Comparative anatomy....... 514
Pathological anatomy...... 523
Methods of inspection........ 524
Thyroid gland [glandula thyroidea (PNA), glandula thyreoidea (JNA, BNA)] — an unpaired hemaden. Y. is located in front area of a neck; it synthesizes and emits the hormones regulating processes of growth, development, a differentiation of fabrics and a metabolism in an organism in blood and a lymph.
Short description of outward Shch. for the first time K. Galen gave. A little more fully the body is described in A. Vezaliya's works (1543). In 1656 T. Varton called this body «thyroid gland». In 1836 King (Th. W. King) the first put forward the concept about intra secretory activity of a thyroid gland. Baumann (E. Baumann) in 1896 noted close connection between intake of iodine in an organism and functional activity of body.
The comparative anatomy
corresponds to the Thyroid gland of the highest vertebrata a subbranchiate fillet of a lancelet, to-ry goes ventrally on the centerline along all branchiate part of intestines. At Cyclostoma Shch. it is presented by accumulation of the single follicles located along cranial department of a gut. Y. selakhiya — not -
pair body of various form, at amphibians Shch. steam room. At reptiles Shch. almost always unpaired, is located on a midline, near escaping of heart of large vessels and, as a rule, has no certain form. At birds this body always pair. At mammals Shch. is located ventrally from caudal department of a throat and an adjacent part of a trachea, consists of two shares connected by an isthmus at most of representatives of this class.
Rudiment shch. arises at a germ of the person on the 4th week vnut
riutrobny development (length of a germ of 2,5 mm) in the form of protrusion of a ventral wall of a throat on the centerline, between I and II couples of visceral furrows. This protrusion represents epithelial tyazh, to-ry grows along a pharyngeal gut to the III—IV level of couple of visceral furrows down. Epithelial tyazh at the beginning of the development represents a shchitoyazychny channel (cinctus thyroglossus) and corresponds to an output channel Shch. Then the distal end e p you iteit l of news agency of l no-go the tyazha forks, and from it the right and left shares shch develop further. P r about to with and m and l n y p the end of an epithelial tyazh to an atrofir
etsyatsya, on its place in the subsequent there is a rudimentary rest — the blind opening of language (foramen caecum linguae) which is localized on border of a body and a root of language. Thus, Y. it is put as a typical excretory gland, and in the course of further development becomes endocrine (see Hemadens).
Rudiments right and left share Shch., originally compact, quickly increase in volume due to growth epithelial cellular tyazhy, or trabeculas. Between trabeculas the mesenchyma with numerous blood vessels burgeons. News agencies 8 — the 9th not -
business of pre-natal development begin to form follicles, the main hmassa to-rykh is made by ti-rotsita (follicular cells, A-cells). Much less as a part of follicles it is put V-cells (cells of Askanazi). Tiro-tsita and the V-cell are close among themselves. There is an opinion that these cells have the general trunk elements or can be transformed each other. In development in a rudiment Shch. derivative V couples of visceral furrows — ultimobranchial little bodies grow, to-rye are a source of the parafollicular cells which are a part of a parenchyma of a thyroid gland (okolofollikulyarny, or S-cells).
Y. begins to function at the fruit having length of 7 cm what the ability arising during this period' glands testifies to absorb a radioiodine, and also emergence of a colloid in gleams of follicles. Functioning of gland involves a differentiation of trabeculas, to-rye begin to be divided into the separate small follicles which are quickly increasing in volume in process of accumulation of a colloid in them.
Weight (weight) Shch. newborns are averaged by 1 — 2 g. In iron of newborns desquamation of a follicular epithelium and the strengthened resorption of a colloid is noted that it is probably connected with functional voltage of Shch. during adaptation to conditions of the environment.
Shch. is located in front area of a neck (see) in front and on each side from a trachea (see). It has the horseshoe form with concavity the turned kzada, and consists of two shares (fig. 1), unequal in size. Right (lobus dext.) and left (lobus sin.) shares Shch. are connected by an unpaired isthmus (isthmus glandulae thyroideae). When the isthmus is absent, both shares Shch. leaky adjoin one to another.
Sometimes the additional (aberrating) thyroid glands (glandulae thyroideae accessoriae), either not related, or connected to shares Shch meet. small thin tyazha. In 30 — 50% of cases with an isthmus or with the left share Shch. the pyramidal share (lobus pyramidalis), edges is connected, going up, can reach upper thyroid cutting of a thyroid cartilage or a body of a hypoglossal bone (fig. 1).
Weight (weight) Shch. the adult is made by 20 — 60 g. The longitudinal size of each share reaches
5 — 8 cm, cross — 2 — 4 cm, thickness — 1 — 2,5 cm. During puberty Shch. increases. Its sizes can change also depending on degree of a krovenapolneniye; at senile age the sizes Shch. decrease.
Outside Shch. it is covered with the fibrous capsule, edges it is connected by connective tissue bunches with a cricoid, rings of a trachea. The most dense connective tissue bunches form peculiar sheaves. Among them are especially expressed an average sheaf shch., edges reaches from the capsule of an isthmus for a front surface of a cricoid, and also the right and left lateral sheaves Shch., located between the capsule of nizhnemedialny sites of side shares, lateral surfaces of a cricoid and the cartilaginous rings of a trachea, next to it.
Shch. are covered grudinopodjyazychny (mm. sternohyoidei) and grudinoshchitovidny muscles (mm. sternothyroidei), upper paunches of the right and left scapular and hypoglossal muscles (mm. omohyoidei dext. et sin.), lying between leaves of a pretracheal plate of a cervical fascia. On border of front and side and zadnemedialny surfaces Shch. the neurovascular bunch of a neck adjoins to it (tsvetn. tab., Art. 432, fig. 3). On a zadnemedialny surface Shch. there passes the recurrent guttural nerve (n. laryngeus recurrens) and raspola-
Fig. 1. The diagrammatic representation of an arrangement of a thyroid gland in relation to a throat, a trachea and a hypoglossal bone (anterior aspect): 1 — a hypoglossal bone; 2 — a shchitopodjyazychny membrane; 3 — a pyramidal share of a thyroid gland (non-constant); 4, 7 — the left and right shares of a thyroid gland; 5 — a trachea; 6“ — an isthmus of a thyroid gland; 8 — a cricoid; 9 — a thyroid cartilage.
gatsya paratracheal limf. nodes. The Zadnemedialny surfaces of gland adjoin to side surfaces of upper rings of a trachea, a throat (see) and to a gullet (see), and above — to cricoid and thyroid cartilages. Lower parts of both shares Shch. reach the fifth, sixth rings of a trachea. Isthmus Shch. is located at
the I—III or the II—IV level of cartilages of a trachea. Its average department is covered with the spliced pretracheal and superficial plates of a cervical fascia and skin.
To a rovosnabzheniye it is carried out from upper thyroid arteries (aa. thyroideae sup. dext. etsi of the item), departing from outside carotid arteries (aa. carotides ext.) and from the lower thyroid arteries (aa. thyroideae inf. dext. et sin.), departing from shchitosheyny trunks (trunci thyrocervicales). Approximately in 10% of cases in blood supply Shch. the lowest thyroid artery (a. thyroidea ima) departing from a brachiocephalic trunk (truncus brachiocephalicus) or from an aortic arch (arcus aortae) participates, is more rare — from the general carotid artery (a. carotis communis). On the surface of gland of an artery form the anastomosing network (tsvetn. the tab., Art. 432, fig. 4,5), edges breaks up to the capillaries surrounding follicles and closely adjacent to a follicular epithelium. A venous blood flows through the veins of the same name in an internal jugular vein (v. jugularis interna) and brachiocephalic veins (vv. brachiocephalicae).
The lymph drainage occurs through limf, the vessels falling in paratracheal deep cervical and mediastinal limf. nodes. Limf, capillaries and small limf, vessels lie E1eposredstvenno between follicles.
Innervation. Sympathetic innervation Shch. it is carried out by the nerves going from cervical nodes of sympathetic trunks. The parasympathetic innervation is provided with branches of a vagus nerve (see) — upper guttural (n. laryngeus sup.) and returnable guttural (item laryngeus recurrens) nerves.
From the fibrous capsule covering units., in depth of gland connective tissue partitions depart, to-rye form a stroma of gland and contain vessels and nerves in the thickness. These connective tissue partitions do not connect with each other in the depth of fabric Shch. Therefore division of a parenchyma into segments incomplete, and gland is is ev to lobular. Y. has gistol. structure typical for hemadens: in it there are no output channels and each
functional unit is closely connected with circulatory system. Base unit Shch. the follicle is — the roundish or slightly oval closed bubble, a wall to-rogo it is covered by a secretory (follicular) epithelium.
In a parenchyma Shch. distinguish three types of cells (And, In and C), to-rye differ from each other both in structural, and in the functional relation. Ground mass of cells of a parenchyma shch. make tirotsita (follicular cells, or the A-cells) producing thyroid hormones. Depending on a functional state Shch. tirotsita can be flat, cubic or cylindrical. At low functional activity Shch. tirotsita, as a rule, flat, at high — cylindrical.
The gleam of a follicle is filled with a colloid, to-ry represents the homogeneous weight which is painted hematoxylin-eosine in pink color. According to electronic >Mick ~ roskopiya (see), a colloid has fine grained structure and average electron density. The ground mass of a colloid is made by the thyreoglobulin (see) cosecreted by tiro-tsita, idiosyncrasy to-rykh active capture of iodine is (see). The colloid directly prilezhit to an apical surface of tirotsit (an apical membrane), on a cut there are numerous microvillis. Nearby tirotsita are connected with each other by means of the closing plates, or terminal crossing points, and desmosomes. On a basal surface of tirotsit there can be deep folds which are especially expressed in the period of functional activity to-rye much increase the surface of cells turned to circulatory capillaries. Between tirotsita and circulatory capillaries there are a basal membrane, the main substance, fine collagenic and reticular fibers oriented in various directions.
In cytoplasm of tirotsit the granular cytoplasmic reticulum is well developed (see. Endoplasmic reticulum). Mitochondrions are located on all cell, however in an apical part it is always slightly more of them, than in a basal part of a cell. Clear topographical communication of mitochondrions with tubules of a granular cytoplasmic reticulum is traced. So, the last quite often «shroud» separate mitochondrions. At the same time mitochondrions can «cover» partially or completely separate elements of a cytoplasmic reticulum. In tiro-tsita the complex is well developed Gaulle
of a dzha (see Golgi a complex), to-ry is presented by the large vacuoles flattened by tanks (vacuoles) and microbubbles. In a ring of a complex of Golgi, and also near it the granules of various size and a form, different electron density revealed at introduction of a radioiodine are found (fig. 2, a). Similar gra-
Fig. 2. The scheme of a ratio of tirotsit and parafollicular cells in a parenchyma of a thyroid gland: and — granularity of tirotsit as a result of absorption of a radioiodine by them; — characteristic argyrophil granularity of parafollicular cells; 1 — the parafollicular cell which is localized between follicles; 2 — para-follicular cells in a wall of a follicle; 3 — the tirotsita covering a cavity of a follicle; 4 — a cavity of follicles; 5 — basally located tirotsit; 6' — In - klet-@; 7 — an epithelial kidney, originative to an interfollikulyarny island; 8 —
a basal membrane.
nula are available not only near Golgi's complex, but also in other sites of a cell; e.g., in its apical part they sometimes form the whole accumulations consisting of several rows of the granules (from 3 to 8) located the friend under the friend. Except characteristic granules, in an apical part of tirotsit intracellular drops of a colloid sometimes come to light.
V-cells (a cell of Askanazi) — larger, than tirotsita, have eosinophilic cytoplasm and roundish the located kernel is central. They contain a large number of oval or roundish mitochondrions, among to-rykh secretory granules are located. In cytoplasm of these cells biogenic amines, including serotonin are revealed (see). For the first time V-cells appear at the age of 14 — 16 years. In a large number they occur at aged people of 50 — 60 years.
Parafollicular cells (an eye-lofollikulyarnye, either S-cells, or the K-cell) differ from tiro-cyton in lack of ability to absorb iodine. They provide synthesis of a calcitonin (see) — the hormone participating in exchange of calcium in
an organism. Separate parafollicular cells or their groups are localized on an outer surface of follicles (fig. 2). They never contact to a colloid, from to-rogo are separated by cytoplasm of tirotsit. Parafollicular cells have rather large sizes, low electron density of cytoplasm, edge densely a fuse
of a nen the proteinaceous granules revealed during the silvering (fig. 2, b). In parafollicular cells the granular cytoplasmic reticulum and Golgi's complex are well developed.
Along with follicles in Shch. the interfollikulyarny (ekstrafollikulyarny) islands formed by cells, structure distinguish to-rykh reminds a structure of typical tirotsit. In the centers of nek-ry interfollikulyarny islands there are microfollicles consisting of several cells. Also parafollicular cells are a part of interfollikulyarny islands. The most often parafollicular cells meet in the islands located in the central part of gland where they make apprx. 2 — 5% of all cells. Interfollikulyarny islands matter in regeneration of fabric Shch. if defeat of the last has extensive character and is followed by death of the whole follicles. At partial damages of follicles regeneration is carried out at the expense of the tirotsit located basally. Thanks to the last there is also phisiological regeneration of a follicular epithelium.
Fiziol. role Shch. consists in biosynthesis and allocation in blood and a lymph of the hormones regulating processes of growth, development, a differentiation of fabrics and activating a metabolism in an organism. Specific feature of tiro-tsit is ability to actively absorb, accumulate iodine and to transfer it to integrally connected form by formation of iodinated thyroid hormones — thyroxine (see) and triiodothyronine (see).
The secretory process proceeding in shch., develops of three phases. In the first phase (a phase of products) there is a formation of thyreoglobulin, and also oxidation of iodides in atomic iodine. In the second phase (a phase of allocation, or secretion) thyreoglobulin is emitted in a gleam of a follicle, condensed in it in the form of a colloid and iodated. The third phase (a phase of removal) consists of a reabsorption of a colloid of a tirotsitama, transportation of reabso-rbirovanny substances through cytoplasm in a basal part of a tirotsit and release of thyroid hormones in blood.
The phase of products of thyreoglobulin begins with accumulation in a granular cytoplasmic reticulum of a tirotsit of the initial amino acids arriving from blood. Under the influence of template-RNA (see Ribonukleinovy acids), contained in ribosomes (see), there is a synthesis of primary polypeptide collecting in lacunas of a cytoplasmic reticulum. Here accession to polypeptide of carbohydrates begins (galactoses and mannoses). The synthesized primary polypeptide moves to Golgi's complex where his glikolizirovaniye comes to the end, there is an assembly and packaging of the molecules of a glycoprotein which are a part of thyreoglobulin (see). The secretory bubbles forming in a zone of a complex of Golgi and containing a glycoprotein (not iodated thyreoglobulin) are displaced in an apical part of a tirotsit, merge the covers with its apical membrane and allocate contents in a gleam of a follicle by an exocytosis.
Iodine comes to tirotsita from blood in the form of iodide (iodine ion), is transported through their cytoplasm and emitted through an apical membrane in the gleam of a follicle filled with a colloid.
Absorption of iodine of a tirotsitama is considered as the active, needing energy consumption process of transfer of iodide against a gradient of concentration. Such highly active and high-specific transport of iodine, and also (zhstry transfer of this element in the connected form define a role Shch. as principal organ of exchange of iodine in an organism (see. Iodic exchange). Content of iodine is Shch. exceeds its level in other fabrics and blood serum by 10 — 100 times.
As only atomic iodine can participate in process of iodination of thyreoglobulin, iodide is exposed to oxidation, a cut is carried out in a subapical zone of cytoplasm of tirotsit with the participation of peroxidase (see Peroxide elements).
The phase of allocation, or secretion, thyroid hormones begins with an exit of not iodated thyreoglobulin in a gleam of a follicle and receipt it in a colloid. Iodination of thyreoglobulin (inclusion of atoms of iodine in tirozilny radicals) happens in a peripheral zone of follicles, on border of an apical part of a tirotsit and colloid. Enter number of the amino acids making a proteinaceous component of a molecule of thyreoglobulin tyrosine (see) and its derivatives — tironina, to-rye, undergoing iodination, give rise to thyroid hormones: to thyroxine (T4) and triiodothyronine (T3). In detail synthesis of thyroid hormones — see Yodtirozina, Yodtironina, Tiroksin, Triyodtironin.
Along with thyreoglobulin in Shch. it is formed tireoalbumin, to-ry it is iodated too, but only partially, to a stage of iodtyrosines. The ratio of concentration of thyreoglobulin is normal and the tireoalbumina makes about 9:1. At patol. the states which are followed by proliferation of a parenchyma Shch., its goitrous transformation and developing of adenomas, formation of a tireoalbumin increases, and at malignant tumors Shch. can even surpass formation of thyreoglobulin. Besides, in Shch. the iodated histidines and tiroksamin are found. All iodated amino acids which are a part of thyroid proteins are L-isomers (see the Isomerism).
Concluding (third) phase of the secretory process proceeding in tirotsita — a phase of removal of thyroid hormones from follicles in blood. As thyroid hormones contain in molecules of thyreoglobulin in the connected state, the need of an organism for them can be satisfied only by splitting of a molecule of thyreoglobulin. The phase of removal is followed by considerable strengthening of processes of dissimilation in tirotsita (what clear increase in absorption of oxygen by them testifies to) and strong swelling of their cytoplasm and kernels. The phase of removal begins with a reabsorption of a colloid of a tirotsitama. Electronic microscopic examinations allowed to establish that the reabsorption of a colloid is carried out by its active phagocytosis by tirotsita by means of pseudopodiums (poppy-roendotsitoz). In cytoplasm of tirotsit drops of a colloid appear, to the Crimea lysosomes come nearer and merge with them. Thyreoglobulin in drops of a colloid is split under the influence of enzymes of lysosomes (see) therefore iodtyrosines are released: monoiodtyrosine and diiodotyrosine and yodtironina (thyroxine and triiodothyronine) accumulating in the vacuoles and tanks which are displaced in a basal part of a tirotsit. Iodtyrosines at the same time are completely deiodinated and do not come to blood, and the iodine which is released from them is used in biosynthesis of thyroid hormones again. Yodtironina after emptying of vacuoles the capillaries braiding a follicle get through a basal membrane and perikapillyarny space in circulatory (partially and to lymphatic).
Emergence of pseudopodiums and drops of a colloid in tirotsita is observed only in an initial stage of a phase of removal. Further at normal function Shch. processes of allocation proceed without the strengthened formation of pseudopodiums and drops of a colloid by a pinocytic (mik-roendotsitoz). The specified mechanisms come into effect consistently: in an initial stage of a phase of removal the makroendo-cytosis pseudopodiums prevails, further it is replaced by microendocytosis.
An exit in blood of thyroid hormones from Shch., the hyperfunction brought to a state repeated influences of thyritropic hormone, from the very beginning proceeds in the form of microendocytosis without formation of pseudopodiums and clearly distinguishable drops of an intracellular colloid. The same ratios are defined at a thyrotoxicosis (see) when the high level of thyroxine and triiodothyronine in blood demonstrates not only increase in products of thyroid hormones, but also their intensive removal in blood; at the same time neither pseudopodiums, nor accurate drops of an intracellular colloid are found.
Except the iodated thyroid hormones, y. forms kaljtsi-tonin (see) — the bezyodny proteinaceous hormone reducing the content of calcium in blood. The calcitonin is formed by parafollicular cells. Parafollicular cells are on the origin modified nervous cells (neuroendocrinal) and keep ability to absorb predecessors of neuroamines (L-DOFA and 5 hydroxytryptophane) and to decarboxylize them respectively in noradrenaline (see) and serotonin. High content of neuroamines and ability to produce proteinaceous hormone cause inclusion of parafollicular cells of a thyroid gland in APUD-system (see. And P U D-system, t. 20, additional materials). Parafollicular cells exponentiate activity of a follicular epithelium and promote maintenance of an intraorganic homeostasis Shch.
Function V-to a letok is defined by accumulation of biogenic amines, in particular serotonin, and potentiation fiziol. activities of a follicular epithelium.
Regulation of secretion of about r m about N about in shchitovidno y glands. Specific stimulator Shch. thyritropic hormone of a hypophysis is considered. Thyritropic function of a front share of a hypophysis, in turn, is activated tiro-liberiny, the cosecreted hypothalamus (see. Hypothalamic neurohormones). Therefore damage of a hypothalamus leads to the same weakening of activity Shch., as well as a hypophysectomy (see the Hypophysis). This way of regulation can be designated as transadenogipofizarny.
In turn, thyroid hormones (especially triiodothyronine) oppress thyritropic function of a hypophysis (and, presumably, secretion of a tiroliberin a hypothalamus), i.e. relationship between functional activity Shch. and intensity of thyritropic function of a hypophysis represent system of the negative feed-back (see) providing preservation of fluctuations of functional activity Shch. in limits fiziol. norms.
The thyritropic hormone arriving to a thyroid gland with a blood flow is perceived by the specific receptors which are localized in a plasma membrane of tirotsit. These receptors, having connected to thyritropic hormone, activate adenilattsiklazny system of tirotsit, edges through cyclic the adenozinmonofos-veil (tsAMF) uses fermental systems of tirotsit therefore their functional activity increases.
It is established that secretion of thyroid hormones is activated by directly sympathetic impulses, though not so intensively as thyritropic hormone. Parasympathetic impulses cause oppression of these processes. Thus, the regulating influences of a hypothalamus (see) on Shch. can occur as through a hypophysis, and passing it (paragipofizarno).
At the same time afferent signals from units., arriving on centripetal nerve pathways, having reached a hypothalamus, weaken thyritropic function of a hypophysis; therefore, a negative feed-back between shch. and by a hypophysis it is shown as well in direct action of nervous impulses. State and activity of parafollicular cells Shch. do not depend on a hypophysis and are not broken after a gi-ttofizektomiya; their function is stimulated by sympathetic impulses, and parasympathetic oppress. At the same time secretory activity of parafollicular cells has direct dependence on concentration of calcium in blood: increase or decrease involves it respectively increase or weakening of secretion of a calcitonin a parafoul to a face lyarny cells. Antagonistic interacting with parathyroid hormone (see Parathormone) epithelial bodies (see Epithelial bodies), the calcitonin provides preservation of constancy of level of calcium in an organism.
Exchange of t both r e about and d N y x hormones in about r and N and z m e. Almost all thyroxine coming to blood reversibly contacts proteins of serum, is preferential with L-globulin — so-called tirok-sinsvyazyvayushchy globulin, and partly with tiroksinsvyazyvayushchy prealbumin and albumine. Therefore concentration of the proteinaceous and connected iodine (see) in blood is often considered as an indicator of secretory activity Shch. Linkng of thyroxine with serum proteins prevents its destruction, but interferes with its active action on cells. Between the connected and free thyroxine in blood the dynamic equilibrium is established, and only free thyroxine has effect on the reacting cells and fabrics. Triiodothyronine contacts proteins of serum more weakly, than tiroksinony Half-decay of the thyroxine which is in blood would last — 7 days, triiodothyronine breaks up quicker (half-life of 2 days).
Reception of thyroxine happens in cells. Having got into a cell, thyroxine at once loses one atom of iodine, passing into triiodothyronine. A point of application of triiodothyronine (as arrived from blood, and formed of thyroxine) is DNA where triiodothyronine stimulates a transcription (see) and formation of RNA.
In cells there is a further deiodinating of thyroxine and triiodothyronine, deamination, a rupture of difenilzfirny communication and decarboxylation (see. Iodic exchange).
In metabolism of thyroid hormones the leading role belongs to a liver, in a cut decomposition products of the deiodinated yodtironin communicate in glucuronic and sulfuric conjugates and then with bile come to the intestines from where released iodine is soaked up back in blood, transferred to Shch. also it re-is utilized.
A role of thyroid hormones in a morphogenesis and regulation of physiological processes. At the heart of the effects caused by thyroid hormones their influence on oxygen absorption and oxidizing processes in an organism lies. It is established that thyroxine in toxic doses acts on a mitochondrion of cells, separating synthesis of ATP with electron transfer on a respiratory chain and blocking thus okrtslitelny phosphorylation (see).
Thyroid hormones strengthen heat generation, and at their insufficiency (hypothyroidism) body temperature goes down. At the same time the hypothyroidism (see) is followed by a delay of water in an organism and reduction of release of calcium and phosphorus with urine.
Thyroid hormones strengthen disintegration of a glycogen (see) and reduce its education in a liver. Insufficiency of these hormones is followed by disorder of regulation of carbohydrate metabolism (see) and increase in tolerance of an organism to glucose. At a hyperthyroidism (see the Thyrotoxicosis) release of nitrogen with urine increases and it is broken (Osforili-rovaniye of creatine (see). In the conditions of a hypothyroidism the content of cholesterol (see) in blood increases, and at excess of thyroid hormones its level decreases. At the same time at a hyperthyroidism excitability of century of N of page amplifies (especially its sympathetic department) that is shown by tachycardia (see), arrhythmias (see Arrhythmias of heart), increase in speed of a blood-groove, increase in the systolic ABP. At the same time motility amplifies went. - kish. path and secretion of digestive juices.
Thyroid hormones are necessary for normal functioning of c. N of page. Insufficiency of thyroid hormones in the embryonal period and at the beginning of the post-natal period can lead to a delay of a differentiation of a cerebral cortex and mental development of the child up to cretinism (see).
Thyroid hormones together with somatotropic hormone (see) participate in regulation of growth of a body (especially stimulate ossification).
Features of function of a thyroid gland in antenatal and postnatalno m the periods. During pregnancy functional activity Shch. mothers amplifies; increase in content in blood of the general thyroxine is connected with strengthening of synthesis of thyritropic hormone under the influence of placental estrogen.
Ability Shch. to concentration and accumulation of iodine appears at a fruit on 10 — the 12th week of pre-natal development. In the same time synthesis monoiodine-tironina, a diyodtironin, triiodothyronine, thyroxine, tiroksinsvya-zyvayushchy globulin begins. In blood serum of a fruit (see) appear ti-roliberin (thyrotropin-rileasing-hormone) and thyritropic hormone of a pituitary origin. Regulatory relationship between thyritropic hormone and thyroid hormones is established from 30th week of pre-natal development.
Parallelism between contents thyritropic and thyroid hormones in blood of mother and a fruit is not revealed since transplacental transport of these hormones makes less than 1%. The highest concentration of thyroid hormones in the pre-natal period comes to light at a fruit before its birth.
Right after the birth the period of the increased functional activity Shch is noted. Level of thyritropic hormone increases in the 30th minute after the birth, and in 24 — 48 hours decreases to the same level, as at adults. Content of triiodothyronine as much as possible increases by the end of the first days. The maximum increase in content of thyroxine is noted in 24 — 48 hours after the birth, then there is a gradual decrease in its level.
At premature children (see) increase in content of thyritropic hormone and thyroid hormones is less expressed, especially at children with low body weight at the birth. Nevertheless within several weeks after the birth such children have a decrease in level of thyroid hormones, as well as at full-term. Both at full-term, and premature children at various diseases have a level thyritropic and thyroid hormones can be considerably reduced, however within several weeks it is normalized.
Age changes of functional activity of a thyroid gland. Content of thyroid hormones at children aged from 1 up to
15 years significantly does not change; gradually the content of tiroksinsvyazyvayushchy globulin, thyroxine decreases and the content of triiodothyronine increases. In the prepu-bertatny and pubertal periods at girls activity Shch. above, than at boys.
Functional activity Shch. it is long remains at the stable level. Only at senile age the atrophic changes in a parenchyma of gland which are followed by inching of level of the general exchange however are observed signs of strengthening of functional activity Shch are noted., what it is possible to consider as the compensatory reaction counteracting weakening of oxidizing processes in fabrics of the growing old organism.
The pathological anatomy
Dystrophy can be observed at disturbances of fabric (cellular) exchange Shch., hl. obr. in the conditions of pathology. Its such types, as granular (parenchymatous) and guide-ropichesky (see. Vacuolar dystrophy) dystrophy of tirotsit represent kinds of proteinaceous dystrophy (see). At granular dystrophy in cytoplasm of tirotsit there are inclusions of the proteinaceous nature, swelling of mitochondrions, flattening of their cristas is noted, expansion of tanks of a cytoplasmic reticulum, accumulation of protein in them comes to light. At gidropichesky dystrophy in cytoplasm of tirotsit, is more rare in a kernel, there are vacuoles filled with liquid.
Amyloidosis Shch. meets seldom. It is observed at a generalized amyloidosis (see) and adjournment is characterizedI eat amyloid in a stroma of gland, a basal membrane of follicles, walls circulatory and limf, vessels. Adjournment of amyloid is characteristic of medullary cancer Shch. Participation in formation of amyloid of epithelial tumor cells is proved.
Substitution of a parenchyma Shch. by fatty tissue it is observed at an atrophy Shch., especially at the so-called hormonal atrophy which is followed by decrease in function of gland, napr at an apituitarism (see), a myxedema (see). Onisano also inborn full substitution Shch. fatty tissue.
Mineral dystrophies Shch. (calcifications) can be intracellular and extracellular, are characterized by loss of salts of calcium in the form of grains of various size in nekrotizirovanny or dystrophic the changed cells and structures. A matrix of intracellular calcification are mitochondrions and lysosomes of tirotsit, and extracellular (most widespread) — collagenic fibers of a stroma. Local factors, and also the general, such as the hypercalcemia (see) arising at a lack of a calcitonin (see) are the reason of calcification at hyperproduction of parathormone (see), the strengthened exit of calcium from depot, reduction of release of calcium from an organism.
Disturbance of exchange of pigments in a thyroid gland, in particular gemoglobinogenny, is observed in the centers of hemorrhages at a hemosiderosis (see) and hemochromatosis (see). At the same time hemosiderin and ferritin are found on the course of fibers of a stroma, in cytoplasm of cells.
The necrosis of tissue of thyroid gland in the form of an ischemic heart attack (see) develops during the bandaging of thyroid arteries or their fibrinferment, at atherosclerosis (see), new growths of bodies of a neck. Small necroses Shch. are observed at various options of a craw (see), at a thyroiditis (see), owing to disturbance of blood circulation, at radiation (see).
Disturbances of blood circulation are shown by frustration of a krovenapolneniye shch., thrombosis of its vessels, embolism, heart attack. The collateral hyperemia is most often observed (at difficulty of a blood-groove as a result of a hyperplastic tissue Shch. or growth of her tumor). Long stagnation of blood in Shch. leads of its parenchyma to death and is followed acellular by a sclerosis. A consequence of the disturbances of a hemodynamics which are observed at a birth trauma, arterial hypertension, system vasculites, inf. diseases (typhus, sepsis), a leukosis, anemia, hemorrhages (see), a plasmorrhagia are (see). A plasmorrhagia in shch. it is observed at disturbance of permeability of vessels of a microcirculator bed (see Mikrotsirkulyation). Flattening of an endothelium of vessels, fibrinoid swelling is microscopically noted (see. Fibrinoid transformation) and necrosis of a vascular wall.
The inflammation of a thyroid gland is observed seldom; can arise at quinsy, osteomyelitis, sepsis, and also at nek-ry specific inf. diseases (e.g., tuberculosis, syphilis, actinomycosis). It can proceed sharply, subacutely and chronically. The acute purulent thyroiditis is characterized by formation vshch. small or large abscesses. Large abscesses can be opened in a mediastinum, a trachea and through skin with formation of fistulas. Specific thyroidites (tubercular, syphilitic, actinomycotic) meet seldom, usually as display of the general disease (see the Thyroiditis).
Cysts of various size most often are found in zobnoizme-nenny Shch.; they arise as a result of the former hemorrhages and a staz of a colloid (follicular cysts), and also as a result of a malformation of ultimobranchial little bodies (ultimobranchial cysts). Cysts (see the Cyst), especially follicular, are covered by a cubic or flat epithelium and have a reinforced fibrous wall.
The atrophy of a thyroid gland is observed at senile age, sometimes at a diabetes mellitus, a hypovitaminosis In, adrenal strumas, diseases of a hypophysis, etc. Allocate primary, or idiopathic, an atrophy Shch. and atrophy as outcome of an autoimmune thyroiditis. Atrophy Shch. it is characterized by reduction of its weight (weight), number and the sizes of follicles and cells. Atrophy of a parenchyma Shch. can be followed by a replacement of tissue of gland connecting fabric. Sometimes in the centers of a sclerosis the metaplasia (see) cylindrical tirotsit in flat is noted (an epidermoid metaplasia).
The hyperplastic tissue of a thyroid gland in the period of sexual a sozrevaiiya (see) is connected with change of function of gonads. In the conditions of pathology the hyperplasia (see) is caused by supersecretion of thyritropic hormone of a hypophysis. It can be diffusion and focal. At a hyperplasia the strengthened proliferation of cells of interfollikulyarny islands with formation of the new follicles and tirotsit forming papillary outgrowths and so-called sandersonova of a pillow is noted (see the Craw sporadic). Increase in height of tirotsit, accumulation in them of ribonucleoproteins, yodidperoksidaza in a perinuclear zone, thyreoglobulin in apical departments of a cell is observed. Increase in the sizes of kernels, quantity and the sizes of cytoplasmatic organellas is characteristic. The hyperplasia of fibrillar structures of a basal membrane of follicles, circulatory capillaries comes to light. In follicles fluidifying and the strengthened resorption of a colloid (can be observed at a diffusion toxic craw).
Methods of inspection
Methods of inspection of patients with diseases Shch. include a wedge, inspection and methods of assessment of function and structure Shch.
Wedge. inspection is an important link in diagnosis of diseases Shch. It consists of collecting complaints, the anamnesis and objective data (a condition of skin, hypodermic cellulose, hair, neuromuscular and cardiovascular systems, went. - kish. path). Special attention is paid to a palpation of units., edges gives information on the sizes, symmetry of shares and a consistence of body.
Function Shch. estimate by means of indirect and specific methods. Indirect methods are based on a research fiziol. functions of an organism, on to-rye thyroid hormones exert impact. The indicators received by means of these methods are not specific to pathology of a thyroid gland since similar changes can take place and at diseases of other bodies. Indirect methods include a basal analysis (see the Metabolism and energy), fatty (content in blood of cholesterol and not esterified fat to - t) and protein metabolism, a state neuromuscular (see the Reflex an omet-riya) and cardiovascular (see Elektrokardiografiya) systems.
Specific methods of assessment of a functional state Shch. include researches of level of thyroid hormones in blood and exchange of iodine (see. Iodic exchange). For definition of thyroid hormones use various methods, including and biochemical. The last allow to establish concentration in blood of the iodine connected by proteins of plasma (see. Proteinaceous and connected iodine), and the iodine extracted by butanol (see Butanolekstragiruyemy iodine). Chemical methods of definition of thyroid hormones of a trudoyekhmka are also difficult. With implementation immunol. methods they lost the value and are used only in special laboratories.
In a basis immunol. methods the principle of competitive binding of hormones and other studied substances specific antibodies lies. As a tag use radionuclide (see. Radio immunologists chesky method). In a crust, time these methods apply to definition in blood serum of the general and free thyroxine (T4), the general, free and reverse, or the return, triiodothyronine (T3), the thyroxine-the connecting globulin (TCG), thyritropic hormone (TTG), a tiro-liberin (TTRG) and tireoglobulino-vy antibodies. Researches are conducted by in vitro by means of special test sets by a standard technique.
To specific methods of assessment of exchange of iodine also radionuclide methods treat with use 1231, 125I, 131I, J32l and 99 t of Ts-per-tekhnetata (see Radiofarmatsevtiche-sky drugs). Absolute contraindications for use of the specified radionuclides do not exist, refer children's age, pregnancy and the period of feeding of the child to relative a breast, and at use of a radioiodine reduced function Shch. In
1 V2 — 2 months prior to a research cancel all iodinated and bromsoderzhashchy drugs, anti-thyroid, sedatives, hormones, introduction of X-ray contrast compounds of iodine, greasing of skin spirit solution of iodine; exclude the products rich with iodine from a diet (a laminaria and fish, mineral waters, a persimmon, etc.). For studying of intra thyroid exchange of iodine use the test of accumulation Shch. radioiodine and 99tts-pertekh-non Tat. For this purpose the patient is given inside or enter intravenously 0,0025 — 0,005 mkyur (0,1 — 0,2 MBK) of 1311. 1251 or 0,001 — 0,02 mkyur (0,4 — 0,8 MBK) 1231, 1321, or 1 mkyur (40 MBK) of 99 t of the CU-pertekhnetata. Gamma radiation is registered by means of single-channel radiometric installation, the sensor a cut have in 25 — 30 cm from a front surface of a neck of the patient. A radiation intensity over Shch. register in 2,4 and 24 hours after reception or administration of radionuclide. The received results of radiometry (see) compare to the general activity of the radionuclide entered into an organism taken for 100%. At healthy faces indicators of accumulation by a thyroid gland of a radioiodine in 2 hours do not exceed 20%, in 24 hours — 50%, accumulation of 99 t Ts-pertekhneta-ta in 2 hours does not exceed 3%. The difference in accumulation of a radioiodine and technetium, to-ry is not included thyroid hormones in 2 hours, gives the chance to establish amount of the iodine entering only into organic fraction i.e. to investigate an organic phase of intra thyroid exchange of iodine.
A research of a transport and organic phase of iodic exchange (see) carry out generally by means of definition of concentration of thyroid hormones and tiroksinsvyazyvayu-shchy globulin in a blood plasma of in vitro radioimmunol. by method. This diagnostic method allows to analyze biologically important components involved in patol with a fine precision. process. At the same time beam load of the patient is completely excluded.
Methods of assessment of structure Shch. include a computer tomography (see the Tomography computer), an ekhografiya (see. Ultrasonic diagnosis), radionuclide scanning (see) and a stsintigrafiya (see), a puncture biopsy (see), and also a row special rentgenol. methods — a rentgenotireografiya (see the X-ray analysis), electro-rentgenotireografiyu (see the Electro-X-ray analysis), a tireoidolimfog-raffia (fig. 3), a pnevmotireografiya, an angiotireografiya (see the Angiography). Implementation of a computer tomography, ekhografiya, radionuclide -
a leg of scanning and a stsintigrafiya led to the fact that special rentgenol. methods lose the value.
The computer tomography allows to receive the image Shch. and surrounding fabrics. Normal Shch. on cross tomograms has an appearance of two ovals, homogeneous on structure, with rather equal contours which are well delimited from surrounding fabrics. At nodal educations in Shch. its structure looks heterogeneous. Contours of educations at a nodal craw and cancer Shch., as a rule, less accurate, than at benign tumors (adenoma, a cyst, etc.). At the palpated malignant tumor the computer tomography allows to define a form, the sizes, contours, structure of a node, existence and prevalence of metastasises, and also extent of involvement in patol. process of vessels of a neck and next fabrics. Use of a computer tomography for diagnosis of nodal new growths and diffusion patol. processes Shch. it is reasonable to combine with radioimmunol. tests, ultrasonic and radionuclide scanning.
The radionuclide tireografiya (scanning and a stsintigrafiya) takes the important place in comprehensive examination of patients with pathology of a thyroid gland. By means of this method estimate topography Shch., its sizes, nature of accumulation of radionuclide in various sites of gland. The patient is given inside 0,025 — 0,05 mkyur (1 — 2 MBK) 1311 or 1,5 — 2,5 mkyur (60 — 100 MBK) of 99 t of the CU-pertekhnetata and conduct a research 2 and 24 hours later. Normal on a skanogramma outlines Shch clearly are allocated., its shares and isthmus. The maximum radioactivity falls on the center of shares, to the periphery of shares the radiation intensity gradually falls and then sharply breaks. The sizes of shares, their form are very variable. The pyramidal share most often does not come to light. By means of this way various anomalies of position of body easily come to light. At diffusion forms of a thyrocardiac craw (see the Craw diffusion toxic) on a skanogramma the enlarged image Shch is noted. with intensive hypodispersion of radionuclide. In other cases (at hron. a thyroiditis, the mixed craw) uneven distribution of radionuclide is observed. Scanning and a stsintigrafiya give the chance to estimate a functional condition of the nodes found in fabric Shch., what is important for the choice of tactics of treatment. So, morfol. substrate of «hot»
Fig. 3. Tireolimfogramma at high-quality («) and malignant tumors of the right share of a thyroid gland: and — the arrow specified the defect of accumulation of radiopaque substance having rounded shape and accurate contours; — the arrow specified the defect of accumulation of radiopaque substance having uneven and
a node most often there is toxic adenoma or a nonautonomous hyperplastic tissue Shch. (fig. 4, a). The «cold» node represents the site of nonfunctioning fabric, a cyst, adenoma, a metastasis of a tumor (fig. 4, b).
By means of a one-dimensional and two-dimensional ekhografiya (ultrasonic scanning) it is possible to obtain information on the sizes Shch. and its certain sites. Normal on an echogram borders of skin, hypodermic cellulose, fastion, shares Shch well come to light., vessels, muscles, trachea and backbone. At a diffusion craw the image Shch. it is not changed, but its sizes are increased. At hron. a thyroiditis and the mixed craw change of the sizes Shch is noted. and focal and diffusion acoustic heterogeneity of the image of gland at a normal picture of surrounding fabrics if the trachea is not displaced. The nodal craw harak
terizutsya by the specific picture depending on structure of a node. Usually dense nodes, adenomas, sites of calcification and a cyst accurately are defined against the background of not changed fabric shch. At cancer Shch. the ekhografichesky picture depends on character and prevalence patol. process. At a local arrangement of a tumor or its metastasises they can not differ from dense nodes or adenoma. During the involvement in process of adjacent fabrics in them the centers of consolidation and a tyazha come to light. Ekhografiya in combination with radionuclide scanning allows to establish in most cases the sizes and structure Shch. and her tumors that is important at the choice of a method and objekhm of an operative measure.
Puncture Shch. by a fine needle (puncture biopsy), carried out with the diagnostic purpose, it can be carried out in out-patient
Fig. 4. Stsintigramma of a thyroid gland at toxic adenoma (a) and at a cyst (b) of a thyroid gland: and — a «hot» node in an isthmus of gland (it is specified by an arrow); — a «cold» node in the right share of gland (it is specified by an arrow).
conditions. Reliability morfol. the diagnosis depends on the accuracy of hit of a needle to the explored site therefore apply a so-called limit biopsy, to-ruyu carry out or under control of an ekhografiya, or according to radionuclide scanning.
In diagnosis of diseases Shch. functional trials (tests) which are carried out by administration of triiodothyronine, thyritropic hormone and a tirolibe-rin (Rifathyroinum) are of great importance. Test of suppression of function Shch. (the ingibitsionny test) use at diagnosis of the erased forms of a thyrotoxicosis (see), a local craw (see the Craw local) and at differential diagnosis of ophthalmopathies. For this purpose in the beginning conduct a research of accumulation Shch. a radioiodine, then within a week of the patient accepts triiodothyronine then repeatedly investigate accumulation of a radioiodine a thyroid gland. At normal function Shch. the size of absorption of a radioiodine decreases by 50% and more in comparison with basic data.
Test of stimulation of function Shch. use for diagnosis of primary and secondary hypothyroidism and function of the nodes found in iron. Determine the content of thyroxine in blood serum then intramusculary enter thyritropic hormone, and then radionuclide (radioiodine) with the subsequent definition of thyroxine and a research of accumulation by a thyroid gland of a radioiodine. At healthy faces accumulation of a radioiodine a thyroid gland or the content of thyroxine in blood is exceeded by basic data more than for 20%. At primary hypothyroidism reaction to thyritropic hormone is absent. In the presence of contraindications apply a method of definition of thyroxine in blood serum before administration of thyritropic hormone to carrying out a radionuclide research and in 24 hours after its introduction.
The test of stimulation of a hypophysis is used for differential diagnosis of different types of a hypothyroidism. At the same time determine the initial level of thyritropic hormone in blood serum, then enter tirolibe-rin (intravenously or per os) then repeatedly determine the level of thyritropic hormone in blood serum. At healthy people and at primary hypothyroidism the level of thyritropic hormone in comparison with initial considerably increases. At a secondary (pituitary) hypothyroidism and a diffusion toxic craw reaction on tiroliberin is absent. If at the patient reaction to exogenous thyritropic hormone and tiroliberin is kept, it is necessary to think of a tertiary (hypothalamic) hypothyroidism.
According to the classification accepted in 1961 on the International congress of the socialist countries on a problem of a local craw allocate congenital anomalies Shch., local craw (and local cretinism), sporadic craw, diffusion toxic craw, hypothyroidism, inflammatory diseases Shch. (nonspecific and specific), damages and tumors.
Malformations. Extremely seldom the aplasia Shch meets., the cut is the reason disturbance of a differentiation of an embryonal rudiment in fabric shch. Aplasia Shch. it is found at early children's age. Hypoplasia Shch. it is caused by a lack of iodine of an organism of mother. Clinically at the same time cretinism is observed (see). Main type of treatment is replacement therapy, to-ruyu appoint right after establishment of the diagnosis and even in case of an estimated hypothyroidism (see). Timely treatment can provide normal physical development of the child.
Preservation of a shchitoyazychny channel often leads to formation of median cysts and fistulas of a neck, a craw of a root of language. Fistulas and cysts of a shchitoyazychny channel are usually distinguished in the first ten years of life of the child. Treatment — full excision of cysts. Forecast favorable.
Shift of a medial rudiment shch. in a mediastinum causes development of an intra sternal craw (see the Mediastinum). Anomaly of a medial rudiment shch. causes an allotopia of thyroid fabric in a wall of a trachea, throat, a myocardium, a pericardium, a fatty tissue of a mediastinum, skeletal muscles of a neck. Distopiro-vannye the centers of thyroid fabric can be a source of development of tumors Shch. Identification of thyroid fabric in limf, nodes of a neck is considered as a metastasis of the differentiated cancer Shch. (see below the section of the Tumour). In the presence of a craw or a tumor in dihundred-pyrobathing thyroid fabric operational treatment is shown.
Damages. The closed damages Shch. meet seldom (e.g., a prelum of a neck a loop in suicide attempt) and are shown by formation of a hematoma. Rest and topical administration of cold is shown. At increase of a hematoma, difficulty of breath resort to a stop of bleeding, and if necessary — to a tracheostomy (see).
Open damages Shch. are usually combined with wound of other bodies of a neck (see) and are followed by plentiful bleeding (see). In similar cases urgent surgical treatment of a wound (see) with an economical resection of the damaged part of gland, the stop of bleeding, sewing up of wounds with leaving of a drainage are necessary. The forecast depends on the volume of damage.
Diseases can proceed with signs of increase in function of Shch-. (thyrotoxicosis) or decrease its functions (hypothyroidism). At nek-ry diseases Shch. disturbances of its function clinically do not come to light (see the Euthyroidism).
The most widespread disease Shch. the local craw (see the Craw local) meeting in geographical districts with the insufficient content of iodine in the environment is. The disease is followed by the diffusion, nodal or mixed increase in gland, in most cases without disturbance of its function. Insufficiency of iodine in an organism is the reason of development of a disease. At preventive use of the iodated sodium chloride and drugs of iodine incidence of the population is sharply reduced.
The craw without the expressed dysfunctions of a thyroid gland at the persons living in not local districts received the name of a sporadic craw (see the Craw sporadic).
A diffusion enlargement of the thyroid gland with its hyperfunction causing disbolism and development patol. changes in various bodies and systems, received the name «toxic craw». Distinguish the diffusion, nodal and mixed toxic craw (see the Craw diffusion toxic).
Depression of function Shch. — the hypothyroidism (see) results from defeat directly Shch. (primary hypothyroidism), damages of a hypophysis (secondary, or pituitary, hypothyroidism) or hypothalamus (tertiary, or hypothalamic, hypothyroidism).
To inflammatory diseases shch. thyroidites belong nonspecific and specific (tubercular, syphilitic, actinomycotic) (see). Distinguish an acute, subacute and chronic thyroiditis. Specific thyroidites meet extremely seldom and usually are local manifestations of general diseases.
Tumors arise against the background of the strengthened thyritropic function of a hypophysis causing proliferation of an epithelium Shch more often. Stimulation of thyritropic function of a hypophysis can be caused by alimentary iodic insufficiency, anti-thyroid means, impact of ionizing radiation (outside and internal radiation), dishormonal disturbances. Distinguish benign and malignant tumors Shch.
Dobrokachestven of N ye tumors. Among benign tumors adenomas meet more often (see Adenoma), usually single, is more rare multiple (a multinodal craw), components, according to Sloun and Franz (L. Sloan, W. Franz), 16% of all nodal educations Shch. Are seldom observed fibroma (see), a teratoma (see), a paraganglioma (see), a hemangioma (see), a lipoma (see), myoma (see).
On gistol. to a structure distinguish trabecular (embryonal), tubular (fetalis), a microfoul-likulyarnuyu and makrofollikulyar-ny (colloid) adenomas. Multiple adenomas Shch. can have various structure and different functional activity.
The adenomas which are not exceeding 1 cm in the diameter clinically are not shown. The tumor of larger size decides in the form of a roundish painless node on a smooth surface, mobile during the swallowing. In process of growth and at localization behind a breast adenoma can squeeze a gullet, a trachea, causing an asthma (see), is more rare — a dysphagy (see).
At patients with adenomas Shch. function of gland is not broken more often (see the Euthyroidism). At toxic adenoma the phenomena of a thyrotoxicosis develop (see).
Trabecular and tubular adenomas do not take a radioiodine. The adenomas having a follicular structure are capable to take iodine in various degree and to synthesize thyroid hormones.
Ability of adenoma to take iodine is defined by scanning Shch. Not the fascinating or poorly taking a radioiodine adenomas are shown as «cold» nodes, and adenomas which are actively taking a radioiodine — as «warm» or «hot» nodes.
In adenomas cells can meet In ~. The tumor entirely consisting of these cells is considered sometimes as macrocellular onko-cytic adenoma. Such adenomas most often of a monomorfna, have a solid and follicular and solid structure. The possibility of their invasive growth is not excluded.
The tumors similar to follicular adenomas, but the containing various number of papillary (papillary) structures, nek-ry researchers carry to malignant. The issue of a possibility of high-quality option of a medullary tumor (adenoma from parafollikulyar-ny cells) is finally not resolved.
The diagnosis is established on the basis of given the kokhmpleksny inspection of patients including clinical laboratory, radionuclide, rentgenol. methods, etc. The leading role in diagnosis is played by a puncture of a tumor Shch. a fine needle (puncture biopsy) with the subsequent tsitol. a research of the received material. In nek-ry cases there is a need for carrying out urgent gistol. researches of a tumor during operation (intraoperative cytodetection).
Treatment of benign tumors shch. operational. Operation consists in a resection or full removal of the struck share of gland (gemitireoidektomiya). Operation of enucleation of a tumor eurysynusic earlier in a crust, time is not applied.
The forecast at radical treatment in most cases favorable.
Malignant tumors. By data A. I. Pachesa and R. M. Propp (1984), cancer makes more than 90% of all malignant tumors Shch. Not epithelial tumors, such as sarcoma (see), a malignant lymphoma (see), a gemangioendotelioma (see Angio-endotelioma), a malignant teratoma (see), in Shch. meet seldom. On a structure and a wedge, to a current they do not differ from similar tumors of other bodies.
Cancer Shch. meets at women at the age of 40 — 60 years more often. Quite often it develops against the background of is long the existing, usually nodal craw (see P redopukholevy diseases), however development of cancer is possible (see) and in not changed gland, it is rare — against the background of a diffusion toxic craw. Question of communication of cancer Shch. with a local craw it is finally not solved. There are data
on an oncogenous role of x-ray radiation of area of the head and neck at children's and youthful age.
Distinguish the differentiated and undifferentiated cancer Shch. Between them medullary cancer is intermediate. Besides, in Shch. malignant tumors from a meta-plazirovannogo epithelium (planocellular cancer) meet.
In group of the differentiated tumors shch. enter papillary and follicular cancer. Papillary cancer (a papillary adenocarcinoma) — the most often meeting (apprx. 65%) a form of cancer Shch. Macroscopically the tumor is presented by the node which is partially encapsulated roundish or irregular shape. The sizes of a tumor considerably vary. It can be very small (to come to light only at microscopic examination) or to occupy all gland and to extend to surrounding fabrics and bodies. At microscopic examination the characteristic papillary (papillary) structures making the ground mass of a tumor, and the cystous cavities filled with a colloid or blood come to light. Along with papillary in a tumor follicular structures, and in nek-ry cases — solid cellular fields can meet. Characteristic symptom of papillary cancer Shch. focal adjournment of salts of calcium in the form of psammozny little bodies is (see).
Papillary cancer is characterized by ability to infiltriruyushchy growth with germination in the capsule Shch., in lymphatic and, more rare, in blood vessels. One of the most typical symptoms of papillary cancer is innidiation in regional limf, nodes.
Development of a tumor slow. Papillary cancer is usually functionally poorly active and is not followed by endocrine frustration.
Follicular cancer (a follicular adenocarcinoma) is observed less often than papillary. Macroscopically represents quite well delimited node of various sizes. The node of small size quite often is found accidentally at gistol. research of fabric Shch., removed in other occasion, or it is shown clinically by metastasises in limf, nodes of a neck, in lungs and bones. Microscopically follicular cancer is presented by follicular and trabecular structures, and also solid growths of tumor cells. Cells of follicular cancer can remind tirotsita normal Shch. The tumor consisting of the high-differentiated follicles containing a colloid, less zlokachestvenn, than a tumor in a cut prevail small, free of a colloid follikulyg trabecular and especially solid structures.
It is difficult to differentiate follicular cancer morphologically with follicular adenoma. An invasion of tumor cells in vessels and the capsule shch. or existence of emboluses from tumor cells in circulatory and limf, vessels allow to make the diagnosis of cancer Shch.
Follicular cancer develops slowly, the tumor is often functionally active. A characteristic sign is hematogenous innidiation, at Krom in the first
Fig. 5. The roentgenogram of a thorax of the patient with cancer of a thyroid gland with metastasises in lungs (a direct projection):
multiple melkoochagovy shadows — metastasises of cancer are visible.
turn are surprised easy (fig. 5) and bones.
Version papillary, and sometimes and follicular cancer Shch. so-called latent cancer, or the sclerosed microcarcinoma is.
The tumor has very small sizes, as a rule, a papillary structure with the expressed phenomena of a sclerosis. Metastasises in regional limf, nodes of a neck, to-rye earlier mistakenly regarded as a tumor of side aberrant thyroid glands, often happen only a wedge, manifestation of this type of cancer Shch.
Shch. — one of the most malignant tumors of the person; it makes 5 — 20% of all types of cancer Shch. Macroscopically the tumor most often consists of several nodes often merging, not having a clear boundary. The tumor is dense, on a section of whitish color, captures usually all Shch., it is functionally inactive. Microscopic picture of undifferentiated cancer Shch. it is heterogeneous. The tumor can consist of small and colossal polymorphic or spindle-shaped cells. Quite often in one tumor find all listed types of cells which grow at continuous cellular fields and do not form follicular or papillary structures.
Rapid development of primary tumor and generalized innidiation is characteristic. The tumor sprouts soft tissues of a neck, a trachea, a gullet, a recurrent guttural nerve and a neurovascular bunch of a neck. Heavy complications are esophageal and tracheal fistulas (see Bronchial tubes, the table), asphyxia (see) and bleeding (see) from vessels of the breaking-up tumor.
Medullary cancer (cancer) makes 2 — 4% of all types of cancer of para-follicular cells Shch. In some cases the tumor is genetically determined, is combined with a pheochromocytoma (see Hromaffinom) and other diseases of endocrine system. Development of medullary cancer to a thicket is preceded by a focal hyperplasia of parafolli-kulyarny cells. Macroscopically medullary cancer is presented by a dense tumoral node without clear boundary, to-ry can be as the microscopic sizes (microcarcinoma), and to occupy all Shch. and to extend out of its limits. The tumor is seldom encapsulated, often is implemented into fabric Shch., infiltrirut its capsule and walls of blood vessels. Gistol. picture of medullary cancer Shch. it is heterogeneous. Cells are preferential small, roundish or extended, spindle-shaped cells can meet. In most cases in fabric of medullary cancer amyloid is defined. At a submicroscopy in tumor cells of medullary cancer, as well as in normal parafollicular cells, characteristic secretory granules and fibrillar structures come to light.
The tumor hormonal is active, produces a calcitonin (see). One of characteristic symptoms of medullary cancer Shch. the diarrhea caused by influence of the humoral factors cosecreted by a tumor is (a calcitonin, serotonin, etc.). Medullary cancer is characterized by rather long current, frequent innidiation in regional limf, nodes and recuring.
Planocellular (epidermoid) cancer Shch. makes 1 — 3% of all malignant tumors Shch. Secondary defeat Shch is more often observed. owing to spread of planocellular cancer from the next bodies (a throat, a gullet, etc.), and also at metastasises from other bodies. Sites of a planocellular metaplasia can meet in papillary and follicular cancer. The tumor can occupy all Shch. and to extend to the fabrics surrounding it. Microscopically the tumor has a typical structure of planocellular cancer. Wedge, current extremely heavy, innidiation early and extensive.
Prevalence of cancer Shch. it is accepted to estimate on stages.
I stage: the small encapsulated tumor in one of shares of gland. II stage: a) the tumor occupies V2 of gland, sprouts its capsule, podvizhon; b) a tumor of the same or smaller sizes with mobile regional metastasises on a neck on the one hand. III stage: a) the tumor borrows more than 1/2 or all gland, is soldered to the next bodies, restrictedly is mobile; b) a tumor of the same or smaller sizes, but with bilateral metastasises in cervical limf. nodes. IV stage: a) the tumor sprouts surrounding fabrics and bodies, is not mobile; b) a tumor of any sizes, but with the remote metastasises.
Diagnosis of cancer Shch. in initial stages it is difficult since the encapsulated cancer tumor has no the signs allowing to distinguish it from adenoma. Use a complex of methods, among to-rykh the leading role belongs to a puncture biopsy (see), apply radiological (a pnevmotireografiya, arteriography, a tireolimfografiya, a computer tomography), radionuclide methods (see Scanning, Stsintigrafiya), an ekhografiya (see. Ultrasonic diagnosis), a termografiya (see). Datas of laboratory matter at medullary cancer since allow to define hypersecretion of a calcitonin. In doubtful cases an operative measure, volume is shown to-rogo depends on results urgent gistol. researches.
Main method of cancer therapy Shch. — operative measure. Cancer operations Shch. make under an endotracheal anesthesia (see. Inhalation anesthesia). The struck fabric is deleted extra-kapsulyarno with bandaging of vessels on an extent, allocation of recurrent guttural nerves and epithelial bodies. In the I stage make a gemitireoidektomiya with removal of an isthmus; in the II stage — a subtotal resection of gland; in III and IV stages — a thyroidectomy (see). In the presence of mobile metastasises in regional limf, nodes along with a thyroidectomy make fascial futlyarnoye excision of cellulose of a neck from one or two parties. At restrictedly movable metastasises in limf, nodes of a neck on the one hand Krayl's operation is shown (see Krayl operation).
As addition to an operational method at the combined treatment of undifferentiated cancer in the preoperative or postoperative period use radiation therapy (see). At the differentiated cancer radiation therapy is appointed at impossibility to carry out radical operation. Radiation therapy of tumors Shch. it can be applied and as an independent type of treatment or in a combination with hormonal therapy at treatment of nonresectable primary tumors, metastasises in regional limf, nodes and the remote metastasises.
When tumor Shch. and its metastasises do not accumulate or poorly accumulate 1311, perform radiation therapy by tele-irradiation. Treatment is carried out on gamma and therapeutic devices with sources 60Co, 137Cs or high-energy accelerators with use of brake or electronic radiation (see the Gamma therapy), and also by intake of radiofarmatsevtiche-sky drug, marked 1311, selectively collecting in normal thyroid fabric and in the tumors from a follicular epithelium keeping the iodabsorbing function.
For preirradiation total doses 3000 — 4000 are recommended I am glad (30 — 40 Gr), for postoperative — 4000 — 5000 I am glad (40 — 50 Gr). In the radiation zone include: area of a thyroid gland, zone of neurovascular bunches of a neck and anterosuperior mediastinum. For treatment of nonresectable tumors and metastasises the total dose not less than 6000 is recommended I am glad (60 Gr).
1311 the hl is used. obr. for treatment of the remote metastasises, nonresectable primary tumors
and regional metastasises possessing the iodabsorbing function. Treatment by a radioiodine is carried out before complete cessation of iodaccumulative function in metastasises.
Hormonal therapy (see) it is shown
after radical treatment as replacement therapy, and also for suppression of products of thyritropic hormone of a hypophysis
for prevention of a recurrence and metastasises. Hormonal therapy is carried out under control of content in blood of thyroid hormones and thyritropic hormone of a hypophysis.
To modern antineoplastic drugs cancer Shch. rezistenten. At widespread process the short effect is gained at treatment by diiodbenzotephum, adriamycin.
The forecast depends on a stage, gistol. structures of a tumor, gender and age of patients. According to All-Union oncological scientific center of the USSR Academy of Medical Sciences, among considerably treated cancer patients Shch.
5-year survival made 90%, 10-summer — 86,4%.
The operations Operative measure on shch. provides its full removal — a thyroidectomy (see) or partial — a resection Shch. In turn, resection Shch. can consist shares of gland (gemitireoidektomiya) or a sub-total resection Shch at a distance. with leaving of 4 — 8 g of its fabric. The indication to an operative measure on Shch. tumors shch are., it is long proceeding hron. a thyroiditis (see), a diffusion toxic craw (see the Craw diffusion toxic), and in nek-ry cases — a nodal craw (see the Craw sporadic, the Craw local). Absolute contraindications to an operative measure on Shch. no.
Operations on HZ. carry out under local anesthesia or under an endotracheal anesthesia. The choice of a method of anesthesia is individual and depends on volume, technical complexity of alleged operation, age and a condition of the patient.
The patients with a nodal and diffusion craw who are in an euthyroid state before operation do not need special preparation. At a thyrocardiac craw preoperative preparation for the purpose of compensation of the disturbances caused by a thyrotoxicosis and achievements of an euthyroid state is necessary that is prevention of thyrocardiac crisis in the postoperative period (see the Craw diffusion toxic).
The complex of the means applied to preoperative preparation includes anti-thyroid means (see), corticosteroids (see), and also the means normalizing cordial activity hypotensive, sedatives (see Antihypertensives, Sedatives). For premedication appoint also and a ntigist mine
means (Pipolphenum) and Promedolum.
Can be the possible complications arising directly after operation: paresis of a recurrent guttural nerve, bleeding, asphyxia; after operation there can soon be thyrocardiac crisis (see Crises), a hypoparathyrosis, a hypothyroidism. In case of full removal Shch. the replacement therapy appointed soon after operation is necessary for prevention of a hypothyroidism.
Xenotransplantation Shch. at a hypothyroidism it is not applied in view of its small efficiency; autotransplantation is possible at preservation remote Shch. in special conditions (see Transplantation).
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