Hyperthyroidism can cause muscle weakness or myopathy. The best treatment is usually in line with your overall hyperthyroidism treatment plan.

Hyperthyroidism is an endocrine condition. It happens when your thyroid produces too much of a hormone called thyroxine. This leads to an increase in metabolism.

Common symptoms of hyperthyroidism include unintentional weight loss, sweating, irritability, and heart palpitations. However, hyperthyroidism can sometimes also lead to a loss of muscle control along with muscle pain and stiffness.

This is called hyperthyroid myopathy. Medications that manage hormone levels can often help treat hyperthyroid myopathy, and additional treatment options, such as surgery, can help when medications aren’t enough.

What does ‘myopathy’ mean?

Myopathy is a word for conditions that affect your muscle tissue.

Typically, myopathies cause muscle weakness, stiffness, and pain. In some cases, myopathy can lead to muscle breakdown, which can be fatal.

Myopathy can be inherited or acquired due to another condition, such as hyperthyroidism.

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The exact link between hyperthyroidism and myopathy is unknown. It might be that because the overproduction of thyroid hormones causes your metabolism and overall body processing to speed up, the body breaks down muscle tissue quicker than it can be replaced.

Muscle strength could also be affected by how hyperthyroidism causes the body to use more energy. Additionally, many people with hyperthyroidism have difficulty sleeping. Without adequate sleep, the muscles don’t have time to heal and recover from the stress of daily use, which could lead to weakness.

People with hyperthyroidism can develop different myopathies. For instance, it’s very common for Graves’ disease to be linked to hyperthyroidism. Graves’ disease is a condition that involves weakness and damage to the muscles that control the movement of your eyes and eyelids. This can cause vision loss.

A type of myopathy called thyrotoxic periodic paralysis is also linked to hyperthyroidism. This myopathy causes sudden, temporary, and often severe attacks of muscle weakness. The attacks occur when the affected person’s serum potassium levels drop.

In some cases, hyperthyroidism can lead to a severe type of myopathy called rhabdomyolysis. This condition causes muscle breakdown. Without treatment, this myopathy can be fatal.

The exact symptoms of hyperthyroid myopathy depend on the severity and on the affected muscles. Some people experience mild muscle weakness, while others are at risk for life threatening muscle breakdown.

Possible symptoms of hyperthyroid myopathy include:

For the majority of people with hyperthyroid myopathy, the best way to treat their myopathy is to find the right treatment for their hyperthyroidism.

Treating hyperthyroidism often resolves all symptoms, including myopathy. You might also receive treatments to help manage your symptoms. Treatment options include:

  • Antithyroid medications: These medications cause your thyroid to make less thyroxine.
  • Beta-blockers: Beta-blockers can help reduce myopathy symptoms by lessening the effect that thyroid hormone has on your body.
  • Radioiodine therapy: This treatment involves taking radioactive iodine capsules or liquid that slowly destroy thyroid hormone-producing cells.
  • Corticosteroids: If you have muscle swelling or enlargement, your doctor might prescribe corticosteroids to help manage this symptom.
  • Surgery: Sometimes, surgery to remove part or all of the thyroid is an option. People who’ve had their thyroids removed will need to take hormonal medication, which replaces the function of the thyroid for the rest of their lives.

How long does it take to recover from thyroid myopathy?

It can take 1 to 2 years for your hormonal levels to adjust when you first begin treatment for a thyroid condition.

However, that doesn’t mean it will take that long for you to recover from thyroid myopathy. Often, beta-blockers and other treatments can provide rapid symptom relief.

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The cost of hyperthyroid myopathy treatment depends on your location and insurance coverage. It also depends on the kind of treatment you receive. For instance, a treatment plan of antithyroid medications and beta-blockers will cost much less than surgery.

According to Medicare, if you don’t have insurance, surgery to remove all or part of your thyroid costs $3,304 at an ambulatory surgical center or $6,110 in a hospital. If you’re enrolled in Medicare, you’d pay $660 at the surgical center and $1,221 at a hospital.

Many insurance plans have a similar lookup tool you can use to find the estimated cost of treatments, including medications, surgeries, and appointments. You can use the ICD-10 code for hyperthyroid myopathy E05.90 to start your search.

Keep in mind that your doctor visits and testing could also add to your costs. In some cases, your primary care doctor will be able to treat hyperthyroid myopathy, but you might need to see a specialist, such as an endocrinologist. Specialist visits cost more with nearly all insurance plans.

Living with hyperthyroidism

Managing hyperthyroidism can be a challenge. The symptoms can leave you feeling tired and weak. Fortunately, there are resources you can turn to for support. If you’ve received a diagnosis of this condition, check out these organizations:

  • The Graves’ Disease and Thyroid Foundation: You’ll find resources like educational materials, support groups, and links to local medical and social services when you visit the Graves’ Disease and Thyroid Foundation.
  • The American Thyroid Association (ATA): The ATA can help connect you to clinical trials, patient resources, local endocrine specialists, and more.
  • ThyroidChange: ThyroidChange is an advocacy organization that can help you find personalized care for hyperthyroidism.
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Hyperthyroidism can lead to muscle weakness. This is called hyperthyroid myopathy.

The symptoms and severity of hyperthyroid myopathy vary depending on the muscles affected. In some cases, vision loss or muscle breakdown can occur.

Typically, the same medications that treat hyperthyroidism can also treat hyperthyroid myopathy. This often includes antithyroid medications and beta-blockers. Sometimes, surgery to remove all or part of the thyroid is required.