Primary Hyperparathyroidism (PHPT)

overview

Primary hyperparathyroidism (PHPT) is a common medical problem caused by over-activity of the parathyroid glands. Most people have four parathyroid glands that are in the neck close to the thyroid gland. The parathyroid glands control the level of calcium in the blood. They do this by making a hormone called ‘parathyroid hormone’. In PHPT one or more of the parathyroid glands starts working too hard and produces too much parathyroid hormone. This causes an increase in the level of calcium in the blood.

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Primary Hyperparathyroidism (PHPT)

overview

Primary hyperparathyroidism (PHPT) is a common medical problem caused by over-activity of the parathyroid glands. Most people have four parathyroid glands that are in the neck close to the thyroid gland. The parathyroid glands control the level of calcium in the blood. They do this by making a hormone called ‘parathyroid hormone’. In PHPT one or more of the parathyroid glands starts working too hard and produces too much parathyroid hormone. This causes an increase in the level of calcium in the blood.

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Symptoms

Symptoms of PHPT are related to elevated calcium levels in the blood. High calcium levels can cause the following:

Kidney stones
Bone pain and muscle weakness
Stomach pain, nausea, vomiting, and constipation
Excessive thirst and frequent urination
Confusion, lethargy, fatigue
Heart palpitations and fainting

Causes

Hyperparathyroidism can be caused by the following:

Parathyroid adenoma: Benign growth of parathyroid tissue that results in excess hormone production. This is the cause of ~85% of PHPT.
Parathyroid hyperplasia: Benign enlargement of all four parathyroid glands. This is the cause of ~15% of PHPT. Associated with multiple endocrine neoplasia syndrome (MEN syndrome).
Parathyroid carcinoma: Cancer of the parathyroid gland is rare. It is associated with very high calcium levels.
Secondary hyperparathyroidism: Elevated parathyroid hormone, but low calcium levels. Typically a result of chronic kidney disease or low Vitamin D levels.
Tertiary hyperparathyroidism: Parathyroid glands continue to produce excess hormone despite correction of an underlying condition that caused the secondary hyperparathyroidism.

Symptoms

Symptoms of PHPT are related to elevated calcium levels in the blood. High calcium levels can cause the following:

Kidney stones
Bone pain and muscle weakness
Stomach pain, nausea, vomiting, and constipation
Excessive thirst and frequent urination
Confusion, lethargy, fatigue
Heart palpitations and fainting

Causes

Hyperparathyroidism can be caused by the following:

Parathyroid adenoma: Benign growth of parathyroid tissue that results in excess hormone production. This is the cause of ~85% of PHPT.
Parathyroid hyperplasia: Benign enlargement of all four parathyroid glands. This is the cause of ~15% of PHPT. Associated with multiple endocrine neoplasia syndrome (MEN syndrome).
Parathyroid carcinoma: Cancer of the parathyroid gland is rare. It is associated with very high calcium levels.
Secondary hyperparathyroidism: Elevated parathyroid hormone, but low calcium levels. Typically a result of chronic kidney disease or low Vitamin D levels.
Tertiary hyperparathyroidism: Parathyroid glands continue to produce excess hormone despite correction of an underlying condition that caused the secondary hyperparathyroidism.

Diagnosis

Diagnosis is based on a combination of the following:

Bloodwork

Elevated parathyroid hormone and calcium levels.

Sestamibi Scan

An imaging technique that uses a radiotracer to help localize a hyperfunctioning parathyroid gland. Imaging results are in 2D only.

Single Photon Emission CT Scan

An imaging technique that utilizes a radiotracer in combination with a CT scan to localize a hyperfunctioning parathyroid gland. Imaging results are in 3D.

4D CT scan

Contrast dye, instead of a radiotracer, is used to help localize an enlarged parathyroid gland.

Ultrasound

Ultrasonic sound waves (no radiation) are used to capture an image of the thyroid gland and surrounding structures. Parathyroid adenomas are often visible on ultrasound.

Diagnosis

Diagnosis is based on a combination of the following:

Bloodwork

Elevated parathyroid hormone and calcium levels.

Sestamibi Scan

An imaging technique that uses a radiotracer to help localize a hyperfunctioning parathyroid gland. Imaging results are in 2D only.

Single Photon Emission CT Scan

An imaging technique that utilizes a radiotracer in combination with a CT scan to localize a hyperfunctioning parathyroid gland. Imaging results are in 3D.

4D CT scan

Contrast dye, instead of a radiotracer, is used to help localize an enlarged parathyroid gland.

Ultrasound

Ultrasonic sound waves (no radiation) are used to capture an image of the thyroid gland and surrounding structures. Parathyroid adenomas are often visible on ultrasound.

Available Treatments

Surgery

Parathyroidectomy, or surgical removal of the parathyroid gland, is the treatment of choice for PHPT, as well as parathyroid carcinoma and tertiary hyperparathyroidism. In the case of a parathyroid adenoma, only one of the four glands needs to be removed. In the case of hyperplasia of all 4 glands, 3.5 glands are removed. Half of a gland is left in the body in order for normal calcium regulation to occur.

Medication

Patients with low vitamin D levels are treated with supplementation. Patients on dialysis for kidney disease may also be given a medication called cinacalcet (Sensipar). This medication mimics calcium, in turn signaling the parathyroid glands to decrease the production of parathyroid hormone.

Treatment