60% of body weight is water. 2/3 intracellular, 1/3 extracellular. 3/4 is interstitial, 1/4 plasma.
Ca=Ca + .8(4-ALB)
Albumin-adjusted calcium not suitable for diagnosis of calcium abnormalities, get an ionized calcium (Crit Care Med 31(5):1389, May 2003)
Ccalc = Cobs/(0.25ALB + 0.1)
Ical to SI = mg/dl x 0.5872= mmol/L
Hypocalcemia
hypo-pth, Vit D deficiency, PTH resistance, Calcium chelation
May see after large transfusion or contrast media
Chvostek-tapping facial nerve causes twitching (Insensitive and non-specific Neurology March 12, 2013 vol. 80 no. 11 1067)
Trousseaus-carpal spasm after 3 min of BP Cuff at 20 over systolic
QT prolongation
May see stridor
1st step should be to get ionized Ca
1 amp of CaCl=270 mg Ca, CaGluc=93 mg of Ca
Rx for Severe
0.5 mcg of ?
Calc Gluconate
Cal Carbonate ?500
Ical > 4
Hypercalcemia
HyperPTH, Malignancy Sarcoid, Vit D, or Thiazides
Parathyroid
Addison’s
Multiple Myeloma
Paget’s
Sarcoid
Cancer (Usually Squamous Lung CA)
Hyperthryoid
Milk Alkali Syndrome
Immobilization
D-Vitamin D
Thiazide Diuretics
Fluids, Furosemide, Mithramycin (lowers Ca by decreasing bone turnover, 25 mcg/kg infused in D5W over 4-8 hours) Calcitonin, Biphosponates, Dialysis, Steroids
Neurology March 12, 2013 vol. 80 no. 11 1067
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