Thyroid enlargement has been a common problem encountered in general surgical practice. Thyroid being an endocrine gland, its involvement has a diverse issue from a meager cosmetic problem to a more concerned malignancy. Multinodular goiter is where the enlarged thyroid appears with a number of separate lumps (nodules) in the gland. It is one of the most common thyroid disorders. The appropriate treatment is often a matter of debate, with different preferences in different countries. Surgery is the recommended treatment of choice when facing a large goiter or when cancer cannot be ruled out.
The incidence of multinodular goiter depends very much on the status of iodine intake of the population. Goiter prevalence may be very high in areas of iodine deficiency. Especially in goiters of longstanding duration; multinodularity develops frequently. Nodule formation is fairly common and in some studies, nodularity was found in 30% to 50% of subjects in autopsy studies, and in 16% to 67% in prospective studies of randomly selected subjects on ultrasound.
Nodular goiter may be the result of any chronic low-grade, intermittent stimulus to thyroid hyperplasia. Several mechanisms, including the interplay of intrinsic and extrinsic factors in the thyroid, cause goiter. The goitrogenic process involves genetic, environmental, dietary, endocrine, and other factors. The most common worldwide cause of endemic nontoxic goiter, is iodine deficiency. In patients with sporadic goiter, the cause is usually unknown. Sporadic goiter is a result of environmental or genetic factors that do not affect the general population.
The history should be obtained not only form patients but also from relatives. Regional symptoms should be addressed relating to respiration, phonation, swallowing and presence of lump sensation. The symtoms may get aggravated in particular position of head. The family also needs to be asked about the nocturnal symptoms. Symtoms related to thyroid function (hyperthyroidism/hypothyroidism) should also be noted.
Thyroid size, consistency and fixation of mass should be noted. Vocal cord examination should also be included.
Tests to be done:
Blood tests like TSH, T3/Free T3 and T4/ Free T4 should be done.
Thyroid nuclear scan is done when tests suggest increase function of thyroid gland, i.e., hyperthyroidism.
Thyroid ultrasound is an important part of evaluating a MNG. It is a good tool for assessing the size of the goiter more accurately, as well as the size and characteristics of nodules within the goiter. Ultrasound has no radiation exposure and, is therefore, completely safe. Ultrasound can also help guide fine needle aspiration cytology/biopsy of nodules.
The natural history of benign goiter is usually slow growth of the nodules. Therefore, observation can be safe. However, there are chances of development of cancer in a multinodular goiter. Hence, if suspicion of cancer is there, then preferably operation for total removal of thyroid is recommended. Also, if reports suggest that cancer has already been formed then also operation is done. Many times, in long standing cases, due to excess growth of goiter, people feel difficulty in breathing (due to compression of windpipe by trachea) or difficulty in swallowing food (due to compression of food pipe). Then also operation is necessary.
In olden days, thyroid hormone tablets were used to shrink the goiter, however it is not a good idea and puts patients at risk for hyperthyroidism.
This page is edited by Dr. Roma Pradhan who is an expert Endocrine and Breast Surgeon. She is presently working as Assistant Professor of Surgery at Central Referral Hospital and SMIMS at Gangtok, Sikkim (India).