Multiple endocrine neoplasia type 1 (MEN I; endocrine adenomatosis; Wermer’s syndrome)

• What is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• Statistics on Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• Risk Factors for Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• Progression of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• Symptoms of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• Clinical Examination of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• How is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) Diagnosed?
• Prognosis of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)
• How is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) Treated?
• Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) References

What is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)

Multiple Endocrine Adenomatosis or Wermer’s syndrome is a disorder of the endocrine glands; the parathyroids are the earliest and most often affected by MEN1.

The human body normally has four parathyroid glands, which are located close to the thyroid gland in the front of the neck. The pancreas gland, located behind the stomach, the pituitary is a small gland inside the head, behind the bridge of the nose.

Statistics on Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)

MEN1 is quite rare, occurring in about 3 to 20 persons out of 100,000. It affects both sexes equally and shows no geographical, racial, or ethnic preferences.

Risk Factors for Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)

Multiple endocrine neoplasia type 1 (MEN1) is an inherited disorder that affects the endocrine glands.

Progression of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)

In patients with MEN1, sometimes more than one group of endocrine glands, such as the parathyroid, the pancreas, and the pituitary become overactive at the same time.

Most people who develop overactivity of only one endocrine gland do not have MEN1.
In MEN1, all four parathyroid glands tend to be overactive. They release too much parathyroid hormone, leading to excess calcium in the blood.

The pancreas gland releases key hormones into the bloodstream. Some hormones produced in the islet cells of the pancreas and their effects are:

• Insulin–lowers blood sugar;
• Glucagon–raises blood sugar;
• Somatostatin–inhibits many cells.

Gastrin is another hormone that can be oversecreted in people with MEN1. The gastrin comes from one or more tumors in the pancreas and small intestine. Gastrin normally circulates in the blood, causing the stomach to secrete enough acid needed for digestion. If exposed to too much gastrin, the stomach releases excess acid, leading to the formation of severe ulcers in the stomach and small intestine. Too much gastrin can also cause serious diarrhea.About one in three patients with MEN1 has gastrin-releasing tumors, called gastrinomas. (Zollinger-Ellison syndrome).The pituitary gland becomes overactive in about one of four persons with MEN1. This overactivity can usually be traced to a very small, benign tumor in the gland that releases too much prolactin, called a prolactinoma. High prolactin can cause excessive production of breast milk or it can interfere with fertility in women or with sex drive and fertility in men.

How is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) Diagnosed?

Screening of those of persons with MEN1, who are at high risk, generally involves testing for hyperparathyroidism, the most common and usually the earliest sign of MEN1. Any doctor can screen for hyperparathyroidism by testing the blood for total calcium and sometimes one or two other substances such as ionized calcium and parathyroid hormone.

An abnormal result indicates that the person probably has MEN1, but a normal finding in all cannot rule out the chance that he or she will develop hyperparathyroidism at a later time. Blood testing can usually show signs of early hyperparathyroidism many years before symptoms of hyperparathyroidism occur.

Prognosis of Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome)

There is no cure for MEN1 itself, but most of the health problems caused by MEN1 can be recognized at an early stage and controlled or treated before they become serious problems.

How is Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) Treated?

It is sometimes difficult to decide whether hyperparathyroidism in MEN1 is severe enough to need treatment, especially in a person who has no symptoms. The usual treatment is an operation to remove the three largest parathyroid glands and all but a small part of the fourth.

After parathyroid surgery, regular testing of blood calcium should continue, since the small piece of remaining parathyroid tissue can grow larger and cause recurrent hyperparathyroidism. People whose parathyroid glands have been completely removed by surgery must take daily supplements of calcium and vitamin D to prevent hypocalcemia (low blood calcium).

The gastrinomas associated with MEN1 are difficult to cure by surgery, because it is difficult to find the multiple small gastrinomas in the pancreas and small intestine. In the past, the standard treatment for gastrinomas was the surgical removal of the entire stomach to prevent acid production. The mainstay of treatment is now very powerful medicines that block stomach acid release, called acid pump inhibitors. Taken by mouth, these have proven effective in controlling most cases of Zollinger-Ellison syndrome.

Most prolactinomas are small, and treatment may not be needed. If treatment is needed, a very effective type of medicine known as a dopamine agonist can lower the production of prolactin and shrink the prolactinoma. Occasionally, prolactinomas do not respond well to this medication. In such cases, surgery, radiation, or both may be needed.

Multiple Endocrine Neoplasia Type 1 (Endocrine Adenomatosis or Wermer’s syndrome) References

1. Ballinger, A. Patchett, S., Saunders’ Pocket Essentials of Clinical Medicine 2nd ed. W.B. Saunders, 2000
2. Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001
3. Multiple Endocrine Neoplasia Type 1 as retrieved from www.nlm.nih.gov on 29/12/2003
4. Multiple Endocrine Neoplasia Type 1 as retrieved from www.kumarandclark.com on 29/12/2003
5. Robbins, S.L., Cotran, R.S., Kumar, V. Robbins Pathologic Basis of Disease 5th ed. W.B. Saunders 1995.