See also: hyperparathyroidism
Generality
Hypercalcemia is a clinical condition characterized by an excess of calcium in the blood (concentrations above 10.5 mg / dL in the adult).
In the article dedicated to calcemia, we saw how the blood levels of the mineral depend on the activity of vitamin D and two hormones, parathormone and calcitonin, which in turn modulate the deposit / release of calcium from the bones, as well as its renal resorption / excretion e
the degree of absorption at the enteric level. It follows that hypercalcemia can be caused by three different mechanisms, which can come into play in isolation or in combination:
- excessive release, localized or generalized, of calcium from bones (for example due to increased secretion of parathyroid hormone, as happens in hyperparathyroidism, the most common cause of hypercalcaemia);
- increased intestinal absorption of calcium (for example due to excessive intake of vitamin D);
- decreased renal calcium excretion (as occurs in renal failure).
Symptoms
Depiction of a parathyroid adenoma, a benign tumor of a parathyroid gland, almost always responsible for hyperparathyroidism with consequent hypercalcaemia. From //en.wikipedia.org
Due to the numerous and important functions performed by calcium in the body, hypercalcaemia can be accompanied by a constellation of signs and symptoms of varying degrees in relation to the degree of abnormality and general health conditions of the patient. These include constipation, nausea, gastric hyperacidity (hypercalcemia increases gastrin secretion), abdominal pain, vomiting, psychological disorders (depression, confusion, apathy, lethargy to coma), weakness, thirst, polyuria, dehydration and pain bone. While in patients with modest hypercalcemia (11-12 mg / dL) the condition can be asymptomatic, in severe forms hypercalcemia is accompanied by fairly severe symptoms, to the point of constituting a real medical emergency (severe arrhythmias, coma, kidney failure ).
Causes and associated diseases
Infections, inflammatory processes, hyperparathyroidism (increased function of the parathyroid glands, usually due to benign tumors, with increased parathormone blood levels), tumors with bone metastases (typical is the case of breast cancer and lung cancer), tumors that release substances similar to the parathyroid hormone (paraneoplastic syndrome), Paget's disease, hyperthyroidism (increased thyroid function), bone fractures combined with prolonged immobilization, high protein diet, excessive intake of vitamin D, vitamin A intoxication, kidney transplant, tuberculosis, sarcoidosis, multiple myeloma, leukemia, trauma, stress and kidney failure.
Among the iatrogenic causes are some diuretics (thiazides), the overdose of thyroid hormones (Eutirox), tamoxifen and lithium therapy (used mainly in the treatment of bipolar disorder).
Treatment
See also: Drugs for the treatment of hypercalcaemia
To establish an adequate treatment of hypercalcemia it is necessary to first determine the cause of origin (in this regard the diagram shown in the figure can be useful, clicking on it to enlarge it).
