Chvostek’s sign is a clinical indicator of neuromuscular excitability resulting from hypocalcemia. It is elicited by tapping the facial nerve approximately 2 cm anterior to the earlobe, just below the zygomatic arch. A positive sign is characterized by twitching of the ipsilateral facial muscles, particularly around the cheek, mouth, or eye.

Pathophysiology

Hypocalcemia increases neuronal membrane excitability by lowering the threshold for depolarization. This heightened excitability makes peripheral nerves, especially the facial nerve, more responsive to mechanical stimuli. Chvostek’s sign reflects this increased excitability and is, therefore, considered a clinical manifestation of underlying electrolyte imbalance.

How to elicit the sign

To elicit Chvostek’s sign:

1. The patient should be relaxed and seated or lying down.

2. Use your index or middle finger to gently tap over the facial nerve, about 2 cm anterior to the external auditory meatus.

3. A positive response is the contraction or twitching of the muscles at the angle of the mouth, nose, or cheek on the same side.

Interpretation

• Positive Chvostek’s Sign: Facial muscle twitching occurs — indicates neuromuscular irritability.

• False Positives: Up to 10–25% of healthy individuals may show a mild twitch, especially children.

• False Negatives: Some patients with hypocalcemia may not show a positive response, particularly in chronic conditions.

Clinical conditions associated with positive Chvostek’s sign

Chvostek’s sign is typically observed in conditions that cause hypocalcemia, such as:

• Hypoparathyroidism (e.g., post-surgical or autoimmune)

• Vitamin D deficiency

• Chronic kidney disease (CKD) with secondary hyperparathyroidism

• Post-thyroidectomy hypocalcemia (due to accidental removal or injury to parathyroid glands)

• Acute pancreatitis

• Pseudohypoparathyroidism

• Magnesium deficiency (which can impair PTH secretion and action)

Summary table. Chvostek’s Sign: Causes, Signs & Symptoms, and Special Considerations

Differentiation from trousseau’s sign

While Chvostek’s sign involves facial nerve stimulation, Trousseau’s sign is elicited by inflating a blood pressure cuff above systolic pressure for 3 minutes, which causes carpal spasm in hypocalcemic states. Trousseau’s is generally more specific for hypocalcemia than Chvostek’s sign.

Limitations and considerations

• Chvostek’s sign is more sensitive but less specific than Trousseau’s sign.

• It should not be used in isolation to diagnose hypocalcemia.

• Always correlate with serum calcium levels and the clinical context.

Clinical importance

In settings where laboratory access is delayed, such as in resource-limited environments, Chvostek’s sign serves as a useful bedside clue for hypocalcemia. Early detection and correction of calcium imbalances can prevent life-threatening complications such as tetany, laryngospasm, or cardiac arrhythmias.

Conclusion

Chvostek’s sign remains a valuable clinical tool in the physical examination of patients suspected of having hypocalcemia. Although not highly specific, when used alongside other clinical features and biochemical assessments, it enhances early recognition and timely management of calcium-related disorders.

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