Difference between revisions of "Chvostek's sign"

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<embedvideo service="youtube" Alignment="right">https://youtu.be/L92A-QbN0Kw</embedvideo>Chvostek’s sign is a twitch, spasm or tetanic, cramp-like contraction of some or all of the ipsilateral facial muscles on tapping over the pes anserinus anterior to the tragus.(1-4) It is classically a sign of tetany but may also occur with hyperreflexia due to upper motor neuron dysfunction.
  
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Various degrees of response may occur (Video). The sign is minimal if only a slight twitch of the upper lip or the angle of the mouth results; moderate if there is movement of the ala nasi and the entire corner of the mouth; maximal if the muscles of the forehead, eyelid, and cheek also contract. When the response is marked, even muscles supplied by the trigeminal nerve may respond. When very active the response may be elicited merely by stroking the skin in front of the ear. Schultz's sign is the same response elicitied by percussing midway between the zygomatic arch and the angle of the mouth.
  
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Chvostek's sign is the result of hyperexcitability of the motor nerves, in this instance the facial nerve, to mechanical stimulation. The motor Tinel’s sign has been reported as evidence of abnormal mechanosensitivity in entrapment neuropathies but may also occur in normals. Both Chvostek’s sign and the Lust peroneal phenomenon are probably examples of a motor Tinel’s sign.
  
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See Kamalanathan for another video, although it is much less dramatic than this one.(5) The Méneret paper shows multiple videos eliciting Chvostek’s sign in normal individuals.(6) YouTube offers multiple examples. Trousseau's sign is more specific than Chvostek's sign for latent tetany.
  
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Video legend. A patient demonstrating her own Chvostek’s sign, due to transient hypocalcemia that developed post-thyroidectomy. She also had a positive Trousseau’s sign. Modified with permission from original video.
  
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References
  
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[[File:Fig 1 OK sign AIN.jpg|thumb|Figure 1]][[File:Fig 2 OK sign high median neuropathy.jpg|thumb|Figure 2]]The OK (pinch, straight thumb) sign refers to an inability to form the “OK” sign. Patients with weakness of the flexor pollicis longus and the flexor digitorum profundus to the index finger are unable to oppose the tips of the thumb and index finger to form a proper circle, but make a triangle instead, touching the finger pads.(1,2) These muscles are innervated by the anterior interosseous nerve, and the OK sign may be seen in either anterior interosseous or high median neuropathy.
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1. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.
  
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The median nerve may rarely be entrapped proximally where it passes between the two heads of the pronator teres or by the ligament of Struthers, an anomalous fibrous band running from a distal humeral supracondylar spur to the medial epicondyle. Anterior interosseous neuropathy palsy often occurs as an isolated manifestation of neuralgic amyotrophy.(3) Recent MRI evidence indicates the process in many cases of AIN palsy predominantly involves AIN fascicles in the main trunk of the median nerve in the upper arm.(4)
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2. Campbell WW. Barohn RJ. DeJong's the neurologic examination, 8th ed. Philadelphia: Wolters Kluwer, 2020.
  
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In this video https://www.youtube.com/watch?v=HVHegl-42PE Dr. Nabil Ebraheim discusses AIN and the OK sign.  
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3. Athappan G, Ariyamuthu VK. Images in clinical medicine. Chvostek's sign and carpopedal spasm. N Engl J Med. 2009;360:e24.  
  
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Figure 1. Patient demonstrating OK sign on the right due to AIN palsy.  
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4. Narayan SK, Sivaprasad P, Sahoo RN, et al. Teaching video NeuroImage: Chvostek sign with Fahr syndrome in a patient with hypoparathyroidism. Neurology 2008;71:e79.  
  
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Figure 2. On the right, patient with proximal median neuropathy, which developed as a complication following a retrograde brachial angiogram. Normal hand on the left.
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5. Kamalanathan S, Balachandran K, Parthan G, et al. Chvostek's sign: a video demonstration. BMJ Case Rep. 2012;2012.  
  
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==References==
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6. Méneret A, Guey S, Degos B. Chvostek sign, frequently found in healthy subjects, is not a useful clinical sign. Neurology. 2013;80:1067.
  
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1. Campbell WW. Barohn RJ. DeJong's the neurologic examination, 8th ed. Philadelphia: Wolters Kluwer, 2020.
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[[Category: Motor Signs]]
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2. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.
 
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3. Akane M, Iwatsuki K, Tatebe M, et al. Anterior interosseous nerve and posterior interosseous nerve involvement in neuralgic amyotrophy. Clin Neurol Neurosurg. 2016;151:108-112.
 
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4. Pham M, Bäumer P, Meinck HM, Schiefer J, et al. Anterior interosseous nerve syndrome: fascicular motor lesions of median nerve trunk. Neurology. 2014;82:598-606.
 
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[[Category:Motor Signs]]
 

Latest revision as of 01:53, 4 November 2023

Chvostek’s sign is a twitch, spasm or tetanic, cramp-like contraction of some or all of the ipsilateral facial muscles on tapping over the pes anserinus anterior to the tragus.(1-4) It is classically a sign of tetany but may also occur with hyperreflexia due to upper motor neuron dysfunction.

Various degrees of response may occur (Video). The sign is minimal if only a slight twitch of the upper lip or the angle of the mouth results; moderate if there is movement of the ala nasi and the entire corner of the mouth; maximal if the muscles of the forehead, eyelid, and cheek also contract. When the response is marked, even muscles supplied by the trigeminal nerve may respond. When very active the response may be elicited merely by stroking the skin in front of the ear. Schultz's sign is the same response elicitied by percussing midway between the zygomatic arch and the angle of the mouth.

Chvostek's sign is the result of hyperexcitability of the motor nerves, in this instance the facial nerve, to mechanical stimulation. The motor Tinel’s sign has been reported as evidence of abnormal mechanosensitivity in entrapment neuropathies but may also occur in normals. Both Chvostek’s sign and the Lust peroneal phenomenon are probably examples of a motor Tinel’s sign.

See Kamalanathan for another video, although it is much less dramatic than this one.(5) The Méneret paper shows multiple videos eliciting Chvostek’s sign in normal individuals.(6) YouTube offers multiple examples. Trousseau's sign is more specific than Chvostek's sign for latent tetany.

Video legend. A patient demonstrating her own Chvostek’s sign, due to transient hypocalcemia that developed post-thyroidectomy. She also had a positive Trousseau’s sign. Modified with permission from original video.

References

1. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.

2. Campbell WW. Barohn RJ. DeJong's the neurologic examination, 8th ed. Philadelphia: Wolters Kluwer, 2020.

3. Athappan G, Ariyamuthu VK. Images in clinical medicine. Chvostek's sign and carpopedal spasm. N Engl J Med. 2009;360:e24.

4. Narayan SK, Sivaprasad P, Sahoo RN, et al. Teaching video NeuroImage: Chvostek sign with Fahr syndrome in a patient with hypoparathyroidism. Neurology 2008;71:e79.

5. Kamalanathan S, Balachandran K, Parthan G, et al. Chvostek's sign: a video demonstration. BMJ Case Rep. 2012;2012.

6. Méneret A, Guey S, Degos B. Chvostek sign, frequently found in healthy subjects, is not a useful clinical sign. Neurology. 2013;80:1067.

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