In this section of the NCLEX-RN examination, you will be expected to demonstrate your knowledge and skills for fluis and electrolyte imbalances in order to:

  • Identify signs and symptoms of client fluid and/or electrolyte imbalance
  • Apply knowledge of pathophysiology when caring for the client with fluid and electrolyte imbalances
  • Manage the care of the client with a fluid and electrolyte imbalance
  • Evaluate the client's response to interventions to correct fluid or electrolyte imbalance

Electrolytes are ions that can have either a negative or positive charge. Electrolytes and the levels of electrolytes play roles that are essential to life. For example, these electrically charged ions contract muscles, move fluids about within the body, they produce energy and they perform many other roles in the body and its physiology.

Electrolytes, similar to endocrine hormones, are produced and controlled with feedback mechanisms when the kidneys or adrenal gland sense a deficit of the particular electrolyte and an imbalance in terms of the client's electrolyte balance.

The body's electrolytes are positively or negatively charged as shown below:

  • Sodium which is abbreviated as Na+
  • Potassium which is abbreviated as K+
  • Calcium which is abbreviated as Ca+
  • Magnesium which is abbreviated as Mg+
  • Chloride which is abbreviated as Cl
  • Hydrogen phosphate which is abbreviated as HPO4
  • Bicarbonate which is abbreviated as HCO3
  • Sulfate which is abbreviated as SO4

Identifying the Signs and Symptoms of the Client's Fluid and/or Electrolyte Imbalances

The functions of the major bodily electrolytes, imbalances of these electrolytes in terms of deficits and excesses and their signs and symptoms as well as the treatments for these imbalances are discussed below.


The normal range for sodium is 135 to 145 milliequivalents per liter (mEq/L).

Sodium plays a primary role in terms of the body's fluid balance and it also impacts on the functioning of the bodily muscles and the central nervous system. This electrolyte is most abundant in the blood plasma; and bodily water goes where sodium is. For example, high levels of fluid in the plasma will occur when the plasma has high sodium content and the converse is also true.

Hypernatremia, that is a sodium level higher than 145, can result from a number of different factors and forces such as diabetes insipidus, dehydration, as the result of a fever, vomiting, diarrhea, diaphoresis, extensive exercise, exposures of long duration to environmental heat, and Cushing's Syndrome.

The signs and symptoms of hypernatremia, among others, include agitation, thirst, restlessness, dry mucous membranes, edema, confusion and, in more severe cases, seizures and coma.

The treatment of hypernatremia, like other electrolyte disorders includes the correction and management of any underlying causes and dietary sodium restrictions. It must be noted, however, that a rapid reduction of sodium in the body can lead to the rapid flow of water which can result in cerebral edema, permanent brain damage which is often referred to as central pontinemyolysis, and even death.

Hyponatremia, that is a sodium level of less than 135, can result from the syndrome of inappropriate antidiuretic hormone, some medications like diuretics, some antidepressants, water intoxication and as the result of diseases and disorders such as a disorder of the thyroid gland, cirrhosis, renal failure, heart failure, pneumonia, diabetes insipidus, Addison's disease, hypothyroidism, primary polydipsia, severe diarrhea or vomiting, cancer, and cerebral disorders.

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The signs and symptoms associated with hyponatremia include confusion, vomiting, seizures, muscle weakness, nausea, headaches, loss of energy, fatigue, and restlessness and irritability.

The treatments of hyponatremia include the correction and management of any underlying causes, diuretic medications, fluid restrictions, intravenous sodium, and, if Addison's disease is the cause then hormone replacement may be necessary.


The normal potassium level is 3.7 to 5.2 mEq/L.

Unlike sodium that is an extracellular electrolyte that is found in the blood plasma, potassium is most abundant in the cells of the body; it is primarily an intracellular electrolyte. This electrolyte promotes and facilitates electrical impulses that are necessary for muscular contractions and also for the normal functioning of the brain.

Hyperkalemia, which is a potassium level greater than 5.2 mEq/L, can be life threatening; the signs and symptoms associated with hyperkalemia include muscular weakness, paralysis, weakness, nausea and possible life threatening cardiac dysrhythmias. Hyperkalemia is most frequently associated with renal disease, but it can also occur as the result of some medications.

Life threatening hyperkalemia is treated with renal dialysis and potassium lowering medications. Lower less threatening levels of hyperkalemia can sometimes be treated with the restriction of dietary potassium containing foods.

Hypokalemia, which is a potassium level less than 3.7 mEq/L, most often as the result of bodily fluid losses that occur as the result of diarrhea, vomiting, and diaphoresis as well as some medications like diuretics and laxatives, and with other disorders and diseases such as ketoacidosis.

Mild cases of hypokalemia can be asymptomatic but moderate and severe hypokalemia can be characterized with muscular weakness, muscular spasms, tingling, numbness, fatigue, light headedness, palpitations, constipation, bradycardia, and, in severe cases, cardiac arrest can occur.

In addition to treating the underlying cause of this electrolyte imbalance, supplemental potassium is typically administered.


The normal level of calcium is between 8.5 – 10.6 mg/dL.

The levels of calcium in the body are managed by calcitonin which decreases calcium levels and parathyroid hormone which increases the calcium levels. Calcium is essential for bone health and other functions.

Hypercalcemia, which is a calcium level of more than 10.6 mg/dL, is most often associated with the endocrine disorder of hyperparathyroidism, but it is also associated with some medications such as thiazide diuretics and lithium, some forms of cancer such as breast cancer and cancer of the lungs, with multiple myeloma, Paget's disease, non weight bearing activity and elevated levels of calcitriol as can occur with sarcoidosis and tuberculosis.

Hypercalcemia is characterized with thirst, renal stones, anorexia, paresthesia, urinary frequency, bone pain, muscular weakness, confusion, abdominal pain, depression, fatigue, lethargy, constipation, nausea and vomiting.

The treatment of hypercalcemia can include intravenous fluid hydration and medications like prednisone, diuretics, and bisphosphonates. Symptomatic relief measures and interventions can include analgesia to decrease the client's level of pain, vitamins D and A, and the protection of the client against injuries and accidents, such as falls, because pathological bone fractures can occur secondary to the bone decalcification that occurs in many cases of hypercalcemia.

Because magnesium levels are highly associated with calcium levels, it is often necessary to also correct and treat the magnesium levels before the calcium levels can be corrected.

Hypocalcemia, which is a calcium level less than 8.5 mg/dL, can occur as the result of renal disease, inadequate dietary calcium, a vitamin D deficiency because vitamin D is essential for the absorption of calcium, a low level of magnesium, pancreatitis, hypoparathyroidism, an eating disorder, and certain medications such as anticonvulsants, alendronate, ibandronate bisphosphonates, rifampin, phenytoin, phenobarbitol, corticosteroids, plicamycin and others.

Symptoms can range from mild and barely noticeable to severe and life threatening. Some of these signs and symptoms include muscular aches and pain, bronchospasm which can cause respiratory problems, seizures, tetany, life threatening cardiac arrhythmias, and tingling of the feet, fingers, tongue and lips.

The treatment of hypocalcemia includes the monitoring of the client's respiratory and cardiac status in addition to providing the client with calcium supplements coupled with vitamin D because vitamin D is necessary for the absorption of calcium.


The normal level of magnesium in the blood is 1.7 to 2.2 mg/dL.

Magnesium plays an important role in the body in terms of enzyme activities, brain neuron activities, the contraction of skeletal muscles and the relaxation of respiratory smooth muscles. Magnesium also plays a role in terms of the metabolism of calcium, potassium and sodium.

Hypermagnesemia, which is a blood magnesium level of more than 2.2 mg/dL, is most frequently found secondary to renal failure, dehydration, diabetic acidosis, hyperparathyroidism, hypothyroidism, Addison's disease, and with the excessive and prolonged use of magnesium containing laxatives or antacids.

The signs and symptoms associated with hypermagnesemia include nausea, vomiting, respiratory disturbances, overall and muscular weakness, cardiac arrhythmias, respiratory paralysis, central nervous system depression and hypotension.

The treatment for hypermagnesemia typically includes the cessation of causative medications like magnesium containing laxatives, renal dialysis, and the administration of calcium gluconate, calcium chloride and/or intravenous dextrose and insulin.

Hypomagnesemia, on the other hand, is a blood magnesium level less than 1.7 mg/dL. Hypomagnesemia often occurs as the result of the prolonged use of diuretics, uncontrolled diabetes, hypoparathyroidism, diarrhea and gastrointestinal disorders such as Chron's disease, severe burns, malnutrition, alcoholism and medications such as cisplatin, cyclosporine, amphotericin, proton pump inhibitors and aminoglycoside antimicrobial drugs.

The signs and symptoms of hypomagnesemia are numbness and tingling, muscular weakness, convulsions, muscle spasms, cramps, fatigue, and nystagmus.

The treatment of hypomagnesemia can include medications to decrease pain and discomfort as well as the administration of intravenous fluids and magnesium.


The normal level of serum phosphate is from 0.81 to 1.45 mmol/L.

Hyperphosphatemia is defined as a phosphate level greater than 1.45 mmol/L. The greatest risk factor for hyperphosphatemia is severe and advanced renal disease, but other risk factors can include hypoparathyroidism, diabetic ketoacidosis, serious systemic infections, and rhabdomyoysis which is the destruction of muscular tissue.

Hyperphosphatemia can be asymptomatic but when it is pronounced the client may have signs and symptoms of muscular spasms and cramping, weakness of the bones, tetany, and crystal accumulations in the circulatory system and in the body's tissue that can lead to sometimes severe itchiness and palpable calcifications in the subcutaneous tissue. This electrolyte disorder also has complications such as impaired circulation, cerebrovascular accidents, myocardial infarctions and atherosclerosis.

The treatment of hyperphosphatemia includes the restriction of dietary food products containing phosphates including foods like milk and egg yolks, and phosphate binders such as lanthanum and sevelamer which make it hard for the client's body to absorb phosphates. These medications are taken with meals.

Hypophosphatemia, which is defined as a phosphate level less than 0.81 mmol/L, is associated with risk factors such as chronic diarrhea, severe burns, hyperparathyroidism, severe malnutrition, pronounced alcoholism, lymphoma, leukemia, hepatic failure, osteomalacia, genetics, the long term use of some diuretics and aluminium antacids, and the long term use of theophylline.

This sometimes life threatening electrolyte disorder can be accompanied with cardiac dysrhythmias, death, respiratory alterations including respiratory alkalosis, irritability, confusion, coma and death.

Treatments for hypophosphatemia include cardiac monitoring, oral and intravenous potassium phosphate, and the encouragement of high phosphorous foods like milk and eggs.


The normal level of chloride is from 97 to107 mEq/L.

Hyperchloremia, which is a chloride level greater than 107 mEq/L can adversely affect the oxygen transportation in the body. Hyperchloremia can occur as the result of dehydration, some medications, renal disease, diabetes, diarrhea, hyperparathyroidism, hyponatremia, and some medications such as supplemental hormones and some diuretics.

The client affected with hyperchloremia may be asymptomatic or symptomatic. Some of the signs and symptoms of hyperchloremia are similar to those signs and symptoms associated with hypernatremia, and they include extreme thirst, pitting edema, dehydration, diarrhea, vomiting, Kussmaul's breathing, dyspnea, tachypnea, hypertension, decreased cognition, and coma.

The treatments, in addition to identifying and treating an underlying disorder, include the cautious administration of fluids because too rapid rehydration efforts can lead to cerebral edema and other complications, the elimination of problematic medications, and the correction of any renal disease and hyperglycemia.

Hypochloremia, which is a low chloride level of less than 97 mEq/L, can occur as the result of vomiting, hypoventilation, cystic fibrosis, metabolic alkalosis, respiratory acidosis, high bicarbonate levels and hyponatremia.

The signs and symptoms of hypochloremia may include dehydration, hyponatremia, nausea, vomiting, muscular spasticity, tetany, respiratory depression, muscular weakness and/or muscular twitching, diaphoresis and a high temperature.

Treatments for this electrolyte imbalance can include the administration of chloride replacements, and, at times, the administration of hydrochloric acid and a carbonic anhydrase inhibitor like acetazolamide for an acute episode of hypochloremic alkalosis.

Fluids and Fluid Imbalances

Hypervolemia is an abnormal increase in the volume of fluid in the blood, particularly the blood plasma and hypovolemia is a deficit of bodily fluids.

Hypervolemia, which is often referred to as fluid overload, can occur as the result of increased sodium in the body which is hypernatremia, excessive fluid supplementation that cannot be managed effectively by the body, and other disorders and diseases such as hepatic failure, renal failure and heart failure.

The signs and symptoms of hypervolemia include hypertension, dyspnea, shortness of breath, adventitious breath sounds such as rales and crackles, abdominal ascites, bulging and distended jugular veins with pulsations, peripheral edema in hands, feet and/or ankles, tachycardia, and a bounding and strong pulse.

In addition to treating the underlying cause whenever possible other treatments for hypervolemia include fluid and sodium restrictions and diuretics.

Hypovolemia, on the other hand, is a deficit of bodily fluids. Hypovolemia can occur secondary to bleeding and hemorrhage, severe dehydration, vomiting, and diarrhea. This fluid deficit can lead to complications such as decreased cardiac output, hypovolemic shock, metabolic acidosis, multisystem failure, coma and death.

Again, in addition to the treatment of an underlying disorder, some of the interventions for hypovolemia can include intravenous rehydration with fluids such as lactated Ringers, the placement of the client in the Trendelenburg position, and the administration of plasma expanders, blood and blood products as indicated by the nature of the client's status and the severity of the hypovolemia.

Applying a Knowledge of Pathophysiology When Caring for the Client with Fluid and Electrolyte Imbalances

The pathological etiology, risk factors and the signs and symptoms related to fluid and electrolyte imbalances were fully discussed immediately above in the section entitled "Identifying the Signs and Symptoms of the Client's Fluid and/or Electrolyte Imbalances".

Managing the Care of the Client with a Fluid and Electrolyte Imbalance

The care and management of the client with fluid and electrolyte imbalances were also discussed in the section entitled "Identifying the Signs and Symptoms of the Client's Fluid and/or Electrolyte Imbalances" which is immediately above.

Evaluating the Client's Responses to Interventions to Correct Fluid and Electrolyte Imbalances

Nurses evaluate the client's responses to interventions that were used to correct fluid and electrolyte imbalances by comparing the client's baseline data, including diagnostic laboratory data and the client's signs and symptoms, to the outcome data after treatments and interventions. For example, pretreatment and post treatment laboratory potassium levels or magnesium levels are compared to determine whether or not the client's electrolyte level is again normal and/or improving towards the achievement of the client's expected outcomes.


SEE – Physiological Adaptation Practice Test Questions

Alene Burke, RN, MSN
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