Trousseau sign of latent tetany is a
medical sign
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
observed in patients with low
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...
. From 1 to 4 percent of normal patients will test positive for Trousseau's sign of latent tetany. This sign may be positive before other manifestations of
hypocalcemia such as
hyperreflexia and
tetany
Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them.
Muscle cramps cau ...
, as such it is generally believed to be more
sensitive (94%) than the
Chvostek sign
The Chvostek sign () is a clinical sign that someone may have a low blood calcium level (a decreased serum calcium, called hypocalcemia). The Chvostek sign is the abnormal twitching of muscles that are activated (innervated) by the facial nerve ( ...
(29%) 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
The brachial artery is the major blood vessel of the (upper) arm. It is the continuation of the axillary artery beyond the lower margin of teres major muscle. It continues down the ventral surface of the arm until it reaches the cubital foss ...
. 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 joint
The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow ...
s flex, the
DIP and
PIP joints extend, and the fingers
adduct. The sign is also known as ''main d'accoucheur'' (
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
for "''hand of the
obstetrician''") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.
The sign is named after French physician
Armand Trousseau
Armand Trousseau (14 October 1801 – 23 June 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 ...
, who described the phenomenon in 1861. It is distinct from the
Trousseau sign of malignancy, which is a type of abnormal blood clot due to certain types of cancer.
Trousseau's sign of visceral malignancy
in GPnotebook, retrieved May 2022
References
Symptoms and signs: Endocrinology, nutrition, and metabolism
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