Are Seizures, Tremors, and Ataxia Common in SREAT?

Yes, seizures, uncontrollable shaking, and clumsiness can occur if you have Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT, also known as Hashimoto’s encephalopathy) ^[1][2]. While these physical neurological symptoms can be terrifying to experience or witness, they are recognized manifestations of the condition. However, these symptoms are not present in everyone, and their presence alone does not confirm a SREAT diagnosis ^[1][3]. A first-ever seizure, a sudden worsening of shaking, or a new inability to walk always requires urgent medical evaluation to rule out other emergencies.

How Common Are These Symptoms?

SREAT is a rare condition. The rates of physical symptoms reported in medical literature come from small case series and retrospective reviews, meaning they reflect highly varied groups of patients and do not predict your individual risk ^[1][4].

• Seizures: Reported in roughly 45% to 47% of patients in clinical reviews ^[1][5]. Seizures can be obvious physical convulsions or more subtle episodes like staring or confusion. However, staring and confusion can also result from medication side effects or metabolic issues, so a neurologist’s evaluation is necessary ^[5].
• Tremors (Rhythmic Shaking): Reported in 28% to 80% of reviewed cases ^[2].
• Myoclonus (Sudden Muscle Jerks): Reported in 42% to 65% of cases ^[2][4].
• Ataxia (Clumsiness/Loss of Coordination): Reported in 33% to 65% of cases ^[2][6]. Isolated ataxia is uncommon in SREAT; it is usually accompanied by other symptoms like confusion, behavioral changes, or memory issues ^[2][1].

What Causes These Symptoms?

The exact cause of SREAT remains uncertain, but it is considered an encephalopathy—a disease affecting the structure or overall function of the brain ^[3]. Researchers propose that SREAT is driven by an immune system response that leads to brain inflammation or disruption of the blood-brain barrier (the protective biological shield that keeps toxins out of the brain) ^[7][8].

While people with SREAT have high levels of antithyroid antibodies, these antibodies are considered “markers” rather than the proven, direct cause of the brain damage ^[7][9]. When the networks in the central nervous system (the brain and spinal cord) are inflamed or irritated, it can cause poor coordination or involuntary movements. If the brain’s overall electrical activity is disrupted, it can trigger abnormal bursts of electricity, resulting in seizures ^[1].

Diagnosis and Management

SREAT is a “diagnosis of exclusion.” This means doctors must systematically rule out other causes—such as infections, strokes, metabolic imbalances, medication toxicity, or other forms of autoimmune encephalitis—before confirming SREAT ^[10][3]. Having antithyroid antibodies in your blood is not enough to prove the diagnosis, as these antibodies are common in the general population ^[10].

To investigate, doctors use tests that can support the evaluation, though no single test proves SREAT ^[3]:

• MRI (Magnetic Resonance Imaging): Takes detailed pictures of the brain to check for structural issues, tumors, or strokes.
• Lumbar Puncture (Spinal Tap) / CSF Analysis: Tests the cerebrospinal fluid surrounding the brain for signs of infection or severe inflammation.
• EEG (Electroencephalogram): Measures brain waves to check for slow activity or hidden seizures.

Medical care for SREAT typically focuses on calming the immune system, often with steroids or other immune-suppressing therapies ^[1]. Because the response to these treatments can vary significantly from person to person, your doctor might also prescribe anti-seizure medications if you are having active seizures ^[11]. Do not wait for steroid treatment to take effect before seeking treatment for a seizure.

Emergency Care and Seizure First Aid

If you or a loved one experience a new or suspected first seizure, or a sudden inability to walk, seek emergency medical care immediately.

Call emergency services if a seizure:

• Lasts for 5 minutes or longer.
• Repeats without the person regaining usual awareness in between.
• Causes breathing difficulty or serious physical injury.

Basic Seizure First Aid:

• Time the event: Note exactly when the seizure starts and stops.
• Protect from injury: Clear the immediate area of hard or sharp objects.
• Position safely: Once convulsions stop, roll the person onto their side to keep their airway clear.
• Do not restrain them and never put anything in their mouth.