Reversible white matter lesions and antithyroid antibodies in the cerebrospinal fluid in Hashimoto's encephalopathy: a case report]

A 71-year-old woman with Hashimoto's disease was admitted to our hospital because of involuntary movement, gait disturbance, and mental decline. Her consciousness was alert but her orientation about time and place was disturbed. She was mentally ill (HDS-R; 12/30, MMSE; 14/30), and could not walk because of truncal ataxia. Myoclonus was present in the upper extremities. Laboratory examinations showed hypothyroidism and very high titers of antithyroid antibodies (ATA) in serum. Head MRI showed no abnormal lesions. On electroencephalogram (EEG), the basic rhythm was slow and bursts of irregular slow waves (4-6 Hz) were present. Her conditions gradually ameliorated so that she was discharged. However, she was hospitalized again because of sudden worsening of the illness: her consciousness got disturbed and the myoclonus became marked. As the result, she got bed-ridden. At the time, thyroid function was almost normal, suggesting that the deterioration could not be attributed to hypothyroidism. The EEG findings were quite different from the former: complex of multiple spikes and slow waves was continuously present. Examination of the cerebrospinal fluid (CSF) revealed an elevated level of protein and IgG (cell 1/m3, protein 101 mg/dl, sugar 60 mg/dl ,Cl 124 mEq/l, IgG 20.4 mg/dl). IgG index was 0.57 and Q albumin (CSF-albumin/serum-albumin ratio) was 15.2 (9.0>) . After the second admission, she recovered from the bed-ridden state but was still unable to walk or communicate. She continued to need complete support for all daily lives. The diagnosis was made as Hashimoto's encephalopathy (HE), from the following points: 1) encephalopathy not due to hypothyroidism, 2) very high titers of ATA, 3) elevated CSF protein. The effectiveness of steroid therapy was so amazing that the neurological problems faded away very soon. Finally she completely recovered. As well as the clinical manifestations, the EEG findings were improved. At the stage in which excellent clinical improvement had achieved, head MRI revealed that T2/FLAIR high lesions without Gd-enhancement temporarily appeared diffusely and extensively in the cerebral white matter. They thereafter almost disappeared on follow-up MRI. Judging from the lesions being non-enhanced and reversible, they supposedly reflected brain edema. It is important to keep it in mind that MRI findings may change abruptly and drastically in HE. ATA was detected not only in serum but also in CSF. Either titer thereafter decreased along with the healing of the illness. Concerning the reason why ATA is present in CSF, we supposed leakage from blood through the disrupted blood-brain barrier, for the following reasons: 1) IgG index was normal, 2) Q albumin was elevated, 3) the change of CSF-ATA titer was almost parallel to that of serum-ATA titer, and 4) the white matter lesions, which presumably reflected brain edema, were observed.