Pin-point pupils with drowsiness as a presentation of Hashimoto's encephalopathy mimicking pontine infarction.
OBJECTIVE
Hashimoto's encephalopathy (HE) is an autoimmune-mediated encephalopathy with various manifestations. Pupil size change has never been previously reported as a presentation of HE.


METHODS
A 65-year-old woman without previous known thyroid disease presented with acute onset of drowsiness and blurred vision. Neurologically, she was drowsy and had bilateral pinpoint-sized pupils without a light reflex, which probably indicated a bilateral pontine lesion. Brain MRI showed two tiny infarctions at the left midbrain and left thalamus, but did not show a pontine lesion, and demonstrated patent vertebral/basilar arteries. Electroencephalography showed intermittent diffuse slowing. She had an elevated protein level (123 mg/dl) in cerebrospinal fluid without pleocytosis. Of note, she had elevated serum levels of anti-TG antibody (282 IU/mL) and anti-TPO antibody (117 IU/mL). Her symptoms improved spontaneously including gradually normalization of her pupil size in 3 days and clear consciousness in 6 days; therefore, corticosteroid was not administered.


CONCLUSIONS
This case illustrates that physicians should be aware of the treatable condition of HE as a possible diagnosis in patients with bilateral pinpoint pupils and drowsiness but without corresponding MRI lesions.
Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
Shin-Joe
SJ
Yeh
Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
Li-Kai
LK
Tsai
Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
Sung-Chun
SC
Tang
Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
Jiann-Shing
JS
Jeng
D000368:Aged; D001927:Brain Diseases / Q000150:complications* / Q000473:pathology; D002544:Cerebral Infarction / Q000209:etiology* / Q000473:pathology; D003937:Diagnosis, Differential; D004660:Encephalitis; D005260:Female; D050031:Hashimoto Disease / Q000150:complications* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D015877:Miosis / Q000209:etiology* / Q000473:pathology; D011149:Pons / Q000473:pathology*; D012894:Sleep Stages