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Calcium questions I
Quiz Calcium Questions Chapter 17 Lewis p. 316
Question | Answer |
---|---|
Of the calcium ingested, how much is absorbed in the GI tract? | 30% |
About what percentage of the calcium is combined with phosphorus and is concentrated in the ______________? | 99% and Skeletal system |
Bones serve as a readily store of _________? | Calcium |
What are some functions of calcium stated in Lewis p. 316? | 1. Transmission of nerve impulses 2. Myocardial contractions 3. Blood clotting 4. Formation of teeth and bone 5. Muscle contractions |
What are the normal values for calcium? | 8.6 mg/dL – 10.2 mg/dL |
What are the three different forms of calcium? Which of the three are biologically active form? | 1. Free or ionized. This is biologically acitve 2. Bound to proteins (primarily albumin) 3. Complexed with phosphate |
How will changes in pH affect total calcium serum level? | Changes in pH will alter the ionized calcium but not total calcium level |
How will a decrease in plasma pH (acidosis) affect ionized calcium? | Decrease pH will decrease the calcium binding to albumin leading to an INCREASE ionized calcium |
How will an increase in plasma pH (alkalosis) affect ionized calcium? | Increase pH will increase the calcium binding to albumin leading to an DECREASE ionized calcium |
How does the pH affect the albumin levels and total calcium levels? | Alteration in serum albumin levels affects the interpretation of total calcium level. Low albumin result in a drop in total calcium level, although the level of ionized calcium is not affected |
List three factors that control calcium balance? | 1. PTH 2. Calcitonin 3. Vitamin D |
Explain how PTH contributes to calcium balance: | 1. PTH is produced by the parathyroid gland 2. Its production and release are stimulated by low serum calcium levels 3. PTH increases bone resorption (movement of calcium out of bones) |
Explain how PTH contributes to calcium balance | 4. Increases GI absorption of calcium 5. Increases Renal tubule reabsorption of calcium |
Explain how CALCITONIN contributes to calcium balance: | 1. Produced by the thyroid gland 2. Stimulated by high serum calcium levels. 3. It opposes the action of PTH lowering calcium levels by decreasing GI absorption 4. Increases deposition into the bone 5. Promotes renal excretion |
Explain how Vitamin D contributes to calcium balance: | 1.Vit D is formed through action of ultraviolet light radiation on a precursor found in the skin or is ingested in the diet. 2. Vit. D is important for the absorption of calcium from the GI tract |
Name the two types of calcium imbalances and give the numerical value | Hypocalcemia is less than(<) 8.6 mg/dL and Hypercalcemia is greater than (>) 10.2 mg/dL |
About 2/3 of hypercalcemia cases are caused by this and 1/3 is cause by this – Explain: | 1. 2/3s are caused by hyperparathyroidism 2. 1/3 caused by malignancy, especially from breast cancer, lung cancer and multiple myeloma |
Explain in more detail how malignancy leads to hypercalcemia: | This occurs through bone destruction through tumor invasion or through tumor secretion of a parathyroid related protein, which stimulates release of calcium from the bone |
Explain how other factors that can contribute to hypercalcemia: | 1. Vitamin D overdose. 2. Prolonged immobilization results in bone mineral loss and increase plasma calcium concentration |
True or False Hypercalcemia is caused by increased calcium intake? | False |
Excess calcium leads to what? | Reduced excitability of both muscles and nerves |
Nursing diagnosis and collaborative problems for patient with hypercalcemia include but are not limited to the following1. Risk for electrolyte imbalance R/T what? 2. Risk for injury R/T what? 3. Potential complication:: | 1. Excessive bone destruction 2. Neuromuscular and sensorium changes 3. Dysrhythmias |
NURSING IMPLEMENTATION: What is the basic treatment for hypercalcemia? | Promotion of excretion of calcium in urine by administration of a loop diuretic (furosimide –lasix) and hydration of the patient with isotonic saline infusions. |
NURSING IMPLEMENTATION: The patient with hypercalemia must drink how much fluid daily? Explain why this volume? | Patient must drink 3 to 4 Liters a day to promote renal excretion of calcium and to decrease the possibility of kidney stone formation. |
NURSING IMPLEMENTATION: Name other ways to treat hypercalcemia: | 1. Synthetic calcitonin 2. Diet low in calcium 3. Mobilization with weight bearing activity is encouraged to enhance bone mineraliztion 4. Plicamycin (Mithracin) – cytoxic antibiotic - inhibits bone resorption and lowers the serum calcium level |
NURSING IMPLEMENTATION: In hypercalcemia associated with malignancy, the drug of choice is what? | Pamidronate (Adredia) which inhibits the activity of osteoclasts (cells that break down bone and result in calcium release). |
NURSING IMPLEMENTATION: Why is Pamidronate (Adredia) the drug of choice over Plicamycin (Mithracin)? | Pamidronate is preferred over plicamycin because it does not have cytotoxic side effects and it inhibits bone resorption without inhibiting bone formation and mineralization. |
Any condition that causes a decrease in the production in what may result in the development of hypocalcemia. | PTH |
How can hypocalcemia occur (X6)? | 1. Surgical removal of a portion of or injury to the parathyroid glands during thyroid or neck surgery. 2. Acute pancreatitis 3. Lipolysis 4. Multiple transfusion 5. Sudden alkalosis 6. Diet or laxative abuse 7. Malabsorption |
How does lipolysis cause hypocalcemia | Lipolysis is a consequence of pancreatitis, produces fatty acids that combine with calcium ions, decreasing serum calcium levels |
How does multiple blood transfusion cause hypocalcemia? | Because the citrate used to anticoagulate the blood binds to the calcium. |
How does sudden alkalosis cause hypocalcemia? | The high pH increase calcium binding to protein, decreasing the amount of ionized calcium despite a normal total serum |
How does diet or laxative cause hypocalcemia? | Just not taking in enough calcium in the diet or laxative abuse and malabsorption will cause increase loss of calcium |
What happens to cells low in calcium? | They become excitable cells, decreasing the threshold of action potential with subsequent depolarization of the cells. This results in increased nerve excitability and sustained muscle contraction that is referred to as tetany |
What is tetany? | Increased nerve excitability and sustained muscle contraction |
What are the 2 main clinical signs of tetany? | 1.Trousseau’s sign 2. Chvostek’s signs |
What are the main clinical signs of Trousseau’s sign. | Trousseau’s sign refers to carpal spasm induced by inflating a blood pressure cuff on the arm. The BP cuff is inflated above the systolic pressure. Carpal spasms become evident within 3 minutes if hyopocalcemia is present. |
What are the main clinical signs of Chvostek’s | Chvostek’s signs is contraction of facial muscles in response to a tap over facial nerve in front of the ear |
What are other clinical signs of tetany? | 1. Laryngeal stridor 2. Dysphagia 3. Numbness 4. Tingling around the mouth or in the extremities |
What are the cardiac effects of hyopcalcemia: | Decreased cardiac contractility and ECG changes. Prolong QT interval may develop into a ventricular tachycardia |
Nursing diagnosis and collaborative problems for patient with hypocalcemia include but are not limited to the following1. Risk for electrolyte imbalance R/T what? 2. Risk for injury R/T what? 3. Potential complication: | 1. Decrease production of PTH 2. Tetany and seizures 3. Fractures, respiratory arrest |
Nursing Implementation: What is the primary goal in treatment of hypocalcemia? | Treating the cause by giving oral or IV treatments |
Nursing Implementation: Can calcium be given IM? Why or why not? | Never give calcium IM because it may cause severe local reaction such as burning, necrosis, and tissue sloughing |
Nursing Implementation: When is intravenous preparations given? Given an example. | IV preps. are used when there is severe hypocalcemia; Calcium gluconate is an example. |
Nursing Implementation: What is usually ordered for a patient with hypolcalcemia? | A diet rich in calcium along with Vitamin D supplement |
Nursing Implementation: What is used for hypocalcemia for those patients that cannot consume enough calcium through a diet plan? | Oral calcium supplement such as calcium carbonate |
Nursing Implementation: Why are pain and anxiety management important in patients with hypocalcemia? | Because hyperventilation induced respiratory alkalosis can precipitate hypocalcemic symptoms. |
Nursing Implementation: Any patient that has had what kind of surgery must be closely observed in the immediate postoperative period for manifestations of hypocalcemia? | Any patient that has had thyroid or neck surgery because of the proximity of the surgery to the parathyroid gland |