TrousseauZeichen

The Trousseau sign, also known as the Trousseau phenomenon or Trousseau’s sign, is a clinical indicator associated with hypocalcemia, a condition characterized by abnormally low levels of calcium in the blood. The sign is named after the French physician Auguste Trousseau, who first described it in the 19th century.

The Trousseau sign is elicited by inflating a blood pressure cuff above the systolic blood pressure on the upper arm for several minutes. In individuals with hypocalcemia, this procedure may induce carpopedal spasm, a temporary contraction of the muscles in the hand and foot. This spasm often manifests as a flexion of the wrist and metacarpophalangeal joints, along with extension of the fingers and adduction of the thumb, resembling a characteristic "claw-like" hand position. In some cases, facial muscle spasms, such as those around the mouth or eyelids, may also occur.

The mechanism behind the Trousseau sign is linked to the role of calcium in nerve and muscle function. Calcium acts as a critical regulator of cellular excitability, and its deficiency increases neuronal hyperexcitability, leading to involuntary muscle contractions. The sign is considered a reliable diagnostic tool for detecting latent hypocalcemia, particularly in patients with conditions such as chronic kidney disease, vitamin D deficiency, or hypoparathyroidism.

While the Trousseau sign is a useful clinical finding, it is not specific to hypocalcemia alone. Other conditions, such as alkalosis or magnesium deficiency, may also contribute to similar muscle spasms. Therefore, it is typically used in conjunction with other diagnostic tests, including serum calcium measurements, to confirm a diagnosis of hypocalcemia. Early detection and treatment of low calcium levels are essential to prevent complications such as tetany, seizures, or long-term skeletal abnormalities.