What is Chvostek's sign?

From the Guidelines

Chvostek's sign is a clinical indicator of hypocalcemia that should prompt further evaluation and treatment, particularly in patients with chronic kidney disease (CKD), as it may indicate a need to increase serum calcium levels or adjust therapy to prevent complications such as tetany, seizures, or laryngospasm. When assessing Chvostek's sign, it is essential to consider the patient's overall clinical presentation, including symptoms such as paresthesia, bronchospasm, or seizures, as these can also be indicative of hypocalcemia 1. The presence of Chvostek's sign, along with other clinical symptoms, may necessitate therapy to increase serum calcium levels, such as calcium salts like calcium carbonate, and/or oral vitamin D sterols, as recommended in the K/DOQI clinical practice guidelines for bone metabolism and disease in CKD 1. Key points to consider when evaluating Chvostek's sign include:

• The sign's physiological basis, which involves calcium's role in stabilizing nerve cell membranes, and how decreased calcium levels can lead to neuronal hyperexcitability 1
• The potential for false positives, as Chvostek's sign can be positive in 10-25% of normal individuals, highlighting the need for comprehensive evaluation
• The importance of maintaining the serum calcium-phosphorus product at <55 mg2/dL to prevent complications associated with abnormal calcium and phosphorus levels in CKD patients 1
• The need for individualized treatment approaches based on the patient's CKD stage, serum calcium and phosphorus levels, and intact PTH levels, as outlined in the K/DOQI guidelines 1.

From the Research

Chvostek Sign

• The Chvostek sign is a clinical indicator of hypocalcemia, characterized by a contraction of ipsilateral facial muscles subsequent to percussion over the facial nerve 2.
• However, studies have shown that a positive Chvostek sign is informative of normal to increased serum calcium levels rather than hypocalcemia 2.
• The sign is often used in conjunction with other clinical manifestations, such as tetany, seizures, and diminished deep tendon reflexes, to diagnose hypocalcemia 3.
• In children with seizures, Chvostek's sign was found to be marked in those with epilepsy or hypocalcemia, while normocalcemic patients had no other signs of neuromuscular hyperexcitability 4.

Association with Hypocalcemia

• Hypocalcemia can be caused by various factors, including decreased calcium absorption, parathyroid hormone deficiency, and skeletal resistance to parathyroid hormone 5, 3.
• The diagnosis of hypocalcemia involves measuring total and ionic calcium, magnesium, parathyroid hormone, and vitamin D metabolites 3.
• Treatment of hypocalcemia typically involves intravenous calcium infusion and oral calcium and/or vitamin D supplementation 5.

Clinical Significance

• The Chvostek sign is an important clinical tool for diagnosing and managing hypocalcemia, but its presence does not necessarily indicate hypocalcemia 2.
• A comprehensive evaluation of the patient's clinical history, physical examination, and laboratory results is necessary to diagnose and treat hypocalcemia effectively 5, 3.