Hyperparathyroidism is a disease that, even in a young person, can lead to osteoporosis and bone fractures, muscle weakness, and kidney failure. All because of a disturbance in the work of the endocrine system and the related incorrect balance of calcium in the body. What are the causes and other symptoms of hyperparathyroidism? What is the treatment of this disease?
Parathyroid and parathyroid hormone (PTH)
Parathyroid glands are endocrine glands (endocrine system) located in the vicinity of the thyroid gland. Their task is to secrete parathyroid hormone (PTH) - a hormone which, together with calcitonin (a hormone secreted by the C cells of the thyroid gland) and calcitriol (the active form of vitamin D3), is responsible for the balance of calcium and phosphorus metabolism, i.e. the regulation of calcium and phosphate concentrations in the blood.
The secretion of PTH by the parathyroid glands depends on two factors: the level of calcium and the active form of vitamin D3 in the blood. If the level of calcium in the blood is too low, the parathyroid glands are stimulated to release PTH in order to restore the normal concentration of this element. Then, PTH contributes to the increased absorption of calcium compounds from the consumed food, inhibits its excretion by the kidneys in the urine and causes its release from the bones, which are its largest component.
In contrast, high levels of calcium in the blood inhibit this secretion. It is similar with the active form of vitamin D3 in the serum - a decrease in its concentration in the blood stimulates the secretion of PTH by the parathyroid glands, and its growth inhibits it. However, overstimulation of the parathyroid glands leads to an increased secretion of PTH, despite the fact that the level of calcium in the body is normal. As a result, the level of this element in the blood increases, i.e. hypercalcemia.
Hyperparathyroidism: causes
Primary hyperparathyroidismcaused by the glands themselves may be due to the presence of a benign adenoma (tumor) or parathyroid hyperplasia. Less frequently, it is the result of the development of hormonally active cancer of the parathyroid gland. Both the hypertrophy and the tumors contribute to the excessive secretion of PTH. In 90 percent. cases are diagnosed with the so-called sporadic form of PNP. The rest of the cases are congenital - genetic (e.g. mutations in the CaSR gene encoding calcium-sensitive surface receptors).SecondaryHyperparathyroidism , or prolonged overstimulation of the parathyroid glands, is a complication of diseases that cause a drop in blood calcium levels. When the concentration of this element in the blood decreases, properly functioning parathyroid glands receive a signal to produce PTH. However, they produce too much of it and, as a consequence, the level of calcium increases dangerously. This process usually occurs in the course of chronic renal failure, especially in patients undergoing long-term dialysis. The increase in circulating PTH concentration can also be caused by the impaired absorption of calcium from the intestines.
Hyperparathyroidism: symptoms
Excessive PTH secretion leads to hypercalcemia, i.e. elevated levels of calcium in the blood, usually at the expense of the calcium accumulated in the bones (which is one of the causes of hypercalcemia), which can lead to osteoporosis, osteoarticular pain and pathological bone fractures. In turn the symptoms resulting directly from hypercalcemia are:
- digestive system disorders - loss of appetite, increased thirst, abdominal pain coexisting with nausea and constipation, gastric ulcer disease (PTH indirectly increases the secretion of hydrochloric acid), acute or chronic pancreatitis;
- weakness, fatigue, depression, headaches, apathy, concentration disorders, disorientation, drowsiness, coma;
- muscle weakness and muscle aches;
- acute or chronic renal failure (hyperparathyroidism causes kidney problems and vice versa - kidney diseases can cause hyperparathyroidism), recurrent nephrolithiasis, cholelithiasis, increased urine output up to 3-4 liters per day;
- hypertension, arrhythmias, refractory anemia.
Hyperparathyroidism: diagnosis
In the case of the primary form of the disease, X-ray, scintigraphy, ultrasound, and even computed tomography are performed to accurately visualize the affected glands.
Final diagnosis is made on the basis of blood tests that measure the levels of calcium, parathyroid hormone and phosphorus. Additionally, blood creatinine levels are measured, and urine calcium and creatinine levels are measured to assess kidney function and the risk of developing kidney stones.
For this purpose, an ultrasound or X-ray of the kidneys is also performed. In turn, to assess the impact of the disease on bone, markers of bone metabolism are tested, such as serum alkaline phosphatase, and collagen breakdown products in the urine. Bone mineral density is also tested to assess bone loss.
Hyperparathyroidism: treatment
In the case of primary hyperparathyroidism, treatment consists of surgical removal of the tumor, and in the case of parathyroid hyperplasia - almost complete removal of the parathyroid glands. In turn, the goal of pharmacological treatment is to inhibit the excessive secretion of parathyroid hormone. Sometimes the doctor recommends taking vitamin D3 and calcium supplements. In the case of secondary disease, treatment of the underlying disease is necessary.