Hypocalcemia

• Facts:
  Serum calcium < 8.5
• History / PE:
  Abdominal muscle cramps
  Tetany
  Perioral and acral paresthesias
  Chvostek's sign
  Trousseau's sign
• Diagnosis:
  Order ionized calcium, magnesium, PTH, albumin, and calcitonin
  Prolonged QT interval
• Treatment:
  Oral calcium supplementation
  IV calcium if severe
  magnesium repletion
• Notes:
  Alkalosis (increase in extracellular pH) causes an increase in the affinity of serum albumin to calcium, thereby increasing the levels of albumin-bound calcium, decreasing the levels of ionized calcium
  
  Serum calcium may be falsely low in hypoalbuminemia (check ionized calcium); unlikely to cause because ionized calcium remains unchanged
  
  See corrected calcium levels for adjustment formula
• See Also:
  Hypercalcemia
• Associated With:
  1) Hypoparathyroidism (post surgical, idiopathic)
  2) Multiple blood transfusions (chelates with citrate)
  3) Malnutrition
  4) Alkalosis
  5) Acute pancreatitis
  6) DiGeorge's syndrome (infants)
  7) ETOHics ( chronic pancreatitis , vitamin D malabsorption)