Mineral Balance Lectures Flashcards
Calcium Reference Range
8.6-10.0 mg/dl
Calcium Functions
- Skeletal mineralization
- Nerve impulse transmission
- muscle contraction
- blood coagulation
- enzyme cofactor
- cell membrane integrity and permeability
Organs associated with Calcium balance
- Small intestine
- Bones
- Kidneys
Hydroxyapatite
components
Calcium+Phosphorus+hydroxide
Hydroxyapatite importance
99% of calcium in bones and teeth is in this form
Calcium bound to proteins (%)
-40%
most bound to albumin
Free “ionized” calcium and pH (acidosis/alkalosis)
Acidosis: more free Ca2+ (less binding)
Alkalosis: less free Ca2+ (more binding)
Free calcium (%)
50%
Calcium in salts (%)
10%
Ionized Calcium function
- Physiologically active calcium
- monitored in heart surgery
Ionized calcium reference range
4.6-5.3 mg/dl
PTH and calcium
- Secretion increases calcium levels
- glands have calcium receptors that respond to Ca levels
How PTH increases calcium
- Bone resorption and release of Ca to blood.
- Increase renal reabsorption of Ca (excretion of phosphorous)
- Intestinal reabsorption
Calcium and Phosphorous relationship
- Inverse relationship
- Reabsorption of Ca = secretion of Phosphorous
- Influenced by PTH
Vitamin D/Calcium
Increases calcium and phosphate by increasing absorption from GI tract
Vitamin D/Calcium
Increases calcium and phosphate by increasing absorption from GI tract
Vitamin D/PTH
Increases bone resorption and enhances PTH
Calcitonin
Inhibits bone resorption, promotes bone formation
primary Hyperparathyroidism
Increased calcium, PTH
Decreased phosphorous
Hypoparathyroidism
Decreased PTH
Decreased calcium
Increased phosphorous
(injury)
Hypercalcemia conditions
.Hyperparathyroidism .Malignancy .Renal failure .Multiple myeloma .Increased Vit. D .Milk Alkali syndrome .Diuretics, Lithium, Vit. A
Hypercalcemia Symptoms
Kidney stones Fractures Hypertension Arrhythmia Constipation Disorientation
Hypocalcemia
Hypoalbuminemima Hypoparathyroidism Renal failure Decreased magesium Citrate toxicity
Hypocalcemia/Hypoalbuminemia
Liver disease
nephrotic syndrome
malnutrition
Hypocalcemia symptoms
Neuromuscular irritability Tetany Trosseau and Chvostek's Depression Cardiac irregularity
Total Calcium Specimen
Serum Li heparin plasma No EDTA Hemolysis (decrease) HCI urine
Ionized calcium requirements
Anaerobic
Heparin whole blood
Serum/plasma
ph and Ca2+ reported
Rickets
Vitamin D deficient
Bone deformity
Abnormal mineralization
Children
Osteomalacia
Adults
Vitamin D deficient
Abnormal mineralization
Osteoporosis
Low bone mass
Assess bone density and PTH/Vitamin D
Paget’s disease
Excessive bone resorption
Increased ALP
Treat w Calcitonin
Phosphorous reference range
2.5-4.5 mg/dl
Phosphorous distribution
80% bone
20% soft tissue
<1% in bloodstream
Phosphorous regulation
Kidneys PTH (decrease) Vitamin D (increase) GH Calcitonin
Hyperphosphatemia
Decreased excretion
Cellular shift (acidosis)
PTH (low)
Hypophosphatemia conditions
Increased excretion Diuretics DKA increased PTH Cell shift (alkalosis) Malabsorption
hypophosphatemia symptoms
Weakness double vision slurred speech dizziness respiratory failure impairment of cardiac contractility
Phosphorous specimen
serum
Li hep plasma
Hemolysis (increase)
Diurnal variation
Magnesium ref range
1.6-2.6 mg/dl
Magnesium distribution
50% bone
40% muscle
1% RBC
Magnesium forms
Ionized: 55%
Protein bound: 30%
Ionic: 15%
Hypomagenesiemia symptoms
Hypertension Arrhythmia Weakness tetany Depression psychosis
Hypermagnesemia symptoms
Hypotension Bradycardia warm skin nausea vomiting hypocalcemia
Magnesium specimen
Serum
Heparin plasma
24 h urine (HCl)
Magnesium specimen
Serum
Heparin plasma
24 h urine (HCl)
Metabolically active Vitamin D
1,25 dihydroxy vitamin D3
Secondary hyperparathyroidism
Increased PTH
Increased phosphorous
Decreased calcium
