An unusual presentation of Hashimoto's encephalopathy
An 18-year-old male patient was diagnosed to have primary hypothyroidism 6 months back following weight gain, edema and facial puffiness of 3 years duration. His initial thyroid function test (TFT) was T4: 2.3 μg/dl (5.01-12.4) T3: 0.35 ng/ml (0.6-1.81) and thyroid stimulating hormone (TSH): 180 μIU/ml (0.35-5.50) and was started on L thyroxine, with a significant improvement of symptoms. He started developing myoclonus for the past 1 month, for which he was referred to our hospital.\nOn examination, he was conscious, with a cognitive impairment and had memory loss for recent events, with the poor attention span, difficulty in finding words, dyscalculia and dysgraphia. His mini mental status examination (MMSE) was 11 suggestive of moderate cognitive impairment. He also had myoclonus, involving both upper limbs and lower limbs.\nOn investigations, blood routine examination and erythrocyte sedimentation rate was normal and liver function test, kidney function test, sodium, potassium, calcium and magnesium were normal and so were the arterial blood gas analysis. His latest TFTs show normal T3 and T4 with mild elevation of TSH (TSH-9.1 μIU/ml). Anti-thyroid peroxidase antibody was positive (>1300 IU ml). His electroencephalogram (EEG) showed a diffuse slow wave activity [] and magnetic resonance images (MRI) showed a pituitary hyperplasia [] with non-specific White matter changes []. Cerebrospinal fluid (CSF) study had normal cytology, but slightly increased protein.\nAntinuclear antibody titer, anti-double-stranded deoxyribonucleic acid, hepatitis B surface antigen, anti-hepatitis C virus, lupus anticoagulant and Venereal Disease Research Laboratory (VDRL) test were carried out to evaluate the cause of decreased cognitive function, myoclonus and seizures, which were all negative. CSF electrophoresis was normal.\nIn view of these neurologic symptoms, associated with high titers of anti-thyroid antibodies and the exclusion of other possible causes of encephalopathy, patient was diagnosed with Hashimoto's encephalopathy. He was started on methylprednisolone 1 g/day for 3 days and was shifted over to prednisone 1 mg/kg/day. There was a marked improvement in the symptoms with no further episodes of myoclonus or seizures. One month after discharge, the patient reported a sustained improvement on all parameters, including memory and cognition, making it possible for his to return to an almost normal routine. His MMSE had improved to 26 and he is seizure free. Prednisone dose was tapped over the period of 3 months without the recurrence of symptoms.