National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Hashimoto encephalopathy


Other Names:
Hashimoto's encephalopathy; Steroid-responsive encephalopathy associated with autoimmune thyroiditis
Categories:
Hashimoto encephalopathy (HE) is a condition characterized by onset of confusion with altered level of consciousness; seizures; and jerking of muscles (myoclonus). Psychosis, including visual hallucinations and paranoid delusions, has also been reported. The exact cause of HE is not known, but may involve an autoimmune or inflammatory abnormality. It is associated with Hashimoto's thyroiditis, but the nature of the relationship between the two conditions is unclear. Most people with HE respond well to corticosteroid therapy or other immunosuppressive therapies, and symptoms typically improve or resolve over a few months.[1]
Last updated: 9/18/2014
The symptoms of Hashimoto encephalopathy can vary from person to person. They most often include sudden or subacute onset of confusion with alteration of consciousness. Some people have multiple, recurrent episodes of neurological deficits with cognitive dysfunction. Others experience a more progressive course characterized by slowly progressive cognitive impairment with dementia, confusion, hallucinations, or sleepiness. In some cases, rapid deterioration to coma can occur.[1]

In addition to confusion and mental status changes, symptoms may include seizures and myoclonus (muscle jerking) or tremor. Psychosis, including visual hallucinations and paranoid delusions, has also been reported.[1]
Last updated: 9/18/2014

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 24 |
Medical Terms Other Names
Learn More:
HPO ID
100% of people have these symptoms
Acute encephalopathy 0006846
80%-99% of people have these symptoms
Cerebral vasculitis 0005318
Hashimoto thyroiditis 0000872
30%-79% of people have these symptoms
Abnormality of the cerebral white matter 0002500
Confusion
Disorientation
Easily confused
Mental disorientation
[ more ] 		0001289
Goiter
Enlarged thyroid gland in neck
0000853
Hyponatremia
Low blood sodium levels
0002902
Hypothyroidism
Underactive thyroid
0000821
Paralysis
Inability to move
0003470
5%-29% of people have these symptoms
Abnormal autonomic nervous system physiology 0012332
Anxiety
Excessive, persistent worry and fear
0000739
Depressivity
Depression
0000716
Fever 0001945
Focal-onset seizure
Seizure affecting one half of brain
0007359
Generalized-onset seizure 0002197
Headache
Headaches
0002315
Immunodeficiency
Decreased immune function
0002721
Leukocytosis
Elevated white blood count
High white blood count
Increased blood leukocyte number
[ more ] 		0001974
Myoclonus 0001336
Nausea and vomiting 0002017
Psychosis 0000709
Status epilepticus
Repeated seizures without recovery between them
0002133
Thrombocytopenia
Low platelet count
0001873
1%-4% of people have these symptoms
Limited neck flexion
Limited neck flexibility
0005991
Showing of 24 |
Last updated: 7/1/2020
The exact cause of Hashimoto encephalopathy (HE) is unknown, but is thought to relate to autoimmune or other autoinflammatory processes. While it is associated with Hashimoto's thyroiditis, the exact nature of the relationship between the two conditions is unclear. It does not appear to be directly related to hypothyroidism or hyperthyroidism.[1]
Last updated: 9/18/2014
Hashimoto encephalopathy (HE) typically is not inherited, occurring sporadically in people with no family history HE. It can occur in association with other autoimmune disorders however, so in some cases it may develop due to an interaction between genetic susceptibility and environmental triggers.[2]
Last updated: 9/18/2014
Diagnosis of Hashimoto encephalopathy can be made when all six of the following criteria have been met:[3]

1. Encephalopathy with seizures, myoclonus, hallucinations, or stroke-like episodes
2. Subclinical or mild overt thyroid disease (usually hypothyroidism)
3. Normal brain MRI or with non-specific abnormalities
4. Presence of serum thyroid (thyroid peroxidase, thyroglobulin) antibodies
5. Absence of well-characterized neuronal antibodies in serum and CSF
6. Reasonable exclusion of alternative causes

A team of leading autoimmune encephalitis researchers have proposed that the term Hashimoto’s encephalopathy only be used when rigorous clinical assessment and comprehensive testing for well characterized neuronal antibodies exclude other potential causes of encephalopathy. The underlying cause of Hashimoto’s encephalopathy is unclear. Experts in the field recommend that cases of Hashimoto’s encephalopathy be classified as probable autoimmune encephalitis.

View the full position paper, entitled A Clinical Approach to Diagnosis of Autoimmune Encephalitis.

For more on diagnosis, visit the following link to the International Autoimmune Encephalitis Society Web site:
https://autoimmune-encephalitis.org/diagnosis
Last updated: 8/5/2019
Medical management of Hashimoto encephalopathy (HE) usually involves corticosteroids and treatment of thyroid abnormalities (if present). The optimal dose of oral steroids is not known. Most patients with HE respond to steroid therapy. Symptoms typically improve or resolve over a few months. Decisions regarding the length of steroid treatment and the rate of tapering off steroids are based on the individual's response to treatment. Treatment may last as long as two years in some patients.[4]

People with HE who experience repeated HE relapses, do not respond to steroids, and/or cannot tolerate steroid treatment have been treated with other immunosuppressive medications such as azathioprine and cyclophosphamide. Intravenous immunoglobulin, and plasmapheresis have also been used.[4]
Last updated: 1/19/2016

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • The Autoimmune Registry supports research for Hashimoto encephalopathy by collecting information about patients with this and other autoimmune diseases. You can join the registry to share your information with researchers and receive updates about participating in new research studies. Learn more about registries.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Hashimoto encephalopathy. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Devon I Rubin. Hashimoto's encephalopathy. UpToDate. Waltham, MA: UpToDate; September, 2014; Accessed 9/18/2014.
  2. Yuceyar N. Thyrotoxic autoimmune encephalopathy in a female patient: only partial response to typical immunosuppressant treatment and remission after thyroidectomy. Clin Neurol Neurosurg. June, 2007; 109(5):458-462. Accessed 9/18/2014.
  3. Graus F, Titulaer MJ, Balu R, et al. A clinical approach to diagnosis of autoimmune encephalitis. Lancet Neurol. April, 2016; 15(4):391-404. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5066574/.
  4. Devon, Rubin. Hashimoto encephalopathy. UpToDate. June 17, 2015; http://www.uptodate.com/contents/hashimoto-encephalopathy. Accessed 1/19/2016.