Pediatric emergency medicine trisk 2870 2870
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gastrointestinal tract and reabsorption from the renal tubules. Calcitonin is a
hormone produced by the parafollicular cells of the thyroid when calcium
levels are high. Calcitonin inhibits osteoclastic activity and promotes
movement of calcium from the blood into the skeletal system.
Treatment of abnormalities of serum calcium will depend on the
underlying cause, with the aim of restoring normal calcium levels and
preventing associated manifestations which are primarily neuromuscular
and cardiac.
CLINICAL PEARLS AND PITFALLS
Serum calcium levels are regulated by PTH; a PTH level should
be considered in the evaluation of abnormal serum calcium levels.
IV calcium is indicated for the treatment of severe hypocalcemia
and in patients with ECG changes or significant neuromuscular
symptoms.
If given too rapidly, IV calcium can precipitate bradycardia or
asystole.
The presence of acidosis or abnormalities of magnesium and
phosphorus have specific implications regarding treatment of
hypocalcemia.
Hypercalcemia results from increased gastrointestinal absorption,
enhanced bone resorption, or impaired renal excretion of calcium.
Treatment of hypercalcemia primarily involves enhancing renal
excretion with volume replacement.
Hypocalcemia
Hypocalcemia has many causes, which include PTH deficiency or
resistance, vitamin D deficiency or resistance, extravascular deposition, and
abnormal magnesium metabolism ( Table 100.10 ). Abnormal serum
calcium should be confirmed by repeat measurement and if confirmed,
ionized serum calcium should be measured. As approximately 90% of
protein-bound calcium is bound to albumin, the serum albumin
concentration should also be determined. For each 1 g/dL reduction in
serum albumin, the total calcium concentration will be lowered by
