Trousseau's Sign

Synonyms: Trousseau sign of latent tetany.

Trousseau's sign occurs in patients with hypocalcaemia and results from enhanced neuromuscular excitability.¹

Named after Armand Trousseau (1801-1867) a French physician who was also the first to perform a tracheotomy in France.

It should not to be confused with his other discovery: Trousseau's sign of malignancy or Trousseau's syndrome (migratory thrombophlebitis from underlying pancreatic, lung, colon, or gastric carcinoma).

• Inform the patient about the procedure as it is very uncomfortable and painful
• A blood pressure cuff is inflated to a pressure above the patients systolic level
• This pressure has to be continued for several minutes
• Look for carpopedal spasm which involves the following³
  • flexion at the wrist
  • flexion at the metacarpophalangeal joints
  • extension of the interphalangeal joints
  • adduction of the thumbs and fingers
• The posture of the hand has been described as "Main d'accoucheur" meaning obstetricians hand¹

Patients may also experience paraesthesia of the fingers and there may be muscle fasciculations.¹

Sensitivity and specificity of this sign¹

Trousseau's sign is said to occur before the other signs of hypocalcaemia e.g. hyperreflexia. It is both specific and sensitive for hypocalcaemia. However, it is less sensitive than Chvostek's sign (tapping on the facial nerve).

This sign may also occur in hypomagnesaemia.

• This is an extension of Trousseau's sign
• As soon as the cuff is deflated the patient is asked to take deep breaths at a rate of 40 per minute
• Again carpopedal spasm can be induced in hypocalcaemia