Chvostek's sign
Chvostek's sign: Excerpt from Handbook of Signs & Symptoms (Third Edition)
Chvostek's sign is an abnormal spasm of the facial muscles that's elicited by lightly tapping the patient's facial nerve near his lower jaw. (See Eliciting Chvostek's sign.) This sign usually suggests hypocalcemia, but can occur normally in about 25% of cases. Typically, it precedes other signs of hypocalcemia and persists until the onset of tetany. It can't be elicited during tetany because of strong muscle contractions.
Normally, eliciting Chvostek's sign is attempted only in patients with suspected hypocalcemic disorders. However, because the parathyroid gland regulates calcium balance, Chvostek's sign may also be tested in patients before neck surgery to obtain a baseline.
Emergency interventions
Test for Trousseau's sign, a reliable indicator of hypocalcemia. Closely monitor the patient for signs of tetany, such as carpopedal spasms or circumoral and extremity paresthesia.
Be prepared to act rapidly if a seizure occurs. Perform an electrocardiogram to check for changes associated with hypocalcemia that can predispose the patient to arrhythmias. Place the patient on a cardiac monitor.
History and physical examination
Obtain a brief history. Find out if the patient has had his parathyroid glands surgically removed or if he has a history of hypoparathyroidism, hypomagnesemia, or a malabsorption disorder. Ask him or his family if they have noticed any changes in the patient's mental status, such as depression or slowed responses, which can accompany chronic hypocalcemia.
Medical causes
Hypocalcemia.
The degree of muscle spasm elicited reflects the patient's serum calcium level. Initially, hypocalcemia produces paresthesia in the fingers, toes, and circumoral area that progresses to muscle tension and carpopedal spasms. The patient may also complain of muscle weakness, fatigue, and palpitations. Muscle twitching, hyperactive deep tendon reflexes, choreiform movements, and muscle cramps may also occur. The patient with chronic hypocalcemia may have mental status changes; diplopia; difficulty swallowing; abdominal cramps; dry, scaly skin; brittle nails; and thin, patchy scalp and eyebrow hair.
Other causes
Blood transfusion.
A massive transfusion can lower serum calcium levels and allow Chvostek's sign to be elicited.
Special considerations
Collect blood samples for serial calcium studies to evaluate the severity of hypocalcemia and the effectiveness of therapy. Such therapy involves oral or I.V. calcium supplements. Also, look for Chvostek's sign when evaluating a patient postoperatively.
Pediatric pointers
Because Chvostek's sign may be observed in healthy infants, it isn't elicited to detect neonatal tetany.
Geriatric pointers
Always consider malabsorption and poor nutritional status in the elderly patient with Chvostek's sign and hypocalcemia.
Pictures
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
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- Carpopedal spasm
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Carpopedal spasm (Handbook of Signs & Symptoms (Third Edition))
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