In medicine, hypocalcaemia (or hypocalcemia) is the presence of low serum calcium levels in the blood, usually taken as less than 2.1 mmol/L or 9 mg/dl or an ionized calcium level of less than 1.1 mmol/L or 4.5 mg/dL. It is a type of electrolyte disturbance. In the blood, about half of all calcium is bound to proteins such as serum albumin, but it is the unbound, or ionized, calcium that the body regulates. If a person has abnormal levels of blood proteins, then the plasma calcium may be inaccurate. The ionized calcium level is considered more clinically accurate in this case.
It manifests as a symptom of a parathyroid hormone [PTH] deficiency/malfunction, a Vitamin D deficiency, or unusually high magnesium levels (hypermagnesaemia), or low magnesium levels (hypomagnesaemia).
Other causes may be-Eating disorders, Exposure to mercury, Excessive dietary magnesium, as with supplementation, Prolonged use of medications/laxatives containing magnesium, Chelation Therapy for metal exposure, particularly EDTA, Absent parathyroid hormone (PTH), Hypomagnesaemia, Following parathyroidectomy, Following thyroidectomy, Ineffective PTH , Chronic renal failure, Absent active vitamin D, Ineffective active vitamin D can be recalled by the mnemonic "CATS go numb"- Convulsions, Arrythmias, Tetany and numbness/parasthesias in hands, feet, around mouth and lips. May appear as on-off spots, then later become confluent, and appear as purpura (larger bruised areas, usually in dependent regions of the body).
Oral, perioral and acral paresthesias, tingling or 'pins and needles' sensation in and around the mouth and lips, and in the extremities of the hands and feet. This is often the earliest symptom of hypocalcaemia.
Carpopedal and generalized tetany (unrelieved and strong contractions of the hands, and in the large muscles of the rest of the body) are seen.
Latent tetany
Life threatening complications
Laryngospasm
Cardiac arrhythmias
ECG changes include:
Intermittent QT prolongation, or intermittent prolongation of the QTc.
ampoules intravenous calcium gluconate 10% is given slowly in a period of 10 minutes, or if the hypocalcaemia is severe, calcium chloride is given instead. This is only appropriate if the hypocalcemia is acute and has occurred over a relatively short time frame. But if the hypocalcemia has been severe and chronic, then this regimen can be fatal, because there is a degree of acclimatization that occurs.n
Dr Shahjada Selim
Endocrinologist & Diabetologist
Email: [email protected]