Parathyroid Problems

The parathyroids are four, pea-sized glands that sit near the thyroid gland in the neck. Their main job is to regulate the balance of calcium and phosphorous in the body by releasing parathyroid hormone (PTH).

When calcium levels in the blood are too low, the parathyroid glands release PTH, which pulls calcium from the bones and increases the amount of calcium absorbed from the intestines. When calcium levels in the blood are normal or high, the parathyroid glands release less PTH.

Sometimes the parathyroid glands do not produce the right amount of their hormone. If they produce too much parathyroid hormone, the condition is called hyperparathyroidism. If they produce too little, it is called hypoparathyroidism. An excess or lack of parathyroid hormone can lead to a calcium imbalance.

Three types of hyperparathyroidism exist: primary, secondary and tertiary.

Causes
Causes of hyperparathyroidism:
Primary hyperparathyroidism is the most common form of hyperparathyroidism. The problem originates within the parathyroid glands. Causes of primary hyperparathyroidism include:

• A noncancerous (benign) tumor called an adenoma on one of the parathyroid glands
• Hyperplasia (enlargement) of all the parathyroid glands
• Parathyroid cancer (rare)

In secondary hyperparathyroidism, there is a problem somewhere else in the body causing low calcium levels. These low calcium levels cause the parathyroid glands to overproduce their hormone. Causes of secondary hyperparathyroidism include:

• Kidney failure
• Rickets
• Severe vitamin D deficiency

If secondary hyperparathyroidism is not treated, tertiary hyperparathyroidism can develop. After a long time of overproducing parthyroid hormone in attempt to correct low calcium levels in the body, the four parathyroid glands become enlarged. Even if the underlying problem that caused the low calcium levels is corrected, the enlarged parathyroid glands will continue to secrete excess hormone. This can cause the body’s calcium levels to get too high.

Causes of hypoparathyroidism:
The two main types of hypoparathyroidism are hereditary or acquired.

• In hereditary hypoparathyroidism, which is passed from parents to their children, a person is born without properly functioning parathyroid glands.
• In acquired hypoparathyroidism, the parathyroid glands are damaged - often during surgery to the neck. This occurs less often today, because surgeons use more precise techniques to identify and save the parathyroid glands.

Other causes of hypoparathyroidism:

• Low magnesium levels (magnesium is needed for the parathyroids to produce PTH)
• Metabolic alkalosis (a chemical imbalance in the bloodstream)
• Radiation to the head or neck may lead to damage and scaring of the parathyroid glands.

Risk Factors
Hyperparathyroidism risk factors:

• An inherited disorder, such as familial multiple endocrine neoplasia type 1 (MEN1) or familial hypocalciuric hypercalcemia (very rare)
• Gender - women are more likely to develop hyperparathyroidism than men
• Increasing age
• Vitamin D deficiency

Hypoparathyroidism risk factors:

• Family history of hypoparathyroidism
• Surgery in the neck
• Radiation to the head or neck

Symptoms
Symptoms of hyperparathyroidism:

When too much PTH is produced, excess calcium is released from bone and into the urine. Blood calcium levels rise, while blood phosphorous levels drop. Some people with this condition will have very severe symptoms, while others have none at all.

Symptoms include:

• Abdominal pain
• Confusion
• Constipation
• Difficulty concentrating
• Fatigue
• Increased thirst and urination (due to excess calcium in the urine)
• Kidney stones (due to excess calcium in the urine)
• Loss of appetite
• Nausea
• Thinning bones and increased fracture risk
• Vomiting
• Weakness

Symptoms of hypoparathyroidism:

• Tingling in the fingertips, toes
• Muscle aches, cramps, and/or spasms
• Anxiety
• Depression
• Dry skin
• Fatigue
• Hair loss in patches
• Headaches
• Painful menstrual periods
• Weakness
• Seizures

Symptoms of parathyroid cancer:

• Constipation
• Difficulty swallowing
• Difficulty thinking clearly
• Extreme thirst
• Fatigue
• Increased urination
• Lump in the neck
• Pain in the abdomen, side, or back
• Pain in the bones
• Voice change, such as hoarseness
• Weakness
• Weight loss for no known reason

Diagnosis
The doctor will start by taking a medical history and performing a physical examination. The doctor may then choose to perform additional tests before making a diagnosis.

Tests of parathyroid function may include:

• Blood tests to look at calcium level, phosphorus level, magnesium level, and parathyroid hormone level
• 24-hour urine collection (to look for high levels of calcium in the urine)
• X-ray (to check for kidney stones)
• Ultrasound (to check for kidney stones, or to find cancer)
• Bone density measurement to determine if changes have occurred in your bones due to high parathyroid hormone levels.
• Electrocardiogram to determine if abnormal calcium levels are affecting your heart’s rhythm

Treatment
Treatment for hyperparathyroidism:
If your symptoms are mild, you may not need treatment; however, you will need to see your doctor for regular blood tests, bone density scans, and other tests to make sure your parathyroid glands are functioning properly.

In patients with symptoms, the main treatment is to surgically remove the affected parathyroid gland(s). Although parathyroid surgery used to require a relatively large incision, a newer technique uses a very small incision. Before the surgery, your doctor may locate your parathyroid glands using an imaging technique called a sestamibi scan. You will be given a radioactive tracer material that is absorbed by an overactive parathyroid gland but not a normally functioning gland. Although there is a small risk of damaging the delicate vocal cords during surgery, newer techniques can help minimize this risk.

Another treatment option is a new class of drugs called calcimimetics, which turns off Parathyroid hormone production. Although these drugs are not approved specifically to treat hyperparathyroidism, many doctors use them for this purpose.

With secondary hyperparathyroidism, doctors treat the medical condition that is causing the problem (often kidney failure).

The main treatment for tertiary hyperparathyroidism is to surgically remove the affected parathyroid glands. After examining the glands, the doctor will then re-implant a small amount of one parathyroid gland into another location so your body can continue to make parathyroid hormone.

After any surgery on the parathyroid glands, it is possible to develop low calcium. This can be treated using Calcium and Vitamin D supplements.

Treatment for hypoparathyroidism:
Treatment focuses on increasing calcium levels, typically with calcium and vitamin D supplements. If you’re having severe symptoms of low calcium, you may need to receive calcium through a vein (intravenously) at the hospital. Your doctor may prescribe a thiazide diuretic (one example is hydrochlorothiazide) - that can increase blood calcium levels by helping the kidney to decrease the amount of calcium lost in the urine.

Treatment for parathyroid cancer:
Treatment depends on how far the cancer has spread, but may include:

• Surgery to remove the affected gland
• Radiation
• Chemotherapy
• Treatment to lower excess calcium levels in the blood

Complications
Complications from hyperparathyroidism include:

• High blood pressure and congestive heart failure
• Kidney stones may form due to high levels calcium being filtered into the urine
• Peptic ulcers (because excess calcium triggers the production of stomach acids)
• Weak bones (osteoporosis)
• Calcium deposits in tissues and organs throughout the body
• Babies born to mothers with hyperparathyroidism may have very low levels of calcium after birth.

Complications from hypoparathyroidism include:

• Irregular heart rhythms
• Tetany (muscle spasms that may potentially cause a block in the airway, making you unable to breathe)
• Seizures
• Weak bones (osteoporosis)
• Cataracts

In addition young children with hypoparathyroidism can develop the following:

• Mental retardation
• Poorly formed teeth
• Stunted growth

Self Care
If you have hyperparathyroidism, follow these steps to minimize your symptoms:

• Drink plenty of water to prevent kidney stones from forming
• Exercise regularly to prevent bone loss
• Get plenty of vitamin D (people under age 50 should get 200 international units (IU) daily, while those over age 50 should get 400-800 IU)
• Quit smoking, as in addition to increased risk of serious health diseases and cancer, smoking can decrease bone density

If you have hypoparathyroidism, take these steps to increase your calcium levels and decrease your phosphorous levels:

• Fill your diet with plenty of leafy green vegetables, and calcium-fortified orange juice
• Avoid excess dairy products, carbonated soft drinks, and some nuts, which are all high in phosphorous.

Prognosis
Surgery for hyperparathyroidism cures the condition in approximately 95 percent of cases. However some complications such as cataracts and calcium build up in other organs are not reversible.

The prognosis for hypoparathyroidism is good as long as the patient is taking enough calcium and vitamin D to meet the body’s needs.

The outlook for parathyroid cancer depends on how far the cancer has progressed (stage) and whether surgery can remove the tumor. In many patients, the cancer returns (recurs) after treatment.

Sources:
Mayo Clinic. Hypoparathyroidism.
http://www.mayoclinic.com/print/hypoparathyroidism/DS00952/DSECTION=all&METHOD=print
NIDDK. Hyperparathyroidism.
http://www.endocrine.niddk.nih.gov/pubs/hyper/hyper.htm.
Wysolmerski JJ, Insogna KL. The Parathyroid Glands, Hypercalcemia, and Hypocalcemia. In:  Goldman L, Ausiello D. Goldman: Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 266.
National Cancer Institute. Parathyroid Cancer.
http://www.nci.nih.gov/cancertopics/pdq/treatment/parathyroid/Patient/page1.