Clinical study of childhood acute disseminated encephalomyelitis, multiple sclerosis, and acute transverse myelitis in Fukuoka Prefecture, Japan.

Acute disseminated encephalomyelitis (ADEM) has recently been studied in several countries owing to the development and wide spread use of imaging technology, but few epidemiological studies of childhood ADEM have been undertaken in Asian countries. To perform a comprehensive survey of ADEM and related diseases in Japanese children, we conducted a multicenter, population-based study on childhood ADEM, multiple sclerosis, and acute isolated transverse myelitis in Fukuoka Prefecture, Japan. We identified 26 children with ADEM, 8 with multiple sclerosis, and 4 with acute transverse myelitis during 5 years between September 1998 and August 2003. The incidence of childhood ADEM under the age of 15 years was 0.64 per 100,000 person-years, mean age at onset was 5.7 years, and male-female ratio was 2.3:1. The prevalence of childhood multiple sclerosis was 1.3 per 100,000 persons. The mean age at onset of multiple sclerosis, 9.3 years, was significantly higher than that of ADEM. Nineteen (73%) and four (15%) patients with ADEM experienced antecedent infectious illnesses and vaccinations, respectively, within 1 month before the onset. Clinical and radiological findings of ADEM revealed that the frequency of seizures, mean white blood cell counts in cerebrospinal fluid, and the frequency of subcortical lesions in Fukuoka study, seemed to be higher than those in previous non-Asian studies. These findings suggest that there are ethnic or geographical differences in the incidence and clinical features of ADEM, and that there might be potent genetic or environmental risk factors for ADEM distinct from those for multiple sclerosis.

[Symmetrical hemispheric porencephalic cysts due to twin embolization syndrome: a case report].

Twin embolization syndrome (TES) is a complication of monozygotic twining following in utero demise of the co-twin. Passage of thromboplastic materials into the circulation of the surviving fetus results in ischemic structural defects of various systemic organs including the central nervous system (CNS). In our case of monozygotic twining prenatal sonography at the 18th week of gestation revealed intracranial abnormality and demise of the co-twin. Postnatal MRI demonstrates localized cerebral parenchymal defects (porencephalic cysts) in the bilateral hemispheres, which probably were the sequelae to the occlusion of the peripheral branches of the bilateral middle cerebral arteries. She developed physio-mental retardation and subsequently West syndrome. At the 6th months, right porencephalic cyst-peritoneal shunt was performed for progressive enlargement of the head. While the enlargement of the head was well controlled, no changes in her epileptic symptoms were noted. The development of generalized epilepsy in our case may indicate that the involvement of the CNS with TES in our case is not restricted to the porencephalic cysts and their surrounding areas.