If parathyroid hormone is low. Functional role of parathyroid hormone in the body

Research methods: linked immunosorbent assay, chemiluminescent immunoassay and radioimmunological method.

Blood is donated on an empty stomach, no earlier than 12 hours after the last meal. Should be excluded nervous tension and heavy physical work on the eve of the test. If the patient is constantly taking medications, you should consult a doctor - some medications affect parathyroid hormone levels. Therefore, if possible, you should stop taking it 24 hours before the test. medicines. You should not drink alcohol the night before the test.

Material for research: venous blood. Serum is obtained from the blood by centrifugation, in which the level of the hormone is determined.

The concentration of PTH is directly related to the concentration of calcium in the blood, and a change in the concentration of the hormone indicates a change in the metabolism of this mineral. Therefore, the level of parathyroid hormone must be correlated with the level of blood calcium.

With increased calcium concentration:

With hypocalcemia - hypofunction of the parathyroid gland.

An increase in parathyroid hormone levels is observed in the following cases:

Simultaneously with hypercalcemia:

Simultaneously with hypocalcemia:

Medicines that affect parathyroid hormone levels

Increase PTH levels: cortisol, anti-tuberculosis drugs (isoniazid), nifedipine, estrogens, verapamil.

Reduce PTH levels: oral contraceptives, famotidine, gentamicin, prednisolone, vitamin D and its analogues.

Literature:

Parathyroid hormone (PTH) is a hormonal substance that is biologically active. It is produced by the parathyroid glands. The chemical structure of the hormone is complex; it consists of several dozen amino acids. Approximately a third of them are responsible for the biological activity of PTH, and the rest ensure the binding of the substance to receptors and its stability.

The purpose of parathyroid hormone is to regulate the level of calcium and phosphorus in the blood. Depending on their content, PTH secretion is stimulated or suspended.

Calcium and PTH

The amount of PTH directly depends on the level of calcium ions in the bloodstream. If it decreases, then the activity of the parathyroid glands that produce parathyroid hormone immediately increases.

The main mission that PTH must perform is maintaining the required amount of calcium cations in the blood. Its implementation includes several actions.

• Under the influence of PTH, vitamin D is intensely activated in the kidneys. It is converted to calcitriol (a hormone-like substance). It stimulates the absorption of calcium by the intestines and its active entry from food into the blood.

  To successfully carry out this action, the body must have a sufficient amount of vitamin D.

• Parathyroid hormone enhances the reabsorption of calcium cations from primary urine (glomerular ultrafiltrate). This happens at the level of the renal tubules. This reduces the loss of the substance in the urine, while increasing the excretion of phosphorus.
• In conditions of calcium deficiency, PTH promotes its extraction from bone tissue and movement into the blood. The hormone increases the activity of osteoclasts - giant multinucleated cells that destroy bone tissue. They remove it by dissolving the mineral component and destroying collagen. Osteoclasts actively break bone beams and release calcium into the blood, which is formed during such actions. Its concentration in the life-giving liquid increases.

But there is also Negative consequences: the strength of bone tissue decreases, which means the likelihood of fractures increases.

It should be noted that this becomes possible only if the hormone exceeds the norm for a long time. With periodic and short-term entry of PTH into the blood, positive impact on bone tissue: it strengthens. Parathyroid hormone promotes the deposition of calcium in the bones if there is too much of it in the blood.

Parathyroid hormone is normal in women

IN female blood The normative level of parathyroid hormone changes rarely. It fluctuates depending on how old the fair sex is.

Until the age of twenty, the PTH content should be within the following limits (pg/ml):

• minimum – 12.0;
• maximum – 95.0.

All subsequent years, up to 70 years, the norm decreases, and its boundaries are as follows (pg/ml):

• minimum – 9.5;
• maximum – 75.0.

After 70 years, the lower value of the norm is fixed at 4.7, which is half the previous level. Upper permissible level PTH increases significantly and amounts to 117.0.

For women during pregnancy, the permissible level of parathyroid hormone should be in the following range (pg/ml):

• minimum – 9.5;
• maximum – 75.0.

Parathyroid hormone is normal in men

The optimal level of parathyroid hormone ranges from 12.0 to 65.0 (pg/ml). Normal PTH for men is no different from women's indicators.

• minimum – 12.0;
• maximum – 95.0.

From 23 to 70:

• minimum – 9.5;
• maximum – 75.0.

Over 70:

• minimum – 4.7;
• maximum – 117.0.

Although the range normal values is the same, it has been established that the production of the hormone increases with age to a greater extent in the fair sex.

Normal parathyroid hormone levels in children

The permissible amount of parathyroid hormone in children remains unchanged from the day of birth until adulthood (up to 22 years). Its interval is as follows (pg/ml):

• minimum – 12.0;
• maximum – 95.0.

Just like in adults, the amount of parathyroid hormone fluctuates throughout the day. This is due to the metabolism in the body and its biorhythms.

Diagnosis of PTH

Testing for parathyroid hormone is prescribed:

• orthopedist;
• endocrinologist;
• therapist.

The need for research appears in the following cases:

• Osteoporosis.
• Urolithiasis with calculi (stones), which are predominantly composed of calcium and phosphorus.
• Spinal sclerosis.
• Possible neoplasm in the parathyroid gland.
• Increased incidence of bone injuries and fractures in seemingly safe situations.
• Reduced or higher level calcium in the body.
• Changes in bone tissue.

The test is carried out in the morning. Before the procedure, you should follow the standard rules:

• after dinner and before the test, do not eat anything;
• do not touch alcohol the day before testing;
• do not smoke at least one hour before diagnosis;
• Sports or intense physical exercise should be suspended three days in advance.

Why does PTH decrease or increase?

Exceeding the level of parathyroid hormone most often indicates damage to the parathyroid glands. The disease is quite common; it is diagnosed three times more often in women.

Reasons for a persistent increase in parathyroid hormone:

• Neoplasms in the thyroid and parathyroid glands, metastases to these organs from a tumor of a different location.
• Rickets (vitamin D deficiency).
• Crohn's disease.
• Tumor in the pancreas.
• Kidney failure.
• Colitis.

Why is the level of parathyroid hormone reduced? Possible reasons decreases in the amount of parathyroid hormone are as follows:

• The development of sarcoidosis is a systemic pathology affecting the lungs.
• Magnesium deficiency.
• Surgical intervention on the thyroid gland.
• Osteoliosis is the complete resorption of bone tissue and all its elements.

The level of parathyroid hormone is affected by drugs such as lithium, isoniazid, cyclosporine, hormonal agents, the basis of which is estrogen. They are able to temporarily increase the level of PTH in the blood.

It is possible to reduce the amount of parathyroid hormone in women oral contraceptives, drugs with vitamin D, prednisolone, magnesium sulfate, famotidine.

Consequences of PTH deviation from normal

When the level of parathyroid hormone deviates from the norm in one direction or another, a disturbance in the metabolism of calcium and phosphorus occurs. This has an adverse effect on everyone's work. internal organs person. He has:

• muscle weakness;
• difficulties in walking;
• constant feeling of thirst;
• dysuria – frequent urination.

There is a high probability of developing a hyperparathyroid crisis - serious condition, which progresses rapidly against the background sharp jump calcium level. It is characterized by:

• significant increase in body temperature;
• confusion;
• painful sensations in the abdominal area.

Long-term excess calcium in the blood slows down the formation bone cells. And the old bone beams continue to dissolve. There is an imbalance between tissue formation and destruction. This is fraught with osteoporosis and pathological softening of bones.

Negative processes reach the kidneys and urinary system: the threat of stone formation increases.

Deviations in PTH levels from normal also affect vascular system. Calcification develops, that is, calcium salts are deposited in those tissues and organs where they should not be. They also affect blood vessels, increasing the risk of ulcers forming in the stomach and causing general disorder blood circulation

If during the examination of the patient there are suspicions about the presence of pathology of the parathyroid glands or other ailments that violate the proportion between calcium and phosphorus, this serves as a reason to conduct a test for the level of parathyroid hormone in the blood.

Photo: Emw - own work, CC BY-SA 3.0

Parathyroid hormone - what is it? It is a biologically active substance produced by the parathyroid glands. He plays important role in the human body. Main function substance is the regulation of calcium and phosphorus levels. A blood test is prescribed to determine its level. If the study shows an increase or decrease in indicators, it is necessary to conduct an additional examination and prescribe treatment.

Parathyroid hormone - its norm is important for normal operation the whole body. It is produced by steam thyroid. The whole parathyroid hormone molecule contains 84 amino acids. She's different short period half-life of no more than four minutes. In such a biological active form hormone and is present in the body.

This substance primarily stimulates an increase in calcium levels in the blood.

Also under his influence:

1. The process of absorption of calcium and inorganic phosphorus occurs in the small intestine.
2. The formation of glucose and glycogen from substances of non-carbohydrate origin in the liver increases.
3. The reabsorption of calcium in the kidneys is stimulated.
4. The amount of calcium deposits in the lens decreases.
5. The level of phosphorus in the blood plasma decreases.
6. The calcium content in the intercellular fluid reaches its optimal concentration.
7. The excretion of phosphorus in the urine is activated.
8. Cholecalciferol derivatives are formed in the kidneys.
9. Osteoclasts are activated.
10. The process of blood clotting occurs.
11. Membrane permeability decreases.
12. The likelihood of developing rickets, thyrotoxicosis, diabetes mellitus.
13. When there is an excessive level of calcium in the blood, it is deposited in the bone tissue.
14. Nervous, endocrine, vascular and muscular system function in the required mode.

Since parathyroid hormone has many important functions, what is its normal level and what does it mean when it is elevated, you need to know in order to eliminate the problem in time.

The concentration of the hormone in the body fluctuates throughout the day. This is influenced by human biorhythms and calcium metabolism. In the morning its concentration is reduced, but by noon it increases, which is associated with high human activity at this time of day.

Parathyroid hormones have a close relationship with vitamin D3. When this vitamin enters the body with food, the absorption of calcium and phosphorus in the intestines increases. Processes stimulated by parathyrin increase the concentration of calcium cations in the blood.

Norms of indicators differ depending on gender and age.

Parathyroid hormone is determined using a blood test.

The procedure is carried out in the following cases:

1. To check the condition of the parathyroid glands.
2. To determine the causes of calcium deficiency or excess and disturbances in its metabolism.
3. In order to differential diagnosis if hyperthyroidism is suspected.
4. To confirm hypothyroidism.
5. To monitor the condition of patients with a chronic form of calcium metabolism disorder.
6. To assess the effectiveness of therapy for pathological processes in the parathyroid gland and their removal in the presence of tumors.

Analysis may also be ordered by:

• if the calcium level has changed, if the levels increase or decrease;
• if there are signs in the form of fatigue, nausea, abdominal pain, thirst, indicating that hypercalcemia is developing;
• for pain in the abdomen, muscle cramps, tingling sensation in the fingers, which indicates hypocalcemia;
• If CT scan, ultrasound or other instrumental study showed that the dimensions and structure parathyroid glands changed;
• during the treatment of disturbances in calcium metabolism;
• if a cyst or other neoplasm appears in the parathyroid glands;
• in the process of diagnosing diffuse goiter;
• for disorders in the structure of bone tissue;
• if osteoporosis develops;
• if there is a history of kidney disease in which the glomerular filtration rate has decreased.

To accurately determine the disease and obtain reliable information about the level of hormones in the blood, it is necessary to properly prepare for blood donation. For research use venous blood.

Before collecting biomaterial, the following rules should be observed:

1. Consult an endocrinologist, orthopedist or therapist.
2. Avoid drinking alcohol the day before the test.
3. Do not eat food for twelve hours before visiting the laboratory.
4. Avoid physical and emotional stress an hour before donating blood.
5. People who smoke You need to give up cigarettes for three hours.

It is important to remember that the norm of a particular hormone depends on age and gender. Also affects hormonal levels menstrual cycle, menopause

If a woman is going through menopause, she should tell her doctor, as this condition affects the level of hormones in the blood.

Hormonal research allows you to determine not only parathyroid hormone, but also other indicators indicating the condition hormonal levels.

During the study they can determine:

1. Prolactin. It is a luteotropic hormone. Under the influence of prolactin, the mammary glands grow and secrete milk. Under its influence, progesterone is also produced.
2. ACTH. This is an adrenocorticotropic hormone that triggers the production of steroid hormones in the adrenal glands. These are cortisone, cortisol, aldosterone and others. Under its influence, testosterone is produced in the body of men, and estrogen and estradiol in the body of women.
3. Renin. Acts as a regulator of water-salt homeostasis and blood pressure in the arteries.

Also, if necessary, the content of many other hormones is determined.

If parathyroid hormone is elevated, bone tissue will be destroyed and the blood will become oversaturated with calcium. These processes will lead to osteoporosis.

When there is too much calcium in the blood, oxalate or phosphate stones form in the kidneys.

An increase in parathyroid hormone occurs:

1. With hypocalcemia. In this case, the level of the hormone increases to mobilize calcium from the depot and improve its absorption.
2. With primary hyperparathyroidism. At the same time, calcium and calcitonin are increased, and phosphorus is decreased. This occurs if diffuse toxic goiter of autoimmune origin, hyperplasia of the parathyroid glands, or cancer of the thyroid or parathyroid gland develops. If you have toxic goiter, also known as Graves' disease, thyrotoxicosis develops.
3. At secondary hyperparathyroidism, in which calcium in the blood is normal or reduced and calcitonin is reduced. It is associated with renal failure in chronic form, vitamin D deficiency, malabsorption syndrome.
4. With tertiary hyperparathyroidism. This disease occurs if long time secondary hyperparathyroidism occurred.
5. With pseudohypoparathyroidism.
6. With multiple endocrine neoplasia.
7. For ulcerogenic pancreatic adenoma.
8. For renal hypercalciuria.
9. With rickets.
10. If there is a disturbance in the production of parathyroid hormone, which occurs when cancer diseases kidneys and lungs.
11. In the presence of metastases in bone tissue.
12. During pregnancy and breastfeeding.

An increased level of the hormone is accompanied by:

• weakness in the muscles and throughout the body;
• painful sensations in the limbs;
• dry skin;
• earthy skin tone;
• duck gait;
• loose joints;
• heavy gait.

If a test for parathyroid hormone is carried out and it is elevated, then at first the person will constantly feel thirsty and urination will become more frequent. With osteoporosis of the jaw, tooth loss occurs. In later stages high level hormone leads to complications in the form of frequent fractures and bone deformations.

The disease also causes symptoms such as:

• drowsiness;
• excessive emotionality;
• irritability and sentimentality.

The consequences of increasing calcium to 5 mmol are very serious. In this case, the patient experiences manifestations of hyperparathyroid crisis, which, if not treated in time, can cause fatal outcome.

You can learn about the crisis by strong feeling thirst, muscle and joint soreness, vomiting, high temperature, loss of consciousness.

This condition is observed during pregnancy, if there is infectious diseases, as a result of intoxication of the body, taking antacids, eating food with high content calcium.

If parathyroid hormone is low, hypoparathyroidism is diagnosed. It can be primary and secondary.

Primary form develops with pathological process glandular tissue of the glands located near the thyroid gland.

In this case, the disease occurs:

1. Innate. It is caused by the absence or insufficient development of the parathyroid glands.
2. Postoperative. If the removal of formations in the thyroid gland resulted in damage to the blood vessels that feed the parathyroid glands.
3. Post-traumatic. The deviation develops if the body comes under the influence of ionizing radiation, when infectious diseases, after injuries to the parathyroid gland area, which led to hemorrhage or inflammation.
4. Autoimmune. Autoimmune hypoparathyroidism develops if, due to a failure in immune system antibodies are produced to the parenchyma of the parathyroid glands. This makes the production of PTH in normal quantity impossible. The pathology is usually combined with a fungus of the mucous membranes and skin or with adrenal insufficiency. Alpha fetoprotein is used to limit the attack of autoantibodies. Thyroiditis of autoimmune origin can also cause the problem. Typical for thyroiditis chronic course inflammation of the thyroid gland.
5. Idiopathic. This genetic pathology, the reasons for which are not clear.

The development of secondary hypoparathyroidism occurs under the influence of pathologies developing outside the parathyroid glands. This may be due to tumors or metastases in skeletal system. The problem is also observed if the thyroid gland produces triiodothyronine, thyroglobulin, thyroid-stimulating hormone and others in smaller quantities than necessary. Thyroglobulin plays a particularly important role. It is necessary for the synthesis of hormones produced by the thyroid gland.

How to normalize parathyroid hormone levels?

Parathyroid hormone performs many functions in the body. Therefore, if the indicator deviates from the norm, treatment is necessary. Therapy is aimed at stabilizing calcium levels in the blood.

Severe calcium elevations should be treated in the intensive care unit. The patient is administered drugs for diuresis. The procedure is carried out using isotonic solution sodium chloride and furasemide.

For treatment primary hyperparathyroidism, which was caused by nodes, adenomas and other neoplasms that appeared in the gland, is used surgical techniques. The disease usually occurs in older people. Only the tumor producing the hormone is excised, or part of the gland is removed.

For secondary hyperparathyroidism, a course of vitamin D and calcium-containing medications is prescribed. If medications are ineffective and hormone levels are three times higher than normal, surgery is performed.

As replacement treatment the condition is normalized:

1. Medicinal parathyroid hormone - teriparatide. It acts in the same way as endogenous parathyroid hormone. This effective option treatment.
2. High doses calcium and vitamin D.
3. Synthetic calcitriol, which is an active metabolite of vitamin D.

Additionally, symptomatic therapy is carried out, including sedatives and anticonvulsants. A doctor must prescribe medications.