Chvostek's Sign and Facial Reflexes in Normal Newborn Infants

Abstract

SUMMARY The response to mechanical stimulation (tapping) over the facial nerve immediately in front of the external auditory meatus and the lobe of the ear, and on the soft tissues of the cheek, has been studied in normal newborn infants. Tapping in front of the meatus produced a unilateral twitch of the facial muscles in one instance only, although pouting of the lips and grimacing was common. Cheek percussion commonly produced the type of facial contraction described by Chvostek; however, it is suggested the term Chvostek's sign should be reserved for cases in which percussion over the facial nerve itself causes a twitch and should not be used for facial twitches elicited by tapping over the muscles. The physiological basis of the responses is discussed. RÉSUMÉ Le signe de Chvostek et les reflexes faciaux chez le nouveau‐né normal La réponse à la stimulation mécanique (chiquenaudes) sur le nerf facial immédiatement en avant du méat auditif externe et du lobe de l'oreille, et sur les tissus mous de la joue a été étudiée chez des nouveau‐nés normaux. Les chiquenaudes en avant du méat ont produit une crispation des muscles faciaux dans un cas seulement, bien que moue et grimace soient communes. La percussion de la joue produit d'habitude le type de contraction faciale décrite par Chvostek; pourtant l'auteur suggère que l'on devrait réserver le terme ‘signe de Chvostek’ pour les cas où la percussion sur le nerf facial lui‐même cause la crispation, et ne pas l'utiliser pour des crispations faciales provoquées par chiquenaudes sur les muscles. Les bases physiologiques de ces réponses sont discutées.

The association between serum calcium levels and Chvostek sign

“…24 The exact location of percussion for the Chvostek sign varies in the literature, and different locations carry different likelihoods of causing a positive Chvostek sign. 8,20 The 2 most common areas of percussion are anterior to the external meatus over the vertical ramus of the mandible and percussion on the soft tissues of the cheek, halfway between the earlobe and the corner of the mouth (figure 2). The rate of positive Chvostek sign for each location varies in the literature, with a recent review on Chvostek sign finding a range of 1%-50% positives for the former and 5%-29% positives for the latter location.…”

“…20 One study comparing these 2 possible techniques speculated that percussion over the soft tissues may result in direct muscle stimulation and therefore not result in a true positive. 8 No consensus exists in the literature on the proper technique to use. In this study, physicians were instructed to percuss over the malar process of the temporal bone.…”

“…search strategy, only 11 included data on positive Chvostek sign rates and serum calcium levels. [4][5][6][7][8][9][10][11][12][13][14] Only 4 measured calcium levels in all evaluated patients, a minimum requirement for evaluating diagnostic accuracy. [5][6][7]12 Sensitivities from these 4 studies ranged from 0% to 100% and specificities from 78.8% to 100%.…”