Hypocalcaemia - description, symptoms, causes and treatment
Hypocalcaemia is the term for an abnormally low level of calcium in the body. Although it is an uncommon condition, it is found equally in men and women and can occur at any age. If there’s a low level of calcium in the blood (serum calcium) it can cause problems since it regulates the many processes that make cells work.
- 45% of serum calcium is transported partly bound to plasma proteins (notably albumin),
- About 15% is partly bound to small ions like phosphate and citrate
- 40% is free or in what we call an ionised state
Although it is only the ionised calcium which is metabolically active, most laboratory tests will refer to total serum calcium levels and these should be between 2.12 and 2.62 mmol/L. Readings lower than this are generally consistent with having Hypocalcaemia
Serum Calcium is mostly regulated by two hormones. These are Parathyroid hormone - commonly referred to as PTH and secreted by 4 parathyroid glands located behind the thyroid - and Vitamin D
Some patients will show no signs of the condition whilst some may experience:
- Bone pain
- Brittle nails with horizontal grooves
- Dry, coarse skin
- Facial Twitch
- Stiff muscles
- Tingling, burning or numbness in the fingers, toes or face (paraesthesia)
When PTH secretion is not acting sufficiently on kidney, bone or intestine the body is unable to keep serum calcium levels stable. This may be characterised by either a high or low PTH reading
- When the parathyroid gland and PTH are functioning normally but there is a Vitamin D deficiency the PTH reading will be high
- When there is decreased PTH due to destruction of the parathyroid gland, abnormal development or altered regulation of production and secretion the PTH reading will be low
Hypocalcaemia can also be caused by a depletion in Magnesium, in this instance the condition is corrected by magnesium rather than calcium.
A blood test to ascertain calcium levels with measurement of vitamin D, PTH and magnesium is the first step. Your doctor may also test for:
- A Chvostek sign – a twitching response when facial nerves are tapped
- A Trousseau sign – a spasm in the feet or hands
All patients with hypocalcaemia will need to seek a specialist opinion and those with a corrected calcium level of less than 1.9mmol/l should seek urgent referral to an Endocrinologist. Left untreated the condition can cause coma or even death.
Patients with mild hypocalcaemia can be effectively treated with calcium and vitamin D. Severe cases will be treated in hospital and given an intravenous infusion of calcium.
Those with temporary hypocalcaemia after thyroid surgery will need daily treatment with alfacalcidol (which acts like PTH) until the situation normalises. This is a vitamin D analogue and is usually combined with a calcium supplement.
Occasionally patients will need lifelong replacement
Daily injections of synthetic human PTH have also been shown to be effective. This is an expensive treatment and is therefore reserved for those patients that are very resistant to conventional treatment.
A very helpful website for patients: is http://hypopara.org.uk/home.php