Somnolence syndrome in a child following 1200-cGy total body irradiation in an unrelated bone marrow transplantation

Neurological complications may occur following intensive chemotherapy and h ematopoietic cell transplantation. Postirradiation somnolence syndrome has been observed in children with acute lymphoblastic leukemia who received ce ntral nervous system preventive therapy with 1800-2400 cGy cranial irradiat ion. The authors report a 16-year-old boy with chronic myelogenous leukemia in chronic phase, who developed symptoms compatible with the somnolence sy ndrome (SS) 6 weeks following HLA-matched unrelated bone marrow transplanta tion (BMT). The preparative regimen consisted of 1200 cGy total body irradi ation (TBI), cytosine arabinoside and cyclophosphamide. The patient develop ed lethargy and low-grade fever, with intermittent rhythmical delta activit y in electroencephalograph. He recovered spontaneously without specific the rapy 3 weeks after developing symptoms. This is the first report describing that as low as 1200 cGy TBI can induce SS in a child. After allogeneic BMT , some patients develop neurological symptoms. The authors suggest that som nolence syndrome should be included in differential diagnosis in these pati ents.