Exam 1: Calcium Imbalances Flashcards
Where is Calcium located?
99% located in the skeletal system , major component of bones and teeth
What about the 1% of Calcium?
Rapidly exchangeable with blood calcium, adnd the rest is more stable and slowly exchanged.
Calcium plays a major role in
transmitting nerve impulses and helps regulate muscle contraction and relaxation, including cardiac muscle
Calcium is instrumental in
activating enzymes that stimulate many essential chemical reactions in the body and plays role in blood coagulation
Range for Hypocalcemia
< 8.5 mg/dL
Range for Hypercalcemia
> 10.5 mg/dL
Hypocalcemia Contributing Factors
Hypoparathyroidism, Vitamin D definicency, massive subcutaneous infection, decreased parathyroid hormone , fistulas, burns
Hypocalcemia Signs / Symptoms
Numbness, Tingling of Fingers, toes, SEizures, Hyperactive Deep Tendon Reflexesm diarrhea, Decreased BP, decreased clotting time, positive trousseau and chvostek , and tetany
Hypocalcemia Labs Indicate
Decrease in Magnesium or phosphorus
Hypercalcemia Contributing Factors
Hyperparathyroidism, Prolonged immobilization, Overuse of Supplements, Vitman D Excess, Increased Parathyroid Hormone
Hypercalcemia Signs/Symptoms
Muscular Weakness, Constipation, Anorexia, Nausea and Vomiting, Dehydration, Hypoactive Deep Tendon REflexes
Hypercalcemia ECG
Shortened ST Segmenet and QT Interval
Normal total serum calcium level?
8.6-10.2
Calcium exists in plasma in what forms?
Ionized, Bound, and Complex
50% Calcium exists in what form?
Ionized, and this is the most important for neuromusculalr activity and blood coagulation.
Normal Ionized Serum Calcium level?
4.5-5.1
Calcium is absorbed from foods in the presence of
normal gastric acidity and vitamin D
Calcium excreted primarily in
the feces, with remainder excreted in the urine.
Serum calcium level controlled by
PTH and Calcitonin
AS ionized serum calcium decreases,
the parathyroid glands secrete PTH. This increases calcium absorption from the GI tract, increases calcium reabsoprtion from the renal tube, and released calcium from the bone.
When calcium increases excessively, the thyroid gland secretes
calcitonin, which inhibits calcium reabsorption from bone and decreases the serum calcium concentration
Hypocalcemia range?
< 8,6 mg/dL
Who is at risk for Hypocalcemia?
Those who spend an increased amount of time in bed, because bed rest increases bone resorption
What is Hypocalcemia associated with?
Thyroid and Parathyroid surgery, but it can also occur after radial neck dissection.
Hypocalcemia is common with what disease?
Pancreatitis, because calcium ions combine with fatty acids rleased by lipolysis, forming soaps
Hypocalcemia is common with those with a kidney injury because
these patients frequently have elevated serum phosphate levels.
Hyperphosphatemia usually causes a
reciprocal drop in the serum calcium level
Medications predisposing to hypocalcemia include
antacids, aminoglycosides, caffeine, cisplatin, phosphates, loop piuretics, proton pump inhibitors
What is Tetany?
The most characteristics manifestation of hypocalcemia and hypomagnesemia, refers to the entire symptom complex induced by neural excitability.
What two Signs occurs in Hypocalcemia?
Chvostek Sign and Trousseau Sign
What is Chovstek sign?
A contraction of the facial muscles elicited in response to light tap over the facial nerve in front of the ear
What is Trousseau Sign?
A carpopedal Spasm induce in by inflating a blood pressure cuff above systolic blood pressure
What else signs/symptoms may occur with Hypocalcemia?
Seizures, and depression, impaired memory, confusion, delirium, and hallucinations.
Signs and Symptoms of Chronic Hypocalcemia include
hyperactive bowel sounds, dry adn brittle hair and nails, and abnormal clotting
When evaluating serum calcium levels, what else must be considered?
The serum albumin level and arterial pH.
When artieral pH increases, calcium///
is more liekly to bound to protein resulting in the ionized portion decreasing. This is Alkalosis
What is Acidosis in terms of Hypocalcemia?
Has the opposite effect; less calcium is bound to protein and therefore more exists i the ionized form.
Acute hypocalcemia and should be treated with
IV administration of a calcium salt; such as calcium gluconate and calcium chloride.
Hypocalcemia; Why should 0.9% NaCl not be used?
It increases renal calcium loss.
What happens when solutions containing phosphates or bicarbonate are used with calcium?
They create prepicitation
Hypocalcemia: Nutritional Therapy: Vitamin D
May be instituted to increase calcium absorption from the GI tract
Hypocalcemia: Nutritional Therapy: In a patient with chronic kdiney disease, what might they be prescribed?
Aluminum Hydroxide, Calcium Acetate, or Calcium Carbonate Antacids to decrease elevated phosphorus levels before treating this
What should dietary intake be increased to in Hypocalcemia?
100 to 1500 mg/day
What is Hypercalcemia?
Its a dangerous imbalance when severe, it has a mortality rate as high as 50% if not treated promptly
Hypercalcemia range?
> 10.2 mg/dL
Most common causes of oHypercalcemia
Malignanices and Hyperparathyroidism
Hypercalcemia: Excessive PTH secretion assited with hyperparathyroidism causes
increased release of calcium from the bones and increased intestinal and renal absorption of calcium
Calcium levels are inversely realted to
phosphorus levels
Hypercalcemia reduces neuromuscular excitability because it
supresses activity at the myoneural junction. Has decreased tone in smooth adn striated muscle
Hypercalcemia: More sever symtpoms appear when its approximately
16 mg/dL or higher
What is often present with Hypercalcemic crisis?
Severe thirst and polyuria. Also includes muscle weakness, intractable nausea, abdominal cramps, constipation, diarrhea
What test can be used to determine the cause and different in Hypercalcemia
Double-Antibody PTH test, can differentiate between hyperparathyroidism and malignancy.
Hypercalcemia: PTH levels in Hyperparathyroidism?
Increased
Malignancy PTH levels? Hypercalcemia
Supressed in hypercalcemia
Hypercalcemia: Therapeutic Aim?
Decreasing the serum calcium level and reversing the process causing the hypercalcemia.
Hypercalcemia: Pharmacolgic Therapy?
Administering fluids to dilute serum calcium and promote its excretion by the kidneys, mobilizing the patient and restricting dietary calcium intake.
Hypercalcemia: What IV Administration is given?
0.9% NaCl solution because it temporaily dilutes the serum calcium level and increases urinary calcium excretion by inhibiting tubular reabsorption of calcium.
What is Calcitonin used for?
Used to lower the serum calcium level and is particularly useful for patients with heart disease or kidney injury who cannot tolerate large sodium loads
What does Calcitonin do?
Reduces bone resportion, increases deposition of calciun and phosphorus in the bones, and increases urinary excreition of calcium and phosphorus.
Hypercalcemia: Why should fluids containing sodium be given?
Because sodium assists with calcium excretion
