Template:For Template:Infobox medical condition (new) Hypocalcemia is low calcium levels in the blood serum.[1] The normal range is 2.1–2.6 mmol/L (8.8–10.7 mg/dl, 4.3–5.2 mEq/L) with levels less than 2.1 mmol/l defined as hypocalcemia.[2][3][4] Mildly low levels that develop slowly often have no symptoms.[5][6] Otherwise symptoms may include numbness, muscle spasms, seizures, confusion, or cardiac arrest.[2][5]
Common causes include hypoparathyroidism and vitamin D deficiency.[5] Others causes include kidney failure, pancreatitis, calcium channel blocker overdose, rhabdomyolysis, tumor lysis syndrome, and medications such as bisphosphonates.[2] Diagnosis should generally be confirmed with a corrected calcium or ionized calcium level.[5] Specific changes may be seen on an electrocardiogram (ECG).[2]
Initial treatment for severe disease is with intravenous calcium chloride and possibly magnesium sulfate.[2] Other treatments may include vitamin D, magnesium, and calcium supplements.[5] If due to hypoparathyroidism, hydrochlorothiazide, phosphate binders, and a low salt diet may also be recommended.[5] About 18% of people who are being treated in hospital have hypocalcemia.[6]
The neuromuscular symptoms of hypocalcemia are caused by a positive bathmotropic effect (i.e. increased responsiveness) due to the decreased interaction of calcium with sodium channels. Since calcium blocks sodium channels and inhibits depolarization of nerve and muscle fibers, reduced calcium lowers the threshold for depolarization.[7] The symptoms can be recalled by the mnemonic "CATs go numb" - convulsions, arrhythmias, tetany, and numbness in the hands and feet and around the mouth.[senza fonte] Template:Columns-list