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Disease Profile

Hashimoto encephalopathy

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset

All ages





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Hashimoto's encephalopathy; Steroid-responsive encephalopathy associated with autoimmune thyroiditis


Immune System Diseases; Nervous System Diseases


Hashimoto encephalopathy (HE) affects the brain and how the brain works. Symptoms of HE may include behavior changes, confusion, cognitive difficulty, and seizures. Psychosis, including visual hallucinations and paranoid delusions, has also been reported. HE occurs mainly in adults and affects females more than males. The exact cause of HE is not known but may involve an abnormal immune or inflammatory response. HE is associated with Hashimoto's thyroiditis, but the nature of the relationship between the two conditions is unclear. Diagnosis of HE is based on the symptoms, clinical exam, and laboratory testing. More common conditions may need to be excluded first. Treatment is focused on managing the symptoms. Most people with HE respond well to corticosteroid therapy or other immunosuppressive therapies. With treatment, symptoms typically improve or resolve over a few months.[1][2][3][4]


The following list includes the most common signs and symptoms in people with Hashimoto encephalopathy (HE). These features may be different from person to person. Some people may have more symptoms than others, and they can range from mild to severe. This list does not include every symptom that has been described in the condition.

Symptoms may include:[1][2][3]

  • Confusion
  • Memory loss
  • Behavior changes
  • Hallucinations or delusions
  • Muscle weakness
  • Seizures

HE usually occurs in adults from 40-50 years of age but it can also occur in children. Some people have episodes of symptoms that come and go over time. Other people may have symptoms that slowly get worse. In some cases, without treatment, coma can occur. Most people with HE will respond to treatment and get better.

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.

Medical Terms Other Names
Learn More:
100% of people have these symptoms
Acute encephalopathy
80%-99% of people have these symptoms
Cerebral vasculitis
Hashimoto thyroiditis
30%-79% of people have these symptoms
Abnormality of the cerebral white matter
Easily confused
Mental disorientation

[ more ]

Enlarged thyroid gland in neck
Low blood sodium levels
Underactive thyroid
Inability to move
5%-29% of people have these symptoms
Abnormal autonomic nervous system physiology
Excessive, persistent worry and fear
Focal-onset seizure
Seizure affecting one half of brain
Generalized-onset seizure
Decreased immune function
Elevated white blood count
High white blood count
Increased blood leukocyte number

[ more ]

Nausea and vomiting
Status epilepticus
Repeated seizures without recovery between them
Low platelet count
1%-4% of people have these symptoms
Limited neck flexion
Limited neck flexibility


The exact cause of Hashimoto encephalopathy is unknown. It is thought to be due to an abnormal immune or inflammatory response.[1][2]


Diagnosis of Hashimoto encephalopathy (HE) is based on the symptoms, clinical exam, and specific laboratory testing. Imaging tests such as an MRI or a CT scan may be helpful. Other more common conditions may need to be excluded before a diagnosis of HE can be made. Several medical groups have proposed a list of conditions that must be met before a diagnosis of HE can be made.[1][4]


Treatment of Hashimoto encephalopathy (HE) is focused on managing the symptoms. Treatment usually involves medications such as corticosteroids and treatment of thyroid abnormalities (if present). Most people with HE respond to steroid therapy. People who do not respond to steroids and/or cannot tolerate steroid treatment have been treated with other immunosuppressive medications or intravenous immunoglobulin therapy.[1][4]

Specialists involved in the care of someone with HE may include:

  • Neurologist
  • Endocrinologist
  • Psychiatrist/Psychologist


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

        Learn more

        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.


            1. Rubin DI. Hashimoto encephalopathy. UpToDate. Waltham, MA: UpToDate; Updated Mar 11, 2019; https://www.uptodate.com/contents/hashimoto-encephalopathy.
            2. Mattozzi S, Sabater L, Escudero D, Ariño H, Armangue T, Simabukuro M, Iizuka T, Hara M, Saiz A, Sotgiu S, Dalmau J, Graus F. Hashimoto encephalopathy in the 21st century. Neurology. Jan 14, 2020; 94(2):e217-e224. https://pubmed.ncbi.nlm.nih.gov/31882532/.
            3. DeBiase JM, Avasthi D. Hashimoto's Encephalopathy: A Case Report and Literature Review of an Encephalopathy With Many Names. Cureus. Aug 7, 2020; 12(8):e9601. https://pubmed.ncbi.nlm.nih.gov/32923205/.
            4. Zhou JY, Xu B, Lopes J, Blamoun J, Li L. Hashimoto encephalopathy: literature review. Acta Neurol Scand. Mar 2017; 135(3):285-290. https://pubmed.ncbi.nlm.nih.gov/27324276/.
            5. Laycock K, Chaudhuri A, Fuller C, Khatami Z, Nkonge F, Stojanovic N. A novel assessment and treatment approach to patients with Hashimoto's encephalopathy. Endocrinol Diabetes Metab Case Rep. Apr 27, 2018; 2018:17-0117. https://pubmed.ncbi.nlm.nih.gov/29732162/.

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