A 12-year-old child, male, was admitted to the Department of Neurology in Beijing Chaoyang Hospital. Three weeks before his admission, he received the vaccination of hepatitis B. He was with symptoms of myasthenia of limbs and alteration of consciousness. He also had high fever, with the body temperature maintained between 38 C and 38.5 C. He was with no symptoms of headache, dizziness, nausea, vomit, sphincter dysfunction, and optic neuritis. Four years ago, he had suffered from essential thrombopenia, which relapsed two years ago. He had no history of toxic substance, allergy, operation, trauma, blood transfusion, and inheritance history. He was a full-term baby, with normal vaginal delivery. His mother had suffered from a disease of allergic purpura.
Physical examination on his admission showed that he was with somnolence and uncooperative. His pupils were equal in size and round. The optic nerve was normal. Bilateral light reflexes retained. Muscle strength of limbs grading (II level) was found with hypomyotonia. Sensory tests were uncooperative. Abdominal reflex and cremasteric reflex were negative. The signs of bilateral Babinski and Gordon were positive. Ankle clonus was also detected. Neck resistance was also found.
On admission, the results of blood test were as follows. WBC level (15.8 x 109/L) and the proportion of neutrophils (85.2%) were markedly increased. Procalcitonin was 0.05 ng/mL, which indicated no bacterial infection. C-reactive protein was increased, which was 1.14 mg/dL (0-0.8 mg/dL). ESR was 50 mm/H (2-15 mm/H). IgG was 1750 mg/mL (751-1560 mg/mL). IgA, IgM, C3, and C4 were normal. Sputum cultures of bacteria, fungus, virus, and tuberculosis were negative. Total protein and albumin in blood were decreased. Globulin and total bilirubin were normal. The cerebrospinal fluid (CSF) examinations showed increased pleocytosis (52/muL) and leucocyte count (40/muL). The CSF was composed of 90% mononuclear cells and 10% polynuclear cells. Pandy test was negative. Total protein was normal. Glucose (4.77 mmol/L) was slightly increased (2.5-4.4 mmol/L). Chloride (115.1 mmol/L) was slightly decreased (118-129 mmol/L). Oligoclonal band was found. The aquaporin 4 antibody was negative. Bacteria, mycobacterium tuberculosis, virus (e.g., herpes simplex encephalitis virus, cytomegalovirus, and Epstein-Barr virus), and fungal cultures from CSF and blood serology, with PCR also performed, were negative.
Three days after his admission, MRI of brain and spinal cord also revealed some abnormal findings. His brain MRI showed widespread abnormal signals on FLAIR image (Figure 1). Spinal cord MRI showed that there were abnormal multifocal, strip long T1 and T2 signals at the cervical and intumescentia lumbalis (Figure 2). Furthermore, evoked potential such as brainstem auditory evoked potentials and somatosensory evoked potential also showed some abnormal changes in this case. The visual evoked potential was normal.
 With treatment with high-dose methylprednisolone and intravenous immunoglobulin and also with some antibiotic and antiviral therapy, he showed a dramatic improvement of the clinical and CSF results. About four months later, he recovered completely and there was no relapse during three years of follow-up.