Hypercalcemia is an increase in serum concentrations of total calcium greater than 2.8 mmol/l or ionized calcium greater than 1.3 mmol/l. The cause of this condition may be hyperparathyroidism, malignant neoplasm, long-term use of drugs. Symptoms include incipidar syndrome (polyuria, polydipsia), general muscle weakness, neuropsychiatric disorders. For diagnosis, the level of ionized calcium (Ca2+) is more important. For treatment, 0.9% NaCl, loop diuretics, bisphosphonates are used.
Calcium is a vital macronutrient that performs many functions in the human body (ensuring muscle contraction, blood clotting, nerve impulse conduction). Calcium is also the main component of bone tissue. In the regulation of its metabolism, the most important part is calcitriol (vitamin D), parathyroid hormone. Hypercalcemia is a fairly common electrolyte disorder and occurs in about 0.17 to 3.9 cases per 10 people. Gender differences vary among people of different ages. This condition is more susceptible to young men, women over 45 years old.
Hypercalcemia almost always indicates a disease or pathological process. However, sometimes it develops due to physiological causes (in newborns on the 4th day of life, in adults after eating). The pathological causes of this condition are as follows:
An increase in the calcium content in the blood changes the membrane potential of cells, which leads to inhibition of neuromuscular conduction in skeletal muscles, myocardium, and the gastrointestinal tract. The pathogenesis of neuropsychiatric symptoms is not completely clear. The role of slowing down the conduction of nerve impulses is assumed. Calcification of blood vessels, internal organs, dystrophy, wrinkling of tissues develops.
Due to hypercalciuria (increased filtration of calcium in the tubules of the nephron), the risk of nephrolithiasis increases. Calcium inhibits adenylate cyclase, which suppresses the renal effect of antidiuretic hormone. Also, due to the high extracellular concentration of this cation, the secretion of hydrochloric acid by the parietal cells of the stomach increases, which leads to the development of peptic ulcers.
Along the course, chronic and acute hypercalcemia (hypercalcemic crisis) are isolated. According to the level of the cation (in mmol / l), the following degrees of severity of hypercalcemia are distinguished:
Separately, pseudohypercalcemia is considered. Part of the calcium binds to plasma proteins, so diseases such as paraproteinemic hemoblastoses (multiple myeloma), characterized by a high content of protein in the blood, are accompanied by an increase in the level of total calcium. The determination of ionized calcium helps to exclude false hypercalcemia.
With a mild degree of pathology, there may be no symptoms at all. With a moderate, severe degree, muscle weakness appears, sometimes reaching such severity that it is difficult for the patient to get out of bed. Symptoms from the gastrointestinal tract are characteristic - nausea, vomiting, abdominal pain. Significantly reduced appetite, constipation occurs. Often there are cardiac symptoms (increased blood pressure, tachycardia).
Even with hypercalcemia of non-oncological origin due to anorexia and muscular dystrophy, the patient loses a lot of weight, acquires a cachectic appearance, which may lead to a false impression that he has a malignant neoplasm. The weakening of the action of antidiuretic hormone on the kidneys causes the appearance of symptoms such as intense thirst, an increase in urination up to 5-6 liters per day.
The neuropsychological symptoms are especially pronounced. First, there is emotional instability, impaired concentration, slight drowsiness. In severe pathology, confusion, delirium, and psychosis develop. Hallucinations are possible. With a long-term high level of calcium, it begins to be deposited in the tissues of the joints (chondrocalcinosis), which causes arthralgia.
Hypercalcemia has a wide range of adverse effects. The most common complications are osteoporosis (due to increased release of calcium ions from the bones), pathological fractures, and urolithiasis. Less common are acute pancreatitis and intestinal obstruction. The most life-threatening condition is the hypercalcemic crisis, in which the mortality rate reaches 60%. The cause of death is heart or kidney failure.
Another severe but rare complication is calciphylaxis (calcifying uremic arteriolopathy), characterized by ischemic necrosis of the skin and subcutaneous fat. It develops in patients with end-stage renal disease. A prolonged increase in blood calcium can also lead to band keratopathy, calcification of the aorta and heart valves with the formation of heart disease.
The profile of a medical specialist who supervises a patient with this pathology is determined by the cause that caused this condition. Most often, such patients are observed by endocrinologists, nephrologists, and oncologists. When interviewing a patient, it is imperative to specify which medications he is taking. During the examination, the doctor draws attention to symptoms such as decreased muscle tone, inhibition of tendon reflexes. An additional examination is scheduled, including:
The differential diagnosis should be based on the predominant symptoms. Incipid syndrome must be differentiated from diabetes and diabetes insipidus. Muscle weakness, hypotonia should be distinguished from that in muscular dystrophy, myasthenia gravis, polymyositis. Neuropsychiatric symptoms require the exclusion of psychiatric diseases.
Scintigraphy. parathyroid adenoma
Patients with any degree of severity for treatment should be hospitalized in a hospital (endocrinology, nephrology department). Patients with severe neurological symptoms, hypercalcemic crisis should be transferred to the intensive care unit. It is required to stop all drugs that can cause an increase in calcium levels. Treatment of hypercalcemia has the following directions:
Surgical removal of the parathyroid glands is the main treatment for primary hyperparathyroidism. The main indication for surgical intervention is the Ca level above 2.75 mmol/l. To prevent postoperative hypocalcemia (“hungry bones syndrome”), the patient is prescribed vitamin D, Ca preparations. Malignant tumors are also subject to removal. For the treatment of oncohematological pathologies, bone marrow transplantation is performed.
New drugs are being developed to treat this condition. The drug osteoprotegerin, which is a cytokine from the tumor necrosis factor family, is at the stage of clinical trials. It inhibits the differentiation of osteoclasts, stimulates their apoptosis. In in vitro experiments, the calcitriol analogue EB 1089 suppressed the expression of the PTH peptide gene.
Hypercalcemia is a severe, and in some cases (especially in acute course) life-threatening pathological condition. In a hypercalcemic crisis, mortality is very high (60%). The frequency of deaths in chronic course averages 20-25%. However, to a greater extent, the prognosis is determined by the cause of the increase in Ca levels.
Prevention of this pathology lies in the timely diagnosis and proper treatment of diseases against which it develops. Before you start taking vitamin D or other medicines that can increase your blood Ca levels, you should have a blood test to check your calcium levels.