- Introduction – Parathyroid Specialist in Rockville, Montgomery County, Maryland
- Normal Functioning of Parathyroid Glands
- Hormones Involved in Calcium-Phosphate Balance
- Parathyroid Hormone
- Active Vitamin D
- Fibroblast Growth Factors 23
- Disorders of the Parathyroid Glands
- 1. Primary Hyperparathyroidism “High PTH Causes High Calcium”
- 2. Secondary Hyperparathyroidism “Low Calcium Causes High PTH”
- 3. Tertiary Hyperparathyroidism “Persistent Secondary Hyperparathyroidism Turns into Primary Hyperparathyroidism”
- 4. Primary Hypoparathyroidism “Low PTH Causes Low Calcium”
- 5. Parathyroid Adenoma
- 6. Parathyroid Hyperplasia
- 7. Parathyroid Cancer
- Biochemical and Imaging Testing for Diagnosis and Treatment Monitoring
Introduction – Parathyroid Specialist in Rockville, Montgomery County, Maryland
As a parathyroid specialist in Rockville, Montgomery County, Maryland, my primary focus is on diagnosing and treating disorders of the parathyroid glands. Utilizing my clinical experience and expertise in biochemical testing, I offer precise assessments and develop customized treatment plans, which may include surgical interventions and medications when necessary. My ultimate goal is to restore parathyroid hormone balance and enhance the overall health of my patients within the local community.
Normal Functioning of Parathyroid Glands
The parathyroid glands, typically four in number, are small, pea-sized glands situated in the neck, often found behind the thyroid gland. They play a critical role in maintaining the body’s calcium and phosphate balance. These glands house specialized sensing cells known as chief cells, which continuously monitor blood calcium levels.
For instance, when blood calcium levels fall below the normal range, the chief cells respond by releasing parathyroid hormone (PTH) into the bloodstream. PTH then acts on various target tissues to raise blood calcium levels back to normal. It accomplishes this by stimulating the release of calcium from bone tissue, enhancing calcium absorption in the intestines, and reducing calcium excretion through the kidneys. PTH also increases phosphate excretion, helping to maintain the correct calcium-to-phosphate ratios.
A tightly regulated negative feedback loop governs PTH secretion: as blood calcium levels return to normal, the parathyroid chief cells sense this change and reduce PTH production, preventing excessive calcium elevation.
In summary, the parathyroid glands are essential for ensuring the body maintains a sufficient supply of calcium, a mineral crucial for numerous physiological functions, including bone health, muscle contraction, nerve transmission, and blood clotting.
Hormones Involved in Calcium-Phosphate Balance
As previously mentioned, the parathyroid glands play a central role in maintaining the body’s calcium and phosphate balance through the secretion and response to key hormones. The primary hormones involved in this regulatory process include:
- Parathyroid Hormone (PTH): Produced and secreted by the chief cells of the parathyroid glands, PTH is the principal hormone responsible for increasing blood calcium levels.
- Calcitonin (CT): Produced by the C cells of the thyroid gland, calcitonin opposes the actions of PTH by promoting calcium uptake by bone tissue, thereby lowering blood calcium levels. However, its role in regulating calcium and phosphate balance is relatively minor compared to that of PTH.
- Active Vitamin D (Calcitriol): Calcitriol, the active form of vitamin D, is primarily synthesized in the kidneys with the assistance of PTH. It plays a crucial role in enhancing calcium absorption from the intestines, working in coordination with PTH to elevate blood calcium levels.
- Fibroblast Growth Factor 23 (FGF23): FGF23, a hormone produced by osteocytes in the bone, regulates phosphate balance. It acts to decrease phosphate absorption in the intestines and reduce phosphate reabsorption in the kidneys. Abnormal FGF23 levels can lead to disorders of phosphate metabolism.
The dynamic interplay among PTH, calcitonin, activated vitamin D, and FGF23 ensures the delicate equilibrium of calcium and phosphate homeostasis in the human body.
Disorders of the Parathyroid Glands
Parathyroid disorders encompass conditions characterized by disruptions in the production or regulation of parathyroid hormone, impacting calcium and phosphate levels in the body. Below, we’ll explore some of the common forms of these disorders.
1. Primary Hyperparathyroidism “High PTH Causes High Calcium”
Primary Hyperparathyroidism (PHPT) is a medical condition characterized by the excessive production of parathyroid hormone by one or more parathyroid glands. This overproduction disrupts the body’s calcium balance, resulting in elevated blood calcium levels (hypercalcemia).
PHPT is most commonly caused by benign tumors called parathyroid adenomas or, less frequently, by the enlargement of multiple parathyroid glands (parathyroid hyperplasia). While parathyroid cancer can also lead to PHPT, it is exceedingly rare. Symptoms of PHPT (via hypercalcemia) include fatigue, muscle weakness, bone pain, kidney stones, and gastrointestinal problems. Left untreated, PHPT can lead to complications such as osteoporosis and kidney damage.
The primary treatment for PHPT is parathyroidectomy, a surgical procedure aimed at removing the overactive parathyroid gland or glands. This surgical intervention aims to restore normal calcium levels and alleviate symptoms. However, in special circumstances where patients may not prefer surgery or are not suitable candidates for it, an alternative approach may involve the use of medications like cinacalcet. These medications can help regulate blood calcium levels by increasing the sensitivity of chief cells to calcium, thereby reducing the secretion of parathyroid hormone.
In the end, early diagnosis and intervention are critical for effectively managing Primary Hyperparathyroidism.
2. Secondary Hyperparathyroidism “Low Calcium Causes High PTH”
Secondary Hyperparathyroidism is a medical condition that develops in response to an underlying issue, most commonly chronic kidney disease (CKD). In this condition, the parathyroid glands become overactive due to low calcium (hypocalcemia) or high phosphorus (hyperphosphatemia) levels in the bloodstream.
In CKD, the kidneys are less effective at eliminating excess phosphorus from the body, leading to elevated phosphorus levels and subsequently lowering serum calcium. To compensate, the parathyroid glands produce excess parathyroid hormone in an attempt to restore normal calcium and phosphorus balance. However, persistently elevated PTH levels can have detrimental effects, causing calcium to be drawn from the bones, resulting in weakened bones and an increased risk of fractures.
Symptoms of secondary hyperparathyroidism may include bone pain, muscle weakness, and vascular calcification. Managing this condition involves treating the underlying cause, such as CKD, and often includes dietary adjustments, phosphorus binders, vitamin D supplements, and medications to lower PTH levels. Regular monitoring and management are requisite to prevent complications and maintain bone and overall health.
3. Tertiary Hyperparathyroidism “Persistent Secondary Hyperparathyroidism Turns into Primary Hyperparathyroidism”
Tertiary Hyperparathyroidism is a rare medical condition that arises as a complication of long-standing Secondary Hyperparathyroidism. As mentioned earlier, in Secondary Hyperparathyroidism, the parathyroid glands become overactive in response to an underlying condition, often chronic kidney disease or severe vitamin D deficiency. However, in some cases, these glands persistently produce excessive PTH even after the underlying illness has been resolved or effectively managed. This transition from Secondary to Tertiary Hyperparathyroidism occurs when the parathyroid glands become autonomously overactive, losing their ability to appropriately respond to changes in calcium levels.
As a result, individuals with Tertiary Hyperparathyroidism experience chronically elevated levels of PTH and calcium in their bloodstream. This can lead to complications such as hypercalcemia, bone pain, fractures, and soft tissue calcifications. Similar to primary hyperparathyroidism, treatment typically involves the surgical removal of one or more overactive parathyroid glands to restore normal PTH and calcium levels. Careful, ongoing monitoring and management of calcium and PTH levels are necessary to prevent further complications in individuals with this disorder.
4. Primary Hypoparathyroidism “Low PTH Causes Low Calcium”
Primary Hypoparathyroidism is a rare disorder characterized by deficient production or function of parathyroid hormone, resulting in abnormally low serum calcium levels and elevated phosphate levels.
The primary causes of hypoparathyroidism include surgical removal or damage to the parathyroid glands during thyroid surgery. Additionally, autoimmune conditions like autoimmune polyendocrine syndrome type 1 (APS-1) and, more rarely, genetic mutations affecting the parathyroid glands can be underlying factors.
Symptoms of hypoparathyroidism can vary in severity and may include muscle cramps, spasms, tingling sensations (paresthesias), seizures, and mood disturbances. Left untreated, long-term hypoparathyroidism can lead to complications such as cataracts, dental problems, and soft tissue calcifications.
Management typically involves supplementation with calcium, calcitriol, and, if available, PTH to restore and maintain normal calcium levels. Careful monitoring and personalized treatment are essential to prevent complications and improve the quality of life for individuals with primary hypoparathyroidism.
5. Parathyroid Adenoma
A parathyroid adenoma is a noncancerous tumor that forms on one of the parathyroid glands. These adenomas are a common cause of primary hyperparathyroidism, a condition characterized by excessive secretion of parathyroid hormone, as discussed earlier.
The adenoma develops when one of the parathyroid cells begins to multiply uncontrollably, leading to the formation of a benign mass. This overactive adenoma produces and releases excess PTH, disrupting the body’s calcium regulation. Consequently, individuals with parathyroid adenomas experience high serum calcium levels, resulting in symptoms like fatigue, kidney stones, bone pain, and digestive issues.
Diagnosis of parathyroid adenomas typically involves blood tests to confirm hyperparathyroidism and imaging studies such as ultrasound or sestamibi scans to locate the adenoma. Treatment usually requires surgical removal of the affected gland, a procedure known as parathyroidectomy, which aims to restore normal calcium levels and alleviate symptoms. Most parathyroid adenomas are noncancerous, and removal often results in a complete cure for primary hyperparathyroidism.
6. Parathyroid Hyperplasia
Parathyroid hyperplasia is a condition in which all four parathyroid glands become enlarged and overactive, causing excessive PTH production and release into the bloodstream. Parathyroid hyperplasia is often associated with genetic factors, such as multiple endocrine neoplasia type 1 (MEN1) or familial hyperparathyroidism.
Diagnosis typically involves blood tests to measure calcium and PTH levels, as well as imaging studies like ultrasound or sestamibi scans to locate the primarily affected glands. Treatment may involve surgical removal of the most enlarged glands to restore normal calcium levels. Careful monitoring and management are vital to prevent complications associated with long-term hyperparathyroidism.
7. Parathyroid Cancer
Parathyroid cancer, an exceedingly rare malignancy, originates from uncontrolled growth and spreading of cells within one or more of the parathyroid glands. It can lead to excessive production of parathyroid hormone, resulting in severe hyperparathyroidism and hypercalcemia. Typical symptoms of parathyroid cancer include advanced hypercalcemia, neck mass, fatigue, bone pain, kidney stones, and digestive issues.
Diagnosing parathyroid cancer often requires extensive imaging, biopsies, and surgical exploration. Treatment typically involves surgical removal of the cancerous parathyroid gland(s) and any affected adjacent tissue. In some cases, radiation therapy and chemotherapy may be considered, though their effectiveness is limited.
Biochemical and Imaging Testing for Diagnosis and Treatment Monitoring
Biochemistry and imaging for parathyroid disorders typically involve a combination of blood tests, urine checks, and imaging studies to assess parathyroid hormone (PTH) levels and its effects, and locate structural anomalies in the parathyroid glands. Here’s an overview:
Blood & Urine Tests:
- Calcium: Measures the blood concentration of calcium in three different forms: total calcium, calculated calcium (by utilizing Albumin), and ionized calcium.
- PTH: Measures the amount of parathyroid hormone in the blood. The most commonly used clinical test is intact PTH, which represents a fraction of the total PTH released by the parathyroid gland. Intact PTH correlates exceptionally well with native PTH.
- Phosphorus: Assesses phosphate levels in the blood, which are closely interconnected with calcium levels.
- Urinary Calcium: It primarily measures the levels of calcium and creatinine in a 24-hour urine sample. This analysis aids in evaluating kidney function and assessing calcium excretion.
- Neck Ultrasound: This non-invasive imaging technique can visualize the parathyroid glands and help identify the presence of adenomas or hyperplasia.
- Sestamibi Scan: A small amount of radioactive material is injected into a vein, and a gamma camera is used to detect where the radioactive material accumulates. This scan helps locate abnormal parathyroid glands.
- CT Scan or MRI: These imaging methods are occasionally used to provide detailed pictures of the neck and the parathyroid glands when other tests are inconclusive or for preoperative planning.
- Bone Density Scan (DEXA): In cases of primary hyperparathyroidism, a DEXA scan may be performed to assess if there has been bone loss (osteopenia or osteoporosis) due to calcium leak from the bones.
These tests and imaging studies are necessary for diagnosing and characterizing parathyroid disorders, determining their cause, and guiding appropriate treatment and follow up.
As a parathyroid specialist in Montgomery County, Maryland, I specialize in diagnosing and treating disorders of the parathyroid glands. With expertise in utilizing specialized serum and urine tests, I provide precise evaluations and offer tailored treatment plans, including surgery and medications when necessary, to restore parathyroid hormone balance and improve patients’ overall health.