Parathyroid Gland

The parathyroid glands are small, pea-sized glands located in your neck, usually behind your thyroid gland. These glands play a crucial role in maintaining healthy levels of calcium and phosphorus in your blood. They do this by producing a hormone called parathyroid hormone (PTH), which is essential for many bodily functions, including bone health and nerve function.

What is the Parathyroid Gland?

The parathyroid glands are typically four tiny, pea-sized glands found in your neck, usually located just behind your thyroid gland. While most people have four, the exact number can sometimes vary. These glands are a vital part of your endocrine system, which is a network of glands that produce hormones to regulate various bodily functions.

Your parathyroid glands are quite small, often described as being about the size of a grain of rice or a pea. They are usually situated on the back surface of your thyroid gland, which is a butterfly-shaped gland located at the base of your neck. Though they are close to the thyroid, the parathyroid glands function completely independently. These glands are typically arranged in two pairs: two superior (upper) parathyroid glands and two inferior (lower) parathyroid glands. However, their precise location can sometimes vary slightly from person to person. In rare cases, some people may have fewer or more than four parathyroid glands, or they might be located in other areas of the neck or chest. Despite their small size, the parathyroid glands are essential for your overall health. They are responsible for producing and releasing parathyroid hormone (PTH), which is the primary regulator of calcium levels in your body. Without properly functioning parathyroid glands, your body cannot maintain the delicate balance of calcium needed for many critical processes.

Function

The main function of the parathyroid glands is to produce parathyroid hormone (PTH), which acts like a thermostat for calcium and phosphorus levels in your blood. PTH helps keep these levels within a very narrow, healthy range. This regulation is critical because calcium is essential for strong bones, proper nerve and muscle function, and a healthy heart rhythm.

Parathyroid hormone (PTH) works by influencing three main areas of your body: your bones, kidneys, and intestines. When calcium levels in your blood drop too low, your parathyroid glands release more PTH. This hormone then signals your bones to release some of their stored calcium into the bloodstream. At the same time, PTH tells your kidneys to reabsorb more calcium from the urine, preventing it from being lost. It also prompts the kidneys to excrete more phosphorus, as calcium and phosphorus levels are often inversely related. Additionally, PTH helps activate vitamin D in your kidneys, which then allows your intestines to absorb more calcium from the food you eat. This intricate system ensures that your body always has enough calcium circulating in your blood. Think of it like a finely tuned balancing act: if calcium levels get too high, the parathyroid glands reduce PTH production, allowing calcium levels to fall back into the normal range. This constant adjustment is vital because calcium is not only a building block for bones but also a key player in transmitting nerve signals, contracting muscles, and maintaining a regular heartbeat.

Related conditions

Conditions related to the parathyroid glands primarily involve an imbalance in parathyroid hormone (PTH) production, leading to abnormal calcium levels in the blood. The two main conditions are hyperparathyroidism, where too much PTH is produced, and hypoparathyroidism, where too little PTH is produced. Both can significantly impact your health.

Hyperparathyroidism occurs when one or more of your parathyroid glands become overactive and produce too much parathyroid hormone (PTH). This excess PTH causes calcium levels in your blood to rise, a condition known as hypercalcemia. High calcium levels can lead to various symptoms, including bone pain, kidney stones, fatigue, and weakness. In most cases, hyperparathyroidism is caused by a benign (non-cancerous) growth, called an adenoma, on one of the glands. Conversely, hypoparathyroidism is a rare condition where your parathyroid glands produce too little PTH. This leads to abnormally low calcium levels in your blood, a condition called hypocalcemia. Low calcium can cause symptoms such as muscle cramps, tingling sensations in your fingers and toes, and even seizures in severe cases. Hypoparathyroidism often results from damage to the glands during neck surgery, such as thyroid surgery, or from certain autoimmune diseases. Both hyperparathyroidism and hypoparathyroidism require careful medical management to restore calcium balance and prevent complications. If left untreated, these conditions can lead to serious health problems affecting your bones, kidneys, nervous system, and heart. It is important to consult a healthcare professional if you experience symptoms related to calcium imbalance.

Related tests

To diagnose parathyroid gland conditions, doctors typically use blood tests to measure levels of parathyroid hormone (PTH), calcium, and phosphorus. These tests help determine if the glands are producing too much or too little PTH and how that affects your body's mineral balance. Sometimes, additional tests like vitamin D levels or imaging may be used.

The most common and crucial tests for evaluating parathyroid gland function are blood tests. Your doctor will likely order a blood test to measure your parathyroid hormone (PTH) level. This test helps assess whether your glands are producing an appropriate amount of the hormone. High PTH levels often suggest hyperparathyroidism, while low levels can indicate hypoparathyroidism. Alongside PTH, blood calcium levels are always measured. Calcium is directly regulated by PTH, so an abnormal PTH level will usually correspond with an abnormal calcium level. For example, high PTH and high calcium often point to hyperparathyroidism, while low PTH and low calcium suggest hypoparathyroidism. Blood phosphorus levels are also commonly checked, as PTH influences phosphorus excretion. Your doctor may also check your vitamin D levels, as active vitamin D is essential for calcium absorption and works with PTH to maintain calcium balance. In some cases, if a parathyroid adenoma (a benign tumor) is suspected, imaging tests like an ultrasound or a Sestamibi scan may be used to help locate the overactive gland. These tests provide visual information about the glands, but blood tests remain the primary diagnostic tools.

Frequently asked questions

What is the main purpose of the parathyroid glands?

The main purpose of the parathyroid glands is to produce parathyroid hormone (PTH). This hormone is crucial for regulating and maintaining healthy levels of calcium and phosphorus in your blood, which are vital for many bodily functions like bone strength and nerve signaling.

How many parathyroid glands do people usually have?

Most people typically have four parathyroid glands. They are usually found in two pairs, located behind the thyroid gland in the neck. However, the exact number and location can sometimes vary slightly from person to person.

What happens if my parathyroid glands produce too much hormone?

If your parathyroid glands produce too much parathyroid hormone (PTH), it's called hyperparathyroidism. This leads to high calcium levels in your blood, which can cause symptoms like bone pain, kidney stones, fatigue, and weakness. It requires medical evaluation.

What happens if my parathyroid glands produce too little hormone?

If your parathyroid glands produce too little parathyroid hormone (PTH), it's called hypoparathyroidism. This results in low calcium levels in your blood, which can cause muscle cramps, tingling sensations, and in severe cases, seizures. This condition also requires medical attention.

Are the parathyroid glands the same as the thyroid gland?

No, the parathyroid glands are not the same as the thyroid gland, even though they are located close to each other in the neck. The thyroid gland produces hormones that regulate metabolism, while the parathyroid glands produce PTH to regulate calcium and phosphorus levels.

What tests are used to check parathyroid gland function?

To check parathyroid gland function, doctors primarily use blood tests to measure levels of parathyroid hormone (PTH), calcium, and phosphorus. Sometimes, vitamin D levels are also checked. Imaging tests may be used to locate an overactive gland if needed.

Sources

• MedlinePlus — Parathyroid Gland
• Mayo Clinic — Parathyroid Gland
• Cochrane Library — Parathyroid Gland