F&E / Homeostasis

Med Surg I

Sodium Value Range

135-145

Hypernatremia

• over 145

• inadequate water intake or excess water loss/Na gain

• causes hyperosmolality leading to dehydration

• primary protection is thirst from hypothalamus

Hypernatremia Manifestations

• thirst

• alterations in mental status, ranging from agitation, restlessness, confusion, and lethargy to seizures and coma

• symptoms of fluid volume deficit

Management of Hypernatremia

• treat underlying cause

• primary water deficit - replace fluid orally or IV w/ isotonic or hypotonic fluids

• excess sodium - dilute w/ sodium free IV fluids and promote excretion w/ diuretics

Hyponatremia

• under 135

• results from loss of sodium-containing fluids and/or from water excess

• perfuse sweating/draining wounds, excessive diarrhea/vomiting

• pt. secretes too much ADH —> SIADH (fluid volume excess)

Hyponatremia Manifestations

• mild - headache, irritability, difficulty concentrating

• more severe - confusion, vomiting, seizures, coma (NS changes)

Management of Hyponatremia (cause is water excess)

• fluid restriction is needed

• loop diuretics (depending; don’t want to push too much out)

• severe symptoms (seizures) - give small amount of IV hypertonic saline solution (3% NaCl)

• watch labs!!

Management of Hyponatremia (cause is abnormal fluid loss)

• fluid replacement w/ sodium-containing solution

• increase oral intake

• withholding diuretics

• drugs that block vasopressin (ADH) - Convaptan (Vaprisol); Tolvaptan (Samsca)

Potassium

• 3.5-5

• major ICF cation

• transmission and conduction of nerve and muscle impulse

• cellular growth

• maintenance of cardiac rhythms

• acid-base balance

• regulated by kidneys heavily

sources for potassium

• fruits and veggies

• salt substitues

• potassium meds (PO, IV)

Hyperkalemia

caused by:

• impaired renal excretion

• shift from ICF to ECF

• massive intake

most common in renal failure

Hyperkalemia Manifestations

• cardiac dysrhythmias (get EKG, telemetry for continuous monitoring)

• cramping leg pain

• weak/paralyzed skeletal muscles

• abdominal cramping and diarrhea

Implementation for Hyperkalemia

• eliminate oral and parenteral K intake

• increase elimination (diuretics, dialysis, Kayexalate)

• force K from ECF to ICF by IV insulin and B-adrenergic agonist or sodium bicarbonate

• reverse membrane effects of elevated ECF K by administering calcium gluconate IV (give insulin if high BP or beta blockers)

Hypokalemia

Caused by

• increased loss of K+ via kidneys or GI tract

• increased shift of K+ from E

• dietary K+ deficiency (rare)

Hypokalemia Manifestations

• CARDIAC

• skeletal muscle weakness (legs)

• weakness of respiratory muscles (shallow respirations)

• decreased GI motility (pariotic ilias - everything stops flowing through GI tract)

• hyperglycemia

Implementation for Hypokalemia

• KCl supplements orally or IV

• always dilute IV KCl

• NEVER give KCl via push or as a bolus (use secondary/piggyback)

• should not exceed 10mEq/hr (slow rate b/c very concentrated)

• use an infusion pump

Calcium Functions

• 8.5-10.5

• formation of teeth and bone

• blood clotting

• transmission of nerve impulses

• myocardial contractions

• muscle contractions

Calcium Info Cont.

• obtained from ingested food

• need Vit. D to absorb (diet/skin)

• present in 3 forms: ionized __ is biologically active

• changes in pH and serum albumin affect levels

• balance controlled by: parathyroid hormone (increase bone reabsorption), calcitonin (thyroid gland, stimulated by high serum __ levels, opposes action of PTH and lowers level of serum by decreasing GH GI absorption and increase __ deposition in bone and promoting renal excretion)

Hypercalcemia

Caused by

• hyperparathyroidism (2/3 of cases)

• malignancy (cancer— blood and bone destruction from tumor, extra __ circulating throughout body)

Implementation for Hypercalcemia

• excretion w/ loop diuretic

• hydration w/ isotonic saline infusion

• low __ diet

• mobilization

• biphosphonates (decrease bone loss and shedding off)

• IM or SC calcitonin (aids in __ excretion)

Hypocalcemia

Caused by

• decreased production of PTH (gland impaired due to surgery)

• multiple blood transfusions

• alkalosis (kidney failure, liver issues)

Hypocalcemia Manifestations

• positive Trousseau’s or Chvostek’s sign

• laryngeal stridor (inability to move air—thyroid surgery)—tetany before

• dysphagia

• tingling around mouth or in extremities

• cardiac dysrhythmias (prolonged QT interval)

Implementation for Hypocalcemia

• treat cause

• oral or IV supplements (no loop diuretics)

• treat pain and anxiety to prevent hyperventilation-induced respiratory alkalosis

Phosphate

• 3-4.5

• bones and teeth

• essential function of muscle, RBCs, and NS

• involved in acid-base buffering system, ATP production, cellular uptake of glucose, and metabolism of carbohydrates, proteins, and fats

• inverse relationship with Calcium

Hyperphosphatemia

Caused by

• acute kidney injury or chronic kidney disease

• chemotherapy

• excess intake of phosphate or Vit. D

• hypoparathyroidism

Manifestations of hyperphosphatemia

• neuromuscular irritability and tetany (hypocalcemia)

• calcified deposition in soft tissue such as joints, arteries, skin, kidneys, and corneas (can cause organ dysfunction)

Management of hyperphosphatemia

• identify and treat underlying cause

• restrict foods and fluids containing phosphorus

• oral phosphate-binding agents (Ca carbonate)

• volume expansion and forced diuresis

• correct any hypocalcemia

• hemodialysis

Hypophosphatemia

Caused by

• malnourishment/malabsorption

• diarrhea

• use of phosphate-binding antacids

• inadequate replacement during parental nutrition

Manifestations of hypophosphatemia

• CNS depression (acute)

• muscle weakness (acute)

• respiratory and heart failure

• rickets and osteomalacia - GI conditons (chronic)

Management Hypophosphatemia

• oral supplementation

• ingestion of foods high in phosphorus (dairy)

• IV administration of sodium or potassium

Magnesium

• 1.3-2.3

• coenzyme in metabolism of carbohydrates

• required for DNA and protein synthesis

• blood glucose control

• BP regulation

• necessary for ATP production

Magnesium cont.

• acts directly on myoneural junction

• important for normal cardiac function

• 50-60% contained in bone

• absorbed in GI tract

• excreted kidneys

hypermagnesia

caused by

• increased intake or ingestion of products containing magnesium when renal insufficiency or failure to present

• excess IV Mg admin.

Hypermagnesia Manifestations

• lethargy

• N/V

• impaired reflexes (deep tendon reflexes lost)

• muscle paralysis

• respiratory and cardiac arrest

• hypotensive

Hypermagnesia Management

• prevention first - restrict Mg intake in high-risk patients

• IV CaCl or calcium gluconate if symptomatic

• fluids and IV furosemide to promote excretion

• dialysis

Hypomagnesia

• prolonged fasting or starvation

• chronic alcoholism

• fluid loss from GI tract

• prolonged parenteral nutrition w/o supplementation

• diuretics

• hyperglycemic osmotic diuresis

• increased renal loss, uncontrolled diabetes

Hypomagnesia Manifestations

• hyperactive deep tendon reflexes

• muscle cramps

• tremors

• seizures

• cardiac dysrhythmias

• corresponding hypocalcemia and hypokalemia

Hypomagnesia Management

• treat underlying cause

• oral supplements

• increase dietary intake

• parenteral IV or IM magnesium when severe