Diseases of the parathyroid glands

Normally, a person has 4 PSGs, which are located near the upper and lower poles of the thyroid gland, the mass of all PSGs is 120-150 mg. In some cases, ectopia (displacement) of PShZH is possible and then they can be located in the thyroid gland, thymus, retroesophageal. This fact should be taken into account when carrying out surgeries on Pschzh and thyroid. Due to the fact that PZHZH are topographically connected with the thyroid gland, during the resection of the latter (full or partial), there is a danger that the PZhZh will be removed.

In the case of PSCH removal, hypocalcemia, tetany and convulsions develop, this life-threatening condition requires medical correction.

The physiological function of PSZHG. In response to a decrease in blood levels of calcium below normal (2.0-2.75 mmol / l) under the influence of parathyroid hormone PSH, its normalization occurs by stimulating the resorptive activity of osteoclasts of the bone, causing them to destroy the bone matrix and, therefore, release calcium from the bone with the subsequent receipt in blood.
Hypercalcemia is the main symptom of hyperparathyroidism, its main causes: destruction of bones, diseases of the colon (chronic dysentery), kidney disease (polycystic). Hypercalcemia leads to the development of calcareous metastases, while calcium salts are deposited in different organs and tissues (lungs, kidneys, gastric mucosa).

Among the diseases of PSH, the primary and secondary hyperplasia of PSGH is of the greatest practical importance. Secondary hyperplasia of PSHD occurs as a reactive phenomenon in hypercalcemia. Primary hyperplasia is associated with a tumor (adenoma) PSH. This is a hormonally active tumor, accompanied by symptoms of hyperparathyroidism; the tumor develops from the lower glands (as a rule). Macroscopically, adenoma is a well-defined knot of soft consistency of a yellowish-brown color, often with cysts, weighing 7-10 grams or more. Microscopically, tumors are classified on the basis of their cellular composition (the main ones are basophilic and oxyphilic cells). Clear cell adenoma and adenoma from the main parathyrocytes have the highest hormonal activity. The cellular composition of adenomas is characterized by atypia of cells (an increase in the size of nuclei, polymorphism,the appearance of giant cells). Tumor cells can form solid layers, sometimes look like trabeculae, there are adenomatous sites and small cysts filled with homogeneous protein masses or colloid. In some cases, papillary growths can be seen in the walls of cysts. Trabecular structures often take the form of garlands located perivascular.
The histological diagnosis of adenoma PShZH is very difficult. The fact is that sometimes tumor cells penetrate into the surrounding tissues and venous vessels, however, they are not regarded as unconditional signs of tumor malignancy, since such infiltrative growth usually does not lead to relapses and metastases.
Adenoma PSZHZH must be differentiated from hyperplasia PSZHZH (secondary, less often – primary). Distinguishing signs of hyperplasia PSZHZH: hyperplasia occurs in all the glandular glands and is most pronounced in the upper pair of glands, dominated by the main parathyrocytes with minimal polymorphism and monomorphic structure of all parts of the organ.

Exceptionally rarely, cancer in the PSZL develops; it is characterized by slow growth, infiltrates surrounding tissues, but rarely and later metastasizes. The tumor is always hormonally active.
All PShZh tumors (adenomas and cancers) lead to the development of parathyroid osteodystrophy (synonym – Reclinhausen’s disease or generalized osteodystrophy). The disease is accompanied by a generalized lesion of the skeleton, mainly in women 40-50 years old. Increased synthesis of parathyroid hormone causes increased mobilization of calcium and phosphorus from the bones, which leads to hypercalcemia and progressive demineralization of the entire skeleton. In the bone tissue foci of lacunar bone resorption, the bone tissue is replaced by the connective. The most intensively indicated processes are expressed in the endosteal sections of the bones. In the lesions, osteoid tissue, a multitude of cysts filled with blood and hemosiderin, is intensively formed.
Clinically marked deformity of the bones of the skeleton, multiple bone fractures. Deformity and fractures primarily affect those bones that are subjected to physical exertion (limbs, spine, ribs).

local_offerevent_note January 9, 2020

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