setting of accidental water intoxication as can be seen with intense exercise. common causes in pediatric patients may be diarrheal illness, frequent feedings with dilute formula, water intoxication via excessive consumption, and enemas. pseudohyponatremia is a false low sodium reading that can be caused by high levels of fats or proteins in the blood. dilutional hyponatremia can happen in diabetics as high glucose levels pull water into the blood stream causing the sodium concentration to be lower. diagnosis of the cause of hyponatremia relies on three factors: volume status, plasma osmolality, urine sodium levels and urine osmolality. symptoms many individuals with mild hyponatremia will not experience symptoms. severity of symptoms is directly correlated with severity of hyponatremia and rapidness of onset. general symptoms include loss of appetite, nausea, vomiting, confusion, agitation, and weakness. more concerning symptoms involve the central nervous system and include seizures, coma, and death due to brain herniation. these usually do not occur until sodium levels fall below 120 meq/l. treatment considerations for treatment include symptom severity, time to onset, volume status, underlying cause, and sodium levels. if the sodium level is <120 meq/l, the person can be treated with hypertonic saline as extremely low levels are associated with severe neurological symptoms. in non-emergent situations, it is important to correct the sodium slowly to minimize risk of osmotic demyelination syndrome. if a person has low total body water and low sodium they are typically given fluids. if a person has high total body water (such as due to heart failure or kidney disease) they may be placed on fluid restriction, salt restriction, and treated with a diuretic. if a person has a normal volume of total body water, they may be placed on fluid restriction alone. dietary sources diet significantly contributes to electrolyte stores and blood levels. below are a list of foods that are associated with higher levels of these electrolytes. sodium it is recommended that an individual consumes less than 2,300 mg of sodium daily as part of a healthy diet. a significant portion of our sodium intake comes from a just a few types of food, which can be surprising as large sources of sodium may not taste salty. breads soups cured meats and cold cuts cheese savory snacks (e.g., chips, crackers, pretzels) phosphate in minerals, phosphorus generally occurs as phosphate. good sources of phosphorus includes baking powder, instant pudding, cottonseed meal, hemp seeds, fortified beverages, dried whey. potassium good sources of potassium are found in a variety of fruits and vegetables. recommend potassium intake for adults ranges from 2,300 mg to 3,400 mg depending on age and gender. beans and lentils dark leafy greens (e.g., spinach, kale) apples apricots potatoes squash bananas dates calcium dairy is a major contributor of calcium to diet in the united states. the recommended calcium intake for adults range from 1,000 mg to 1,300 mg depending on age and gender. yogurt cheese milk tofu canned sardines magnesium magnesium is found in a variety of vegetables, meats, and grains. foods high in fiber generally are a source of magnesium. the recommended magnesium intake for adults range from 360 mg to 420 mg depending on age and gender. epsom salt nuts and seeds (e.g., pumpkin seeds, almonds, peanuts) dark leafy greens (e.g., spinach) beans fortified cereals