Calcium Flashcards
What are the normal serum ranges for calcium?
9-11 mg/dl
What is the main job of calcium?
Causes contraction, coagulation, nerve impulses
Calcium levels are inverse with ____
phosphorus
What two things regulate calcium levels? How?
Parathyroid hormone and Vitamin D
- Bone reabsorption
- INtestional uptake
- Kidney excretion
Explain the three main characteristics of calcium in the ECF
Mostly Protein bound
nearly all of it is chelated
50% of the total calcium is ionized
What is the benefit of ionized calcium?
It can leave the vascular compartment and participate in cellular functions
What occurs when serum calcium is low?
It increased sodium movement across membranes causing depolarization to occur more easily and inappropriately
What are the four main causes of hypocalcemia?
IMpaired ability to mobilize calcium from bone
Decreased intake or absorption
Abnormal renal loss
INcreased protein binding or chelation
What can cause an impaired ability to mobilize calcium from the bone?
Hypoparathyroidism
What can cause a decreased absorption of calcium?
Protein deficiency
What is an important consideration to make r/t blood products and calcium levels?
serum calcium will bind to citrates in blood products and this can have a negative effect if more than 4 units are given in 24h
What are some neuromuscular signs of hypocalcemia?
Overstimulation of nerves and muscles
Paresthesias
Trousseau’s sign
Chvostek’s sign
What is trousseau’s sign?
The hand curls with bp cuff
What is Chvostak’s sign?
Cheek raises with touch
What are some cardiovascular signs of hypocalcemia?
ECG changes-long ST and QT
Weak thready pulse
What are some GI signs of Hypocalcemia?
increased peristalsis
Cramps
Dihrreah
Low calcium often coinsides with low ___ and ___
Potassium and magnesium
What are the 4 main interventions for hypocalcemia?
Drug therapy
Nutrition therapy
Environmental managment - Decrease stimuli
Injury prevention -coagulation is low
What is the main effect of hypercalcemia?
Excitable tissues need more stimuli to function
What 4 things are affected most by hypercalcemia?
the heart
muscles
nerves
intestinal smooth muscles
What occurs to clotting with hypercalcemia? what increased risk does this bring?
Clotting becomes faster
DVT risk
What are some causes of hypercalcemia?
Regulatory hormones are overwhelmed
Kidneys cant remove excess
What are some causes of excess calcium?
Excessive intake
Bone destruction
Prolonged immobilization
Drugs such as lithium and thiazide diuretics
What happens to the cardiovascular system with hypercalcemia?
Increased hr and bp changing to decreased
Shortened QT interval
Dysrhythmias
HTN
