Chvostek sign
Chvostek Sign[edit]
Chvostek Sign[edit]
The Chvostek sign, pronounced /ˈkvɒstɪk/, is a clinical indication of hypocalcemia, characterized by the twitching of muscles innervated by the facial nerve (CNVII). It reveals an abnormal reaction to facial nerve stimulation.
Overview[edit]
Chvostek sign is a notable diagnostic tool used to identify hypocalcemia, a condition characterized by low levels of calcium in the blood.
Pathophysiology[edit]
When the facial nerve is tapped near the tragus, the facial muscles on the same side of the face (ipsilateral) contract momentarily. This reaction, often seen as a twitch of the nose or lips, is due to the hyperexcitability of nerves caused by hypocalcemia. Conditions leading to hypocalcemia include hypoparathyroidism, pseudohypoparathyroidism, and hypovitaminosis D.
Clinical Significance[edit]
Hypocalcemia[edit]
Hypocalcemia is the primary condition associated with the Chvostek sign. This electrolyte imbalance leads to increased nerve excitability and muscular spasms.
Other Conditions[edit]
Though classically associated with hypocalcemia, the Chvostek sign can also manifest in respiratory alkalosis conditions like hyperventilation, which causes a decrease in serum calcium levels while maintaining normal overall calcium due to a shift of Ca2+ ions.
Diagnostic Application[edit]
The Chvostek sign is used in clinical settings to quickly assess the possibility of hypocalcemia. Its presence prompts further investigation and management of underlying conditions.
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