Calcium disorders

Question 1

Normal values of Calcium

Answer 1

-8.5 - 10.5 mEq/L
-intracellular and extracellular

Question 2

Presence of Calcium in the body

Answer 2

-intra and extracellular
-bound to albumin -> correction in patients with low albumin (hypoalbuminemia)
Ca(corrected) = Ca(actual) + 0.8 (4 - Albumin)

Question 3

Homoestasis of Calcium

Answer 3

maintained by
PTH
Phosphorus
Vitamin D
Calcitonin

Question 4

Causes of Hypocalcemia

Answer 4

-Hypoalbuminemia
-Hypoparathyroidism
-Vitamin D deficiency
-Hypomagnesemia (Ca and Mg are required for proper absorption)
-Tumor lysis syndrome (also seen in Hyperkalemia)

Question 5

Symptoms and Signs of Hypocalcemia

Answer 5

-usually asymptomatic
Rickets (bone softening in kids)
Osteomalacia (bone softening in adults)
tetany (muscle cramp of the jaw, also in Hypomagnesemia)
muscle cramps
CV manifestations: arrhythmias (Ca is important for cardiac conduction (contraction))
cataract development

Question 6

IV Treatment of Hypocalcemia

Answer 6

-Calcium gluconate 2-3 g (less concentrated, less vein irritation)

-Calcium chloride 1 g via central line ONLY (due to vein irritation)

-AVOID co-administration of Ca with phosphates (precipitation)

Question 7

PO Treatment of Hypocalcemia

Answer 7

Outpatient

-2-3 g of elemental calcium per day divided TID
-Calcium carbonate ~ 40% elemental (has to be taken with meals, TUMS)
-Calcium citrate ~ 21% elemental

Question 8

Causes of Hypercalcemia

Answer 8

-Calcium of more than 10.5 mEq/L

-Malignancy (more common)
-Hyperparathyroidism (more common)
-meds: Lithium, HCTZ (diuretics usually cause lowering of electrolytes)
-Sarcoidosis
-Thyrotoxicosis

Question 9

Signs and Symptoms of Hypercalcemia

Answer 9

in severe cases
-AKI
-confusion
-arrhythmia
-coma

Question 10

Treatment of Hypercalcemia

Answer 10

-depends on the severity

-mild: 10.5 - 12 mEq/L: IV fluids

-moderate 12-14 mEq/L: aggressive hydration (IV fluids)

-severe more than 14 mEq/L or symptoms:

->aggressive hydration IV and Loops (dilute the calcium with hydration and remove it with the loop),

->Bisphospahte and Calcitonin: drugs for osteoporosis -> they osteoclasts and bone breakdown -> lower serum Calcium

Question 11

MOA Bisphosphate

Answer 11

-Alendronate (Fosamax), Risedronate (Actonel), Ibandronate (Boniva)

-Inhibition of bone resorption (stopping breakdown by osteoclasts) -> increase in bone density and lower serum Calcium

-long onset, long duration

Question 12

MOA Calcitonin

Answer 12

-Micalcin

-antagonizes the impact of parathyroid hormone, inhibits osteoclasts, promotes renal excretion of calcium

-quick onset, short-acting

-> so use Bisphosphate and Calcitonin in combination!