Trousseau's sign

Trousseau's Sign is a clinical phenomenon often associated with hypocalcemia and latent tetany. It is named after Armand Trousseau, a French physician who first described the sign in the 19th century. Trousseau's Sign is considered an important diagnostic tool in identifying calcium deficiency and related metabolic disorders.

Overview

Trousseau's Sign is elicited by inflating a blood pressure cuff on the upper arm to a pressure exceeding the patient's systolic blood pressure and maintaining it for three minutes. The test is positive if a carpal spasm occurs, which is characterized by the adduction of the thumb and flexion of the wrist and metacarpophalangeal joints, resembling a hand posture known as main d'accoucheur or "obstetrician's hand."

Pathophysiology

The pathophysiological basis of Trousseau's Sign lies in the neuromuscular irritability caused by hypocalcemia. Calcium plays a crucial role in muscle contraction and nerve conduction. A decrease in the ionized calcium levels in the blood increases the neural membrane permeability to sodium, leading to depolarization and enhanced neuromuscular excitability. This heightened excitability is what leads to the spasmodic contractions observed in Trousseau's Sign.

Clinical Significance

Trousseau's Sign is primarily used to diagnose latent tetany, which is a condition that indicates a predisposition to spasms or seizures due to neuromuscular excitability, often as a result of hypocalcemia. It is also indicative of other conditions that may cause hypocalcemia, such as hypoparathyroidism, vitamin D deficiency, and magnesium deficiency. Recognizing Trousseau's Sign is crucial for the early detection and treatment of these underlying conditions to prevent potential complications.

Differential Diagnosis

While Trousseau's Sign is indicative of hypocalcemia, it is essential to differentiate it from other causes of neuromuscular excitability, such as hyperventilation syndrome and alkalosis. A comprehensive evaluation, including a detailed medical history, physical examination, and laboratory tests, is necessary to establish the underlying cause of the sign.

Treatment

The treatment of a positive Trousseau's Sign focuses on addressing the underlying cause of hypocalcemia. This may involve supplementation with calcium and vitamin D, correction of magnesium levels, or management of the conditions leading to hypocalcemia. In emergency situations, intravenous calcium may be administered to quickly correct the calcium levels and alleviate symptoms.

Conclusion

Trousseau's Sign is a valuable diagnostic tool in the identification of hypocalcemia and latent tetany. Its recognition can lead to the timely diagnosis and treatment of various metabolic disorders, preventing complications and improving patient outcomes.