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Hypocalcemia is a calcium deficiency in the body. Calcium is one of the macronutrients, it is present in the human body in a small amount, yet it is extremely important. Plays a key role in the proper functioning of muscles and nerves. Find out what its symptoms are, what diseases lead to this condition, and why and when hypocalcemia can be life-threatening.

Hypocalcaemiais a condition in which the serum calcium level is below 2.25mmol / L. Hypocalcaemia can be caused by: decreased absorption, increased excretion and the resulting hormonal imbalance.

Symptoms of hypocalcaemia are most noticeable in the skeletal and nervous systems.

Causes of hypocalcemia

The most common cause of hypocalcaemia is insufficient amount of it in the food, which may contribute to the development of osteoporosis, and exceptionally, it may be the cause of tetany.

Other, less common causes of hypocalcemia are:

  • Impairment of calcium absorption from the gastrointestinal tract, caused by vitamin D deficiency or diseases related to absorption (e.g. short bowel syndrome) and digestion.
  • Excessive calcium deposition in bones or other tissues: acute pancreatitis leading to pancreatic calcification, use of certain medications (e.g. treatment of osteoporosis).
  • Loss of calcium in the urine due to certain congenital kidney diseases or diuretics.
  • Vitamin D deficiency, this vitamin is responsible for increasing the absorption of calcium in the digestive tract and inhibits its excretion. The decrease in its amount may be caused by damage to the organs involved in the synthesis of this vitamin: the liver, kidneys, and the lack of sunlight, which is essential in the production of vitamin D. Its deficiency may be caused by certain medications or an excess of phosphorus.
  • Hypoparathyroidism, and hence the deficiency of parathyroid hormone, when despite the adequate amount of calcium in the body, the plasma concentration is too low, because this element is not released from the bones.
  • Tissue resistance to parathyroid hormone.

Symptoms of hypocalcemia

Symptoms of hypocalcaemia result primarily from a deficiency of biologically active calcium in the plasma.

Reducing extracellular calcium levels causes the disorderelectrolyte balance and electrical potentials between cells and the extracellular space. This leads to a state where the nerve and muscle cells become more excitable.

The result is the so-called hypocalcemic tetany, its attacks are manifested by numbness and symmetrical contractions of: the muscles of the hands, forearms, arms, and then the face, chest and lower limbs.

These can be very dangerous because if the throat muscles tighten, which is rare, it can lead to obstruction of the airways.

There are also a number of characteristic symptoms associated with tetany: Chvostka or Trousseau.

The so-called tetany equivalents, i.e. symptoms not characteristic of this condition, which may be caused by hypocalcaemia, are also less common.

These include:

  • eyelid spasm
  • photophobia
  • double vision
  • bronchospasm causing asthma attack
  • stomach ache
  • migraine attack
  • fainting

In addition, a calcium deficiency causes some changes in the ECG.

If the hypocalcaemia is chronic, symptoms are usually absent, as various electrolyte shifts cause the electrical potentials to equalize and the ionized calcium concentration drops to just below the lower limit of normal.

Commonly associated with calcium deficiency, osteoporosis is a disease of the metabolism of the entire skeleton in which too much activation of osteoclasts, the cells responsible for dissolving bone, occurs.

This disease is rarely caused by a deficiency of this element, and its supplementation is mainly aimed at providing a building material for the reconstructed bones.

Therefore, calcium is needed to treat this disease, but in more advanced cases, calcium preparations are insufficient and treatment to strengthen the bone structure or to target abnormal metabolic processes is necessary.

It is worth remembering that osteoporosis is rarely associated with hypocalcemia, because bone damage is associated with bone deficiency, and the plasma concentration is usually normal.

Laboratory tests for hypocalcaemia

Hypocalcaemia is diagnosed by examining the concentration of ionized calcium in the serum, the diagnosis of the cause of this condition is more complicated.

For this purpose, among others: creatinine (assesses kidney function), other electrolytes: phosphates, magnesium, potassium (to assess the entire electrolyte balance), an enzyme related to bone metabolism:alkaline phosphatase and substances that influence the calcium metabolism: vitamin D and parathyroid hormone.

In order to assess the amount of calcium lost in urine, the daily excretion of this element is determined.

Treatment of hypocalcemia

Accurate diagnosis of hypocalcaemia is essential because effective treatment of calcium deficiency can only be performed when the cause of calcium deficiency is known and eliminated, so first of all, treat the disease causing hypocalcaemia.

If symptoms of tetany occur, intravenous calcium preparations (e.g. calcium chloride) are administered to quickly adjust its concentration, in the case of chronic diseases that cannot be cured or the treatment is long-lasting, ensure an adequate amount of calcium in the diet, use oral preparations and an adequate supply of vitamin D.

The calcium economy is influenced by many factors: hormones, vitamin D, diseases of the gastrointestinal tract and kidneys. Chronic hypocalcemia is usually asymptomatic and usually requires taking calcium supplements.

A sudden drop in calcium in the blood is usually the result of another disease, such as tetany, and can be very dangerous due to the risk of airway obstruction.

In such a state, it is necessary to immediately balance the calcium level in the blood and to further diagnose the cause. Osteoporosis is rarely directly related to calcium deficiency, but adequate dietary intake is essential in treating this disease.

Calcium economy

Calcium is an element essential for life, it is not only a building material, but is also responsible for many life processes, especially at the cellular level.

It is estimated that the human body contains about 20g of calcium per kilogram of body weight, which is about 1.5% of the total weight. 99% of this element is built into the bone in the structure of so-called hydroxyapatites, giving them hardness and mechanical resistance. The remaining 1% is present in plasma and many different cells of our body, where it is responsible for enzymatic processes, blood clotting, and also participates in muscle contractions and nerve activity, i.e. impulse conduction.

A he althy, balanced diet provides us with about 1.0 g of calcium per day, 30% of which is absorbed in the intestines, which is a sufficient amount for a he althy person.

It is worth remembering that the absorption of this element is limited by: oxalates, phosphates and fatty acids, because they bind calcium in the digestive tract, preventing its absorption, while vitamin D3 and proteins have the opposite effect. We excrete trace amounts of this element in the urine, because most of itis reabsorbed in the renal tubules.

The amount of calcium contained in our body is most strongly influenced by: parathyroid hormone, calcitonin and calcitriol (the active form of vitamin D3), they modulate the state of this element in various ways through the current regulation of absorption and excretion.

The last of these hormones increases the amount of calcium in the body, calcitonin - reduces, and parathomorphs release this macronutrient from the bones, thus increasing its plasma concentration.

In addition, the calcium content is influenced by: gliocorticosteroids, growth hormone, estrogens and the so-called parathyroid hormone-like protein (PTHrP).

The correct concentration of calcium in the serum is 2.25-2.75 mmol / l, remember that it is only about 1% of the calcium contained in our body, half of which is biologically active - it is in the form of an ion , the rest are bound to plasma proteins and form a kind of reserve.

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