Encephalopathy in megacystis-microcolon-intestinal hypoperistalsis syndrome patients on long-term total parenteral nutrition possibly due to selenium deficiency

This report concerns two patients (female, 9 and 6 years) who were diagnosed with megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). Although they exceeded the usual life expectancy of patients diagnosed with MMIHS because of total parenteral nutrition (TPN), they demonstrated progressive neurological deficits and showed histopathological features in the brain. Both patients were diagnosed with MMIHS in the neonatal period and were fed by TPN. The first patient developed visual and gait disturbances at the age of 7 years. Two months later, she developed dysarthria and muscular weakness, and could not maintain her posture. The level of serum selenium was extremely low. The second patient developed flexion and spasticity of the extremities followed by decorticate posture at the age of 3 years. Both patients died of sepsis. The brain weights of the two cases were 880 g and 715 g. In both cases, severe neuronal loss and gliosis were present in the medial convolutions of the occipital lobe, including the visual cortex. The postcentral gyrus and temporal transverse gyrus were also involved. In addition, extensive loss of Purkinje cells and granular neurons, and gliosis were observed in the cerebellum. We measured the selenium content of the brains and livers using the graphite furnace atomic absorption spectrometry method. Selenium was not detected in either brain, although the livers of both cases contained a low level of selenium. On immunohistochemical examination of the antioxidative enzymes, histiocyte-macrophage lineage cells in MMIHS cases, including microglia and Kupffer cells, showed only a weak reaction for glutathione peroxidase, of which selenium is an essential component. However, the cells in the control cases were strongly positive. In cases of MMIHS and methylmercury intoxication, the brain features similar lesions, in both their topographical and histopathological aspects. We considered that the brain lesions of the MMIHS patients mainly resulted from oxidative damage of the brain related to the low levels of glutathione peroxidase and other selenoproteins due to selenium deficiency.