Hyperparathyroidism is a disease caused by excessive production of a hormone called parathyroid hormone (PTH). This hormone is produced by the parathyroid glands, small glands located in the thyroid area.
The role of parathyroid hormone is to increase calcium levels in extracellular fluids.
This is achieved by:
- loss of calcium in bones;
- activation of vitamin D3, and thereby increasing calcium absorption in the intestine;
- decreased renal excretion of calcium (at the same time increased excretion of phosphate).
Therefore, hyperparathyroidism is associated with:
- increased levels of parathyroid hormone;
- increased calcium;
- reduced concentration of phosphates.
This is important for diagnosing and treating the disease.
Causes of the disease
The reason for this is clinical manifestations: it hurts in places that have nothing to do with the parathyroid glands.
The parathyroid glands are located near the thyroid gland and there are usually four of them. They are responsible for calcium metabolism. The glands produce parathyroid hormone (parathyroid hormone, PTH), whose task is to supply calcium to the blood.
The work of the parathyroid glands is limited by vitamin D. With age, it is absorbed less and less well, therefore, control deteriorates. Having received complete freedom of action, the parathyroid gland begins to increase the level of calcium in the blood.
Causes of hyperparathyroidism
The content of the article
The main cause of the pathology is an adenoma (benign tumor) of one of the parathyroid glands. Sometimes hypertrophy of all parathyroid glands is diagnosed. In rare cases, the cause of hyperparathyroidism is cancer of the parathyroid glands.
Parathyroid cancer
Why do these disorders appear? Sometimes this is unknown, sometimes it is possible to determine the presence of a factor that stimulates the parathyroid glands to hypertrophy. Most often this is vitamin D deficiency, dietary errors or kidney failure.
When the effect of a stimulating factor (for example, insufficient calcium absorption due to vitamin D3 deficiency) lasts long enough and then disappears, the hypertrophied parathyroid glands rapidly become active, resulting in increased calcium levels. Endocrinologists call this process tertiary hyperparathyroidism (primary is spontaneous, secondary is an increased level of PTH in response to an irritant).
Adenomas/cancer may be components of multiple endocrine adenomatosis syndrome. These are genetically determined diseases that affect many endocrine organs.
Nervous system
There is still debate about the effect of excess calcium levels in the blood on the function of the nervous system.
On the one hand, patients with hyperparathyroidism exhibit weakness, mood swings, and increased fatigue, which are significantly reduced after normalization of calcium and parathyroid hormone levels.
On the other hand, the symptoms are too nonspecific to be associated directly with parathyroid hormone.
The parathyroid glands themselves increase in size, and can often be noticed by an ultrasound doctor when examining the thyroid gland.
Parathyroid hormone, intact
Parathyroid hormone (PTH) is a polypeptide hormone that is synthesized by the parathyroid glands and plays an important role in regulating calcium and phosphorus levels in the body.
Synonyms Russian
Parathyroid hormone, parathyrin, PTH.
English synonyms
Parathyroid hormone, intact PTH, parathormone, parathyrin.
Research method
Solid-phase chemiluminescent enzyme-linked immunosorbent assay (“sandwich” method).
Determination range: 1.2 - 5000 pg/ml.
Units
Pg/ml (picograms per milliliter).
What biomaterial can be used for research?
Venous blood.
How to properly prepare for research?
- During the day before the test, do not drink alcohol or take medications (as agreed with your doctor).
- Do not eat for 12 hours before the test.
- Avoid physical and emotional stress for 24 hours before the test.
- Do not smoke 3 hours before the test.
General information about the study
Parathyroid hormone (PTH) is produced by the parathyroid glands, located in pairs on the posterior surface of each lobe of the thyroid gland. Intact PTH (the whole hormone molecule) consists of 84 amino acids, has a short half-life (about four minutes) and is the main biologically active form of the hormone. Its N- and C-terminal fragments have a longer lifespan, and their activity and metabolism are being studied.
PTH plays an important role in the regulation of phosphorus-calcium metabolism and ensures the maintenance of stable concentrations of calcium and phosphorus in the extracellular fluid. The level of PTH is closely related to the amount of calcium, vitamin D, phosphorus, calcium, magnesium in the body; the regulation of its secretion is carried out according to the feedback principle. When the concentration of calcium in the blood decreases (hypocalcemia), the release of PTH by the parathyroid glands increases, and when it increases (hypercalcemia), on the contrary, it decreases. These mechanisms are aimed at maintaining a stable level of calcium in the blood. An increase in PTH promotes the activation of osteoclasts, bone resorption and the release of calcium from bones, enhances the absorption of calcium from the intestine, delays the excretion of calcium by the kidneys and inhibits the reverse reabsorption of phosphorus. The PTH antagonist is the hormone calcitonin, secreted by the C cells of the thyroid gland. Normally, when the normal concentration of calcium in the blood is reached, PTH production decreases.
With pathology and excessive synthesis of PTH (hyperparathyroidism), hypercalcemia, hyperphosphaturia, generalized osteoporosis, vascular calcification, and damage to the gastrointestinal mucosa develop. Insufficient secretion of PTH (hypoparathyroidism) is accompanied by hypocalcemia and hyperphosphatemia and can lead to convulsions and tetany.
It is important to simultaneously assess the level of free, or ionized, calcium in the blood and PTH, taking into account clinical manifestations and the results of other laboratory and instrumental studies, this allows for differential diagnosis of very similar pathological conditions and development of the correct treatment tactics.
What is the research used for?
- To assess the function of the parathyroid glands.
- To find out the causes of hypo- or hypercalcemia, calcium metabolism disorders.
- For differential diagnosis of primary, secondary and tertiary hyperparathyroidism.
- For the diagnosis of hypoparathyroidism.
- For monitoring patients with chronic calcium metabolism disorders.
- To evaluate the effectiveness of treatment of pathology of the parathyroid glands and their surgical removal for neoplasms.
When is the study scheduled?
- When the level of calcium in the blood changes (hyper- or hypocalcemia).
- For symptoms of hypercalcemia (fatigue, nausea, abdominal pain, thirst) or hypocalcemia (abdominal pain, muscle cramps, tingling fingers).
- When the size and structure of the parathyroid glands change according to instrumental methods (for example, CT).
- In the treatment of calcium metabolism disorders.
- For neoplasms of the parathyroid glands, as well as immediately after their surgical removal.
- For osteoporosis and changes in bone structure.
- For chronic kidney disease and reduced glomerular filtration rate.
What do the results mean?
Reference values: 15 - 65 pg/ml.
A normal level of PTH with low calcium in the blood is a sign of hypoparathyroidism (insufficient synthesis of PTH by the parathyroid glands). High PTH and elevated blood calcium concentration indicate hyperparathyroidism. The PTH level is assessed together with the blood calcium level.
Causes of increased parathyroid hormone levels
- Hypocalcemia (with normal function of the parathyroid glands, the level of PTH increases in order to mobilize calcium from the depot and increase its absorption).
- Primary hyperparathyroidism (accompanied by increased levels of calcium and calcitonin, the level of phosphorus in the blood is normal or reduced):
- hyperplasia of the parathyroid glands,
- adenoma or cancer of the parathyroid glands.
- chronic renal failure,
- vitamin D and calcium deficiency,
- malabsorption syndrome.
Causes of decreased parathyroid hormone levels
- Hypercalcemia (a decrease in PTH with normal function of the parathyroid glands contributes to a decrease in the concentration of calcium in the blood).
- Primary hypoparathyroidism (insufficient function of the parathyroid glands).
- Secondary hypoparathyroidism (for example, a complication of surgical treatment of thyroid diseases, a condition after removal of the parathyroid glands).
- Excess vitamins A and D.
- Idiopathic hypercalcemia.
- Autoimmune diseases with the formation of autoantibodies to calcium receptors.
- Wilson-Konovalov disease, hemochromatosis.
- Graves' disease, severe thyrotoxicosis.
- Magnesium deficiency.
- Multiple myeloma.
- Sarcoidosis.
What can influence the result?
- Drinking milk before the test may result in low PTH readings.
- An increase in PTH is observed during pregnancy and lactation.
- A false decrease in PTH is observed in milk-alkali syndrome (Burnett's disease).
- The administration of radioisotope drugs a week before the test distorts the test result.
- Medicines that increase PTH levels in the blood: phosphates, diuretics, lithium, rifampicin, furosemide, isoniazid, steroids, thiazide or anticonvulsants.
- Cimetidine and propanodol reduce PTH levels.
- PTH levels are subject to circadian rhythms and normally vary throughout the day, reaching a maximum at 2-4 p.m. and a basal value at 8 a.m.
Important Notes
- It is recommended to take blood for analysis around 8 a.m., when the level of PTH in the blood is minimal.
- The PTH level must be assessed together with the calcium concentration in the blood. If the level of parathyroid hormone in the blood changes, further examination is recommended to clarify the etiology of the process.
- Elevated PTH increases the risk of hypercalciuria and urolithiasis, osteoporosis, renal failure and hypertension.
Also recommended
- Vitamin D, 25-hydroxy (calciferol)
- N-osteocalcin (bone remodeling marker)
- Beta-CrossLaps (bone resorption marker)
- Serum calcitonin
- Serum calcium
- Ionized calcium
- Serum phosphorus
- Calcium in daily urine
- Phosphorus in daily urine
- Total alkaline phosphatase
- Laboratory examination for osteoporosis
- Prevention of osteoporosis
Who orders the study?
Endocrinologist, therapist, oncologist, rheumatologist, orthopedist, traumatologist.
Literature
- Fischbach FT, Dunning MB A Manual of Laboratory and Diagnostic Tests, 8th Ed. Lippincott Williams & Wilkins, 2008: 1344 p.
- Practical Endocrinology and Diabetes in Children. 2nd ed./ Joseph E. Raine and others. Blackwell Publishing, 2006: 247 p.
- Wilson D. McGraw-Hill Manual of Laboratory and Diagnostic Tests 1st Ed. Normal, Illinois, 2007: 666 p.
Blood test for parathyroid hormone
Analysis for parathyroid hormone
is one of the most important in the list of examinations prescribed for suspected calcium metabolism disorders, including the development of osteoporosis.
Blood for parathyroid hormone is usually donated simultaneously with an analysis for ionized calcium, phosphorus, calcitonin
, since such a block of studies allows the endocrinologist to most fully assess the metabolic state. It is also highly advisable to immediately perform densitometry - a study of bone tissue density, which shows the likelihood of developing bone fractures.
Parathyroid hormone - analysis
, the quality of which varies greatly between different laboratories. Currently, the most common methods of performing a blood test for parathyroid hormone are enzyme immunoassay (the so-called 2nd generation method) and immunochemiluminescence (3rd generation method).
Most laboratories analyze parathyroid hormone using a 2nd generation method
, since equipment and reagents for enzyme-linked immunosorbent assay (ELISA) are inexpensive, you can even use domestically produced reagents. At the same time, the use of the ELISA method leads to a decrease in the accuracy of the analysis of parathyroid hormone in the blood and an increase in error.
The specialized laboratory of the North-Western Center for Endocrinology uses a 3rd generation automatic immunochemiluminescent analyzer DiaSorin Liaison XL (Italy) to perform analysis for parathyroid hormone.
– a device with exceptionally high analytical accuracy. In the work of endocrinologists at our center, the accuracy of a test such as a blood test for parathyroid hormone is the main diagnostic component, so we take issues of research quality very seriously. The specialized laboratory of the center NEVER performs parathyroid hormone analysis using the 2nd generation method and NEVER uses either domestic or Chinese reagents - only reagents made in Italy by the DiaSorin company.
If you are deciding where to donate parathyroid hormone
, and are not sure what tests should be taken additionally -
do the following blood test: parathyroid hormone and calcium (ionized is very desirable), phosphorus, calcitonin
. If you also donate your daily urine test for calcium, that will be simply wonderful; any endocrinologist will appreciate your erudition in matters of taking tests.
In the laboratory of the Endocrinology Center, the analysis for ionized calcium is carried out using an automatic biochemical analyzer Olympus AU-680 (Japan) - a high-performance, high-precision automatic machine capable of conducting up to 680 biochemical tests per hour! Combined with the high accuracy of parathyroid hormone and calcitonin tests, an accurate calcium test will provide optimal diagnostic results.
Parathyroid hormone is normal
When you donate blood in a specialized modern laboratory and receive the result of a test for parathyroid hormone, the norm is indicated on the laboratory form
immediately after your individual result.
Parathyroid hormone levels can be expressed in two different units of measurement - pg/ml and pmol/l. Recalculation between them is possible using the following formula:
parathyroid hormone level in pmol/l x 9.8 = parathyroid hormone level in pg/ml
Parathyroid hormone is normal
, when it fits within the boundaries specified as reference limits (standards).
This indicator is not dependent on gender - if you take a parathyroid hormone test, the norm for women will not differ from the norm for men
.
Methods for correcting parathyroid hormone levels
If there are deviations of PTH from the norm to a greater or lesser extent, treatment is necessary. This is usually hormone replacement therapy. Thus, if the secretion of parathyroid hormones is insufficient, a complex of hormone-containing drugs is prescribed to correct their levels. The course can last several months, or you have to take the pills for life. It depends on the cause of the failure and the effectiveness of treatment procedures.
If parathyroid hormone is produced in excess, the disorder is corrected by eliminating the root cause (treatment of diseases that provoked hyperproduction of hormones). In some cases, partial or complete resection of the parathyroid gland is performed. If malignant tumors are present, the glands are removed.
Where to get parathyroid hormone
The specialized laboratory of the North-Western Endocrinology Center takes tests for parathyroid hormone and calcium, phosphorus and calcitonin
, as well as receiving other analyzes (more than 1000 studies) at the following addresses in St. Petersburg and Vyborg:
— Petrograd branch of the endocrinology center
– center of St. Petersburg, 200 meters to the left on foot from the Gorkovskaya metro station, Kronverksky Prospekt, building 31. Branch opening hours: 7.30-20.00, seven days a week. Phone: 498-10-30. There is parking for cars.
— Primorsky branch of the endocrinology center
– Primorsky district of St. Petersburg, 250 meters to the right from the Begovaya metro station. Branch address: st. Savushkina, house 124, building 1. Branch opening hours: 7.00-20.00, seven days a week. Phone: 565-11-12. There is parking for cars.
— Vyborg branches of the Endocrinology Center:
- Vyborg, st. Gagarina, 27A, tel., from 7.30 to 20.00, seven days a week. There is parking available for cars.;
- Vyborg, Pobedy Ave., 27A, tel. (81378) 36-306, from 7.30 to 20.00, seven days a week. There is parking for cars.
The branches of the endocrinology center provide everything for the comfort of patients who came to take parathyroid hormone, calcium and other tests
– no queues, comfortable treatment rooms with comfortable chairs and cartoons for a positive attitude, air conditioning and deep air purification systems, modern vacuum blood collection systems.
You can receive the results of a blood test for parathyroid hormone and other indicators by email
immediately after they are completed. In the vast majority of cases, tests are performed within 1 day (often the test for parathyroid hormone and calcium is ready in the evening of the day the patient came for the test).
You can find a complete list of laboratory branches in the Leningrad region (the cities of Luga, Gatchina, Kingisepp, Svetogorsk) here.
If you are not yet sure where to take parathyroid hormone in St. Petersburg or the Leningrad region
– contact the Northwestern Endocrinology Center. You will be confident in the quality of the research and conduct it with comfort. It is important that in the same center you can get a consultation with an endocrinologist who has significant experience in treating disorders of parathyroid hormone production.
Parathyroid hormone during pregnancy
Pregnant women should periodically donate blood to determine PTH levels, as the risk of abnormalities increases. Monitoring the hormone will allow timely detection of disorders and prevent the development of abnormalities in the fetus.
As a rule, pregnant women experience a slight decrease in parathyroid hormone, which is associated with a decrease in albumin concentration. This occurs due to the active production of vitamin D by the placenta, which activates the absorption of calcium by the intestinal walls (hypercalciuria). If too much of it is produced, muscle cramps (tetany) appear, so women in this position often have “cramped legs.” Sometimes children have seizures. But it responds well to treatment with a vitamin D2 supplement.
PTH levels in pregnant women vary depending on the trimester. So, in the 1st trimester the norm is 10-15 pg/ml, in the second – 18-25 pg/ml, in the third – 9-26 pg/ml.
Norms and deviations from the norm
The production of PTH depends on the age of the person. So, the hormone norm for older men and women is:
- from 20 to 22 is 12-95 pg/ml;
- 23-70 years – 9.5-75 pg/ml;
- 71 years and older – 4.7-117 pg/ml.
During pregnancy, the rate ranges from 9.5-75 pg/ml.
If the result of the analysis showed that the PTH content is increased, this may indicate primary or secondary hyperparathyroidism as a result of oncology, Crohn's disease, excess vitamin D, renal failure, rickets, colitis, pancreatic tumor. Thus, primary hyperparathyroidism is indicated by an increase in the hormone by 2-4 times, and secondary hyperparathyroidism by 4-10 times. Also in medicine there is the concept of tertiary hyperparathyroidism. It manifests itself in the form of adenoma of the parathyroid glands and an excess of hormone production - the concentration level exceeds the norm by 10 times or more. This occurs when the need for PTH is low and it is produced in excess.
A reduced concentration of parathyroid hormone indicates magnesium deficiency and hypoparathyroidism (primary, secondary), vitamin D deficiency, sarcoidosis, osteolysis (destruction of bone tissue). Also, a similar result is often found in patients who have undergone thyroid surgery.
References
1. Kiseleva, N.G. Diagnosis of osteoporosis in childhood. // N.G. Kiseleva, T.E. Taranushenko, N.K. Golubenko. – Medical Council, 2021. – pp. 186-193. 2. Lysenko, I.M. Diseases of the parathyroid glands. Hyperparathyroidism and hypoparathyroidism. – Protection of motherhood and childhood, 2012. – pp. 60-67. 3. Leder, B. Parathyroid hormone and parathyroid hormone-related protein analogs in osteoporosis therapy. Current osteoporosis reports, 2021. – Vol.15(2). – P.110-119. Doi: 10.1007/s11914-017-0353-4. 4. Clinical recommendations “Primary hyperparathyroidism” / approved. Ministry of Health of the Russian Federation, 2021. – URL: https://www.endocrincentr.ru/sites/default/files/specialists/science/clinic-recomendations/kr88.pdf.
Treatment of hyperparathyroidism
In essence, treatment is an operation. The difficulty is associated with localization problems - it is not always possible to localize pathological parathyroid glands with ultrasound, scintigraphy and other examination options. This is where a good specialist comes in and examines and looks for the parathyroid glands, sometimes using intraoperative testing of PTH levels in suspicious areas.
Surgery
Do all patients need surgery? No! There are detailed indications for surgery, these are based on the levels of damage due to hyperparathyroidism, calcium and phosphorus levels, age, etc. The task of the endocrinologist is to correctly assess the need for intervention. Often, hyperparathyroidism is diagnosed with moderate tertiary hyperthyroidism (due to long-term vitamin D deficiency), when surgical treatment is not advisable.
If surgery is not indicated, bisphosphonates, a popular drug used to treat osteoporosis, can stop the damaging effects of parathyroid hormone on bones and lower calcium levels.
Another group of drugs are calcimimetics. These medications mimic the effects of calcium by suppressing the secretion of the parathyroid glands. Unfortunately, the price of such drugs is currently very high.
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