How the body regulates calcium
Most of the calcium is found in the bones, but its level in the blood is kept within narrow limits. When it decreases, the parathyroid glands secrete parathyroid hormone, which removes calcium from the bones, reduces its loss in urine and activates vitamin D in the kidneys; vitamin D, in turn, enhances the absorption of calcium in the intestine. If any link breaks - the parathyroid glands are removed or damaged, there is not enough vitamin D, kidney function is impaired - calcium levels drop. Magnesium also plays an important role: without it, parathyroid hormone does not work well.
- Parathyroid hormone increases blood calcium
- Vitamin D enhances calcium absorption
- The kidneys are involved in the activation of vitamin D
- Magnesium is necessary for the functioning of parathyroid hormone
- Some calcium is bound to albumin
- With low albumin, the indicator is falsely underestimated
Reasons
The most common reason in practice is vitamin D deficiency, especially in the elderly, with lack of sun and intestinal diseases with impaired absorption. The second most important is insufficiency of the parathyroid glands, most often after surgery on the thyroid gland, when the glands are damaged or removed. Chronic kidney disease plays a significant role. A separate issue is magnesium deficiency, in which calcium does not rise until magnesium is replenished. Less common causes include acute pancreatitis, massive blood transfusions, and certain medications.
- Vitamin D deficiency
- Damage to the parathyroid glands after surgery
- Chronic kidney disease
- Magnesium deficiency
- Malabsorption in the intestines
- Acute pancreatitis
- Taking certain medications, including those used to treat osteoporosis
Symptoms
A slight decrease is often asymptomatic and is detected in the analysis. With a more pronounced deficiency, increased neuromuscular excitability appears: tingling and numbness around the mouth, in the tips of the fingers and toes, painful sensations in the muscles of the hands and feet, twitching. Anxiety, irritability, and spasms in the throat with a feeling of lack of air may occur. With severe hypocalcemia, generalized seizures and cardiac arrhythmias occur. Long-term deficiency affects the condition of the skin, nails, hair and teeth.
- Tingling around the mouth and in the fingers
- Painful information on the hands and feet
- Muscle twitching
- Anxiety and irritability
- Sensation of spasm in the throat
- Interruptions in heart function
- Dry skin, brittle nails
Survey
First of all, the result needs to be checked: a decrease in total calcium can be false when albumin is low, so ionized calcium is assessed or the indicator is recalculated with a correction. Then they look for the cause: they determine parathyroid hormone, vitamin D, magnesium, phosphorus, creatinine and kidney function indicators. The combination of parathyroid hormone and phosphorus levels makes it possible to distinguish parathyroid insufficiency from vitamin D deficiency. If symptoms are severe, an ECG must be taken, since low calcium affects the conductivity of the heart.
- Calcium total and ionized
- Albumin for correct interpretation
- Parathyroid hormone
- Vitamin D (25-OH)
- Magnesium and phosphorus
- Creatinine and kidney function assessment
- ECG for severe symptoms
Treatment and prevention
Tactics depend on the cause and severity. For severe hypocalcemia with seizures, calcium is administered intravenously in the hospital under ECG monitoring. In other cases, calcium and vitamin D supplements are prescribed, and in case of parathyroid gland insufficiency, active forms of vitamin D are prescribed, which require regular monitoring of tests. If magnesium is low, first replace it. Self-administration of calcium without finding out the cause is useless, and in some conditions it is dangerous: excess increases the risk of kidney stones. A diet with sufficient calcium remains the basis of prevention.
- Intravenous calcium administration in severe forms
- Calcium and vitamin D supplements as prescribed by a doctor
- Active forms of vitamin D for damage to the parathyroid glands
- Replenishment of magnesium in case of its deficiency
- Dairy products, fish, greens, sesame in the diet
- Adequate sun exposure
- Regular monitoring of calcium and kidney function
