Familial hypothyroidism associated with Chovtek’s sign
After experiencing four generalized seizures in the past week, a 2-year-old who had previously been healthy was taken to the emergency room. He had been treated for a low serum calcium level after being transported to another hospital following his second seizure. The physical examination revealed brisk tendon reflexes in all four limbs at the current presentation. Chvostek’s sign, which is characterised with symotoms including neuromuscular irritability, was seen when the ipsilateral facial nerve was tapped, causing the face’s muscles to twitch involuntarily. This case highlights the corrrelation between hypoparathyroidism and Chovtek’s sign.
Low levels of parathyroid hormone, magnesium, and total calcium, as well as a high phosphorus level, were noteworthy in laboratory testing. Patchy hyperdensities in the basal ganglia were seen on head computed tomography, which is consistent with persistent hypoparathyroidism. Whole-exome sequencing was carried out because of worries about a genetic basis for hypoparathyroidism, and it identified one de novo variant allele in GCM2. Type 2 familial isolated hypoparathyroidism was diagnosed. After receiving intravenous and oral calcium, the patient’s convulsions stopped. Calcium and calcitriol supplementation was started as a long-term treatment. The patient had a low-normal blood calcium level and no seizures during the 3-month follow-up.
Clinical significance
Hypocalcemia is one of the most frequent postoperative consequences after thyroid surgery. After a thyroid lobectomy, the incidence of hypocalcemia status was 13.8%, and after a total thyroidectomy, it was 38.8%, according to research by Rio Del et al. Because it can produce fatal arrhythmias, QT prolongation is a serious consequence of hypocalcemia. One of the most serious arrhythmias that can result in cardiac arrest is ventricular arrhythmia. Due to the risk of hypocalcemia, calcium carbonate supplements have become standard therapy for patients who have had thyroid surgery.
It is generally recognized that proton pump inhibitors exacerbate hypocalcemia, so patients taking calcium supplements should stay away from them. As was previously mentioned, there is a weak link between calcium levels and the Chvostek sign. Nevertheless, if tetany manifests as facial nerve stimulation, it can be helpful to measure the blood calcium level.
Background
Dr. Chvostek discovered in the late 1800s that ipsilateral facial muscles might twitch in response to mechanical stimulation of the facial nerve, such as with the examiner’s fingertip. This link became known as the Chvostek sign, and the long-accepted explanation is that it was caused by hypocalcemia. After albumin correction, a calcium level of less than 8.8 mg/dl is deemed inadequate.
The body needs calcium as an electrolyte. It is linked to numerous processes, but two of the most important ones are nerve impulse transmission and muscle contractions. Congestive cardiac failure, QT prolongation, cardiomyopathy, and seizures can all result from calcium deficiencies. As a result, replacement therapy is frequently administered to patients in hospitals. Thyroidectomy complications are a frequent cause of hypocalcemia.
Four parathyroid glands, often found on the back of the thyroid gland, are present in a healthy person. Thyroid surgery may result in the unintentional resection of one or more parathyroid glands. Parathyroid hormone (PTH) is produced by the parathyroid glands, and PTH levels can drop if those glands are removed. Because PTH controls the body’s calcium levels, lowering its serum level will result in hypocalcemia.
Correlation between Chovtek’s sign and hypocalcemia
Although there isn’t much evidence to back it, the medical world has long accepted the link between hypocalcemia and the Chvostek sign. Dr. Hujoel’s population-based analysis revealed no connection between hypocalcemia and the Chvostek sign. Furthermore, the likelihood of a positive Chvostek sign increased by 4% for every 1 mg/dl increase in calcium. Consequently, it was determined that there was a stronger association between hypercalcemia and facial nerve tetany upon stimulation. According to additional research, 29% of people with hypocalcemia did not produce a positive Chvostek sign, while 25% of healthy people can elicit a good sign.
Children with measles, diphtheria, scarlet fever, whooping cough, rickets, and myxedema have also been reported to exhibit the Chvostek sign.
Source: NEJM