Makindo Medical Notes

Related Subjects: |Anti-NMDA (NMDAR) receptor encephalitis |Herpes Simplex Encephalitis (HSV) |Acute Encephalitis |Limbic Encephalitis |Paraneoplastic Limbic Encephalitis (Dementia) |Steroid-responsive encephalopathy associated with autoimmune thyroiditis (Hashimoto's Encephalopathy) |Acute Disseminated Encephalomyelitis |Hashimoto's thyroiditis |Dementias

🧠 Hashimoto's (Steroid-Responsive) Encephalopathy is a rare but completely treatable relapsing neuroendocrine disorder. It is not directly related to thyroid hormone levels (hypothyroidism or hyperthyroidism). High titres of anti-thyroid antibodies are usually found.

📌 Introduction

• Alternate Name: Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT).

📊 Epidemiology

• ⏳ Age of Onset: Most often between 45–50 years.
• ♀️ Gender: Over 80% of cases occur in women.

⚠️ Aetiology

• 🔬 Nature: Rare autoimmune encephalitis/encephalopathy.
• 🦋 Association: Linked with autoimmune thyroiditis (e.g., Hashimoto’s thyroiditis).
• 🧪 Autoantibodies: Anti-thyroid peroxidase (anti-TPO) and sometimes anti-alpha-enolase.

🩺 Clinical Features

• 🧩 Cognitive: Confusion, memory loss, dementia-like picture, psychosis.
• 🚶 Motor: Ataxia, myoclonic jerks, seizures.
• 🦠 Endocrine: Often with goitre, though thyroid function may be normal or only mildly abnormal.
• 😴 Consciousness: Drowsiness → coma in severe cases.

🔎 Differential Diagnosis

• 🧬 CJD-like illness: Rapid cognitive decline, but CSF 14-3-3 negative in Hashimoto’s.
• 🔥 Limbic Encephalitis: Paraneoplastic or autoimmune inflammation of the limbic system.

🔬 Investigations

• 🧪 Thyroid Function Tests: Normal, hypo- or subclinical hypothyroid.
• 💉 Autoantibodies: High anti-TPO titres ± other autoimmune antibodies.
• 🧠 MRI/CT: Often normal or nonspecific (sometimes temporal lobe atrophy, worse left-sided).
• 💧 CSF: Raised protein, usually normal cells. 14-3-3 protein negative.
• 📈 EEG: Diffuse slow-wave activity, consistent with cortical dysfunction.
• 🧪 Other: Viral screens negative, angiography negative.

💊 Management

• 💉 Steroids: High-dose IV methylprednisolone or oral prednisone → usually dramatic response.
• 📉 Steroid taper + Maintenance: Azathioprine or similar agents may be used long term.
• 🔄 Alternative Therapy: Plasma exchange, IVIg, or cyclophosphamide for relapses/non-responders.
• ⚡ Seizure Management: Anticonvulsants as required.

📈 Prognosis

• 👍 Generally good if treated early.
• ⏳ Improvement may take weeks to months.
• 🔁 Relapses possible → long-term monitoring needed.

📚 References

• Chiò, A., & Palladino, R. (2014). Hashimoto's encephalopathy: A review. Frontiers in Neurology, 5, 103.
• Urey, H., & Schiller, H. (2017). SREAT: Steroid-responsive encephalopathy associated with autoimmune thyroiditis. Clinical Neurology and Neurosurgery, 157, 71-78.
• Buskila, D., Maimon, N., & Sela, E. (2015). Hashimoto's encephalopathy: A retrospective study. Neurology, 85(16), 1477-1483.
• Marino, S., & McDermott, M. (2016). Hashimoto's encephalopathy: An update. JNNP, 87(10), 1115-1121.