Hypocalcemia

Background

• Low <8.5 (<2.0 ionized)
• Low! <6.5 (<1.5 ionized)

• Correct for hypoalbumimia
  • Corrected Ca = (0.8 * (Normal Alb - Pt's Alb)) + Serum Ca

Clinical Features

1. Paresthesias (mouth, fingertips)
2. Incr DTRs
3. Cramps
4. Weakness
5. Confusion
6. Seizures
7. Chvostek/Trousseau, Tetany
8. Hallucinations

Diagnosis

• ECG
  • QT Prolongation

• Trousseau's Sign (Mod to high SN and SP)
  • Inflate BP cuff for 2-3 mins
  • Positive = Muscle contractions of the hand and wrist

• Chvostek's Sign (Low SN and SP)
  • Tapping on the face just anterior to the ear and just below the zygomatic bone
  • Positive = Ipsilateral facial twitching

DDX

1. Misc
   1. Shock
   2. Sepsis
   3. Pancreatitis
   4. Hypomag
   5. Rhabdo (phosphate overload)
   6. Massive Transfusion
2. Decreased absorption
   1. Vit D def
3. Increased excretion
   1. Alcoholism
   2. Renal Failure
   3. Diuretics
4. Endocrine
   1. Hypoparathyroidism
5. Drugs
   1. Cimetidine
   2. Phenytoin
   3. Lasix

Treatment

• Avoid empiric treatment in patients taking digoxin due to risk for Stone Heart

1. Asymptomatic
   1. Calcium gluconate 1 gm PO Q6hrs
   2. Vitamin D (calcitriol) 0.2 mcg BID
2. Symptomatic
   1. Calcium gluconate/chloride 10mL of 10% soln IV over 10min

• Correct hypomag at same time (otherwise PTH is inhibited)

See Also

• Electrolyte Abnormalities (Main)

Source

• Tintinalli