Hyperparathyroidism vs. Hyperthyroidism: What Are the Differences?

Hyperparathyroidism (HPT) and hyperthyroidism (HT) sound a lot alike. While the glands involved are somewhat related, they produce different hormones that have different effects on your body. They have different symptoms and require different treatments, as well.

Your thyroid gland is shaped like a butterfly. It sits at the front of your throat, right in the center. The four parathyroid glands are usually located just behind the thyroid, near the upper and lower tips of the “wings.” They're about the size of peas.

This article will explore the differences between the two conditions, their symptoms and causes, how they’re diagnosed and treated, and how you can prevent them.

Symptoms

Your parathyroid glands produce a hormone called parathyroid hormone. Its primary job is controlling calcium levels in your blood. 

Your nervous system and muscles need calcium to function correctly. It also keeps your bones strong. HPT causes an increase in parathyroid hormone and hypercalcemia (high calcium levels). 

When your parathyroid glands tell your body to raise calcium levels in the blood, your body leeches it from your bones and your kidneys hold onto it.

Your thyroid gland produces thyroid hormones. Their jobs are largely to do with homeostasis (your body’s automatic functions). 

Thyroid hormones regulate heart rate, breathing, body temperature, body weight, cholesterol levels, energy expenditure, and menstrual cycles. HT causes all of these processes to speed up.

The conditions have some symptoms in common, but this is just a coincidence. The causes of the symptoms are different.

Symptoms they have in common include:

• Fatigue
• Muscle pain and weakness
• Anxiety
• Depression
• Frequent urination
• Trouble concentrating
• Nausea
• Heart problems

Some of their symptoms are opposites. For example, HPT causes constipation and decreased appetite. HT causes diarrhea and increased appetite.

The other symptoms of HPT and HT are unrelated.

Causes

Both HPT and HT can be caused by growths on the glands that cause them to overproduce hormones. In HPT, it’s usually a noncancerous growth called an adenoma. Cancer is possible but rare.

In HT, if there are thyroid nodules, your healthcare provider will order the appropriate test to make sure they are not cancerous.

However, both conditions have other causes as well.

Causes of Hyperparathyroidism

HPT can result from several things. In addition to growths on the gland (adenoma), they include:

• Hyperplasia (two or more enlarged parathyroid glands)
• In rare cases, inherited conditions such as multiple endocrine neoplasia (a group of disorders affecting hormone-producing glands)

Sometimes HPT results from another condition that depletes calcium. That can include: 

• Kidney failure
• Vitamin D deficiency
• Severe calcium deficiency

Cause of Hyperthyroidism

HT is often due to one of the following:

• Autoimmune activity (the immune system attacking the thyroid gland) called Graves’ disease
• Thyroiditis (inflammation in the gland), which can be caused by an infection or immune-system problem
• Excessive iodine consumption, because iodine is used to produce thyroid hormone

Diagnosis

The diagnostic processes for HPT and HT both involve blood tests and imaging. However, the specific tests are different.

Diagnosing Hyperparathyroidism

To diagnose HPT, healthcare providers order several tests:

• Blood tests: Your healthcare provider will order a comprehensive blood panel to check your calcium and vitamin D levels, parathyroid hormone, and kidney function.
• 24-hour urine collection: This test also looks at calcium levels.
• Sestamibi scan: This is a specialized imaging scan to look for enlargement or growths.
• Ultrasound: This imaging test can detect an unusually large parathyroid gland, which can cause HPT. It may also be used to check for kidney stones in the kidneys.

To check for possible complications of calcium dysregulation, your healthcare provider may also order:

• Bone density test: This scan checks for bone loss and osteoporosis

Diagnosing Hyperthyroidism

The diagnostic process for hyperthyroidism is simple and includes:

• Physical exam: Your healthcare provider will feel your neck for swelling or inflammation of the thyroid and check your heart rate.
• Blood tests: A comprehensive blood panel will show your thyroid hormone levels.
• Ultrasound: This imaging test is used to confirm the presence of thyroid nodules and inflammation.
• Radioactive iodine uptake test: During this test, radioactive iodine is used to show how much thyroid hormone is being produced and any inflammation in the gland.

The thyroid hormones that are tested include triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH). T3 and T4 are produced by the thyroid. TSH is produced by the pituitary gland when it detects the need for more T3 and T4.

Treatment

HPT and HT are treated completely differently.

Treating Hyperparathyroidism

HPT is usually diagnosed if the patient is under age 50 and blood tests show extremely high levels of calcium and parathyroid hormone. Markers of impaired kidney function, bone density loss, kidney stones, and 24-hour urine calcium excretion over 400 are also indicators of HPT.

If you have these symptoms, your healthcare provider will likely recommend surgery to remove the parathyroid growth and/or overactive gland (or glands). This cures the disease about 95% of the time.

Cases of secondary HPT (HPT that is caused by another condition, usually kidney disease) may be treated with a drug called Sensipar (cinacalcet), which signals the HPT glands to produce less parathyroid hormone.

Treating Hyperthyroidism

Hyperthyroidism can be treated in a few different ways.

• Antithyroid drugs: Tapazole (methimazole) or PTU (propylthiouracil) keep the thyroid from making hormones.
• Radioactive iodine: This destroys thyroid cells to stop hormone production.
• Surgery (thyroidectomy): Surgery removes part or all of the thyroid gland.

Radioactive iodine and surgery are considered cures. However, afterward you’ll likely have hypothyroidism (low thyroid hormones) and need to take thyroid-replacement hormones for the rest of your life.

Prevention

There’s no known way to prevent HPT or HT. However, some risk factors may be changeable and therefore reduce your risk.

Preventing Hyperparathyroidism

Risk factors for HPT include:

• Getting older
• Being female
• Inherited hormonal problems
• Depression
• Obesity

If you know you’re at risk, you should:

• Avoid dehydration.
• Make sure you’re getting enough vitamin D.
• Get treatment for depression.
• Try to reach and maintain a healthy weight.

If you need radiation treatment for cancer in or near your neck, ask your medical team if there’s any way to protect your parathyroid and other nearby structures.

Preventing Hyperthyroidism

While these aren’t proven to prevent HT, they may help lower your risk:

• Ask for a thyroid collar (a lead collar that blocks radiation) during X-rays of your upper body, especially dental X-rays.
• Stop smoking.
• Limit soy in your diet.
• Ask your healthcare provider about selenium supplements.

You may also want to get tested for celiac disease, an autoimmune disease triggered by eating gluten. People with celiac are three times more likely to develop autoimmune thyroid disease.

Summary

Despite sounding alike and dealing with glands that are close to each other, hyperparathyroidism and hyperthyroidism are very different diseases.

HPT involves high blood calcium, while HT involves high thyroid hormones that speed up the body. They coincidentally share some symptoms, such as fatigue and weakness, but each has its own set of symptoms that aren't shared by the other.

HPT can be caused by growths on the gland, enlarged glands, and radiation exposure. HT is caused by thyroid nodules, an inflamed gland, or excess iodine in the diet.

Both conditions are diagnosed using a combination of blood tests and scans.

HPT treatment depends on its severity. It may include medications, supplements, and surgery. HT treatments involve medications, radioactive iodine, and surgery.

No proven ways exist to prevent HPT or HT. By focusing on changeable risk factors, you may be able to reduce your risk.

A Word From Verywell

If you have symptoms that could point to hyperparathyroidism or hyperthyroidism, talk to your healthcare provider. Both conditions are treatable, so you don’t have to live with symptoms. Getting a proper diagnosis and treatment can make you feel better now and prevent complications down the road.