Trousseau’s Sign

Trousseau’s Sign, first described by French physician Armand Trousseau in 1861, is a clinical bedside test used to detect hypocalcemia. The sign is elicited during inflation of a blood pressure cuff and indicates increased neuromuscular excitability.

Hypocalcemia can arise from a range of conditions, including hypoparathyroidism, vitamin D deficiency, chronic kidney disease, and electrolyte disturbances. Trousseau’s Sign may also appear in hypomagnesemia or metabolic alkalosis. Detecting this sign early is crucial, as untreated hypocalcemia can lead to tetany, seizures, and life-threatening cardiac arrhythmias.

Purpose

The primary aim of Trousseau’s Sign is to:

• Reveal latent tetany associated with hypocalcemia

• Provide a quick, low-cost bedside test without specialized equipment

• Serve as a clinical trigger for further investigation and urgent treatment

The test provokes a carpopedal spasm by inflating a blood pressure cuff, temporarily reducing circulation and amplifying neuromuscular irritability.

Clinical Features

The hallmark finding of Trousseau’s Sign is a hand spasm (carpopedal spasm) characterized by:

• Flexion at the wrist

• Flexion of the thumb and MCP joints

• Hyperextension of the IP joints

• Fingers drawn together in the classic “obstetrician’s hand” or “midwife’s hand” position

• May be accompanied by tingling or numbness in the fingers

Test Procedure

Patient position:

• The patient sits or lies comfortably with the arm relaxed.

Cuff inflation:

• A blood pressure cuff is applied around the upper arm.

• Inflate to 20 mmHg above systolic blood pressure.

• Maintain this pressure for 2–3 minutes.

Observation:

• Watch for the development of carpopedal spasm in the hand and wrist.

Interpretation

• Positive test: Reproducible carpopedal spasm

• Negative test: No spasm or abnormal movement

A positive finding indicates increased neuromuscular excitability and is strongly associated with hypocalcemia. Although it may also occur in hypomagnesemia or metabolic alkalosis, it is primarily regarded as a sign of low serum calcium levels.

Clinical Significance

Trousseau’s Sign is considered a highly sensitive and specific bedside marker of hypocalcemia:

• Sensitivity: 94%

• Specificity: 99%

When positive, it should prompt further evaluation of:

• Serum calcium and albumin

• Magnesium levels

• Acid-base balance

It is essential to distinguish Trousseau’s Sign of Hypocalcemia from Trousseau’s Sign of Malignancy (migratory thrombophlebitis linked to occult cancer), as they are unrelated clinical entities despite sharing the same name.

Evidence

• < 4% of healthy individuals may demonstrate a false-positive Trousseau’s Sign.

• The test is therefore highly effective as a “rule-in” test.

• Often used in conjunction with Chvostek’s Sign and laboratory testing for diagnostic confirmation.

Limitations

• Rare false positives in otherwise healthy individuals (up to 4%)

• Requires correct technique and sufficient duration of cuff inflation

• Should always be interpreted in the context of other clinical findings and laboratory results

Summary

Trousseau’s Sign is a simple, reliable bedside test for hypocalcemia, performed using a blood pressure cuff to elicit carpopedal spasm. With very high sensitivity and specificity, it remains a key clinical tool for detecting latent tetany and guiding urgent evaluation of electrolyte imbalances. While positive results strongly suggest hypocalcemia, the test must always be confirmed with biochemical analysis and interpreted alongside other clinical signs.

Sources:

1. Trousseau a. Clinique médicale de l'Hôtel-Dieu de Paris. Paris, 1861. Volume 2: 112-114.

2. Patel M, Hu EW. Trousseau Sign. In: StatPearls . Treasure Island (FL): StatPearls Publishing; 2020 Jan

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5. Gjennomgått - Trukket

6. Yale SH, Tekiner H, Yale ES. Revisiting the meaning of Trousseau sign and syndrome. J Gynecol Oncol. 2024 May;35(3):e90. doi: 10.3802/jgo.2024..

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