Hashimoto encephalopathy is a rare autoimmune condition that causes brain inflammation. It’s linked to thyroid disease and can lead to severe neurological symptoms, but it’s treatable with the proper care.

Hashimoto encephalopathy is a rare and often misunderstood condition. People sometimes confuse it with Hashimoto thyroiditis because both concern the thyroid. But, they have very different symptoms.

Affecting around 2 out of 100,000 people, Hashimoto encephalopathy is an autoimmune disorder that causes inflammation in your brain and can lead to a wide range of neurological symptoms.

In this article, we’ll explore Hashimoto encephalopathy, its differences from Hashimoto thyroiditis, causes, symptoms, treatment, and other important topics.

Hashimoto encephalopathy and Hashimoto thyroiditis share a common link: they’re both thyroid-related autoimmune diseases. This means that they make your immune system produce antithyroid antibodies. But, they affect your body in different ways.

Hashimoto thyroiditis is the more common of the two conditions. In this condition, antithyroid antibodies directly attack your thyroid. It leads to hypothyroidism, where your thyroid doesn’t produce enough hormones. This can cause fatigue, constipation, and other symptoms.

Hashimoto encephalopathy targets your brain through a not-yet-known mechanism. This leads to inflammation and cognitive (related to thinking) symptoms.

Both conditions sometimes appear in the same person, but Hashimoto encephalopathy can happen even if your thyroid function is regular. To avoid confusion between the two conditions, some researchers have proposed renaming Hashimoto encephalopathy as “steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT).”

People with Hashimoto encephalopathy can have a wide range of symptoms, which makes it easy to mistake for other neurological conditions. Symptoms can develop slowly over time or come on suddenly. Common symptoms include:

The exact cause of Hashimoto encephalopathy is still unclear. Many researchers believe it’s caused by your immune system mistakenly attacking healthy brain tissue as if it were a virus or bacteria. The molecules that attack your own tissues are called autoantibodies.

It’s not known whether antithyroid antibodies found in people with Hashimoto encephalopathy directly cause brain inflammation. Researchers have recently discovered other autoantibodies — called anti-enolase antibodies — in people with this condition that may have a more direct role.

When to contact a doctor

If you or a loved one starts experiencing sudden or unexplained neurological symptoms like confusion, memory loss, seizures, or personality changes, it’s important to seek medical help.

Although it’s not likely to be Hashimoto encephalopathy, these symptoms could indicate a serious brain-related condition.

Diagnosing Hashimoto encephalopathy can be challenging because its symptoms are similar to other neurological conditions. Your doctor will likely start with a detailed medical history and a physical exam.

There’s no definitive way to diagnose this condition. Tests that may be helpful in diagnosis include:

  • Blood tests: These can check for antithyroid antibodies and thyroid hormone levels to see if there’s a connection with thyroid disease.
  • Electroencephalogram (EEG): This test measures electrical activity in your brain and can help detect abnormal brain waves common in people with Hashimoto encephalopathy. The EEG can also help detect seizures.
  • Magnetic resonance imaging (MRI): An MRI can help rule out other causes of your symptoms, such as a brain tumor or stroke.
  • Cerebrospinal fluid (CSF) analysis: This series of tests checks the CSF for various substances that might indicate a problem with your central nervous system. It requires a lumbar puncture, aka spinal tap.

Doctors usually diagnose Hashimoto encephalopathy after excluding other potential causes of your symptoms and confirming the increased presence of antithyroid peroxidase antibodies (TPOAb) or antithyroglobulin antibodies (TgAb).

Hashimoto encephalopathy is treatable. The primary treatment involves high dose intravenous (IV) corticosteroids, which reduce inflammation in your brain. Most people respond well to corticosteroid therapy, and symptoms may improve within weeks of starting treatment.

Occasionally, your condition may persist even with corticosteroid treatment. In cases where corticosteroids don’t work, or if you can’t take corticosteroids, a doctor may prescribe IV immunosuppressants, like azathioprine and cyclophosphamide, or IV immunoglobulin (IVIG).

With the proper treatment, many people with Hashimoto encephalopathy experience significant improvement in their symptoms. Some may even see complete remission, though relapses are possible.

Still, about one-quarter of people with Hashimoto encephalopathy continue to experience some degree of cognitive impairment.

Treatment should continue even during remission to prevent future relapses.

Hashimoto encephalopathy is more common in women, particularly those over age 40. But, it can affect people of all ages, including children and teenagers.

There’s no known way to prevent Hashimoto encephalopathy. But, managing your thyroid health may help lower your risk of complications.

To prevent future flare-ups, it’s recommended to:

  • take medications as prescribed
  • monitor your symptoms
  • schedule regular checkups with a healthcare professional

Is Hashimoto encephalopathy fatal?

Hashimoto encephalopathy usually isn’t fatal, especially with early diagnosis and treatment. But, severe cases without treatment could lead to life threatening complications.

Is Hashimoto encephalopathy curable?

There’s no cure for Hashimoto encephalopathy, but it is treatable. Many people go into remission with appropriate treatment. But, you may need lifelong treatment to control inflammation.

What is the life expectancy of someone with Hashimoto encephalopathy?

There’s not much data regarding life expectancy with Hashimoto encephalopathy. But, most people who receive treatment are able to avoid serious complications. Some even achieve complete remission.

Regular follow-ups and managing flare-ups are essential for maintaining quality of life.

Hashimoto encephalopathy is a rare, poorly understood autoimmune condition that causes brain inflammation, leading to neurological symptoms. While it may be connected to thyroid disease, Hashimoto encephalopathy directly affects your brain.

Early diagnosis and treatment are crucial for managing the condition, and most people respond well to corticosteroids and other therapies. If you or a loved one develops neurological symptoms, contact a doctor as soon as possible.