Chapter 16 Fluid Electrolyte and Acid Base Imbalances Flashcards
normal sodium ranges
135 to 145 mEq/L
normal BUN ranges
7-20 mg/dL
HCT normal levels
35-47% for women and 39-50% for men
Many diseases and their treatments affect fluid and electrolyte balance. For example, a patient with metastatic colon cancer may develop?
hypercalcemia because of bone destruction from tumor invasion.
Chemotherapy used to treat the cancer may result in nausea and vomiting and, subsequently?
dehydration and acid-base imbalances
When correcting dehydration with IV fluids, the patient requires?
close monitoring to prevent fluid overload.
The body is composed primarily of water. It accounts for about _______ of body weight in the adult.
50% to 60%
Water content varies with?
body mass, gender, and age
Lean body mass has a higher percentage of?
water, while adipose tissue has a lesser percentage of water.
water content in women
Women generally have a lower percentage of body water because they tend to have less lean body mass than men
Water content in older adults
Older adults also tend to have less lean body mass, resulting in a lower percentage of body water when compared to younger adults. In older adults, body water content 271averages 45% to 50% of body weight. This places them at a higher risk for fluid-related problems than young adults.
The two fluid compartments in the body are the?
intracellular space (inside the cells) and the extracellular space (outside the cells)
About two thirds of the body water is located?
within cells and is termed intracellular fluid (ICF). ICF makes up about 40% of body weight of an adult.
The two main compartments containing ECF are the?
interstitial fluid, or the fluid in the spaces between cells, and the intravascular fluid or plasma, the liquid part of blood. Other ECF compartments include lymph and transcellular fluids.
Electrolytes are substances whose?
molecules dissociate, or split, into ions when placed in water. Ions are electrically charged particles.
Cations are?
positively charged ions. Examples include sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+) ions
Anions are?
negatively charged ions. Examples include bicarbonate (HCO3−), chloride (Cl−), and phosphate (PO43−) ions. Most proteins bear a negative charge and are thus anions.
Electrolyte composition varies between ECF and ICF. The overall concentration of electrolytes is nearly the same in the two compartments. However, concentrations of specific ions differ greatly.
1) In ECF
2) In ICF
1) ECF the main cation is sodium, with small amounts of potassium, calcium, and magnesium. The primary ECF anion is chloride, with small amounts of bicarbonate, sulfate, and phosphate anions.
2) ICF the most prevalent cation is potassium, with small amounts of magnesium and sodium. The prevalent ICF anion is phosphate, with some protein and a small amount of bicarbonate. See Table 16-1 for normal serum electrolyte values.
Bicarbonate (HCO3−) Levels
22-26 mEq/L (22-26 mmol/L)
Chloride (Cl−) Levels
96-106 mEq/L (96-106 mmol/L)
Phosphate (PO43−) Levels
2.4-4.4 mg/dL (0.78-1.42 mmol/L)
Potassium (K+) Levels
3.5-5.0 mEq/L (3.5-5.0 mmol/L)
Magnesium (Mg2+) Levels
1.5-2.5 mEq/L (0.75-1.25 mmol/L)
Sodium (Na+) Levels
135-145 mEq/L (135-145 mmol/L)
Calcium (Ca2+) (total) Levels
8.6-10.2 mg/dL (2.15-2.55 mmol/L)
Calcium (ionized) Levels
4.6-5.3 mg/dL (1.16-1.32 mmol/L)
The movement of electrolytes and water between ICF and ECF to maintain homeostasis involves many different processes, including simple diffusion, facilitated diffusion, and active transport. Water moves as driven by two forces:
hydrostatic pressure and osmotic pressure.
Diffusion is the movement of molecules from?
an area of high concentration to low concentration. Net movement of molecules stops when the concentrations are equal in both areas. It occurs in liquids, gases, and solids. Simple diffusion requires no external energy.
Facilitated diffusion involves the use of a protein carrier in the cell membrane. The protein carrier combines with a molecule, especially one too large to pass easily through the cell membrane, and assists in moving the molecule across the membrane from?
an area of high to low concentration. Like simple diffusion, facilitated diffusion is passive and requires no energy. An example of facilitated diffusion is glucose transport into the cell. The large glucose molecule must combine with a carrier molecule to be able to cross the cell membrane and enter most cells.
Active transport is a process in which molecules move?
Against the concentration gradient. External energy is required for this process. An example is the sodium-potassium pump. The concentrations of sodium and potassium differ greatly intracellularly and extracellularly. To maintain this concentration difference, the cell uses active transport to move sodium out of the cell and potassium into the cell. The energy source for this movement is adenosine triphosphate (ATP), which is made in the cell’s mitochondria.
Osmosis is the movement of water “down” a concentration gradient, that is, from a region of?
low solute concentration to one of high solute
- requires no outside energy sources
- stops when concentration differences disappear or when hydrostatic pressure builds and opposes any further movement of water
- Imagine a chamber with two compartments separated by a semipermeable membrane, one that allows only the movement of water. If you add albumin to one side, water will move from the less concentrated side (has more water) to the more concentrated side of the chamber water (has less water) until the concentrations are equal.
Whenever dissolved substances are contained in a space with a semipermeable membrane, they can pull water into the space by osmosis. The concentration of the solution determines the strength of the osmotic pull. The higher the concentration, the?
greater a solution’s pull, or osmotic pressure
Osmotic pressure
- Amount of pressure required to stop osmotic flow of water
* Determined by concentration of solutes in solution
Fluid tonicity
Isotonic, hypotonic, hypertonic
The osmolality of the fluid surrounding cells affects them. Fluids with the same osmolality as the cell interior are termed?
isotonic. Normally, ECF and ICF are isotonic to one another, so no net movement of water occurs.
Changes in the osmolality of ECF alter the volume of cells. Solutions in which the solutes are less concentrated than in the cells are termed?
hypotonic (hypoosmolar). If a cell is surrounded by hypotonic fluid, water moves into the cell, causing it to swell and possibly to burst.
Fluids with solutes more concentrated than in cells, or an increased osmolality, are termed?
hypertonic (hyperosmolar). If hypertonic fluid surrounds a cell, water leaves the cell to dilute ECF; the cell shrinks and may eventually die
Hydrostatic pressure is the?
force of fluid in a compartment pushing against a cell membrane or vessel wall. In the blood vessels, hydrostatic pressure is the BP generated by the contraction of the heart. Hydrostatic pressure in the vascular system gradually decreases as the blood moves through the arteries until it is about 30 mm Hg in the capillary bed. At the capillary level, hydrostatic pressure is the major force that pushes water out of the vascular system and into the interstitial space.
Oncotic pressure (colloidal osmotic pressure) is the osmotic pressure caused by plasma colloids in solution. The major colloids in the vascular system contributing to osmotic pressure are proteins, such as albumin. Plasma has?
substantial amounts of protein, while the interstitial space has very little. The plasma protein molecules attract water, pulling fluid from the tissue space to the vascular space. Under normal conditions, plasma oncotic pressure is about 25 mm Hg. The small amount of protein found in the interstitial space exerts an oncotic pressure of about 1 mm Hg
Osmotic pressure caused by plasma proteins
Oncotic pressure
Blood pressure generated by heart contraction
Hydrostatic pressure
As plasma flows through the capillary bed, four factors determine if fluid moves out of the capillary and into the interstitial space or if fluid moves back into the capillary from the interstitial space. The amount and direction of movement are determined by the interaction of
(1) capillary hydrostatic pressure
(2) plasma oncotic pressure
(3) interstitial hydrostatic pressure
(4) interstitial oncotic pressure
Capillary hydrostatic pressure and interstitial oncotic pressure move water?
out of the capillaries
Plasma oncotic pressure and interstitial hydrostatic pressure move fluid?
into the capillaries
At the arterial end of the capillary?
At the venous end of the capillary?
- At the arterial end of the capillary, capillary hydrostatic pressure exceeds plasma oncotic pressure, and fluid moves into the interstitial space
- At the venous end of the capillary, the capillary hydrostatic pressure is lower than plasma oncotic pressure, drawing fluid back into the capillary by the oncotic pressure created by plasma proteins
Fluid Shifts
If capillary or interstitial pressures change, fluid may?
abnormally shift from one compartment to another, resulting in edema or dehydration.
Shifts of Plasma to Interstitial Fluid.
Edema, an accumulation of fluid in the interstitial space, occurs if?
venous hydrostatic pressure rises, plasma oncotic pressure decreases, or interstitial oncotic pressure rises. Edema may also develop if an obstruction of lymphatic outflow causes decreased removal of interstitial fluid.
Elevation of Venous Hydrostatic Pressure.
Increasing the pressure at the venous end of the capillary inhibits fluid movement back into the capillary, which results in edema. Causes of increased venous pressure include?
fluid overload, heart failure, liver failure, obstruction of venous return to the heart (e.g., tourniquets, restrictive clothing, venous thrombosis), and venous insufficiency (e.g., varicose veins)
Decrease in Plasma Oncotic Pressure.
Fluid remains in the interstitial space if the plasma oncotic pressure is too low to draw fluid back into the capillary. Low plasma protein content decreases oncotic pressure. This can result from?
excessive protein loss (renal disorders), deficient protein synthesis (liver disease), and deficient protein intake (malnutrition).
Plasma-to-interstitial fluid shift results in edema
Interstitial fluid to plasma decreases edema
.
Elevation of Interstitial Oncotic Pressure.
Trauma, burns, and inflammation can damage capillary walls and allow plasma proteins to accumulate in the interstitial space. This?
increases interstitial oncotic pressure, draws fluid into the interstitial space, and holds it there.
Shifts of Interstitial Fluid to Plasma.
An increase in the plasma osmotic or oncotic pressure draws fluid into the plasma from the interstitial space. This could happen with administration of?
colloids, dextran, mannitol, or hypertonic solutions. Increasing the tissue hydrostatic pressure is another way of causing a shift of fluid into plasma. Wearing elastic compression gradient stockings or hose to decrease peripheral edema is a therapeutic application of this effect.
Fluid spacing is a term used to describe the distribution of body water.
1) First spacing describes?
2) Second spacing refers to an?
3) Third spacing occurs when?
1) First spacing describes the normal distribution of fluid in ICF and ECF compartments.
2) Second spacing refers to an abnormal accumulation of interstitial fluid (i.e., edema).
3) Third spacing occurs when excess fluid collects in the nonfunctional area between cells. This fluid is trapped where it is difficult or impossible for it to move back into the cells or blood vessels. Third spacing occurs with ascites; fluid leaking into the abdominal cavity with peritonitis or pancreatitis; and edema associated with burns, trauma, or sepsis.
Normal distribution
First spacing
Abnormal (edema)
Second spacing
Fluid accumulation in part of body where it is not easily exchanged with ECF
Third spacing
A number of factors are involved in maintaining the finely tuned balance among water intake, use, and excretion. For proper fluid balance, an average healthy adult requires a daily water intake between?
2000 and 3000 mL
This amount replaces what is lost from the body in urinary output and insensible losses. Oral fluid intake accounts for most of the water intake. Water intake also includes water from food metabolism and water present in solid foods.
Normal fluid balance in adults Intake Fluids Solid food Water from oxidation Total Output Insensible loss (skin and lungs) In feces Urine Total
Intake Fluids 1200 mL Solid food 1000 mL Water from oxidation 300 mL Total 2500 mL Output Insensible loss (skin and lungs) 900 mL In feces 100 mL Urine 1500 mL Total 2500 mL
Insensible water loss, which is invisible vaporization from the lungs and skin, assists in regulating body temperature. Accelerated body metabolism, which occurs with increased body temperature and exercise, increases the amount of water lost and may result in the need for additional water replacement.
Do not confuse water loss through the skin with the vaporization of water excreted by sweat glands. Insensible perspiration causes only water loss. Excessive sweating (sensible perspiration) caused by exercise, fever, or high environmental temperatures may lead to?
large losses of water and electrolytes.
Hypothalamic-pituitary regulation
- Osmoreceptors in hypothalamus sense fluid deficit or increase
- Deficit stimulates thirst and antidiuretic hormone (ADH) release
- Decreased plasma osmolality (water excess) suppresses ADH release
The primary function of the kidneys is to regulate?
fluid and electrolyte balance by adjusting urine volume and the excretion of most electrolytes
Regulation of water balance: Renal regulation
- Primary organs for regulating fluid and electrolyte balance
- Adjusting urine volume
- Selective reabsorption of water and electrolytes
- Renal tubules are sites of action of ADH and aldosterone
Regulation of water balance: Adrenal Cortical Regulation
Glucocorticoids and mineralocorticoids secreted by the adrenal cortex help regulate water and electrolyte balance.
- The glucocorticoids (e.g., cortisol) primarily have what effect ?
- the mineralocorticoids (e.g., aldosterone) enhance?
- The glucocorticoids (e.g., cortisol) primarily have an antiinflammatory effect and increase serum glucose levels
- the mineralocorticoids (e.g., aldosterone) enhance sodium retention and potassium excretion. When sodium is reabsorbed, water follows because of osmotic changes.
Aldosterone is a mineralocorticoid with strong sodium-retaining and potassium-excreting capabilities. Decreased renal perfusion or decreased sodium in the distal portion of the renal tubule activates the renin-angiotensin-aldosterone system (RAAS), resulting in aldosterone secretion. In addition to the RAAS, increased serum potassium, decreased serum sodium, and adrenocorticotropic hormone (ACTH) stimulate aldosterone secretion. Aldosterone increases?
sodium and water reabsorption in the renal distal tubules, decreasing plasma osmolality and restoring fluid volume.
Cortisol is the most abundant glucocorticoid. In large doses, cortisol has both?
glucocorticoid (glucose-elevating and antiinflammatory) and mineralocorticoid (sodium-retention) effects. Normally cortisol secretion is in a diurnal or circadian pattern. Increased cortisol secretion occurs in response to physical and psychologic stress. This affects many body functions, including fluid and electrolyte balance
Adrenal cortical regulation main points
- Releases hormones to regulate water and electrolytes
1) Glucocorticoids
Cortisol
2) Mineralocorticoids
Aldosterone
Gastrointestinal Regulation
In addition to oral intake, the GI tract normally secretes around ____ mL of digestive fluids each day. The GI tract normally reabsorbs most of this fluid, with only a small amount eliminated in feces. This is why diarrhea and vomiting, which prevent GI reabsorption of?
8000 mL
prevent GI reabsorption of secreted fluid, can lead to significant fluid and electrolyte loss.
Gastrointestinal regulation main points
- Oral intake accounts for most water
- Small amounts of water are eliminated by gastrointestinal tract in feces
- Diarrhea and vomiting can lead to significant fluid and electrolyte loss
Insensible water loss main points
- Invisible vaporization from lungs and skin
- Loss of approximately 600 to 900 mL/day
- No electrolyte loss
Two possible reasons for fluid and electrolyte imbalance
1) Directly caused by illness or disease (burns or heart failure)
2) Result of therapeutic measures (IV fluid replacement or diuretics)
Perioperative patients are at risk for developing fluid and electrolyte imbalances because of?
fluid restrictions, blood or fluid loss, and the stress of surgery
ECF volume deficit (hypovolemia) and ECF volume excess (hypervolemia) are common clinical conditions. ECF volume imbalances are usually accompanied by one or more electrolyte imbalances, particularly changes in the?
serum sodium level
ECF Volume Deficit
Causes
- ↑ Insensible water loss or perspiration (high fever, heatstroke)
- Diabetes insipidus
- Osmotic diuresis
- Hemorrhage
- GI losses: vomiting, NG suction, diarrhea, fistula drainage
- Overuse of diuretics
- Inadequate fluid intake
- Third-space fluid shifts: burns, pancreatitis
ECF volume Deficit Manifestations
- Restlessness, drowsiness, lethargy, confusion
- Thirst, dry mucous membranes
- Cold clammy skin
- Decreased skin turgor, ↓ capillary refill
- Postural hypotension, ↑ pulse, ↓ CVP
- ↓ Urine output, concentrated urine
- ↑ Respiratory rate
- Weakness, dizziness
- Weight loss
- Seizures, coma
ECF Volume Excess Causes
- Excessive isotonic or hypotonic IV fluids
- Heart failure
- Renal failure
- Primary polydipsia
- SIADH
- Cushing syndrome
- Long-term use of corticosteroids
ECF Volume Excess Manifestations
- Headache, confusion, lethargy
- Peripheral edema
- Jugular venous distention
- S3 heart sound
- Bounding pulse, ↑ BP, ↑ CVP
- Polyuria (with normal renal function)
- Dyspnea, crackles, pulmonary edema
- Muscle spasms
- Weight gain
- Seizures, coma
ECF volume deficit (hypovolemia)
- Abnormal loss of?
- Clinical manifestations?
- Treatment?
- Abnormal loss of normal body fluids, inadequate intake, or plasma-to-interstitial fluid shift
- Clinical manifestations related to loss of vascular volume as well as CNS effects
- Treatment: Replace water and electrolytes with balanced IV solutions
Fluid Volume Deficeit Interprofessional Care
- Managing fluid volume deficit involves correcting the underlying cause and replacing both water and any needed electrolytes.
- Replacement therapy depends on the severity and type of volume loss. In mild losses, oral rehydration may be used. If the deficit is more severe, volume is replaced with blood products or balanced IV solutions, such as isotonic (0.9%) sodium chloride or lactated Ringer’s solution. The choice of fluid depends on the cause and patient’s electrolyte status. For rapid volume replacement, 0.9% sodium chloride is preferred. Blood is administered when volume loss is due to blood loss.
Fluid volume excess may result from?
- excess intake of fluids, abnormal retention of fluids (e.g., heart failure, renal failure), or a shift of fluid from interstitial fluid into plasma fluid. Weight gain is the most consistent manifestation of fluid volume excess.
Fluid volume excess may result from excess intake of?
Fluids, abnormal retention of fluids (e.g., heart failure, renal failure), or a shift of fluid from interstitial fluid into plasma fluid. Weight gain is the most consistent manifestation of fluid volume excess.
Fluid volume excess interprofessional care
Managing fluid volume excess involves treating the underlying cause and removing fluid without producing abnormal changes in the electrolyte composition or osmolality of ECF. Diuretics and fluid restriction are the primary forms of therapy. Some patients also need sodium restrictions. If the fluid excess leads to ascites or pleural effusion, an abdominal paracentesis or thoracentesis may be necessary.
Fluid volume excess (hypervolemia) main points
- Excessive intake of?
- Clinical manifestations related to?
- Treatment:
- Excessive intake of fluids, abnormal retention of fluids, or interstitial-to-plasma fluid shift
- Clinical manifestations related to excess volume
- Treatment: Remove fluid without changing electrolyte composition or osmolality of ECF
Nursing diagnosis for hypovolemia
- Deficient fluid volume
- Decreased cardiac output
- Risk for deficient fluid volume
- Potential complication: Hypovolemic shock
Nursing diagnosis for hypervolemia
- Excess fluid volume
- Impaired gas exchange
- Risk for impaired skin integrity
- Activity intolerance
- Disturbed body image
- Potential complications: Pulmonary edema, ascites
Nursing implementation
- Daily weights
- I&O
- Laboratory findings
- Cardiovascular care
- Respiratory care
- Patient safety
- Skin care
- Fluid therapy
Daily weights are the most accurate measure of volume status. An increase of 1 kg (2.2 lb) is equal to _______ of fluid retention, provided the person has maintained usual dietary intake or has not been on NPO status. Obtain the weight under standardized conditions. Weigh the patient at the same time every day, wearing the same garments and on the same carefully calibrated scale. Remove excess bedding and empty all drainage bags before the weighing. If items are present that are not there every day, such as bulky dressings or tubes, note this along with the weight.
1000 mL (1 L) of fluid retention
Intake and output records provide valuable information about fluid and electrolyte problems. An accurately recorded intake and output will identify sources of excessive intake or fluid losses.
1) Intake should include?
2) Estimate fluid loss from wounds and perspiration. Note the amount and color of the urine and measure the urine specific gravity. Readings greater than?
1) Intake should include oral, IV, and tube feedings and retained irrigants. Output includes urine, excess perspiration, wound or tube drainage, vomitus, and diarrhea.
2) Readings greater than 1.025 indicate concentrated urine, while readings less than 1.010 indicate dilute urine.
Laboratory Findings: Monitor laboratory results when available and calculate the serum osmolality. The patient with a fluid volume deficit often has increased?
- With fluid volume excess, the patient will have decreased?
- The patient with a fluid volume deficit often has increased BUN, sodium, and hematocrit levels with increased plasma and urine osmolality.
- With fluid volume excess, the patient will have decreased BUN, sodium, and hematocrit levels with decreased plasma and urine osmolality.
Cardiovascular Care
Monitor vital signs and perform a thorough cardiovascular assessment as needed. Changes in BP, central venous pressure, pulse force, and jugular venous distention reflect ECF volume imbalances.
- In fluid volume excess, the pulse is?
- In mild to moderate fluid volume deficit, sympathetic nervous system compensation increases the?
- pulse is full, bounding, and not easily obliterated. Increased volume causes distended neck veins (jugular venous distention), increased central venous pressure, and high BP. Auscultate heart sounds, being alert for the presence of an S3.
- heart rate and results in peripheral vasoconstriction in an effort to maintain BP within normal limits. Pulses may be weak and thready. Assess for orthostatic changes. A change in position from lying to sitting or standing may elicit a decrease in BP or a further increase in the heart rate (orthostatic hypotension). In more severe deficits, hypotension may be present.
Respiratory Care: What should the nurse monitor for?
- pulse oximetry and auscultate lung sounds as needed.
- ECF excess can result in pulmonary congestion and pulmonary edema, as increased hydrostatic pressure in the pulmonary vessels forces fluid into the alveoli. The patient will experience shortness of breath and moist crackles on auscultation.
- The patient with ECF deficit will demonstrate an increased respiratory rate because of decreased tissue perfusion and resultant hypoxia. Administer oxygen as ordered.
Skin Care
Examine the skin for turgor and mobility. Normally a fold of skin, when pinched, will readily move and, on release, rapidly return to its former position.
- In ECF volume deficit, skin turgor is?
Skin areas over the sternum, abdomen, and anterior forearm are the usual sites for evaluation of tissue turgor. In older people, decreased skin turgor is less predictive of fluid deficit because of the?
- skin turgor is diminished, and there is a lag in the
- tissue elasticity
Administer IV fluids as ordered. Carefully monitor the rates of infusion of IV fluid solutions, especially when large volumes of fluid are being given. This is especially true in patients with?
cardiac, renal, or neurologic problems.
Sodium, the main cation of ECF, plays a major role in maintaining the concentration and volume of ECF and influencing water distribution between ECF and ICF. Sodium has an important role in the generation and transmission of?
nerve impulses, muscle contractility, and regulation of acid-base balance
The serum sodium level reflects the ratio of sodium to water, not necessarily the amount of sodium in the body. Changes in the serum sodium level can reflect a primary water imbalance, primary sodium imbalance, or combination of the two. Sodium imbalances are typically associated with imbalances in ECF volume. Because sodium is the primary determinant of ECF osmolality, sodium imbalances are typically associated with?
parallel changes in osmolality.
Sodium main points
- Imbalances typically associated with parallel changes in osmolality
- Plays a major role in
1) ECF volume and concentration
2) Generation and transmission of nerve impulses
3) Muscle contractility
4) Acid-base balance
The GI tract absorbs sodium from foods. Typically, daily intake of sodium far exceeds the body’s daily requirements. Sodium leaves the body through urine, sweat, and feces. The kidneys primarily regulate sodium balance. The kidneys control ECF sodium concentration by?
excreting or retaining water under the influence of ADH. Aldosterone plays a smaller role in sodium regulation by promoting sodium reabsorption from the renal tubules.
Hypernatremia (elevated serum sodium) may occur with inadequate water intake, excess water loss or, rarely, sodium gain. Because sodium is the major determinant of ECF osmolality, hypernatremia causes hyperosmolality. ECF hyperosmolality causes water to move out of the cells to restore equilibrium, leading to cellular dehydration. As discussed earlier, the primary protection against the development of hyperosmolality is thirst. Hypernatremia is not a problem in an alert person who has access to water, can sense thirst, and is able to swallow. Hypernatremia secondary to water deficiency is often the result of an?
impaired level of consciousness or an inability to obtain fluids
Hypernatremia: Several clinical states can produce hypernatremia from water loss. A deficiency in the synthesis or release of ADH from the posterior pituitary gland (central diabetes insipidus) or a decrease in kidney responsiveness to ADH (nephrogenic diabetes insipidus) can result in profound diuresis, producing a water deficit and hypernatremia. Hyperosmolality with osmotic diuresis can result from?
hyperglycemia associated with uncontrolled diabetes mellitus or administering concentrated hyperosmolar tube feedings
Hypernatremia: Excess sodium intake with inadequate water intake can also lead to hypernatremia. Examples of sodium gain include?
IV administration of hypertonic saline or sodium bicarbonate, use of sodium-containing drugs, excessive oral intake of sodium (e.g., ingestion of seawater), and primary aldosteronism (hypersecretion of aldosterone) caused by a tumor of the adrenal glands.
Clinical Manifestations
The manifestations of hypernatremia are primarily the result of water shifting out of cells into ECF with resultant?
dehydration and shrinkage of cells. Dehydration of brain cells results in alterations in mental status, ranging from agitation, restlessness, confusion, and lethargy to coma. If there is any accompanying ECF volume deficit, manifestations such as postural hypotension, tachycardia, and weakness occur.
