Hashimoto Encephalopathy : Causes, Symptoms, Diagnosis, and Treatment

Hashimoto encephalopathy is a rare condition that is known to affect the brain. The symptoms, severity, and progression may vary between people affected by it. It can affect people of any age but is seen affecting middle-aged women more.⁽⁴⁾

What really causes it is not known, but it is believed to be linked to Hashimoto’s thyroiditis.

There is no cure for Hashimoto encephalopathy but the treatment can be helpful in reducing the effects.

The exact of Hashimoto encephalopathy is not known. It is believed to occur from a typical immune system response to infection.⁽¹⁾ It occurs when the immune system attacks the healthy tissue instead of harmful bacteria and viruses.

In Hashimoto encephalopathy, neurological symptoms occur as the immune cells attack the central nervous system.

Hashimoto encephalopathy’s causes are not fully understood, but it is believed to be caused due to an autoimmune response against the brain triggered by Hashimoto’s thyroiditis or other autoimmune illnesses.

In Hashimoto’s thyroiditis, the body’s immune system mistakenly attacks the thyroid gland and causes inflammation and damage. In some cases, the autoimmune response may also target the brain leading to Hashimoto encephalopathy.

Other immune system illnesses such as systemic lupus erythematosus or Sjogren’s syndrome have also been associated with Hashimoto encephalopathy. But, most cases of Hashimoto encephalopathy are associated with Hashimoto’s thyroiditis.⁽⁵⁾

All people with Hashimoto’s thyroiditis do not develop Hashimoto encephalitis. The factors contributing to the development of Hashimoto encephalopathy are not understood. Research shows people with a high level of antibodies are at an increased risk of developing Hashimoto’s encephalopathy.⁽²⁾

The risk factors for Hashimoto encephalopathy are not well understood. It is known that Hashimoto encephalopathy was previously known as steroid-related encephalopathy associated with autoimmune thyroiditis (SREAT). There are certain factors associated with the development of SREAT in people with Hashimoto’s thyroiditis, which include:

• High thyroid antibodies level
• Females are more likely to develop Hashimoto’s encephalopathy
• Having other autoimmune conditions
• Family history of autoimmune disorders
• Middle-aged women
• People with one or more risk factors not necessarily may develop SREAT but may be more vigilant for the symptoms of SREAT.

The symptoms of Hashimoto encephalopathy may appear suddenly or over time. Neurological symptoms may be the first indication of the symptoms. There are a range of cognitive, neurological, and neuropsychiatric symptoms associated with Hashimoto encephalopathy. These include:

• A person may experience problems with memory, attention, and concentration and also be confusion and disorientation.
• The neuropsychiatric symptoms include anxiety, depression, mood swings, irritability, and personality change. There may also be psychosis and delusion.
• Neurological symptoms include seizures, headache, tremors, and ataxia. Some people may also experience weakness and paralysis on one side of the body.
• Neurological symptoms may be the first indication of the person suffering from Hashimoto’s encephalopathy.

The symptoms may vary from person to person and may fluctuate over time. This may make diagnosis and management stressful. Some may develop mild cognitive or neuropsychiatric symptoms while others may have more severe symptoms. Sometimes, the symptoms may improve and disappear completely while in sometimes they may relapse or worsen. The duration and frequency of remission may also vary in people.

There is no definitive test for Hashimoto encephalopathy. A combination of medical history, physical evaluation, and various other diagnostic tests are done by the doctor.

Before diagnosing Hashimoto encephalopathy, the doctor first rule-out stroke, dementia and Alzheimer’s disease, Creutzfeldt-Jakob disease, and other neurological illnesses.

The diagnosis of Hashimoto encephalopathy involves a combination of clinical evaluation, laboratory tests, and imaging studies. A specialist with expertise in the diagnosis of autoimmune disorders and neurological conditions diagnose any autoimmune disorder or neurological condition. A few of the diagnostic tests include:

• Test for the presence of autoimmune thyroid disease
• Presence of encephalopathy, a term used for neurological symptoms affecting cognitive function, behavior, and consciousness. It may manifest as confusion, disorientation, memory loss, or cognitive or neuropsychiatric symptoms
• The doctor may look for the presence of an inflammatory process by checking the inflammatory markers in the blood and the cerebrospinal fluid.
• A positive response to the treatment with steroids is considered a hallmark of Hashimoto’s encephalopathy. There may be an improvement in the symptoms.
• Additionally, electroencephalogram (EEG), magnetic resonance imaging (MRI) or brain biopsy may be done to rule out other neurological conditions.
• EEG measures the brain’s electrical activity and shows the changes in the brain function. It can also help detect seizures. MRI scan excludes the causes of symptoms. It creates 3D images of the brain.
• Failure in identifying the underlying cause can cause delayed or inappropriate treatment. This can lead to long-term neurological damage or specific changes to the brain.

The treatment for Hashimoto encephalopathy may vary in people. Firstly, the doctor may recommend corticosteroids such as prednisone and methyl prednisone. This suppresses the immune system and reduces inflammation in the brain.

Sometimes the doctor may also give a high dose of intravenous corticosteroids followed by a gradual tapering down of the dose over several weeks or months depending on the response of the person to the treatment and the severity of the symptoms.

Additionally, with corticosteroids, immunosuppressive agents such as azathioprine or mycophenolate mofetil may be given in combination.

Other treatments to manage Hashimoto’s encephalopathy include:

• Antiepileptic drugs to control seizures
• Antidepressants or antipsychotics to manage neuropsychiatric symptoms
• Intravenous immunoglobin to modulate the immune system

The treatment of Hashimoto encephalopathy can be challenging and require a trial and error approach to determine the most effective treatment for each patient. The symptoms should be closely monitored and the neurologist or rheumatologist should be followed up with.

In addition to the medical treatment, it is important to bring in lifestyle modifications such as reducing stress, getting regular exercise, and adequate sleep. All this helps in managing the symptoms and improving the overall health and wellbeing.

The above-mentioned treatments may help with symptoms of Hashimoto encephalopathy, but may also be the cause of a few side effects including:

• Some people may not be able to tolerate corticosteroids and may experience side effects.
• Other immunosuppressants such as azathioprine, mycophenolate mofetil, or rituximab may lead to an increased risk of infection, liver damage, and decreased blood cell count.
• Antiepileptic drugs such as levetiracetam or valproic acid may cause drowsiness, dizziness, and mood changes.
• Intravenous immunoglobins may lead to headache, nausea, and allergic reactions.

The prognosis may vary depending on the symptom. Some patients may experience rapid recovery while others may have more persistent ad chronic symptoms despite treatment. A study done in 2016 found that more than 9 in 10 people responded completely or at least 50% to steroid treatment.⁽³⁾

Predicting long-term outcomes for patients with Hashimoto encephalopathy is difficult to predict as the disease can be highly variable in terms of symptoms presentation, response to treatment, and risk of relapse.

Sometimes patients experience only one episode of Hashimoto encephalopathy and remain symptom-free with ongoing treatment.

There are several factors that may worsen prognosis including age, gender, and severe neurological symptoms. Receiving regular follow-ups is important for the patients.

Overall, the prognosis of Hashimoto encephalopathy is good with prompt diagnosis and appropriate treatment.

Hashimoto encephalitis is a rare autoimmune disorder affecting the brain and leading to a range of neurological, neuropsychiatric, and cognitive symptoms. It is caused due to the autoimmune response of the thyroid gland.

The diagnosis can be challenging as the symptoms are highly variable and may mimic other neurological and psychiatric disorders.

Treatment involves corticosteroids and other immunosuppressive agents and epileptic drugs.

Early recognition and prompt treatment of Hashimoto encephalopathy can help in improving the outcome and can minimize the impact of this rare and complex condition on the quality of life of the patient.