Week 5- Electrolytes Flashcards
1
Q
What are the electrolytes?
A
- Calcium
- Sodium
- Potassium
2
Q
Calcium
A
- Extracellular cation (Ca++)
- Comes in food, supplements, stored in bones and excreted in urine and feces
- Balance is controlled by:
- PTH (Parathyroid Hormone) and calcitonin
- Influenced by vitamin D and phosphate levels
3
Q
What is the role of calcium?
A
- Structural strength for bones & teeth
- Stability of the nerve membrane- controls the permeability and excitability needed for nerve conduction
- Muscle contractions
- Metabolic processes and enzyme reactions like blood clotting
4
Q
What are the causes of hypocalcemia?
A
- Hypoparathyroidism (decreased parathyroid hormone secretion
- Malabsorption
- Renal failure (retention of phosphates- loss of calcium) (Vitamin D is not activated)
5
Q
What happens with hypocalcemia pt’s?
A
- Increases the permeability and excitability of the nerve membranes- spontaneous stimulation of the skeletal muscles (muscle twitching, carpopedal spasms)
- Severe: laryngospasms & airway obstruction
- Heart: contractions are weak, conduction delayed, arrhythmia develop, cardiac output drops
6
Q
What is the difference between heart and skeletal muscles?
A
- Skeletal muscle: Increased irritability of the nerve that control muscle fibers, calcium is stored in the muscle to provide for the contractions
- Cardiac: There are no nerves, Contraction is directly affected by calcium levels only available through calcium channels
7
Q
What causes hypercalcemia?
A
- Cancer
- Neoplasms (uncontrolled release of calcium)
- Hyperparathyroidism (increased PTH secretion)
- Immobility- disease stress on bones and demineralization
- Increased intake through diet, Vitamin D
- Overdose of milk and antacids
8
Q
What happens with hypercalcemia pts?
A
- Depress neuromuscular activity- muscle weakness. Loss of tone
- Interfere with ADH- less absorption of water- polyuria (increased urination)
- Severe: blood volume drops, renal function impaired, wastes accumulate- cardiac arrest
- Heart: contractions increase in strength and duration with dysrhythmia developing
- Bones: Excess PTH, calcium intake- bone density and strength affected
9
Q
S/S of hypocalcemia
A
- Tetany, muscle spasms
- Tingling fingers, mental confusion, irritability
- Arrhythmias, weak contraction of the cardiac muscles
10
Q
S/S of hypercalcemia
A
- Lethargic, anorexia, nausea, constipation, polyuria, thirst
- Kidney stones
- Arrhythmia- prolonged cardiac contractions
- Increased BP
11
Q
Sodium
A
- Extracellular cation (Na+)
- Transport across cell membrane is controlled by the Sodium-Potassium pump or active transport- higher levels outside the cells (fluids)
- Salts: sodium chloride, bicarbonate
- Ingested in foods and drinks
- Lost in perspiration, urine, feces
- Primarily controlled by the kidney via aldosterone (responsible for maintaining proper levels)
12
Q
What is sodium’s function?
A
- Extracellular fluid volume (affects osmotic pressure)
- Force with which a solvent (fluid) passes through a membrane separating solution of different concentrations
- Nerve impulse conduction
- Muscle contraction
13
Q
What are the causes of hyponatremia?
A
- Excessive sweating, vomiting, diarrhea
- Diuretic medications used with low salt diets
Hormonal imbalances:
- Insufficient aldosterone secretion
- Adrenal insufficiency
- Excessive ADH secretion
- Chronic renal failure
- Excessive water intake
14
Q
What happens to hyponatremia pts?
A
- Impaired nerve conduction- slower
- Fluid imbalances (fatigue, muscle cramps, abdominal discomfort or cramps with nausea and vomiting)
- Decreased osmotic pressure outside cells- fluid shift into the cells- hypovolemia and drop in blood pressure
- Brain swelling- CNS effects (headache, confusion, seizures)
15
Q
What are the causes of hypernatremia?
A
- Ingestion of large amounts of sodium
- Disproportionate water intake
- Insufficient ADH
- Loss of thirst mechanism
- Watery diarrhea
16
Q
What happens to hypernatremia pt’s?
A
- Weakness
- Agitation
- Increased thirst with dry, rough mucous membranes
- Decreased urinary output (ADH secretions)
- Increased urinary output if the cause is ADH insufficiency
17
Q
S/S of hyponatremia?
A
- Anorexia, nausea, cramps
- Fatigue, lethargy, muscle weakness
- Headache, confusion, seziures
- Decreased BP
18
Q
S/S of Hypernatremia?
A
- Thirst with dry tongue and mucosa
- Weakness, lethargy, agitation
- Edema
- Elevated BP
19
Q
Potassium
A
- Intracellular cation (K+)
- Ingested in foods: bananas, citrus foods, tomatoes, lentils
- Supplements potassium chloride tablets
- Insulin promotes movement of potassium into the cells
- Excreted in the urine under the influence of aldosterone
20
Q
Potassium Levels
A
Influenced by acid-base balance of the body:
- Acidosis: shifts K out of the cells
- Alkalosis: shifts K into the cells
- Acidosis: Hydrogen ions move into cells and displace K ions to maintain electrical neutrality- K in the fluid diffuses into the blood (hyperkalemia)
- Reverse with alkalosis
- Acidosis: promotes hydrogen ion excretion by the kidneys and retention of potassium in the body
21
Q
What is the role of potassium?
A
- Regulates intracellular fluid volume
- Metabolic processes in the body
- Nerve conduction
- Contraction of all muscle types
- Membrane potential
- Cardiac muscle contractions- ECG changes- Cardiac arrest
22
Q
What are the causes of hypokalemia?
A
- Excessive loss of K from diarrhea, diuretic drugs
- Excessive aldosterone or glucocorticoids- sodium retention, potassium excretion
- Decreased dietary intake (alcoholism, eating disorders, starvation)
23
Q
What happens to hypokalemia pts?
A
- Cardiac dysrhythmias (prolonged repolarization- arrest)
- Neuromuscular function interference- muscles are less responsive to stimulus (fatigue, muscle weakness)
- Paresthesias (pins & needles)
- Decreased GI motility (anorexia & nausea)
- Weak respiratory muscles (shallow respirations
- Renal malfunction (polyuria)
24
Q
What are the causes of hyperkalemia?
A
- Renal failure
- Deficit of aldosterone
- K sparing diuretics
- K leakage out of cells with tissue damage
- Acidosis- displaces potassium
- Crush syndrome
25
Q
What happens to hyperkalemia pts?
A
ECG:
- P waves wide and flat
- Longer PRI
- Wide, flat QRS
- T wave is high and wide
- Muscle weakness- paralysis
- Fatigue, nausea, paresthesias
26
Q
S/S of hypokalemia
A
- Arrhythmias - arrest
- Anorexia, nausea, constipation
- Fatigue, weakness, cramps
- Shallow respirations
27
Q
S/S of hyperkalemia
A
- Arrhythmias - arrest
- Nausea, diarrhea
- Muscle weakness - paralysis
- Paresthesias
- Oliguria
28
Q
What is the treatment for hyperkalemia?
A
- Depends significantly on the level of suspected hyperkalemia
- Provincial directive currently includes ACP only:
- Ventolin high doses and Calcium gluconate
