American Medical Association Family Medical Guide - American Medical Association [615]
A diagnosis of aldosteronism is based on the symptoms and a physical examination. The doctor will recommend blood and urine tests to measure aldosterone levels. If the results of the blood and urine tests show high levels of aldosterone, the doctor may recommend a CT scan (see page 112), an MRI (see page 113), or a radionuclide scan (see page 114) to look for a tumor that could be causing the disorder.
Treatment
If aldosteronism is caused by an adrenal tumor, the doctor may recommend surgery to remove the tumor, which often cures the disorder. If aldosteronism is not caused by a tumor, the doctor will prescribe medications to block the action of aldosterone and control high blood pressure. If drug treatment is not effective, the doctor may recommend surgery to remove part of the adrenal glands to reduce production of aldosterone. In rare cases, both adrenal glands are removed.
Pheochromocytoma
Pheochromocytoma is a very rare condition in which a noncancerous tumor in the core of an adrenal gland (the adrenal medulla) causes the gland to produce too much epinephrine and norepinephrine. These hormones, which are produced in the adrenal medulla, work with the nervous system to control heart rate and blood pressure.
Symptoms
The main symptoms of pheochromocytoma are significantly elevated blood pressure and a rapid, pounding heartbeat. Other symptoms may include light-headedness; pale, cold, and clammy skin; excessive sweating; rapid breathing; and chest pain. Some people may experience numbness and tingling in the hands, faintness, severe headaches, constipation, nausea and vomiting, or visual disturbances.
The elevated blood pressure may be persistent, or it may come and go along with other symptoms. The symptoms can be triggered by pressure on the tumor, medication, mild physical exertion, exposure to cold temperatures, or mild stress.
Diagnosis
A diagnosis of pheochromocytoma is based on the symptoms and the results of blood and urine tests that measure the levels of epinephrine and norepinephrine. If the blood and urine tests show an excess of these hormones, the doctor may recommend a CT scan (see page 112), an MRI (see page 113), or radionuclide scanning (see page 114) to locate the tumor.
Treatment
To treat pheochromocytoma, a doctor performs surgery to remove the tumor, which usually cures the disorder. Before surgery, the doctor may prescribe a combination of the blood pressure medications alpha blockers and beta blockers to lower the person’s blood pressure.
Disorders of the Thyroid and Parathyroid Glands
The thyroid is a small, butterfly-shaped gland in the lower part of the neck, directly in front of the trachea (windpipe). The thyroid has two lobes that are joined by a thin strand of thyroid tissue called the isthmus. Under the control of thyrotropin (also called thyroid-stimulating hormone, or TSH), which is produced by the pituitary gland, the thyroid gland produces thyroid hormones that control the speed of metabolism (the chemical processes that take place in the body). In general, the higher the level of thyroid hormones in the blood, the faster the speed of metabolism. To produce thyroid hormones, the thyroid needs an adequate supply of iodine, which comes from food (especially fish and iron-fortified products) and water.
At each of the four corners of the thyroid gland, but unrelated to the thyroid gland itself, are four parathyroid glands, each about the size of a pea. The parathyroid glands produce parathyroid hormone, which works with a thyroid hormone called calcitonin and vitamin D to control the level of calcium in the blood. Calcium is essential for healthy bones and teeth and has a significant role in the functioning of nerves and muscles. Parathyroid hormone, calcitonin, and vitamin D raise the calcium level in the blood in several ways—by causing the intestines to absorb more calcium from food, by causing the body to excrete less calcium in urine, and by causing calcium to be released from bone tissue.
The thyroid and parathyroid glands
The thyroid