Hypocalcemia: symptoms, causes of treatment
May 25, 2018
Approximately 1000-1500 g of calcium is contained in the human body.This macronutrient is necessary for the full functioning of many body systems.Reducing the level of calcium in the blood called hypocalcemia.This condition is accompanied by certain symptoms and in some cases may even pose a real threat to life.Table of contents: Biological role of calcium Causes of hypocalcemia
Biological role of calcium
Calcium is given to humans with food.Getting into the body, most of the calcium( about 99%) is captured by bone tissue.This is his main depot.The rest of the calcium( about 1%) is in the blood, here it comes from the intestine and bone tissue.
Many biological processes require calcium. This macronutrient performs the following functions in the body:
- Is a component of bone tissue;
- Participates in muscular contraction;
- Increases cell permeability for potassium ions;
- Participates in blood clotting;
- Regulates cardiovascular activity.
Thus, a decrease in calcium in the blood will inevitably lead to a violation of the above processes.
Regulates the calcium metabolism of three hormones: parathyroid hormone, calcitonin, calcitriol.
Parathyroid hormone is produced in the parathyroid glands.It corrects the level of calcium.When the content of the macronutrient in the blood decreases, the parathyroid hormone activates and promotes the release of calcium from the bones into the blood.Also acting on calcitriol, it helps to increase the absorption of calcium through the wall of the intestine.So the calcium level rises and the balance is restored.However, with reduced parathyroid function, the synthesis of parathyroid hormone decreases, and the level of calcium in the blood plasma also decreases.
The action of another hormone - calcitriol is also aimed at increasing calcium in the blood plasma.Calcitriol helps to increase the absorption of calcium from the intestine into the blood, the reabsorption( return absorption) of calcium in the kidneys.When calcitriol is small, the level of calcium in the blood also decreases.
The third hormone, calcitonin , is produced by the cells of the thyroid and parathyroid glands and exerts an opposite effect to the parathyroid hormone.In high concentration, it inhibits the calcium output of their bone depots, stimulates the excretion of calcium in the urine.It would be logical to assume that an increase in calcitonin will lead to hypocalcemia, but in reality everything happens differently.When examining patients with medullary cancer with increased secretion of calcitonin, it was found that in most patients the calcium level is within the normal range.Therefore, in the emergence of hypocalcemia, the most significant role is played by lowering the levels of parathyroid hormone or calcitriol.
Causes of hypocalcemia
Calcium in the blood is either in bound or free( ionized) form.Normally, the concentration of total calcium in the blood is in the range of 2.1-2.6 mmol / l.A decrease in the concentration of less than 2.0 mmol / l indicates hypocalcemia.
Causes leading to hypocalcemia may include:
- Radioiodine therapy of the neck;
- Hypovitaminosis D;
- Chronic renal failure;
- Acute pancreatitis;
- Rhabdomyolysis( severe damage to skeletal muscles);
- Consequences of extensive injuries, burns;
- Massive transfusion of citrated blood;
- Taking certain medications( furosemide, anticonvulsants, phosphates, antibiotics from the aminoglycoside group, phenobarbital).
This disease of the parathyroid glands, in which the synthesis of parathyroid hormone decreases and as a consequence, hypocalcemia develops.Hypoparathyroidism often occurs after surgery on the thyroid or parathyroid glands.In addition, hypoparathyroidism may be a consequence of congenital anomalies or an autoimmune process.
Pseudohypoparathyroidism is a hereditary disease in which parathyroid hormone is produced in full, but peripheral tissues remain insensitive to the action of the hormone.As a result, metabolic disorders develop, including hypocalcemia.
Magnesium deficiency is often accompanied by the development of hypocalcemia.The cause of hypomagnesemia in particular can be chronic alcoholism, a violation of absorption in the digestive tract, nephropathy.The fact is that a deficiency of magnesium blocks the synthesis of parathyroid hormone and causes a decrease in the sensitivity of bones and kidneys to the action of the hormone.
Vitamin D is synthesized in the skin by the action of sunlight, and also comes with food.In kidneys, the vitamin turns into calcitriol.As it was already written above, calcitriol strengthens the absorption of calcium from the intestine and stimulates its release from the bone tissue.When vitamin D is low, calcitriol is not sufficiently formed, which is why the concentration of calcium in the blood plasma decreases.
For example, hypocalcemia may occur due to insufficient intake of vitamin D, impaired absorption, or reduced sensitivity of target organs to vitamin D. Vitamin deficiency leads to diseases of the digestive system.In chronic renal failure, the process of converting vitamin D into calcitriol is disrupted, so the disease is accompanied by hypocalcemia.
Vitamin D deficiency is the cause of rickets.Therefore, hypocalcemia is a companion of this disease.
Symptoms of hypocalcemia
Calcium deficiency, primarily, leads to an increase in neuromuscular excitability.With hypocalcemia, tonic muscle cramps develop, this phenomenon is called tetany.The earliest sign of this pathological condition can be a feeling of tingling at the fingertips and around the mouth.Tingling sensation( paresthesia) spreads all over the face, as well as hands and feet.Soon in these parts of the body there are muscle twitchings.During the tetanic attack, there are tonic convulsions - a prolonged muscle spasm, because of which limbs and the body freeze in various forced poses.
For the attack, the cramps of distal flexor muscles( carpopedal spasm), flexion of the fourth and fifth fingers of the hand( "the hand of the obstetrician") are especially characteristic.The person's face during the tetanic attack acquires a specific appearance: the corners of the mouth drop, the eyelids are lowered, and the eyebrows are brought together.The muscles are hard and painful.This unusual phenomenon was called the "sardonic smile".Seizures can acquire a generalized character.
Threats to life are convulsions of the intercostal muscles and diaphragm, which causes breathing problems, dyspnea, hoarse voice.The condition is dangerous with the development of asphyxiation.
Not only the skeletal muscles spasmodic, but also the muscles of the internal organs.So, due to spasm of the coronary arteries, there are chest pains.And with spasm of the muscles of the gastrointestinal and urinary tracts - abdominal pain, vomiting, diarrhea, hepatic and renal colic, violation of urination.
Hypocalcemia can also be accompanied by such symptoms:
- Difficulty swallowing( dysphagia);
- Obstruction of urination;
- Depressed mood, irritability;
- Dry, flaky skin, brittle nails, hair loss;
- Arrhythmia, heart block.
Light forms of tetany can occur without noticeable manifestations.On the development of the pathological condition in this case will testify paresthesias in the hands and feet, their cooling, convulsions do not develop.
Treatment of hypocalcemia
Features of treatment will depend on the cause that caused hypocalcemia.So for chronic hypocalcemia, calcium and vitamin D in tablets are usually prescribed.In addition, the patient is recommended to enrich the diet with dairy products, dried apricots, fish.
In severe form of hypocalcemia, intravenous calcium solution is administered( calcium gluconate, calcium chloride).If treatment does not bring the expected positive result, then it is necessary to think about hypomagnesemia.To stop this condition, prescribe magnesium preparations( magnesium sulfate, magnesium asparaginate, magnesium orotate).
Grigorova Valeria, medical reviewer