POSITIVE bathmotropic effects due to decreased interaction of Ca2+ with Na+ channel
REMEMBER: CATS GO NUMB
C: Convulsions
A: Arrhythmias
T: Tetany: Trousseau [TRUE-SEW] Sign seen in hypocalcemia
To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure 20mmHg above than the systolic blood pressure and held in place for 3 minutes
This will occlude the brachial artery
In the absence of blood flow (ischemia), the patient’s hypocalcemia and subsequent neuromuscular irritability is exacerbated and will induce carpo-pedal spasm of the muscles of the hand (main d’accoucheur posture)
The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct
AND Chvostek [Cha-Vost-sTik] sign: clinical sign of hyperexcitability (tetany) classical associated hypocalcemia. TWO VARIATIONS:
Type 1: percussion of the facial nerve just anterior to the external auditory meatus elicits ipsilateral spasm of the orbicularis oculi or orbicularis oris muscles
Type 2: produced by tapping on a different location of the face. This point is located on the line joining the zygomatic prominence and the corner of the mouth, one third of the distance from the zygoma
WHY??? Low Ca2+ in the ECF increases permeability of neuronal membrane to Na+ ions causing progressive depolarization…..increasing the possibility of action potentials. Less Ca2+ in the cell, increases the permeability to Na+
Chvostek’s sign is neither sensitive nor specific for hypocalcemia
Trousseau’s sign, however, is more sensitive and specific
Present in 94% of patients with hypocalcemia
However will present in 1-4% of persons with normal calcium levels
ALSO :
numbness/paresthesia in hands, feet, around mouth and lips