electrolytes

Sodium

• 135-145 mEq/L

• ECF (most abundant)

• controls and regulates volume of body fluid

Potassium

• 3.5-5.0 mEq/L

• ICF (most abundant)

• chief regulator of cellular enzyme activity and water content

• Role in the transmission of electrical impulses in nerve, heart, skeletal, intestinal, and lung tissue

Calcium

• 4.5-5.5 mEq/L

• ECF

• nerve impulses, clotting, muscle contraction, B12 absorption

• major component of teeth and bones

Magnesium

• 1.5-2.5 mEq/L

• ICF (second most abundant)

• metabolism of carbohydrates and protein and vital action involving enzymes

• Role in neuromuscular function

• Acts on cardiovascular system, producing vasodilation

Chloride

• 90-110 mEq/L

• ECF

• maintains osmotic pressure in blood

• produces hydrochloric acid

Bicarbonate

• primary buffer system

• arterial=22-26

• venous=24-30

• ICF and ECF

phosphate

• 2.5-4.5 mg/dL

• ICF

• involved in important chemical reactions in the body, cell division, and hereditary traits

• Promotes energy storage; carbohydrate, protein, and fat metabolism

• Bone and teeth formation

• Role in muscle and red blood cell function

hyponatremia

• Sodium deficit in ECF (serum sodium <135 mEq/L) caused by a loss of sodium or a gain of water. Sodium may be lost through vomiting, diarrhea, fistulas, sweating, or as the result of the use of diuretics.

• The decrease in sodium causes fluid to move by osmosis from the less concentrated ECF compartment to the ICF space. This shift of fluid leads to swelling of the cells, with resulting confusion, hypotension, edema, muscle cramps and weakness, and dry skin.

• Severe cases (serum sodium <120 mEq/L) is manifested by signs of increasing intracranial pressure, which may include lethargy, muscle twitching, hyperreflexia, coma, and seizures; death may occur

hypernatremia

• Refers to a surplus of sodium in ECF (serum sodium >145 mEq/L) caused by excess water loss or an overall excess of sodium.

• Fluid deprivation, lack of fluid consumption, diarrhea, and excess insensible water loss (hyperventilation, burns) lead to excess sodium.

• Fluids move from the cells because of the increased extracellular osmotic pressure, causing them to shrink and leaving them without sufficient fluid.

• The cells of the central nervous system are especially affected, resulting in signs of neurologic impairment, including restlessness, agitation, weakness, disorientation, delusions, hallucinations, and seizures.

hypokalemia

• Refers to a potassium deficit in ECF (serum potassium <3.5 mEq/L) and is a common electrolyte abnormality.

• Potassium may be lost through vomiting, gastric suction, alkalosis, or diarrhea, or as the result of the use of diuretics. When the extracellular potassium level falls, potassium moves from the cell, creating an intracellular potassium deficiency.

• Typical signs of hypokalemia include muscle weakness and leg cramps, fatigue, paresthesias, and dysrhythmias

hyperkalemia

• Refers to an excess of potassium in ECF (serum potassium >5 mEq/L). Excess potassium may result from renal failure, hypoaldosteronism, or the use of certain medications such as potassium chloride, heparin, angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal antiinflammatory drugs (NSAIDs), and potassium-sparing diuretics

• s/s: skeletal muscle weakness, paresthesia, paralysis, and cardiac arrest

hypocalcemia 

• Refers to a calcium deficit in ECF (<4.5 mg/dL).

• Common causes related to a calcium deficit involve inadequate calcium intake, impaired calcium absorption, and excessive calcium loss.

• Manifestations include numbness and tingling of fingers, mouth, or feet; tetany; muscle cramps; and seizures.

hypercalcemia

• Refers to an excess of calcium in ECF. Two major causes are cancer and hyperparathyroidism.

• Manifestations include nausea, vomiting, constipation, bone pain, excessive urination, thirst, confusion, lethargy, and slurred speech.

• Severe is an emergency situation (>15)

hypomagnesemia

• Refers to a magnesium deficit in the ECF (serum magnesium <1.3 mEq/L). Magnesium loss may occur with nasogastric suction, diarrhea, chronic alcohol use, administration of tube feedings or parenteral nutrition, sepsis, or burns.

• This abnormality may lead to muscle weakness, tremors, tetany, seizures, cardiac arrhythmias, change in mental status, hyperactive deep tendon reflexes (DTRs), and respiratory paralysis.

hypermagnesemia

• Refers to a magnesium excess in the ECF (serum magnesium >2.5 mEq/L). It usually occurs with renal failure when the kidneys fail to excrete magnesium or from excessive magnesium intake (use of magnesium-containing antacids or laxatives)

• Clinical manifestations include nausea, vomiting, weakness, flushing, lethargy, hypoactive DTRs, respiratory depression, coma, and cardiac arrest

Hypophosphatemia

• Refers to a below-normal concentration of phosphorus in the ECF. Although this may indicate phosphorus deficiency, multiple factors may lower serum phosphate levels while total body phosphorus stores are normal.

• Can result from administration of calories to malnourished patients, alcohol withdrawal, diabetic ketoacidosis, hyperventilation, absorption problems, and diuretic use.

• Manifestations include muscle weakness, slurred speech, dysphagia, decreased respiratory effort, paresthesias, irritability, confusion, seizures, and coma

Hyperphosphatemia

• Refers to above-normal concentrations of phosphorus in the ECF (serum phosphate >4.5 mg/dL or 2.6 mEq/L). Common causes are impaired kidney excretion and hypoparathyroidism.

• Can result in hyperreflexia, anorexia, muscle weakness, decreased mental status, and dysrhythmias

Hypochloremia

• Refers to below-normal level of chloride in the ECF (serum chloride <98 mEq/L).

• A low level of chloride can result from severe vomiting and diarrhea, drainage of gastric fluid (GI tube), metabolic alkalosis, diuretic therapy, and burns.

• Manifestations include hyperexcitability of muscles, tetany, hyperactive DTRs, weakness, and muscle cramps; severe hypochloremia may result in seizures, coma or respiratory arrest

Hyperchloremia

• Refers to an above-normal level of chloride in the ECF (serum chloride >108 mEq/L).

• Can result from metabolic acidosis, hypernatremia, increased chloride retention by the kidneys, and hyperparathyroidism.

• Signs and symptoms include tachypnea, weakness, lethargy, diminished cognitive ability, decreased cardiac output, dysrhythmias, and coma.

hypervolemia

excessive retention of water and sodium in ECF

hypovolemia 

• deficiency in the amount of water and electrolytes in ECF

• thirst, dry mucous membranes, decreased urine output, rapid heart rate (tachycardia), and dizziness or lightheadedness, especially when standing up (orthostatic hypotension)

water deficit/fluid volume deficit

• water moves out of cells to interstitial and intravascular spaces—cells shrink and die

• Occurs when loss of ECF volume exceeds the intake of fluid

• Involves a loss of both water and solutes in the same proportion from the ECF space. This state is known as Hypovolemia or isotonic fluid loss

water excess/fluid volume overload

• water moves into cells—cells swell and burst

• Excessive retention of water and sodium in ECF in near-equal proportions results in…

• may be a result of fluid overload (excess water and sodium intake) or due to impairment of the mechanisms that maintain homeostasis

• Common causes include malfunction of the kidneys, causing an inability to excrete the excesses, and failure of the heart to function as a pump, resulting in accumulation of fluid in the lungs and dependent parts of the body.

• The excessive ECF may accumulate in either the intravascular compartments (Hypervolemia) or interstitial spaces (Edema)

third space fluid shift

Refers to a distributional shift of body fluids into the transcellular compartment, such as the pleural, peritoneal (ascites), or pericardial areas; joint cavities; the bowel; or an excess accumulation of fluid in the interstitial space. The fluid moves out of the intravascular spaces (plasma) to any of these spaces.