Autoimmune neurological disorders associated with group-A beta-hemolytic streptococcal infection.

Although central nervous system (CNS) disorders associated with group-A beta-hemolytic streptococcal (GABHS) infection occur only rarely, Sydenham's chorea is a well-recognized disease that can arise following infection. Children may develop a tic, obsessive compulsive disorder (OCD), and extrapyramidal movement subsequent to GABHS infection. These disorders have been termed pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS). Herein we report one case each of acute disseminated encephalomyelitis (ADEM), PANDAS and subacute encephalitis associated with GABHS infection. To evaluate the pathogenesis of the CNS disorders associated with GABHS infection, we measured levels of neurotransmitters, cytokines, anti-neuronal autoantibodies, and performed immunohistochemistry using patient sera to stain human brain sections. All three cases showed psychiatric behavioral disorders. Immunotherapy was effective, and homovanillic acid levels in the cerebrospinal fluid (CSF) were elevated at the acute stage in all three cases. In each case of ADEM and PANDAS, immunohistochemistry demonstrated neuronal impairment in the basal ganglia during the acute stage. Neuronal immunoreactivity was visualized in the cerebral cortex at the acute stage in the case of subacute encephalitis. There was no direct correlation between immunoreactivity of patient sera on the brain sections and positivity of anti-neuronal autoantibodies or CSF biomarkers. The results suggest that autoimmune responses may modulate neurotransmission, and the use of patient serum for immunohistochemistry is a sensitive screening method for the detection of anti-neuronal autoantibodies in CNS disorders associated with GABHS infection.

[Effects of piracetam therapy in a case of Lance-Adams syndrome].

We report a 17-year-old female patient with Lance-Adams syndrome caused by anoxic encephalopathy during a severe attack of bronchial asthma. She had difficulty in writing because of action myoclonus in her arms. She also exhibited freezing gait and was unable to walk without cane. Although her gait disturbance resembled those seen in patients with parkinsonism secondary to anoxic encephalopathy, surface electromyography revealed that it was caused by action myoclonus in her legs. The presence of giant somatosensory evoked potentials and enhanced cortical reflexes in response to the electrical stimulation to her posterior tibial nerves supported our diagnosis. A combined therapy with valproate sodium, clonazepam and piracetam (15 g/day) was not effective. However, her freezing gait remarkably improved and she was able to walk without help, after the treatment with sufficient dose of piracetam (21 g/day). Cortical hyperexcitability as revealed by electrophysiological examination also improved. We concluded that the combined therapy with antiepileptic drugs and piracetam was effective in the treatment for action myoclonus. However, because the effects seemed dose-related, the dosage of piracetam needed to be increased until the optimum effects were obtained.