Chvostek’s Sign + Hypocalcemia
Chvostek’s sign is momentary contraction of the nose and/or lips in response to tapping the facial nerve at the angle of the jaw. Associated with hypocalcemia, it has been found to be poorly sensitive and specific. It is seen in 10-25% of healthy individuals with normal calcium levels (as demonstrated by two of our own EM residents below), whereas approximately one third of patients with hypocalcemia will not demonstrate this sign1-3.
- 50 % is ionized
- 40% is bound to proteins (90% of which binds to albumin)
- 10% circulates bound to anions (phosphate, carbonate, citrate, lactate, sulfate, etc)