Pediatric emergency medicine trisk 2873 2873
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findings in patients with neuromuscular instability include Trousseau sign
and Chvostek sign. A positive Trousseau sign is causing a carpopedal
spasm by inflation of a sphygmomanometer above systolic blood pressure
for 3 minutes. A positive Chvostek sign is contraction of the ipsilateral
facial muscle induced by tapping of the facial nerve in front of the ear. Of
note, Chvostek sign may be present in up to 10% of normal subjects. In
addition to neuromuscular findings, acute hypocalcemia may result in
significant cardiovascular disturbance, including hypotension, congestive
heart failure, prolonged QT interval, and dysrhythmias. Papilledema may
also be present and resolves with correction of hypocalcemia.
Management. Numerous forms of calcium salts are available, and
therefore, attention to the salt form is critical when dosing to determine the
elemental calcium dose. Calcium may be provided by either oral
supplementation or IV solution. The appropriate choice is guided by
pertinent clinical findings. In general, IV calcium is indicated if the patient
has prolonged QT, significant symptoms (tetany, seizures, carpopedal
spasm), or acute decrease in serum corrected calcium to less than or equal
to 7.5 mg/dL regardless of symptoms. Oral supplementation is more
appropriate when symptoms are absent or mild and corrected calcium is
greater than or equal to 7.5 mg/dL. In patients with asymptomatic chronic
hypocalcemia associated with CKD, oral calcium supplementation is
preferred with concomitant replacement of 1,25-dihydroxyvitamin D. If
hypocalcemia is associated with metabolic acidosis, correction of the
acidosis will reduce the ionized calcium level. Therefore, if metabolic
acidosis is not causing clinical compromise, priority should be given to
increasing the serum calcium. If hypocalcemia is associated with severe
hyperphosphatemia, the provision of calcium may result in the precipitation
of calcium and phosphate in the tissues, a disorder known as calciphylaxis.
In patients with associated hypomagnesemia, magnesium supplements
should be provided, as persistent hypomagnesemia will hinder the
correction of hypocalcemia.
Prompt treatment of symptomatic or severe acute hypocalcemia should
be initiated intravenously with either calcium chloride or calcium
gluconate. Central access is usually necessary for calcium chloride
infusions, although peripheral infusions may be permissible in emergent
situations. Central access is also preferred for calcium gluconate, though
