mt training: endocrine

Enlargement of the thyroid is known as goiter. Goiter may be a symptom of many different conditions. Endemic goiter occurs in certain regions and people as a result of deficiency of iodine in the diet. A glue-like or gelatinous material called colloid collects in the thyroid and the gland enlarges as it works harder to compensate for the scarcity of iodine. Treatment of this type of goiter is to increase the supply of iodine in the diet.

Another type of goiter is nodular or adenomatous, in which hyperplasia occur as well nodules and adenomas. Some patients develop hyperthyroidism with symptoms such as rapid pulse, tremors, nervousness, and excessive sweating. Treatment consists of use of thyroid to hormone to suppress the normal thyroid functioning (by reducing TSH production).

Hyperscretion

Hyperthyroidism Overactivity of the thyroid gland.

The most common form of this condition is known as thyrotoxicosis or graves disease. Hyperplasia of the parenchyma (glandular cells) occurs. The metabolic rate in cells is increased, leading to toxic symptoms as in nodular or adenomatous goiter In addition, exophthalmia (protrusion of the eyeballs) occurs as a result of swelling of tissue behind the eyeball. Treatment may include thyroidectomy, management with antithyroid drugs that reduce the amount of thyroid hormone produced from the gland, or administration of radioactive iodine, which destroys the overactive glandular tissue.

Hyposecretion

Hypothyroidism Underactivity of the thyroid gland.

Any one of several conditions can produce hypothyroidism (thyroidectomy, endemic goiter, destruction of the gland by irradiation), but all have similar physiological effects. These include fatigue, muscular and mental sluggishness, and constipation.

Two examples of hypothyroidism are.

¨ Myxedema-This is advance hypothyroidism in adulthood. Atrophy of the thyroid gland occurs, and practically no hormone is produced. The skin becomes dry and puffy (edema) because of collection of mucus-like material under the skin. Many patients also develop atherosclerosis because lack of thyroid hormone increases the quantity of blood lipids (fats). Recovery may be complete if thyroid hormone is given soon after symptoms appear.

¨ Cretinism-Extreme hypothyroidism during infancy and childhood leads of normal physical and mental growth. Skeletal growth is more inhibited than soft tissue growth,

Neoplasms

Thyroid carcinoma (Cancer of the thyroid gland).

Some tumors are very slow growing, and other may metastasize widely. Adenomas (benign growths) can be distinguished from carcinomas (malignant growths) by radioactive iodine tracer scans. “Hot” tumor areas (those collecting more radioactivity than surrounding tissues) usually indicate hyperthyroidism and benign growth; “cold,” nonfunctional nodules can be either benign or malignant. Ultimately, fine-needle aspiration, surgical biopsy, or excision is often required is often required to make the diagnosis.

2. Parathyroid Glands

Hypersecretion

Hyperparathyroidism Excessive production of parathormone.

Hypocalcaemia occurs as calcium leaves the bones and enters the bloodstream. Bones are decalcified and susceptible of fractures and cysts, as in osteitis fibrosa cystica. Kidney stones can occur from hypercalcemia. Etiology is often a parathyroid tumor, which is resected as treatment for the condition.

Hyposecretion

Hypoparathyroidism Deficient production of parathyroid hormone.

Hypocalcemia results as calcium remains in bones and is unable to enter the bloodstream. This leads to muscle and nerve weakness with spasms of muscles, a condition called tetany (constant muscle contraction). Administration of calcium plus large quantities of vitamin D (to promote absorption of calcium) can control the calcium level in the bloodstream.

3. Adrenal Cortex

Hypersecretion

Adrenal virilism Excessive output of adrenal androgens.

Adrenal hyperplasia or tumor can cause this condition in adult women Symptoms include amenorrhea, Hirsutism (excessive hair on the face and body) acne, and depending of the voice. Drug therapy to suppress androgen production adrenalectomy are possible treatments.

Cushing’s syndrome A group of symptoms produced by excess of cortisol from the adrenal cortex.

Obesity, moon-like fullness of the face, excess deposition of fat in the thoracic region of the back (so-called buffalo hump), hyperglycemia. Hypernatremia, hypokalemia, osteoporosis, and hypertension occur with excess cortisol secretion. Etiology may be excess ACTH secretion (called Cushing’s disease) or tumor of the adrenal cortex.

Hyposecretion

Addison’s disease Hypofunctioning of the adrenal cortex.

Mineralocorticoids and glucocorticoid are produced in deficient amounts, Hypoglycemia (from deficient glucocorticoid), hyponatremia (excretion of large amounts of water and salts from deficient mineralocorticoid), weakness weight loss, and darker pigmentation of the skin (because of increased blood levels of MSH) are symptoms of the condition. Treatment consists of daily cortisone administration and intake of salts.

4. Adrenal medulla

Hypersecretion

Pheochromocytoma Tumor of the adrenal medulla. The tumor cells produce excess secretion of epinephrine and norepinephrine. Symptoms are hypertension, palpitations, severe headaches, sweating. washing of the face, and muscle spasms. Surgery to remove the tumor and administration of antihypertensive drugs are possible treatments.

5. Pancreas

Hypersecretion

Hyperinsulinism Excess secretion of insulin causing hypoglycemia.

Etiology may be tumor of the pancreas (benign adenoma or carcinoma) or overdose of insulin. Hypoglycemia occurs as draws sugar out of the bloodstream. Fainting spells, convulsions, and loss of consciousness are common because a minimal level of blood sugar is necessary for proper mental functioning.