The thyroid gland
The thyroid gland is one of the largest gland, which normally weighs 15 to 20 grams. Thyroid gland excrete three kinds of thyroid hormones, thyroxine (T4), triiodothyronine (T3), and calcitonin.
Figure 1. Thyroid anatomy
In anatomy, the thyroid is an endocrine gland (ductus have not) and bilobular (right and left), connected by the isthmus (bridge) located in front of the trachea just below the cartilago cricoidea. Sometimes there are additional lobes that extends into the upper (ventral body), the lobes of the pyramid.
In embryology, the stage is the formation of the thyroid gland:
• The thyroid gland was originally a two protrusions of the front wall of the middle farings, which is formed at the age of 4 weeks of birth. The first protrusion called the pharyngeal pouch, which is between 1 and 2 brachial arch. The second protrusion on ceacum foramen, which is under the ventral branch farings I.
• At week 7, the protrusion of the foramen caecum pharyngeal pouch will go through a channel called the ductus thyroglossus.
• The thyroid gland will reach maturity at the end of the 3rd month, and the ductus thyroglossus will disappear. Final position of the thyroid gland is located in front of the cervical vertebrae 5, 6, and 7.
• However, in clinical disorders, the rest of the thyroid gland is also still commonly found at the base of the tongue (ductus thyroglossus / lingua thyroid) and the other on the neck.
The thyroid gland is drained by several arteries:
A. A. thyroidea superior (main artery).
2. A. thyroidea inferior (main artery).
3. A. Sometimes there are still too thyroidea ima, a direct branch from the aorta or A. anonyma.
The thyroid gland has three pairs of major veins:
A. V. thyroidea superior (empties into the V. jugularis interna).
2. V. thyroidea medialis (empties into the V. jugularis interna).
3. V. thyroidea inferior (V. anonyma empties into the left).
Lymph flow consists of two interwoven:
A. Interwoven lymph nodes intraglandularis
2. Interwoven lymph nodes extraglandularis
Both the fabric will be putting out its contents into the pretracheal limfonoduli then headed to the surrounding lymph nodes in V. jugular. Of about V. jugular is forwarded to the superior mediastinum limfonoduli.
Innervation of the thyroid gland:
A. Sympathetic ganglion (of truncus sympaticus) media and inferior cervical
2. Parasympathetic, ie N. Laryngea superior and N. Laryngea recurrens (branch N.vagus)
N. Laryngea commonly injured superior and inferior operating time, resulting in impaired vocal cord (stridor / hoarseness).
Histologically, this gland parenchyma consists of:
A. Follicles with epithetlium simplex kuboideum surrounding a colloid mass. Epithelial cells will be developed into a more active follicles Katika kolumner (such as muscle development continue to be trained).
2. Cellula perifolliculares (C cells) that lie between a few follicles are far apart.
Figure 2. Thyroid follicular histology
Iodine is ingested Pathway
Iodine can be obtained from beyodium seafood or salt (iodized salt added). Iodine is mikromeneral because the body needs in small amounts, ie 50 mg / year or 1 mg / week. Oral iodine will be absorbed into the digestive system of the body into the blood. Usually, most of the iodide is rapidly removed by the kidneys, but only after about one perlimanya removed from circulation by the cells of the thyroid gland and used to selectively sitesis hormone.
Thyroid hormone synthesis and secretion
A. Trapping iodide, the iodine pejeratan by pumping Na + / K + ATPase.
2. Iodine into the colloid and undergoes oxidation. The thyroid gland is the only network that can oxidize I to achieve a higher valence state. This stage involves the enzyme peroxidase.
3. Iodinated tyrosine, which is oxidized iodine will react with residual tirosil in thyroglobulin in the reaction may also involve tiroperoksidase enzyme (peroxidase enzyme type).
4. Iodotironil coupling, the coupling of two molecules of DIT (diiodotirosin) to T4 (thyroxine, tetraiodotirosin) or coupling MIT (monoiodotirosin) and DIT to T3 (triiodotirosin). This reaction is also influenced by the enzyme estimated tiroperoksidase.
5. Hydrolysis is assisted by the TSH (Thyroid-Stimulating Hormone) but is inhibited by I, so that the inactive compounds (MIT and DIT) will remain in the follicle cells.
6. Thyroxine and triiodotirosin out of the follicle cells and into the blood. This process is assisted by TSH.
7. MIT and DIT are left in the follicle cells would have deiodinasi, which will be separated again from tyrosine I. Deiodinase enzyme plays an important role in this process.
8. Tyrosine will be formed into thyroglobulin by the endoplasmic reticulum and Golgi complex.
Thyroxine and Triiodotirosin to the transport network
Once released into the blood, thyroid hormones are highly lipophilic rapidly binds to several plasma proteins. Less than 1% of T3 and T4 is less than 0.1% remain in a form not bound (free).
Figure 3. Molecular structure of Thyroid Hormone
This situation is remarkable considering that only hormone-free whole thyroid hormone access to target cells and can cause an effect.
There are three important plasma protein binding of thyroid hormone in:
A. TBG (Thyroxine-Binding Globulin) which selectively binds 55% 65% T4 and T3 in the blood.
2. Albumin is a nonselective bind many lipophilic hormones, including 10% of T4 and 35% of T3.
3. TBPA (Thyroxine-binding prealbumin) which binds the remaining 35% T4.
In the blood, approximately 90% of thyroid hormones in the form of T4, T3 despite having the biological activity of approximately four times more potent than T4. However, most of the secreted T4 is then converted into T3, or enabled, through the expenditure of the iodine in the liver and kidneys. Approximately 80% of T3 in the blood derived from the secretion of T4 who are spending the iodine in peripheral tissues. Thus, T3 is a form of thyroid hormones that are biologically active at the cellular level.
Physiological functions of thyroid hormone
A. Enhance transcription of the gene when thyroid hormone (T3 mostly) binds to its receptor in the cell nucleus.
2. Increase the number and activity of mitochondria so that the formation of ATP (adenosine triphosphate) is increased.
3. Increase the active transformation of ions through cell membranes.
4. Promote growth and brain development, especially in the fetus.
Thyroid hormone secretion regulation
At first, as a regulator of the hypothalamus secretes TRH (thyrotropin-releasing hormone), secreted by nerve endings in the median hypothalamus eminansia. Of the median, TRH then transported to the anterior pituitary via the hypothalamic-pituitary portal blood. TRH directly affects the anterior hifofisis TSH to increase spending.
Figure 4. Feedback Feedback
TSH is one of the anterior pituitary gland which has a specific effect on the thyroid gland:
A. Increase thyroglobulin proteolysis stored in the follicles, with the end result is the release of thyroid hormones into the blood circulation and reduced substances such follicles.
2. Increase the pump activity of iodine, which increases the speed of the process of iodide trapping in the cells of the gland, kadangakala increase intracellular iodide concentration ratio of extracellular iodide concentrations as much as eight times normal.
3. Increase the iodinated tyrosine to form thyroid hormones.
4. Increase the size and activity of the sensory cells of the thyroid.
5. Increase the number of thyroid cells, accompanied by a change of cuboidal cells into cells and cause a lot kolumner folds into the thyroid follicular epithelium.
Thyroid Hormone Feedback Effects in the Lower Anterior pituitary secretion of TSH by
Increased thyroid hormone in body fluids will reduce the secretion of TSH by the anterior pituitary.
This is mainly due to the direct effects of thyroid hormone on anterior pituitary.
Thyroid aberrant / ectopic thyroid
Aberrant aberrant means "wanderer" and the thyroid tissue can be found throughout the body out of the normal thyroid gland can be called deviant. This term is reserved for thyroid tissue located in the neck and does not include a similar network in other places, for example, in the midline of the neck in a thyroglossal Canalis, Struma ovaries, or other deposit in the secondary part of the body. The "lateral aberrant thyroid" is a term used of Albers (1829) is used to describe tumor containing thyroid tissue on the side of the neck at the jugular vein. Fibrosis and tumors are usually papillary pattern on histopathology. In 1896 Barker describes a case of "cystic thyroid accessory" and since then there are some cases of lateral aberrant thyroid, but there has been disagreement about the exact meaning of the appearance of thyroid tissue on the side of the neck. Now generally agreed that lateral aberrant thyroid tissue is always secondary deposits from primary carcinoma of the thyroid gland. It seems a little literature on the condition, but one case described by Murley (1950). In recent years we have found six cases, and this series seems a bit to be worthy of further research.
Embryology & aetiopathogenesis
The thyroid gland anlage is formed by fusion of the medial and lateral anlage. Medial anlage appears as part of the primitive mouth dropped to the bottom, while the lateral anlage derived from the fourth or fifth gill arch. There are several theories to explain the origin of the thyroid tissue on the side of the neck. Schrager (1906) suggested that parts of the lateral anlage separated by melting and subsequent hyperplasia has been a benign tumor. For years, this theory is accepted, although some parties believe that lateral aberrant thyroid tissue is secondary deposit of carcinoma in the ipsilateral lobe of the thyroid gland (bass, 1903). Crile (1939) believes that a benign condition, but later changed his mind and told her that in all 21 cases of primary carcinoma was found in the thyroid gland (Crile, 1947).
Predominant age
This type of thyroid carcinoma may occur at any age, but it is important to note that often occur relatively early in a person's lifespan. Age of onset in the cases ranged between 13 and 42 years, but cases have been found in children even younger. Secondary deposits in lymph nodes are often related and growth may extend behind the carotid sheath, with the recurrent laryngeal nerve.
Clinical symptoms and
It has been suggested that aberrant lateral Tyhroid could be thyroid tumors arising in the accessory is placed lateral or epithelial inclusions in lymph nodes Adenolymphoma similar to the parotid, but now agree that this condition is always a secondary carcinoma. Introduction is often very small and can not be detected clinically, but it is always a careful examination of the thyroid - liver after surgical removal. Growth is usually malignant papillary and often slow growing and relatively low CF. Thyroid lymphocytic infiltration and frequently show areas of abnormal calcification. Found an inflammation of the neck showed papillary thyroid tissue after the biopsy. The six cases reported here confirm the point. Five patients with inflammation of the neck showed papillary thyroid tissue after the biopsy. In such cases the tissue was found in the scalene nodule biopsy but clinically no palpable lump. All cases of thyroid carcinoma. Primary growth is usually in the ipsilateral thyroid lobe, but a small focus of carcinomatous tissue often found in the opposite lobe.
Diagnosis
Diagnosis based on history, physical examination and investigation. Which should be considered at each lateral neck lumps.
Anamnesis
Complaints can usually be found lumps on the side / lateral neck near the jugular vein.
Physical examination
Palpation in the neck area in a systematic, may be palpable lump on the side / lateral neck, is usually not palpable in the normal thyroid tissue should be, consistency can be hard, and tenderness.
Investigations
Plain
Radiopaq image obtained on examination of plain lateral neck at the neck ..
Ultrasonography
Ultrasound can distinguish between cystic component and solid component, this technique can confirm the clinical picture and rule out the possibility of a thyroid mass is solid. The picture can be found in the form of a mass structure with multiple ekhoik in it.
Scintigraphy
Observations by radioactive iodine is usually normal, but can indicate the presence of ectopic thyroid tissue that is similar to duct cyst tiroglossus. Scintigraphy is used in the treatment of normal thyroid tissue preoperatively to prevent postoperative hypothyroidism caused by excision of all thyroid tissue function
C-T Scan
CT scan is helpful to diagnose an ectopic thyroid with a position corresponding to the anatomical structure. Picture of the type of ectopic thyroid mass on CT-Scan sirkumskrip with demarcated lesions. Ectopic thyroid tissue appears as a smooth, rounded, lateral lesions. Density of the lesions can vary, but usually less dense than surrounding muscle tissue. Density of the nodules such as painting a picture can refer to a possibility of a carcinoma.
Management
Cases previously reported to have d do total thyroidectomy followed by radioactive iodine therapy treatment when suspected distant metastases. All patients were then dried thyroid by mouth. Dunhill (1937) describes two cases of thyroid cancer in young men in whom recurrent growth disappeared on treatment with dried thyroid and thyroid carcinoma showed a lot of hormonedependent (Crile, 1957). If the patient becomes hypothyroid after treatment for thyroid cancer, an excess of TSH-produced by the pituitary gland, and this may stimulate the growth of carcinoma. Therefore, it is important that all cases should be given adequate thyroid replacement therapy after thyroidectomy or radioactive iodine treatment to suppress the production of TSH.
Figure 5. Management of Thyroid Nodules algorithm
Pulmonary metastases is not uncommon, as in the case of 1 and 5. Case 1 had received x-ray treatment of the thymus gland in childhood and has been declared (and Rosvoll Winship, 1961) can be obtained the same story in 75-80% of cases of child thyroid cancer. Interestingly, cases 1 and 5 is believed to be probable cases of sarcoidosis in the shadow of the lung, and 5 cases had previously been treated as a nodular tuberculosis of the lungs. Winship and Rosvoll (1961) mentions five cases have been treated for tuberculosis.
Total Thyroidectomy technique
Definition
A surgical removal of the thyroid tissue in both lobes.
The scope
Lump in neck front, come to move the emphasis accompanied by signs of swallowing, hoarseness, shortness of breath, impaired swallowing, hard consistency, mobility is limited, be accompanied by enlarged lymph nodes neck, require FNAB to determine the malignancy
Indications of surgery
• Operable Carcinoma of the thyroid remains.
• endemic goitre, both right and left lobe pathologic all.
Contraindicated surgery
• an advanced stage of thyroid carcinoma (inoperable).
• anaplastic thyroid carcinoma.
Differential Diagnosis for thyroid carcinoma
• chronic thyroiditis.
• adenomatous goitre.
Examination Support
Plain neck (if necessary), chest X-ray, FNAB, thyroid I131 prints if any facilities, USG Abdomen, paraffin coupe when there are facilities
Mechanical Operation
Ahead of the operation
• Explanation to patient and family about the operation that will be undertaken and the risk of complications is accompanied by the signature of approval and requests from patients for surgery. (Informed consent).
• Checking and preparation of equipment and fittings to complete the operation.
• Patients with fasting at least 6 hours before surgery.
Stages of operation
• with endotracheal anesthesia, the patient's head hyperextended position with a pillow under the shoulders of the patient.
• Disinfection with antiseptic solution, and then narrowed down to the sterile linen.
• collar incision two fingers on the jugulum, deepened by cutting m. platisma to Kolli superficial fascia.
• Created eminentia flap up to the thyroid cartilage and down until the jugulum, both in teugel flap up and down on linen.
• Kolli superficial fascia was opened in the midline of the cartilage hioid to jugulum.
• Muscle pretrakealis (sternohioid and sternotiroid) separated towards the lateral sides of the release of the thyroid capsule.
• protrusion of thyroid diluksir and evaluated for size, consistency, nodularity and the presence of pyramidal lobe.
• Ligation and cutting v. thyroid medium, and a. inferior thyroid a little proximal to the distal tip of the thyroid easy, be careful not to disturb vascularization of kel. parathyroid.
• Identification of N. Recurrent trakeoesofagikus sulcus. Nerve was followed until it disappeared in the cricothyroid.
• Identify kel. on the surface of the posterior inferior parathyroid kel. thyroid adjacent to the entry of a. inferior thyroid on thyroid.
• Pole top kel. thyroid release of thyroid cartilage from the posterior to the identification of the external branch of n. laringikus superior to separate it from a & v superior thyroid. Both vessels are ligated and cut. Made removal of the thyroid tissue.
• Bleeding is still being treated, then the surgical wound was closed layer by layer with Redon drain left.
Complications of surgery
Early postoperative complications:
Bleeding
• If blood in vials Redon> 300 ml per 1 hour, need to be re open. If arterial bleeding, Redon drain fast enough to accommodate the bleeding and blood collects in the neck to form hematoma and tracheal pressure so that the patient short of breath.
• Perform intubation. Or poke through the Medicut 12 percutaneous cricothyroid membrane.
• the operation wound was opened and blood clot evacuation
• The patient was taken to the surgery room to look for sources of bleeding and stopped, plugged drain Redon.
Lesion n. laringius superior
• Injury to the external branches lead to changes in the patient tone of voice, when speaking a bit longer then the patient feels tired and sound more and more disappear.
• Injury to the internal branch mengakibatakan people choke when drinking water.
N damage. Recurrent
• When the surgery is both recurrent nerves are identified then the possibility of accidents reported paralise 0 0.6% only. Disorders that are transient in 2 4% and will heal itself within a few weeks or months
• There is interference on n. early recurrences can be seen with laryngoscope direkta at the time of extubation.
The occurrence of late complications:
Hipoparatiroidism
• Transient Hypocalcemia may occur 1 2 days after surgery. Edema due to parathyroid hipoparatiroidism manipulation can increase the occurrence of transients.
• If the clinical symptoms such as paresthesias, cramps, convulsions, therapy should be given by slow intravenous administration of calcium gluconate 10% as much as 10 ml, along with oral calcium. The occurrence of permanent hipoparatiroidism when kel. Parathyroid fetched as much as 2 pieces or more, or there is damage vaskularisasinya. To prevent this it is recommended to perform autotransplantasi kel. parathyroid in m. sternokleidomastoideus. Autotransplantasi kel. parathyroid has a high survival
Hypothyroidism
Hypothyroidism after total thyroidectomy is the logical consequence that occurs because people no longer have a thyroid tissue at all.
Mortality
Mortality after total thyroidectomy performed by an experienced surgeon who is less than 0.2% and the number of many series reported mortality rate is 0%.
Post-Surgical Care
Postoperative patients admitted to the room during the first two days, observed the possibility of early life-threatening complications such as bleeding and patients with airway obstruction.
Redon drain is removed after 24 hours, surgical wounds and sutures removed on day 7.
Follow-up
Post-surgical total thyroidectomy for thyroid carcinoma, examination 3-4 weeks later sidikan I131 whole body. If there is uptake of iodine ablation performed with I131 in Section Radionuclide. If there is no uptake, given the hormonal therapy of thyroid hormone extract, a dose of 50 mcg / day and increased up examination showed TSH <0.01. This dose is given for life.
Schedule follow-up:
Year to 1: every 3 months
2 years: every 4 months
3-4 years: every 6 months
5 years: every year
Things that need to be evaluated:
• clinical condition and physiology of thyroid (T3, T4, TSH) every time the control patients
• For post-total thyroidectomy for thyroid carcinoma, it is necessary:
Wanted metastases in cervical lymph nodes or distant metastasis.
Hormones checked every control when hormone thyroglobulin thyroglobulin> 10 ng / l, check
Sidikan I131 whole body to look for recurrence or metastasis. X-ray photograph once every year
REFERENCES
A. Guyton, Arthur C and John E Hall. , 2007. Textbook Medical Physiology, E/11. New York: EGC.
2. Sherwood, Lauralee. Of 2001. Medical Physiology: from cells to systems, E / 2. New York: EGC.
3. Murray, Robert K et al. , 2003. Biochemistry Harper, E/25. New York: EGC.
4. Sanderson RJ, Montague ML, Surgical management of head and neck malignancy, Surg JR Coll Surg Edinb Irel, 2 February 2004
5. Sjamsuhidajat R, Wim de Jong. Buku ajar Bedah, 2nd edition. jakarta: EGC. 2005
6. Herry yudha, the frequency of malignancy in cold nodules .....1993
7. http://bedahunmuh.wordpress.com/2010/05/18/tiroidektomi-total/
8. http://ilmubedah.info/anatomi-dan-fisiologi-kelenjar-thyroid-20110213.html
9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1958877/pdf/brmedj02872-0048.pdf
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