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“Hashimoto’s Encephalitis”?

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Question

Dear Thyroid experts:

I had a patient who was admitted to hospital with confusion. she is 39 yo with known Hashimotos found last month to present with tonic-clonic seizure. Not doing well for one month and problems with word finding. ct at outlying hospital reported as cerebral edema. EEG revealed bifrontal rhythms and polymorphic slowing. Had a ventriculostomy placed due to CSF pressure of 20. Pt discharged and then represented with confusion …Further investigations showed questionable cerebritis around ventriculostomy site on MRI . Other w/u at outside hospital neg HSV/PCR, transthoracic echo neg, CT angiogram positive for PE with positive anticardiolipin antibody. Pt then anticoagulated prior to transfer to our institution— Found to have elevated microsomal ab 1:6400, and anti TPO 2517. Patient was seen by rheumatologist with negative workup at our institution (neg for ANA, anti DNA , anti RNA, SSA, SSB, SCL70 and chromatin antibodies negative, c3 208 ). Underwent plasmapheresis and steroids. She was then place on prednisone 100mg /d. No other residual neurological problems. No other explanation by rheum who felt the original antibodies for anticardiolipn was negligible (am trying to get records). I had seen her one year ago with a goiter about 120g and placed her on thyroid hormone for biopsy positive autoimmune thyroid Hashimotos. Other complicating history–with PE dx on coumadin, not optimal surgical candidate at this time. Is there some information /references on Hashimoto’s encephalopathy/cerebritis as that is the suspected diagnosis by the rheumatologist. . If this is true -optimal treatment? Ablation with I-131 vs surgical resection of goiter?….Should I be worried about thyroid lymphoma ? Re bx ? Re-ultrasound thyroid for size pending.

Appreciate any input or recommendations for further history or investigations.

Anne Marie Lee

Response 1

Surely your case fits into the category of “Hashimoto’s encephalitis”. By now there have been more than 50 similar patients reported.-(Neurology 1991:41:223-233, Neurol 1996;243:585-593, Neurology 1997;49:623-626, Euro Neurol 1999;41:79-84, and many others on Medline). The manifestations are typically confusion, obtundation, dementia, seizures, sometimes psychosis, movement disorders, stroke-like episodes with abnormal EEG, variable minor abnormalities on CAT or MRI, sometimes elevated CSF protein, and typical findings of Hashimoto’s with high antibodies. Usually the patients respond to prednisone, and some have been given other therapies including IV IgG and cyclophosphamide. Some do not respond totally. I am not aware that removal of the thyroid by surgery and 131-I has been reported or attempted, although it obviously is an interesting idea. If the patient fails to respond to immuno-suppressive therapy , one could make a case for total removal of thyroid antigens. However I must immediately point out that there is absolutely no published support or experience with this approach, so far as I know. . Some observers believe this is the case, and others contend that it is simply the combination of some yet undiagnosed unusual encephalitis, and a fairly common thyroid disease. My bias is that it will be found to be tied in some way to autoimmunity to CNS antigens that somehow overlap with antigens in the thyroid.

Leslie J De Groot, MD
Univ of Chicago/Endocrinology

Response 2

Your case is compatible with so called Hashimoto’s encephalopathy or encephalitis, although the existence of such a specific disease is not completely established. As you know Hashimoto’s thyroiditis is very common. Around 10 % of adult women in the general population have positive anti-thyroid microsomal antibodies. Thus I speculate that an autoimmune encephalitis is coincidentally associated with Hashimoto’s thyroiditis. It is well known that Hashimoto’s thyroiditis frequently aggravates during the postpartum period, but development of associated encephalopathy has not been reported. Therefore I believe that encephalopathy in your patient might occurred independently from Hashimoto’s thyroiditis. Therefore total thyroidectomy may not release the patient’s symptoms. We need more definitive evidence that encephalopathy is really causatively associated with autoimmune thyroid disease. In your case, the patient is suffered from PE, and has positive anticardiolipin antibodies. It is strongly suggested that encephalopathy might be related to a vascular problem induced by an autoimmune mechanism, such as lupus anticoagulant and/or other antibodies to various coagulation factors. As reported in other patients, steroid therapy would be preferable, if patient relapses.

Dr. Nobuyuki Amino