OVERVIEW
Toxic nodular goiter is a different type of hyperthyroidism from Graves’ disease reported by Plummer in 1913, hence the name Plummer’s disease, which is caused by the secretion of excess thyroid hormone by nodular lesions within the thyroid gland.The nodular lesions of Plummer’s disease narrowly refer to hyperfunctional follicular adenomas, toxic adenomas, and broadly also include toxic nodular goiter.
Etiology
Toxic nodular goiter is most often secondary to nodular goiter, or thyroid tumors (high-functioning adenomas or toxic thyroid tumors), which account for a small percentage of hyperthyroidism. The nodule or adenoma may persist for a long period of time, and autonomic secretory dysfunction may occur. Sometimes the onset of hyperthyroidism is more sudden, due to an increase in iodine intake, which triggers an increase in autonomous thyroid hormone secretion, producing the typical symptoms of hyperthyroidism.
Symptoms
1. The patient has a long history of simple goiter. The age of onset is usually greater than 30 years old. There are more females than males. The degree of goiter varies and is often asymmetric. The number and size of nodules vary, usually multiple nodules, or only one nodule in the early stage. The nodules are soft or slightly hard, smooth and non-tender. Sometimes, the boundary of the nodules is not clear, and the surface of the thyroid gland only feels irregular or lobulated when touched. The disease progresses slowly and most patients are asymptomatic. Larger nodular goiter may cause compression symptoms, such as dyspnea, dysphagia and hoarseness.
2. In nodular goiter with hyperthyroidism (Plummer’s disease), patients have symptoms such as fatigue, weight loss, palpitation, arrhythmia, fear of heat and excessive sweating, and agitation, etc. However, there is no localized vascular murmur and tremor in the thyroid gland, and protruding eyes are rare, and finger tremor is also rare.
3. If it is a hot nodule or toxic nodule, the patient’s age is more than 40-50 years old, and the nodule is medium hard, with symptoms of hyperthyroidism, even atrial fibrillation and other cardiac arrhythmia, and if there is hemorrhage, there may be pain and even fever. When the nodule is large, compression symptoms may occur, such as dysphonia, dyspnea, chest tightness, shortness of breath and irritating cough.
4. If patients with nodular goiter come from iodine-deficient areas, their thyroid function may be hypothyroid, and clinically, heart rate may be slowed down, edema and skin roughness and anemia may occur. A small number of patients may also have carcinoma. Nodules of warm nature are more common and can be treated with thyroid preparations, and the enlarged glands may be reduced in size.
Examination
1. Ultrasound of thyroid gland
Clinical examination of thyroid ultrasound can clarify whether the thyroid nodule is substantial or cystic, and the diagnosis rate reaches 95%. Thyroid nodules with cysts are mostly benign and can be cured by aspiration or reduced in size. Thyroid scans or puncture pathology should also be performed in cases of substantial nodules. Ultrasonography with high resolution can analyze nodules down to 1mm lesions.
2. Radionuclide imaging
Commonly used thyroid scans are nuclide 131Ⅰ and 99mTc i.e. 131 iodine scan 99 technetium scan. Thyroid nodules are categorized by their ability to take up iodine, and the images are different. 99mTc can be taken up by the thyroid gland like iodine, but it cannot be converted. Malignant nodules cannot take up iodine and areas of malignancy will appear as radiopaque areas. Depending on their ability to take up iodine, they can be categorized as nonfunctioning cold nodules, normally functioning warm nodules, and highly functioning hot nodules. The disadvantage of radionuclide or 99mTc scanning is that it cannot completely differentiate between benign or malignant nodules, but is only a preliminary judgmental analysis. In recent years, a positive phase scanning method of the thyroid gland applying 75 selenium-selenomethionine as a tracer has also been carried out, which shows more cell divisions and higher cell densities within the lesion area of malignant nodules compared with normal thyroid tissue, and positive phase images at the lesions. Those who were scanned as cold nodules by 131 I or 99mTc and then showed positive phase imaging by 75 selenium-selenomethionine scanning had more than 50% probability of malignant nodal lesions. The application of Americium-241 fluorescence scanning technology can be used to identify benign and malignant nodules by indirectly measuring iodine volume, which is more sensitive and effective than 131 Ⅰ and 99mTc scanning, but false positives also occur. In addition, there are also nuclear magnetic resonance (NMR), dry plate radiography, electronic radiographs and temperature recorders, which need to be further applied.
3. Thyroid puncture histopathologic examination
Fine needle aspiration biopsy is valuable and safe for the diagnosis of thyroid nodules. The result of puncture helps the indication of surgical treatment, and its cytologic accuracy reaches 50% to 97%, such as lesions smaller than 1cm, the accuracy of puncture can be difficult. Fine-needle biopsy cannot be determined, and a coarse-needle re-puncture biopsy can also be used, and its results may be more accurate. However, after the puncture needle enters into the malignant nodal carcinoma, the cancer cells may spread as its harm, and special attention should be paid.
Diagnosis
Nodular goiter with varying degrees of hyperthyroidism and signs of hyperthyroidism and high or normal total thyroid uptake of 131I. One or more hot nodules concentrating 131I and not suppressed by exogenous thyroxine are visible on scan. Iodine uptake by thyroid tissue other than the nodules is hypoactive, but it is excited by TSH and suppressed by exogenous thyroxine, leading to the diagnosis of toxic nodular goiter.
Treatment
1. Surgery
Surgery is the treatment of choice for toxic nodular goiter. Surgery can quickly remove non-functional nodules (no iodine uptake, 131I treatment is ineffective) and fibrotic and calcified foci in the thyroid gland, and rarely cause hypothyroidism and recurrence of hyperthyroidism after surgery, making it a safe and effective treatment. It is a safe and effective treatment. The scope of surgery need not be too large, and it is feasible to perform lobectomy or subtotal resection of one side of the adenohypophyseal lobes, and the thyroid tissues other than the nodule can recover its function very soon after the surgery.
2. Isotope 131I radiation therapy
For patients with poor general condition who cannot tolerate anesthesia and surgery, 131I therapy can be used. 131I therapy is convenient and safe, but because the iodine uptake capacity of the thyroid gland of such patients is worse than that of Graves’ disease patients, a larger dose is needed to have an effect, and it is often necessary to give the drug several times. Therefore, some patients are not willing to accept, in addition, 131I treatment can not make the goiter shrink significantly, so it is only applicable to important organs with serious organic lesions and can not tolerate surgery.
3. Drug therapy
The long-term remission rate of thiourea is very low, and it is only used as an auxiliary drug before surgery.
4. Treatment of comorbidities
The treatment of hyperthyroidism combined with hyperthyroidism heart disease must start from two aspects, i.e., treating the heart and actively controlling the symptoms of hyperthyroidism at the same time, in order to make the patient’s cardiac condition completely improved. Cardiac symptoms can be controlled with propranolol and digoxin, and since renal clearance of digoxin is accelerated in hyperthyroidism, the dose should be slightly higher at the start of treatment. Hyperthyroidism can be controlled with radioactive 131I therapy or with surgery. Heart failure in combination with hyperthyroidism is not a contraindication to surgery; surgery is quite safe with adequate preparation, and the patient’s cardiac condition improves rapidly after thyroidectomy.