Situation: A 49-year-old woman who had most of her small bowel removed 6 months ago is admitted after 2 weeks of very poor intake. She weighs 38 kg (body mass index 15 kg/m²) and reports tingling around her mouth and in her fingertips. Her serum total calcium is 7.1 mg/dL (1.77 mmol/L) (8.6–10.2 mg/dL; 2.15–2.55 mmol/L), and her serum albumin is 3.9 g/dL (39 g/L). The nurse inflates a blood pressure cuff on her upper arm to above her systolic pressure. Which response within 3 minutes is recorded as a positive Trousseau sign?

A positive Trousseau sign is carpal spasm (flexion of the wrist and thumb with extended fingers) after a blood pressure cuff is inflated above systolic pressure for up to 3 minutes. It reflects the neuromuscular irritability of hypocalcemia. Facial twitching after tapping the facial nerve is the Chvostek sign.

Core mechanism of a positive Trousseau sign

Hypocalcemia lowers the threshold for neuronal depolarization, making peripheral nerves more excitable. When a blood pressure cuff is inflated above systolic pressure for up to 3 minutes, the resulting ischemia further irritates the already hyperexcitable nerve fibers. In the setting of low ionized calcium, this triggers spontaneous repetitive firing of motor nerves supplying the forearm and hand. The resulting involuntary contraction is recorded as carpal spasm: the wrist and metacarpophalangeal joints flex, the thumb strongly adducts and flexes across the palm, and the interphalangeal joints extend. This is the classic Trousseau sign, and it reflects neuromuscular irritability caused by hypocalcemia.^[1][2]

In this patient, the serum total calcium is 7.1 mg/dL with a normal albumin of 3.9 g/dL, so the low total calcium is not explained by hypoalbuminemia. The tingling around the mouth and fingertips is an early sensory manifestation of the same neuronal hyperexcitability. The history of extensive small bowel resection is relevant because it impairs calcium and vitamin D absorption, contributing to chronic hypocalcemia.^[1][3]

Watch out! Trousseau sign is carpal spasm, not simply worsening numbness or tingling. Numbness and tingling spreading along the fingers describes the sensory prodrome of hypocalcemia, but it is not the objective motor response recorded as a positive test.

Key point! Trousseau sign and Chvostek sign are distinct bedside findings. Trousseau sign is elicited by cuff inflation and produces hand spasm. Chvostek sign is elicited by tapping the facial nerve anterior to the ear and produces ipsilateral facial twitching.^[1][4]

Sign	Maneuver	Positive response	Mechanism
Trousseau sign	Inflate BP cuff above systolic pressure for up to 3 minutes	Carpal spasm: wrist and thumb flexion, fingers extended	Ischemia-induced nerve hyperexcitability from hypocalcemia
Chvostek sign	Tap facial nerve anterior to the earlobe	Twitching of the ipsilateral upper lip and cheek	Mechanical nerve irritability from hypocalcemia

Option 3 describes the response seen with a positive Chvostek sign, not Trousseau sign. Option 4 describes petechiae below the cuff, which is a sign of capillary fragility or a tourniquet test finding, unrelated to hypocalcemia. Option 2 captures the sensory complaint but not the objective carpal spasm that defines a positive Trousseau test.

The correct response to record is spasm of the hand with the wrist and thumb flexed, because this is the objective motor manifestation of latent tetany unmasked by ischemia in a patient with hypocalcemia.^[1][2]