Calcium Flashcards
Calcium is obtained from:
Ingested foods
Calcium balance is controlled by: (3)
PTH - increases bone resorption (moves Ca2+ from bone → blood)
Calcitonin - stimulates when serum calcium levels are high (moves Ca2+ from blood → bone)
Vitamin D- allows calcium to be absorbed from the GI tract
Approximately ⅔ of hypercalcemia cases are caused by ___ and ⅓ are caused by ___
⅔ - hyperparathyroidism
⅓ - malignancy
Malignancies lead to hypercalcemia through ___ ___ from tumor invasion.
Bone destruction
Causes of hypercalcemia
Malignancies
Prolonged immobilization
Hyperparathyroidism
Vitamin D overdose
Acidosis
Causes of hypocalcemia
Chronic renal failure
Primary hypoparathyroidism
Vitamin D deficiency
Magnesium deficiency
Loop diuretics
Acute pancreatitis
Diahrrea
Chronic alcoholism
Alkalosis
Surgical removal of a portion of the parathyroid gland
Excess administration of citrated blood
Manifestations of hypercalcemia
Excessive calcium blocks the effect of sodium in skeletal muscles which leads to reduced excitability of both muscles and nerves.
Impaired memory, confusion, disorientation
Muscle weakness
Decreased reflexes
Fatigue
Renal calculi
Constipation
Cardiac dysrhythmias
Manifestation of hypocalcemia
Low calcium levels allow sodium to move into excitable cells, which increases depolarization.
This results in increased nerve excitability and sustains muscle contraction referred to as tetany
Tetany is a broad term that involves involuntary muscle contractions & overstimulated peripheral nerves.
Hyperreflexia
Seizure
Muscle cramps
Nursing Care/Correction of hypercalcemia
Promote excretion of calcium in the urine via loop diuretic
Administering synthetic calcitonin
Low diet of calcium
Mobilization with weight-bearing exercises to enhance bone mineralization
Nursing Care/Correction of Hypocalcemia
Correcting the cause
Mild/asymptomatic - diet of calcium-rich foods and calcium + vit. D supplements
Severe - IV calcium (e.g. calcium gluconate)
