Digestive System

Digestive system / Calcium metabolism disorders

Calcium is essential for the smooth functioning of many important functions of the body and therefore, in normal conditions, blood levels are maintained within tight limits (8.5 - 10.5 mg / dl).

Keeping blood calcium at a constant level (homeostasis) is achieved through three organs (intestine, bone, kidney), whose function is regulated by the so-called calcium-releasing hormones (mainly parathyroid hormone, vitamin D, cytokines).
When whole blood calcium values (corrected for any changes in albumin-albumin) are below 8.5 mg / dl we have hypocalcemia.

Theoretically and reasonably it can be due to:
(a) PTH deficiency or receptor activation; (b) Vitamin D deficiency or homogeneous receptor activity; (c) Magnesium metabolism disorders; and (d) Severe clinical conditions involving many factors (pancreatitis, sepsis, complications of extensive burns or severe illnesses).

Vitamin D deficiency

In our country, over the last 20 years, a significant proportion of people have been exposed to vitamin D poverty in large urban areas, mainly due to inadequate exposure to the sun (vitamin D is 80% synthesized by cholesterol through the action of ultraviolet radiation).

This poverty of vitamin D is greater in the winter months and especially in the elderly and reaches a high level of 70-80%. In addition to the elderly and especially those in institutions, there is a high incidence and vitamin D deficiency that can exceed 90%.
Also, vitamin D deficiency is observed in patients with malabsorption syndrome (in temperate climates such as our country, only 20% of vitamin D comes from food), alcoholism, antiepileptic medication (mainly due to reduced hydroxylation of D liver, at 25 position) and chronic renal failure (failure to hydroxylate vitamin D at 1 position, which occurs in the kidneys).

The treatment aims at controlling the symptoms and - at the same time - minimizing the complications.

Preferred active metabolites of Vitamin D (I-25 (OH) 2 Vitamin D or 1αOHvitamin D) are preferred because of their fast action (1-2 days) and rapid breakdown (2-3 and 5-7 days respectively) with consequently, the possibility of overdose is easily controlled.

The target of long-term treatment with calcium and vitamin D is to control symptoms, maintain calcium in the lower normal range (8.0 - 8.5 mg / dl), and avoid asvestouria(lime) (24-hour urine calcium less than 300mg).

In conclusion: The chronic treatment of hypocalcaemia with calcium and vitamin D, while not ideal, remains the only feasible (with all the restrictions and precautions it requires).


International Health Organizations:

European Society of Endocrinology


The text was based in part on the following posts:
1) Makras P, Papapoulos S (2009) Medical treatment of hypercalcemia. Hormones 8: 83-95.
2) Shoback D (2008) Hypoparathyroidism N Enl J Med 359: 391-403.

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