NeuroTeach 39 - Signs of tetany

 Signs of tetany

“Trousseau sign of malignancy, Trousseau sign of latent tetany, Trousseau–Lallemand bodie”
French internist Armand Trousseau (1801–1867)


2) Definition
Tetanus - it is different disease w/ different pathology Tetanic contractions (physiologic tetanus) - broad range of muscle contraction types Tetany - a type of tetanic contraction

3) Clinical manifestations of tetany
“spasm and tonic contractions of the skeletal muscles, principally the distal muscles of the extremities”

4) Pathophysiology
- more easily obtained if the patient first hyperventilates for a few minutes (latent tetany)


5) Chvostek’s sign
“tapping over the facial nerve causes a twitch” Hyperexcitability of the motor nerves 2 points of stimulation -Chvostek: just below zygomatic process of temporal bone, in front of ear -Schultz: midway between the zygomatic arch and the angle of the mouth


6) Conditions associated w/ Chvostek sign
- tetany - CST lesion (hyperreflexia) - children w/ epilepsy - neonatal period disappearing w/ aging Limitation - crude indicator of neuro-muscular irritability and an unreliable indicator of hypocalcemia

7) Chvostek’s sign


8) Chvostek’s sign


9) Trousseau’s sign
“compression of the arm by manual pressure cause contraction of the muscles of the hand” Ischemia increases nerve excitability & spontaneous discharges Obstetrician’s/accoucheur’s hand, main d’accoucheur Similar pressure around thigh will cause pedal spasm

10) Phases
First, paresthesia progress centripetally Second, finger twitching Third, contraction - there may be a latent period of 1/2 to 4 minutes - 20 mmHg over their systolic blood pressure for 3 minutes

11) Limitations
- sometimes positive in hysterical subjects - workers whose hands are held in a semi-tetanic position for some hours daily

12) Trousseau’s sign


13) Trousseau’s sign


14) Clinical significance
a. Sensitivity for latent tetany - Trousseau (94%) vs Chvostek (29%) b. Healthy individuals - 4% of healthy individuals have Trousseau

15) Hyperventilation test
Elicitation: hyperventilate at rate of 55-60/min for 3 min. Sitting upright, with hands placed loosely on knees Response: if no tetanic manifestation develops, tetany is ruled out Disadvantages: disturbing symptoms after hyperventilation


16) Hyperventilation test


17) Trousseau-von Bonsdorff test
(tourniquet&hyperventillation) a. sitting up, hands placed on knees b. tourniquet for 4 min c. if no cramp appear, tourniquet is removed d. hyperventilate at the rate of 40 breaths/min d. test is stopped at 75sec/sooner if carpel cramp appears

18) Pool-Schlesinger sign
Pool/arm phenomenon - abduct&elevate patient's arm w/ his forearm extended - brachial plexus tension Schlesinger/leg phenomenon - flex patient's extended leg at the hip - sciatic nerve tension


19) Peroneal (Lust phenomenon)
Elicit: tap over the common peroneal nerve (lateral neck of the fibula with the patient's knee relaxed and slightly flexed) Response: dorsiflexion and abduction of the foot


20) Escherich's sign
Elicit: percussion of the inner surface of the lips/tongue Response: contractions of the lips, masseters, and tongue

21) Hochsinger’s sign
Elicit: pressure on inner aspect of biceps muscle Response: spasm and contraction of the hand (variant of Trousseau sign)

22) Kashida thermic
Elicit: application of either hot or cold irritants Response: hyperesthesias and spasms

23) Schultze’s sign
Elicit: mechanical stimulation of protruded tongue Response: transient depression or dampling at the site of stimulation (similar to myotonia)

24) Erb’s sign
- increased irritability of motor nerves, detected by electromyography