Endocrine System and Syndromes

What can go wrong?

Hormones affect systems throughout the body. They control the development of male and female sexual characteristics, fertility, growth, energy consumption, digestion, glucose utilization, stress response, fluid/water balance, and maintenance of proper blood pressure. Endocrine abnormalities usually result in the production of either too much or too little of a specific hormone. Some conditions have been given names, such as Cushing syndrome (associated with excess cortisol) because they are linked to a typical set of symptoms and complications.

Endocrine gland dysfunction may be due to either a problem with the gland itself, a problem in the feedback system, and/or due to a lack of response by the target tissues. There may be decreased hormone production related to trauma, disease, infection, crowding of the hormone-producing cells by a tumor, or an inherited gene mutation that affects the quantity, quality, or structure of a hormone. Decreased production may also be due to failure of one gland to produce and release enough hormone to stimulate the target gland to produce and release its hormone. Increased production may be related to a feedback system imbalance such as the pituitary producing too much ACTH, leading to the production of too much cortisol, or increased production may be related to hyperplasia or a tumor of the hormone-producing cells, lack of tissue response, medication use, or an inherited condition.

Tumors are generally small and usually benign. Most of them are located inside the affected gland and produce a single type of hormone. Rarely they may be cancerous. It is also very rare that tumors may be located elsewhere in the body. A tumor may cause symptoms because of the excess hormone it is producing, because its growth crowds out and decreases the production of other hormones in the gland, or because its physical size presses against surrounding nerves and structures.

Most inherited conditions are rare and are usually related to deficient or dysfunctional production of a single hormone or to the hormone production of a particular gland (for example, congenital hypothyroidism). However, there are genetically-linked conditions that affect the glands themselves. Two that have been identified as affecting several endocrine glands are MEN-1 and MEN-2 (Multiple Endocrine Neoplasia, types 1 and 2). These conditions are related to alterations in specific genes, and they increase the lifetime risk that those affected will develop tumors in one or more of their endocrine glands.