Trousseau Sign
Trousseau sign is a clinical test for detecting latent hypocalcemia, performed by inflating a blood pressure cuff above systolic pressure for 3 minutes to induce carpopedal spasm (hand contraction with fingers adducted in a "main d'accoucheur" or "obstetrician's hand" position). 1
What It Detects
Trousseau sign indicates neuromuscular irritability due to hypocalcemia. It is one of two key physical examination findings used to assess for latent tetany in patients with suspected calcium disorders, the other being Chvostek's sign 1.
How to Perform the Test
- Inflate a blood pressure cuff on the patient's upper arm to a pressure above systolic blood pressure (typically 20 mmHg above)
- Maintain inflation for 3 minutes
- Observe for carpopedal spasm: The hand will contract with:
- Fingers drawn together in a cone or pyramid shape
- Thumb adducted across the palm
- Wrist flexed
- This classic position is called "main d'accoucheur" (obstetrician's hand) 2
Clinical Significance
A positive Trousseau sign indicates increased neuromuscular excitability and should prompt immediate evaluation of serum calcium levels 3, 4, 5. The test is particularly valuable in:
- Post-thyroidectomy patients at risk for hypoparathyroidism 4
- Suspected hypoparathyroidism (surgical or nonsurgical) 1
- Pseudohypoparathyroidism 5, 6
- Any condition causing hypocalcemia requiring urgent assessment
Important Caveats
- False positives can occur with hyperventilation-induced respiratory alkalosis, even without true hypocalcemia 2
- The sign may be present before symptoms become severe 3
- Always confirm with laboratory testing: measure albumin-corrected calcium or ionized calcium, along with PTH, phosphorus, and magnesium 1, 7
When to Act Urgently
If Trousseau sign is positive, check for life-threatening manifestations requiring immediate IV calcium:
- Prolonged QTc interval (>0.45s in men, >0.47s in women)
- Laryngospasm or bronchospasm
- Seizures or severe tetany
- Albumin-corrected calcium <7.5 mg/dL (1.9 mmol/L) 7
Treat with calcium gluconate 1-2 ampules (90-180 mg elemental calcium) IV over 10-20 minutes with cardiac monitoring, followed by continuous infusion if needed 1, 7.