Elevated thyroid hormone levels can lead to neuropathy and other neurological problems. Neuropathy may be a more common complication of hypothyroidism than hyperthyroidism.

Hyperthyroidism is the medical term for thyroid hormone levels that are higher than normal. The most common cause is the autoimmune condition Graves’ disease.

Neuropathy, also called peripheral neuropathy, is damage to nerves outside your brain and spinal cord. People with neuropathy can develop symptoms like:

  • pain
  • tingling
  • numbness
  • weakness
  • vision problem
  • hearing problems

Read on to learn more about the connection between hyperthyroidism and neuropathy, and other potential neurological complications of hyperthyroidism.

People with hyperthyroidism have too much thyroid hormone in their blood. Common causes include:

  • the autoimmune condition Graves’ disease
  • thyroid nodules, lumps on your thyroid gland that usually aren’t cancerous
  • thyroiditis, inflammation of the thyroid gland

Thyroid hormone acts on almost every cell in your body, and changes to thyroid hormone levels can affect many tissues in your body.

Neuromuscular disorders — conditions affecting nerves or muscles — may occur in as many as 20% to 60% of people with thyroid disorders. They appear to be more common in people with hypothyroidism (lower levels of thyroid hormone than typical) rather than hyperthyroidism.

Neuropathy is a general term that refers to damage to the nerves outside your brain and spinal cord. It’s an uncommon complication of hyperthyroidism.

It’s thought that hyperthyroidism may cause your body to go into a hypermetabolic state where it consumes energy too quickly. This hypermetabolic state may deplete your nerves of essential nutrients and may contribute to the development of neuropathy.

Hyperthyroidism can also lead to fluid retention, which might put pressure on your nerves. Over time, this pressure may impair the ability of your nerves to receive adequate oxygen and may lead to nerve damage.

Graves’ ophthalmopathy (thyroid eye disease)

Some people with Graves’ disease develop a complication called Graves’ ophthalmopathy, characterized by swelling and inflammation around the eyes. About 1% to 2% of Graves’ ophthalmopathy cases are sight-threatening.

People with Graves’ ophthalmopathy may develop vision loss due to a complication called dysthyroid optic neuropathy. It’s thought that this condition can develop when the optic nerve is compressed by the surrounding muscle and fat, which may decrease its blood supply and lead to nerve damage.

Symptoms of neuropathy can include:

  • numbness
  • tingling
  • sharp pains or cramps
  • muscle weakness
  • extreme sensitivity to touch
  • serious foot problems, such as ulcers or infections due to loss of sensation

Thyroid eye disease may cause signs and symptoms like:

Hyperthyroidism has been linked to some other neurological problems, such as:

Tremors

Tremors are a common symptom of hyperthyroidism and are seen in roughly 75% of people with abnormally high thyroid levels. They usually improve with treatment to lower thyroid levels.

Mood and cognitive disorders

Cognitive impairment and reduced well-being are common in people with Graves’ disease. They may occur even after thyroid levels are corrected. Hyperthyroidism in childhood may lead to irreversible cognitive impairment.

Adults may experience psychiatric symptoms, such as:

Encephalopathy

Encephalopathy refers to severe neurological changes in your brain. It’s often associated with Hashimoto’s thyroiditis and occasionally with Graves’ disease.

Encephalopathy can cause symptoms like:

  • confusion
  • disorientation
  • poor attention span
  • memory loss
  • sleepiness

Insomnia

Hyperthyroidism is a well-known cause of sleep dysfunction. Often, sleep disturbance is characterized by:

  • increased time to fall asleep
  • difficulty staying asleep
  • excessive daytime sleepiness

It’s important to seek medical attention if you suspect you may have hyperthyroidism. Many of the complications of hyperthyroidism can be controlled with proper treatment.

Some of the warning signs of hyperthyroidism include:

  • increased heart rate
  • increased sweating
  • unexplained weight loss
  • trouble sleeping
  • increased irritability, nervousness, or mood changes

The most common treatments for hyperthyroidism include:

Can thyroid problems cause numbness or tingling in hands and feet?

Both hyperthyroidism and hypothyroidism have been linked to neuropathy and associated symptoms like tingling in your hands and feet. Neuropathy seems to be common in people with low thyroid hormones.

How does hyperthyroidism affect the nerves?

Thyroid hormone acts on almost every cell in your body. High levels of thyroid hormone can potentially damage your nerves and can cause symptoms like problems with movement, loss of sensation, or vision changes.

What are the peripheral symptoms of hyperthyroidism?

Peripheral neuropathy may cause symptoms like tingling in your limbs or muscle weakness.

Neuropathy may be an uncommon complication of hyperthyroidism. Neuropathy may cause vision changes or other symptoms like numbness and tingling in your limbs.

It’s important to see a doctor if you suspect you may have hyperthyroidism. Receiving proper treatment can help you minimize your chances of developing complications.