Physical examination of someone with hypocalcemia may show tetany, but it is also possible to provoke tetany of the facial muscles by tapping on the facial nerve (a phenomenon known as Chvosteks sign) or by using the cuff of a sphygmomanometer to temporarily obstruct the blood flow to the arm (a phenomenon known as Trousseaus sign of latent tetany).A number of medical emergencies can arise in people with low calcium levels. These are seizures, severe irregularities in the normal heart beat, as well as spasm of the upper part of the airways or the smaller airways known as the bronchi (both potentially causing respiratory failure). Related conditions
Causes
Hypoparathyroidism can have the following causes:
Removal of, or trauma to, the parathyroid glands due to thyroid surgery (thyroidectomy), parathyroid surgery (parathyroidectomy) or other surgical interventions in the central part of the neck (such as operations on the larynx and/or pharynx) is a recognized cause. It is the most common cause of hypoparathyroidism. Although surgeons generally make attempts to spare normal parathyroid glands at surgery, inadvertent injury to the glands or their blood supply is still common. When this happens, the parathyroids may cease functioning. This is usually temporary but occasionally long term (permanent). Kenny-Caffey Syndrome
Autoimmune invasion and destruction is the most common non-surgical cause. It can occur as part of autoimmune polyendocrine syndromes. Hemochromatosis can lead to iron accumulation and consequent dysfunction of a number of endocrine organs, including the parathyroids.
The phrase "snapping of the brain" was coined in 1920 by the British physician and psychiatrist Robert Armstrong-Jones. A detailed description of the syndrome and the name "exploding head syndrome" was given by British neurologist John M. S. Pearce in 1989. More recently, Peter Goadsby and Brian Sharpless have proposed renaming EHS "episodic cranial sensory shock" as it describes the symptoms more accurately and better attributes to Mitchell. References
Further reading
Møller, Aage R.; Langguth, Berthold; DeRidder, Dirk; Kleinjung, Tobias (2010-11-16). Textbook of Tinnitus. Springer Science & Business Media. ISBN 9781607611455. == External links ==