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may be absent or present, or one or the other lobe. Either a part of the gland or the whole may be lacking. Pyramid lobe exists in about one-third of the cases.
In early embryonal life the gland has a duct, the thoracic glossal duct, which passes from the isthmus of the thyroid to the foramen caecum of the dorsum of the tongue. The lumen of this duct is obliterated early and becomes a cord of ephithelium.
The thyroid gland arises from a median body at the root of the tongue, and two lateral bodies which begin as small bodies from each side of the posterior wall of the fourth bronchial cleft. Accessory thyroids, same histologically in structure, are frequently found in front and above the thyroid bone, or laterally near the great cornua of the thyroid cartilage, or as low as the arch of the aorta. Goiter and tumor may develop in them just the same as occurs in the main gland.
The structure of the normal thyroid consists of vast numbers of vesicles or alveoli, and are of various shapes and sizes. They are held together by an areolar tissue. The vesicles contain a glairy fluid (colloid matter) which escapes on the gland, being cut and lined by cuboidal or columnar epithelial cells. There is a capillary retreat of vessels throughout the gland and an abundance of lymph spaces, which are found outside the capillaries.
The thyroid gland is abundantly supplied with blood vessels and an extensive anastomosis. The two superior thyroids, from the external carotid, enter the gland at the top, and two inferior thyroids, from the thyroid axis of the subclavian of each side. The veins are principally the superior, middle, and inferior thyroid.
Normally, in man there are present four parathyroid glandules, situated on the posterior part of the thyroid gland behind the capsule. They vary in size, number and location. The average dimension is six to seven millimeters long by three to four millimeters wide. They are supplied by the inferior thyroid artery. The role that the parathyroid glands play in tetany is sometimes observed after operation on the thyroid gland. The relation of tetany to parathyroid destruction has
been definitely proven, and their preservation in operations on the thyroid is of vast importance. In 1880, Sandstrom, discovered the parathyroid gland, but it was not until several years later that it was demonstrated that they had different functions from the thyroid and controlled to a great exent the nervous system. The parathyroids are also liable to tumor formations.
The function of the thyroid gland is to furnish an internal secretion, which is indispensible for the maintenance and building up of the organism. As to its complete function, which is a complex one, it probably is to be observed best by its complete removal. A small portion of the thyroid left in the body is usually sufficient for the retaining of all the functions of the organ. If the thyroid gland is completely removed from the body, or its function fail for any reason, the peculiar changes of myxoedema result, in a great majority of cases, as first described by William Gull in 1874. Transplanting the thyroid and also the parathyroids has given satisfactory results, where there were indications for this procedure. The Reverdins and later Theodore Kocher studied the effect of extirpation of the gland and found on the whole, the same symptoms of myxoedema.
Deficient thyroid secretion in the young prevents growth and may vary greatly in degree, and which can be brought about, in the majority of cases, by removing the entire gland. The symptoms and changes common to cretinism, myxoedema are improved by feeding them thyroid, and the result of such feeding demonstrates the influence and effect of the thyroid on mental and body development.
The symptoms of myxoedema are principally dry skin, swelling of the subcutaneous tissues, falling of the nails and hair, memory fails, and the senses are less acute. Myxoedema coming on in young people, the symptoms are more pronounced. The long bones cease to grow, and if the epiphyses are ununited they remain so. Puberty may be retarded or prevented.
The enlargement of the thyroid is frequently noticed in girls at the age of puberty. The gland will become a normal size, in a great majority of cases, in the course of a year or so,
unless there is a tumor within the gland. In this event it would cause disturbance with the function of the gland and ought to be removed. Iodine, locally and internally, may be of benefit in some of these cases. Pregnant women often develop an enlarged gland during the latter months of pregnancy. Fruod and Lange have shown that the thyroid gland normally hypersecret during pregnancy, and that the cases that do not have hypertrophy have more tendency to albuminuria and eclampsia.
The diseases of the thyroid are classified as tumors, inflammations, functional derangements and hypertrophies. It is not the object of this paper to take up each type, but to discuss the subject of goiter generally and its surgical treatment.
Recent works on goiter places the drinking water as the causative factor. It is a well known fact that goiter occurs more frequently in some parts of Europe than others. In the British Medical Journal, February 13, 1909, R. McCarrison communicated recently to the Royal Society the results of a research to determine by experiment on man, whether goiter was caused by matter held in suspension in water, and to ascertain, as far as possible, the nature of the suspended ingredient. The experiment was made at Gilgit Kashmir, and the results, of course, can only be directly applied to goiter as it occurs there.
Including McCarrison, thirteen individuals were given suspended matter which had been removed by filtration from goiter producing water every morning before the first meal. McCarrison and three others developed enlargements of the thyroid. The experiment was repeated in eight individuals, who were given the same suspended matter, which had previously been boiled for ten minutes; in no cases did enlargements occur. The conclusion drawn is, that goiter is due to a living organism present in the water. I believe it is the generally received opinion that goiter is not more prevalent in one part of the United States than another.
Goiter is more common in females than in males, and it appears more frequently between twenty and forty years. The enlargement may be bilateral, unilateral, or median, but where one lobe is affected it is usually the right. In regard to the
heredity in exophthalmic goiter, there seems to be more opposition than to the theory of heredity in simple goiter. In the simple types of goiter the diagnosis is easily made, as the condition is so apparent that it is readily recognized, except possibly in the intra-thoracic form, and that could be easily overlooked. When in doubt about the existence of this form of goiter, an X-ray picture will clear up the diagnosis.
Intra-thoracic goiters are dangerous, therefore, they should be removed early. In some simple types of goiter the enlargement may extend to the submaxillary region or as low as the arch of the aorta. It is surprising how patients will endure the discomforts of a large goiter before surgical relief is sought.
In one of our cases, where a large goiter, a proliferating adenoma of the fetal type, had been allowed to remain for years, illustrates the effect of pressure from the growth and the displacement of surrounding structures. X-ray shows the trachea and the larynx were displaced to left side of neck, and also shows lateral curvature of the cervical vertebrae from pressure of the growth. History of growth was of twenty-five years duration, some symptoms of hyperthyroidism, but her principal symptoms lately were those from pressure, which were very marked, more pronounced the past five years. Her sleep was greatly interferred with on account of attacks of suffocation. There was a distinct whistling sound on inspiration, and she has been unable to take solid food for over three years. On removal, the carotids were found displaced to the back of the growth. The veins were greatly enlarged owing to the obstruction to the flow of the venous blood to the heart. The trachea was displaced in the region under the left ear. The tumor was enuncleated, which occupied the whole gland. All that remained of the gland was a very thin capsule, which was sutured together. This patient has no symptoms of myxoedema developing, despite the fact that she has very small amount of healthy thyroid tissue left. In these cases where absorption of almost the entire gland, due to pressure of the tumor within, has extended over a long period, they do not manifest the symptoms of loss of the thyroid as a rule, as do the ones where the removal is sudden, although it is possible
in these cases that the accessory thyroids are doing the work of the main gland.
I think it is well to keep in mind that the simple type of goiter, the so-called harmless forms of enlargement of the thyroid, which the patient has carried with her for years without any symptoms, may suddenly or gradually develop a form of Grave's disease and place the patient in a most desperate condition. These are the cases that their real condition is frequently overlooked, and are treated for various forms of nervous diseases. Some acute illness, overwork, or whatnot, will frequently be accompanied by symptoms in many of these old goiters.
The histories and symptoms of many of these patients are much alike. They will notice enlargement of the thyroid gland, which has slowly grown or remained stationery for ten or fifteen years and which has not especially given symptoms. After an acute illness they date their beginning of tachycardia, palpitation and nervousness, which are rather constant and early symptoms in these simple types of goiter. If the case progresses, these symptoms become more pronounced, accompanied with tremor, emaciation, uncomfortably moist skin from perspiration, muscular weakness and exophthalmus, although exophthalmus is not of frequent occurrence in these
They suffer from all the ordinary changes of hyperthyroidism for short periods. They are frequently encapsulated adenoma, and the patients are getting symptoms from absorption of their own gland from the pressure of the tumor within. They go on and have end results just as pronounced and as serious as true exophthalmic goiter.
A quickly growing nodular thyroid, without any other symptoms, should be removed early, as it suggests malignancy.
Exophthalmic goiter, the most important form of disease of the thyroid gland, has been recognized as a distinct disease as early as 1786, when Parry described the disease. It was described by Graves in England in 1835. In 1840 Basedow pub