Clinical Skill Muse #20: Chvostek Sign and Trousseau Sign

Unfortunately there will never be a Luterman sign....so here's the question: what are these signs, when were they discovered and who were the docs who discovered them? Bonus question..which is more sensitive? And how reliable are they?

The Chvostek sign (also Weiss sign) is one of the signs of tetany seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve. When the facial nerve is tapped at the angle of the jaw, the facial muscles on the same side of the face will contract momentarily (typically a twitch of the nose or lips) because of hypocalcaemia (ie from hypoparathyroidism, pseudohypoparathyroidism, hypovitaminosis D) with resultant hyperexcitability of nerves.

Frantisek Chvostek (1835–1884) was an Austrian surgeon who was born in Moravia, Czech Republic. Chvostek investigated the pathology and treatment of neurologic illnesses, including the use of electrotherapy, and described the sign that was to bear his name in 1876.

Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. This sign may become positive before other gross manifestations of hypocalcemia such as hyperreflexia and tetany, but is generally believed to be more sensitive than the Chvostek sign for hypocalcemia.

To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure greater than the systolic blood pressure and held in place for 3 minutes. This will occlude the brachial artery. In the absence of blood flow, the patient's hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct. The sign is also known as main d'accoucheur (French for "hand of the obstetrician") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.

Armand Trousseau (October 14, 1801 — June 27, 1867) was a French internist. His contributions to medicine include Trousseau sign of malignancy, Trousseau sign of latent tetany, Trousseau-Lallemand bodies (an archaic synonym for Bence Jones cylinders), and the truism, "use new drugs quickly, while they still work." Trousseau was instrumental in creating new modes of treatment of croup, emphysema, pleurisy, goiter, and malaria. He received the prize of the French Academy of Medicine for his classic essay on laryngology which originally appeared in 1837. He was the first in France to perform a tracheotomy, and he wrote a monograph on this as well as intubation in 1851. His textbooks on clinical medicine and therapeutics were both extremely popular and translated into English. Trousseau coined the terms aphasia and forme fruste and popularized eponyms in disease description such as Addison's
disease and Hodgkin's lymphoma.

Trousseau was considered an outstanding teacher. Numerous students of his achieved fame in their own right, including Puerto Rican pro-independence leader, surgeon and Légion d'honneur laureate, Ramón Emeterio Betances. Trousseau’s grandson was the distinguished ophthalmologist Armand Trousseau (1856-1910).

As previously mentioned, Chvostek’s sign is a classic signification of hypocalcemia. However, some studies have demonstrated that hypocalcemia is not the only condition in which a positive Chvostek’s sign may be seen. Other conditions that have produced Chvostek’s sign include rickets, diphtheria, measles, scarlet fever, whooping cough, and myxedema. The sign has also been positive in persons without any known disease. One study demonstrated a positive Chvostek’s sign in nearly 25% of healthy individuals. Another study showed that 29% of patients with laboratory- confirmed hypocalcemia had a negative Chvostek’s sign. In turn, the medical community considers Chvostek’s sign as only a crude indicator of neuromuscular irritability and an unreliable indicator of hypocalcemia.

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Maynard