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
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
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
A. No. Most patients are discovered to have primary
hyperparathyroidism incidentally, in the course of a routine blood
7. Q. Do all patients with primary hyperparathyroidism develop
complications including bone loss, kidney stones, weakness, fatigability,
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
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
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.
was written by:
- John P. Bilezikian,
College of Physicians & Surgeons
New York, NY
editorial assistance of:
- Orlo Clark,
University of California-San Francisco/Mount Zion
San Francisco, CA
- Michael Levine,
Johns Hopkins University School of Medicine
- Munro Peacock,
Indiana University School of Medicine
- D. Sudhaker
Henry Ford Hospital
- Shonni Silverberg,
College of Physicians & Surgeons
New York, NY
R. Singer, MD
John Wayne Cancer Institute
Santa Monica, CA
- Monica Skarulis,
National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK) of the National Institutes of Health (NIH)
- Robert Udelsman,
Johns Hopkins University School of Medicine