Steroid-responsive encephalopathy associated with autoimmune thyroiditis.
BACKGROUND
Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), often termed Hashimoto encephalopathy, is a poorly understood and often misdiagnosed entity.


OBJECTIVE
To characterize the clinical, laboratory, and radiologic findings in patients with SREAT to potentially improve recognition of this treatable entity.


METHODS
Retrospective analysis of clinical features and diagnostic test data.


METHODS
Two affiliated tertiary care referral institutions.


METHODS
Twenty consecutive (6 male) patients diagnosed as having SREAT from 1995 to 2003.


METHODS
Clinical features and ancillary test findings associated with SREAT.


RESULTS
The median age at disease onset was 56 years (range, 27-84 years). The most frequent clinical features were tremor in 16 (80%), transient aphasia in 16 (80%), myoclonus in 13 (65%), gait ataxia in 13 (65%), seizures in 12 (60%), and sleep abnormalities in 11 (55%). All patients were assigned an alternative misdiagnosis at presentation, most commonly viral encephalitis (n = 5), Creutzfeldt-Jakob disease (n = 3), or a degenerative dementia (n = 4). The most frequent laboratory abnormalities were increased liver enzyme levels in 11, increased serum sensitive thyroid-stimulating hormone levels in 11, and increased erythrocyte sedimentation rate in 5. In only 5 patients (25%) did cerebrospinal fluid abnormalities suggest an inflammatory process. Magnetic resonance imaging abnormalities believed to be related to the encephalopathy were present in 5 patients (26%).


CONCLUSIONS
The clinical, laboratory, and radiologic findings associated with SREAT are more varied than previously reported. Misdiagnosis at presentation is common. This treatable syndrome should be considered even if the serum sensitive thyroid-stimulating hormone level and erythrocyte sedimentation rate are normal, the cerebrospinal fluid profile does not suggest an inflammatory process, and neuroimaging results are normal. Until the pathophysiologic mechanism of this and other autoimmune encephalopathies is better characterized, we believe that descriptive terms that reflect an association rather than causation are most appropriate for this syndrome.
Department of Neurology, Mayo Clinic College of Medicine, Rochester, Minn 55905, USA.
Pablo
P
Castillo
Bryan
B
Woodruff
Richard
R
Caselli
Steven
S
Vernino
Claudia
C
Lucchinetti
Jerry
J
Swanson
John
J
Noseworthy
Allen
A
Aksamit
Jonathan
J
Carter
Joseph
J
Sirven
Gene
G
Hunder
Vahab
V
Fatourechi
Bahram
B
Mokri
Daniel
D
Drubach
Sean
S
Pittock
Vanda
V
Lennon
Brad
B
Boeve
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000188:drug therapy* / Q000209:etiology* / Q000473:pathology; D005260:Female; D050031:Hashimoto Disease / Q000150:complications*; D006801:Humans; D008099:Liver / Q000201:enzymology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013256:Steroids / Q000627:therapeutic use
D013256:Steroids