Lecture Notes on Chvostek's Sign and Trousseau's Sign

Summary

In this lecture, we discussed two classic physical exam findings associated with hypocalcemia: Chvostek's Sign and Trousseau's Sign. We examined the sensitivity and specificity of these tests in diagnosing hypocalcemia.

Chvostek's Sign

• Definition: Twitching of facial muscles in response to tapping over the facial nerve area.
• Diagnostic Value:
  • Not very sensitive or specific.
  • Absent in about 30% of patients with hypocalcemia.
  • Present in about 10% of patients with normal levels of calcium.

Trousseau's Sign

• Definition: Carpal pedal spasm that results from ischemia.
• Method of Induction:
  • Inflation of a blood pressure cuff over the arm.
  • Observe the gradual flexion of the fingers and thumb, flexion at the wrist, and some degree of pronation.
• Diagnostic Value:
  • More sensitive and specific compared to Chvostek's Sign.
  • Present in approximately 94% of patients with hypocalcemia.
  • Occurs in about 1% of patients with normal calcium levels.

Conclusion

Trousseau's Sign demonstrates higher sensitivity and specificity and is therefore a more reliable indicator of hypocalcemia compared to Chvostek's Sign.

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