Paget Paget
Paget Paget
General Information about Paget's Disease
 
Primary Hyperparathyroidism is a hormonal problem due to one or more of the parathyroid glands producing too much parathyroid hormone. When this happens, the blood calcium becomes higher than normal. Bones may lose calcium, and too much calcium may be excreted by the kidneys.
 

1. Q. What are the parathyroid glands?
A.
They are four small glands located in the neck, close to the thyroid gland. Rarely there are more than four, and they may be located in other parts of the neck, or even in the chest.

2. Q. What is their purpose?
A. The glands produce parathyroid hormone which plays a critical role in maintaining normal blood calcium levels.

3. Q. How do these small glands maintain normal calcium levels in the blood?
A. A. Parathyroid hormone, released by these glands, keeps the amount of calcium in the blood from falling below normal:

  • By conserving calcium at the kidneys
  • By releasing calcium from the bones
  • By increasing absorption of calcium from food

4. Q.What goes wrong in primary hyperparathyroidism?
A. One or more of the glands becomes enlarged and overactive, producing too much parathyroid hormone. This leads to a rise in the blood calcium. In most patients (80-85%), a single parathyroid gland becomes enlarged and develops into a benign tumor, known as an adenoma. In nearly all other patients (15-20%), two or more glands enlarge, again in a benign fashion, a condition called hyperplasia. Parathyroid cancer is an extremely rare cause of primary hyperparathyroidism.

5. Q. What are the harmful effects of primary hyperparathyroidism?
A. The most common symptoms of too much calcium in the blood are loss of appetite, thirst, frequent urination, lethargy, fatigue, muscle weakness, joint pains and constipation. More severe symptoms include nausea and vomiting, abdominal pain, memory loss and depression. These signs are not generally present unless the blood calcium is very high. Most patients with primary hyperparathyroidism in the United States do not have blood calcium levels in the range where these signs typically occur. In fact, many patients with primary hyperparathyroidism have no signs or symptoms at all. Primary hyperparathyroidism, even when patients are completely asymptomatic, can cause bones to become weak from loss of calcium. Skeletal weakening is one of the classical effects of primary hyperparathyroidism. Primary hyperparathyroidism can also lead to kidney stones.

6. Q. Do all patients with primary hyperparathyroidism have symptoms?
A. No. Most patients are discovered to have primary hyperparathyroidism incidentally, in the course of a routine blood test.
7. Q. Do all patients with primary hyperparathyroidism develop complications including bone loss, kidney stones, weakness, fatigability, etc?
A. No. Many patients do not develop obvious complications but bone loss is not uncommon.

8. Q. How does the physician know who will develop complications?
A. The physician can't predict. But complete evaluation will identify the more serious complications at early stages.

9. Q. What is a complete evaluation?

A. Blood is tested for calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and parathyroid hormone to determine the activity of the disease. A urine test (24-hour collection) is obtained to measure urinary calcium, kidney function and "bone markers" that indicate whether a patient is likely to be losing bone calcium. In some cases, urinalyses and kidney X-rays are needed to evaluation kidney stone formation. All patients should have a bone density test. This test is important because it is much more sensitive than routine X-rays and detects early bone loss, if it is present. Although it is advisable to measure all three sites (back, hip, and forearm), the most sensitive area to measure in primary hyperparathyroidism is the forearm.

10. Q. What causes primary hyperparathyroidism?
A. In most cases the cause is unknown. Previous exposure to radiation in the facial or neck area is thought to be a cause in some patients as are certain medications (thiazide diuretics, lithium). Some families inherit the tendency to develop primary hyperparathyroidism. A careful family history and special tests of blood and urine can usually exclude these rare conditions. A great majority of individuals with primary hyperparathyroidism do not have any relatives with this disorder.

11. Q. How common is primary hyperparathyroidism?
A. . In the United States, 28 out of every 100,000 people can be expected to develop primary hyperparathy-roidism each year. Women outnumber men by three to one, and the frequency of the condition increases with age.

12. Q. . Is there a cure for primary hyperparathyroidism?
A. Yes. Surgery to remove the affected gland(s) cures the condition. When performed by an experienced parathyroid surgeon, the operation is successful in over 95% of cases. Serious surgical complications are uncommon. The surgery usually leaves a thin, faint horizontal scar about three inches long in the lower neck.

13. Q. Should all patients with primary hyperparathyroidism undergo surgery?

A. Not necessarily. Although surgery is considered an appropriate treatment even in patients without signs or symptoms (i.e., asymptomatic), patients with asymptomatic primary hyperparathyroidism are not always operated upon. Most, but not all, patients who are monitored without surgery do not get worse over years of follow-up care. If surgery is not to be performed, these patients should be monitored regularly with blood testing for calcium every six months and with urinary calcium and bone density yearly. This will allow the physician to identify those who show signs of progression at an early stage.

14. Q.
Who should have surgery?
A. Experts have developed guidelines to help determine who should have surgery. In each case, the decision about surgery requires careful evaluation and individual assessment.

15. Q. What is the standard surgical?
A. The traditional approach is to perform the operation under general anesthesia. All four parathyroid glands are identified. Any enlarged glands, usually one, are removed.

16. Q. Is there a way to locate the enlarged parathyroid gland(s) before surgery is performed?
A. In most cases, patients do not require any special imaging studies to locate the affected parathyroid gland prior to surgery. An experienced surgeon who performs many parathyroid operations yearly is generally not helped by a preoperative localization test. There are exceptions to this rule, however. Patients who have had previous neck surgery represent a special situation. A second parathyroid operation should not be undertaken without first attempting to locate the "missing" parathyroid gland.

17. Q. What preoperative localization tests are available?
A. There are a number of non-invasive imaging tests to locate abnormal parathyroid glands. They include ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and the Sestamibi scan. Sestamibi is a chemical that localizes in the abnormal parathyroid gland. The Sestamibi scan, especially when it is performed with computerized tomography (SPECT) is the most sensitive and specific test available. In some cases, the quest to find the parathyroid gland advances to invasive tests (arteriography and blood sampling of veins in the neck for parathyroid hormone) that require great expertise and are more difficult. Patients who are considering minimally invasive parathyroid surgery (see question 18) require preoperative Sestamibi imaging to localize the abnormal parathyroid glands.

18. Q. Are there alternatives to this standard approach?
A. Yes. Recently three techniques have been developed. They go under the term "minimally invasive parathyroidectomy." These include preoperative lo-calization with a Sestamibi. The "minimal" operation is performed under local anesthesia with removal of the single gland visualized by the parathyroid scan. This operation is usually combined with the use of the intraoperative parathyroid hormone measurement, which can be done literally in minutes. If the blood parathyroid hormone falls to normal, the operation has succeeded in removing the culprit parathyroid gland. A second new approach calls for the Sestamibi scan to be done literally a few hours before the sur-gery. At the time of surgery, a detector is passed over the area of the operation to identify the gland(s) that are overactive. After the gland is identified and re-moved, the detector no longer picks up any signals of abnormal residual overactivity in the neck. A third approach is endoscopy to remove the parathyroid gland. These three approaches are performed only in select centers by expert surgeons with great experi-ence in parathyroid surgery.

19. Q. Can the standard parathyroid operation be performed under local anesthesia?

A. Yes. Parathyroid surgery can be performed under general, regional, or local anesthesia. In some centers, local anesthetic techniques have become the most common and the procedure of choice. The use of local anesthesia does not prevent the surgeon from identifying all parathyroid glands before the operation is concluded. In all cases, an experienced surgeon is strongly recommended.

20. Q. Is there a role for parathyroid autotransplantation?
A.Yes, in certain situations. Parathyroid autotransplantation is reserved for those patients who undergo a repeat parathyroid operation when there is concern that when the parathyroid gland is removed, the patient will be left without any parathyroid tissue, resulting in hypoparathyroidism. This is also a concern in the multiple gland hyperplasia syndromes in which all four parathyroid glands are involved. All parathyroid tissue in the neck is removed and a small amount is transplanted to the forearm. In this way, the patient is left with some functioning parathyroid tissue. If the forearm parathyroid enlarges over time, the transplanted tissue can be readily reduced by a simple, local office procedure. Parathyroid autotransplantation should be performed only in medical centers and by surgeons with experience in this technique.

21. Q. What are the results of successful surgery?
A. Successful removal of the parathyroid gland(s) leads to normal calcium and parathyroid hormone levels. In patients who have had kidney stones, they do not tend to recur. In patients with reduced bone density, major improvements are seen typically over a period of 1-4 years. Non-specific symptoms such as weakness and easy fatigability are not always affected, with some feeling better and others not noticing any difference after surgery.

22. Q. Are there alternatives to surgery?
A. There are no other cures besides surgery for primary hyperparathyroidism. Estrogen therapy may reduce some effects of the disease in postmenopausal women, but this will not directly control the glandular overactivity. There are also some experimental drugs that are being investigated to control the serum calcium, including a calcimimetic (a drug that suppresses the release of parathyroid hormone from the parathyroid glands). These drugs are not yet approved or available. Bisphosphonates, a group of drugs used to treat osteoporosis and Paget's disease of bone, are currently being evaluated in primary hyperparathyroidism.

23. Q. Are there general measures patients with primary hyperparathyroidism should follow?
A. Yes. Patients should drink enough fluids to avoid becoming dehydrated. (Dehydration will lead to an increase in the blood calcium). Similarly, to avoid worsening calcium levels, immobilization should be avoided. Calcium-containing foods should not be avoided nor should the diet be deficient in calcium because this could actually stimulate the parathyroid glands further. On the other hand, it is not advisable for patients to take too much calcium. The calcium content in the diet should be normal (approximately 1200mg).

24. Q. Which types of physicians are specialists in treating primary hyperparathyroidism?
A. Endocrinologists (medical specialists who specialize in hormonal disorders); metabolic bone disease specialists; and surgeons who specialize in endocrine surgery. Upon request, The Paget Foundation will supply a list of medical specialists.

Acknowledgments

This publication was written by:

  • John P. Bilezikian, MD
    Columbia University
    College of Physicians & Surgeons
    New York, NY

With the editorial assistance of:

  • Orlo Clark, MD
    University of California-San Francisco/Mount Zion
    San Francisco, CA
  • Michael Levine, MD
    Johns Hopkins University School of Medicine
    Baltimore, MD
  • Munro Peacock, MD
    Indiana University School of Medicine
    Indianapolis, IN
  • D. Sudhaker Rao, MD
    Henry Ford Hospital
    Detroit, MI
  • Shonni Silverberg, MD
    Columbia University
    College of Physicians & Surgeons
    New York, NY
  • Frederick R. Singer, MD
    John Wayne Cancer Institute
    Santa Monica, CA
  • Monica Skarulis, MD
    National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health (NIH)
    Bethesda, MD
  • Robert Udelsman, MD
    Johns Hopkins University School of Medicine
    Baltimore, MD

 
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