Categories: Endocrinology

Signs of Hypocalcemia


  • Low serum calcium levels in the blood
  • < 2.12mmol/L (TOTAL) and <1.16mmol/L (+)

Signs and Symptoms

  • POSITIVE bathmotropic effects due to decreased interaction of Ca2+ with Na+ channel


  • 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


  1. numbness/paresthesia in hands, feet, around mouth and lips
  2. laryngospasm
  3. Prolonged QT interval on ECG


  1. Kumar, Abbas, Fausto. Pathologic Basis of Disease, 7th edition. Philadelphia: Elsevier-Saunders, 2005. 1188.
  2. Cooper MS, Gittoes NJ. Diagnosis and management of hypocalcaemia. BMJ. 2008;336(7656):1298–302.
  3. Murphy E, Williams GR. Hypocalcaemia. Medicine. 2009;37(9):465–8
  4. Harrison’s Principles of Internal Medicine, 19e.  65: Hypercalcemia and Hypocalcemia
  5. Chapter 8. Metabolic Bone Disease. Greenspan’s Basic & Clinical Endocrinology, 9e. Dolores Shoback, MD; Deborah Sellmeyer, MD; Daniel D. Bikle, MD, PhD
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Dr. C Humphreys

Internal Medicine

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