Calcium Disorders Flashcards
What is the most abundant cation?
Calcium
What are the physiologic functions of calcium
Bone mineralization
Muscle contraction
Nerve conduction, coagulations
Cell division
hormone secretion
What are the hormones involved in calcium regulations
Vitamin D, PTH, and calcitonin
Normal plasma concentration of calcium
8.8-10.4
What are the names of ultrafilterable calcium
Citrate, phosphate, lactate, iCa
Free ionized calcium normal levels
4.4-5.2
What is the relationship between iCa and CaSRs
Rise in plasma iCa causes a activation of CaSRs and inhibits PTH secretion
Fall in iCa causes an inactivation of CaSRs and increases PTH secretion
What is the function of PTH
Mobilizes calcium from bone stores
Increase renal reabsorption of ca
Increases conversation of vitamin D to vitamin D3 increasing intestinal absorption of ca
What is the function of calcitonin
Produced by the thyroid
Opposes PTH
Inhibits osteoclast activity
How does acid base balance and albumin effect calcium levels
Acidemia = increase in iCa
Alkalemia = decrease in iCa
Hypoalbuminemia = reduced calcium
Hyperalbuminemia = increased calcium
Risk factors for hypocalcemia
Elderly, sepsis, ARF, blood transfusions, malnutrition, mag deficiency, shock, colloid volume resuscitation
Causes of hypocalcemia
Hypoaprathyroidism
Vitamin D deficiency
Parathyroidectomy
Hungry bone syndrome
Citrate
Blood transfusions
Na bicarb
Phosphate mechanism
Rhabdo
Severe acute pancreatitis
Neuro, cardiology, psychiatric clinical manifestations of hypocalcemia
Neuro: paresthesias, hyperactive reflexes, tetany, and seizures. Chvostek and Trousseau signs, laryngeal and bronchospasms
Cards: Prolonged QT, Bradycardia, hypotension, heart block, HF, Cardiac arrest
Psych: anxiety, irritability, confusion, and psychosis
Diagnositc tests for hypocalcemia
iCa, mag and phos, PTH, vitamin D
Treatment for hypocalcemia
IV or PO calcium
HD
Phosphate binder
Replete mag
Await metabolic acidosis correction
Side effects from hypocalcemia treatment
Hypertension
Skin flushing
Nausea
Vomiting
Chest pain
Causes of hypercalcemia
Hyperparathyroidism or malignancy are the main
Others include: rhabdo, immobilization, milk alkali syndrome
Risk factors of hypercalcemia
Bed rest, spinal cord injury, skeletal fractures, Paget’s disease, medications (lithium, thiazide, vitamin A and D)
Neuro, cardiology, GI, and renal manifestations of hypercalcemia
Neuro: muscle wasting, fatigue, depression, AMS, coma, myopathy
Cards: shortened QT interval
GI: anorexia, nausea, vomiting, and constipation
Renal: polyuria, polydipsia, renal failure
What do suppressed PTH and vitamin D levels suggest in hypercalcemia
Advanced cancer
Mild hypercalcemia level and treatment
<12 mg/dl
-withdraw offending agent, volume resuscitation, early mobilization
Moderate hypercalcemia level and treatment
12-14 mg/dl
Volume expansion
Isotonic fluid
Loop diuretics
Severe hypercalcemia level and treatment
> 14mg/dl
Emergent treatment
Remove offending cause
NSS 200-300ml/hr
Loop diuretics
Biphosphonates or calcitonin reduce bone reabsorption
Corticosteroids decrease Ca absorption
HD if refractory
