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General info about Ca2+
- Primary source is from ingested foods
- >99% combined w/PO4 & concentrated in skeletal system
- Inverse relationship w/PO4
- Bones provide readily available store of Ca2+
- Controlled by PTH, calcitonin, vitamin D
- Normal 8.5-11 mg/dL
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What are the functions of Ca2+
- Blocks sodium Na+ transport & stabilizes cell membrane
- Transmission of nerve impulses
- Contraction of muscle (including myocardium)
- Aids in blood clotting
- Aids in formation of teeth & bone
- Only the ionized form is biologically active
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What is the pathophys of hyperCa2+
- Hyperparathyroidism--Parathyroid-->PTH-->release of Ca2+ from bone into blood stream (resorption) and ^ reabsorption of Ca2+ in the GI and renal tubules.
- Malignant cancer-->destruction of bone and release of calcium into BS.
- Prolonged immobilization-->Ca2+ release into blood stream from bones.
- Hypophosphatemia due to inverse relationship between PO4 and Ca2+ levels.
- Excess vit D-->^reabsorption of Ca2+ from GI.
- Acidosis (increases ionized Ca2+ ). Decreases binding of Ca2+ with albumine to ^ levels of biolgically active Ca2+ in BS.
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SnSs of hyperCa2+
- Decreased memory, confusion, disorientation
- Fatigue
- Bone pain and fractures
- Irritability of cardiac muscle
- Renal calculi w/renal impairment
- ^DTRs.
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What are some nursing interventions for pt w/hyperCa2+
- Administer loop diuretic (ie Lasix) to eliminate via urine
- PO4. Due to inverse relationship with Ca2+ increasing one will decrease the other.
- Hydration w/isotonic saline infusion
- Synthetic calcitonin/etidronate
- Mobilization with weight bearing exercise to encourage Ca2+ reabsorption into bones.
- Increase hydration to 3-4L water/day to eliminate excess Ca2+ and to avoid producing kidney stones.
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What are the common pathologies of hypoCa2+?
- Decreased production of PTH, ie due to partial removal of the thyroid gland.
- Acute pancreatitis-->lipolysis-->^binding of Ca2+ to fatty acids--> v levels of biologically active Ca2+
- Multiple blood transfusions due to addition of citrate (anticoagulant) during transfution. Ca2+ binds to citrate--> v levels of biologically active Ca2+
- Alkalosis. ^pH-->^binding of Ca2+ to protiens.
- Decreased intake
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SnSs of hypoCa2+
- Trousseau’s sign: dorsaflexion of hand with BP cuff for a few minutes.
- Chvostek’s signs: tetany of face with mild finger poke to cheek.
- Laryngeal stridor
- dysphagia
- siezure
- numbness & tingling around the mouth or extremities
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What are some nursing intervensions for the pt w/hypoCa2+?
- Oral or IV supplements
- Tx pain or anxiety to prevent hyperventilation-induced respiratory alkalosis-->hypoCa2+
- Sz precautions
- Tx cause
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